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Ruiz-Botella M, Manrique S, Gomez J, Bodí M. Advancing ICU patient care with a Real-Time predictive model for mechanical Power to mitigate VILI. Int J Med Inform 2024; 189:105511. [PMID: 38851133 DOI: 10.1016/j.ijmedinf.2024.105511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Revised: 05/24/2024] [Accepted: 05/29/2024] [Indexed: 06/10/2024]
Abstract
BACKGROUND Invasive Mechanical Ventilation (IMV) in Intensive Care Units (ICU) significantly increases the risk of Ventilator-Induced Lung Injury (VILI), necessitating careful management of mechanical power (MP). This study aims to develop a real-time predictive model of MP utilizing Artificial Intelligence to mitigate VILI. METHODOLOGY A retrospective observational study was conducted, extracting patient data from Clinical Information Systems from 2018 to 2022. Patients over 18 years old with more than 6 h of IMV were selected. Continuous data on IMV variables, laboratory data, monitoring, procedures, demographic data, type of admission, reason for admission, and APACHE II at admission were extracted. The variables with the highest correlation to MP were used for prediction and IMV data was grouped in 15-minute intervals using the mean. A mixed neural network model was developed to forecast MP 15 min in advance, using IMV data from 6 h before the prediction and current patient status. The model's ability to predict future MP was analyzed and compared to a baseline model predicting the future value of MP as equal to the current value. RESULTS The cohort consisted of 1967 patients after applying inclusion criteria, with a median age of 63 years and 66.9 % male. The deep learning model achieved a mean squared error of 2.79 in the test set, indicating a 20 % improvement over the baseline model. It demonstrated high accuracy (94 %) in predicting whether MP would exceed a critical threshold of 18 J/min, which correlates with increased mortality. The integration of this model into a web platform allows clinicians real-time access to MP predictions, facilitating timely adjustments to ventilation settings. CONCLUSIONS The study successfully developed and integrated in clinical practice a predictive model for MP. This model will assist clinicians allowing for the adjustment of ventilatory parameters before lung damage occurs.
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Affiliation(s)
- M Ruiz-Botella
- Departament of Chemical Engineering, Universitat Rovira I Virgili, Tarragona, Spain; Instituto de Investigación Sanitaria Pere i Virgili, Universidad Rovira i Virgili, Tarragona, Spain.
| | - S Manrique
- Instituto de Investigación Sanitaria Pere i Virgili, Universidad Rovira i Virgili, Tarragona, Spain; Critical Care department, Hospital Universitario Joan XXIII, Tarragona, Spain
| | - J Gomez
- Instituto de Investigación Sanitaria Pere i Virgili, Universidad Rovira i Virgili, Tarragona, Spain; Critical Care department, Hospital Universitario Joan XXIII, Tarragona, Spain
| | - M Bodí
- Instituto de Investigación Sanitaria Pere i Virgili, Universidad Rovira i Virgili, Tarragona, Spain; Critical Care department, Hospital Universitario Joan XXIII, Tarragona, Spain; Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES). Instituto de Salud Carlos III, Spain
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Simonte R, Cammarota G, Vetrugno L, De Robertis E, Longhini F, Spadaro S. Advanced Respiratory Monitoring during Extracorporeal Membrane Oxygenation. J Clin Med 2024; 13:2541. [PMID: 38731069 PMCID: PMC11084162 DOI: 10.3390/jcm13092541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2024] [Revised: 04/16/2024] [Accepted: 04/23/2024] [Indexed: 05/13/2024] Open
Abstract
Advanced respiratory monitoring encompasses a diverse range of mini- or noninvasive tools used to evaluate various aspects of respiratory function in patients experiencing acute respiratory failure, including those requiring extracorporeal membrane oxygenation (ECMO) support. Among these techniques, key modalities include esophageal pressure measurement (including derived pressures), lung and respiratory muscle ultrasounds, electrical impedance tomography, the monitoring of diaphragm electrical activity, and assessment of flow index. These tools play a critical role in assessing essential parameters such as lung recruitment and overdistention, lung aeration and morphology, ventilation/perfusion distribution, inspiratory effort, respiratory drive, respiratory muscle contraction, and patient-ventilator synchrony. In contrast to conventional methods, advanced respiratory monitoring offers a deeper understanding of pathological changes in lung aeration caused by underlying diseases. Moreover, it allows for meticulous tracking of responses to therapeutic interventions, aiding in the development of personalized respiratory support strategies aimed at preserving lung function and respiratory muscle integrity. The integration of advanced respiratory monitoring represents a significant advancement in the clinical management of acute respiratory failure. It serves as a cornerstone in scenarios where treatment strategies rely on tailored approaches, empowering clinicians to make informed decisions about intervention selection and adjustment. By enabling real-time assessment and modification of respiratory support, advanced monitoring not only optimizes care for patients with acute respiratory distress syndrome but also contributes to improved outcomes and enhanced patient safety.
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Affiliation(s)
- Rachele Simonte
- Department of Medicine and Surgery, Università degli Studi di Perugia, 06100 Perugia, Italy; (R.S.); (E.D.R.)
| | - Gianmaria Cammarota
- Department of Translational Medicine, Università del Piemonte Orientale, 28100 Novara, Italy;
| | - Luigi Vetrugno
- Department of Medical, Oral and Biotechnological Sciences, University of Chieti-Pescara, 66100 Chieti, Italy;
| | - Edoardo De Robertis
- Department of Medicine and Surgery, Università degli Studi di Perugia, 06100 Perugia, Italy; (R.S.); (E.D.R.)
| | - Federico Longhini
- Department of Medical and Surgical Sciences, Università della Magna Graecia, 88100 Catanzaro, Italy
- Anesthesia and Intensive Care Unit, “R. Dulbecco” University Hospital, 88100 Catanzaro, Italy
| | - Savino Spadaro
- Department of Morphology, Surgery and Experimental Medicine, University of Ferrara, 44100 Ferrara, Italy;
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Fioccola A, Nicolardi RV, Pozzi T, Fratti I, Romitti F, Collino F, Reupke V, Bassi GL, Protti A, Santini A, Cressoni M, Busana M, Moerer O, Camporota L, Gattinoni L. Estimation of normal lung weight index in healthy female domestic pigs. Intensive Care Med Exp 2024; 12:6. [PMID: 38273120 PMCID: PMC10811311 DOI: 10.1186/s40635-023-00591-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Accepted: 12/21/2023] [Indexed: 01/27/2024] Open
Abstract
INTRODUCTION Lung weight is an important study endpoint to assess lung edema in porcine experiments on acute respiratory distress syndrome and ventilatory induced lung injury. Evidence on the relationship between lung-body weight relationship is lacking in the literature. The aim of this work is to provide a reference equation between normal lung and body weight in female domestic piglets. MATERIALS AND METHODS 177 healthy female domestic piglets from previous studies were included in the analysis. Lung weight was assessed either via a CT-scan before any experimental injury or with a scale after autopsy. The animals were randomly divided in a training (n = 141) and a validation population (n = 36). The relation between body weight and lung weight index (lung weight/body weight, g/kg) was described by an exponential function on the training population. The equation was tested on the validation population. A Bland-Altman analysis was performed to compare the lung weight index in the validation population and its theoretical value calculated with the reference equation. RESULTS A good fit was found between the validation population and the exponential equation extracted from the training population (RMSE = 0.060). The equation to determine lung weight index from body weight was: [Formula: see text] At the Bland and Altman analyses, the mean bias between the real and the expected lung weight index was - 0.26 g/kg (95% CI - 0.96-0.43), upper LOA 3.80 g/kg [95% CI 2.59-5.01], lower LOA - 4.33 g/kg [95% CI = - 5.54-(- 3.12)]. CONCLUSIONS This exponential function might be a valuable tool to assess lung edema in experiments involving 16-50 kg female domestic piglets. The error that can be made due to the 95% confidence intervals of the formula is smaller than the one made considering the lung to body weight as a linear relationship.
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Affiliation(s)
- Antonio Fioccola
- Department of Health Sciences, University of Florence, Florence, Italy
- Department of Anesthesiology, University Medical Center Göttingen, Göttingen, Germany
| | - Rosmery Valentina Nicolardi
- IRCCS San Raffaele Scientific Institute, Milan, Italy
- Department of Anesthesiology, University Medical Center Göttingen, Göttingen, Germany
| | - Tommaso Pozzi
- Department of Anesthesiology, University Medical Center Göttingen, Göttingen, Germany
- Department of Health Sciences, University of Milan, Milan, Italy
| | - Isabella Fratti
- Department of Anesthesiology, University Medical Center Göttingen, Göttingen, Germany
- Department of Health Sciences, University of Milan, Milan, Italy
| | - Federica Romitti
- Department of Anesthesiology, University Medical Center Göttingen, Göttingen, Germany
| | | | - Verena Reupke
- Department of Experimental Animal Medicine, University of Göttingen, Göttingen, Germany
| | - Gianluigi Li Bassi
- Critical Care Research Group, The Prince Charles Hospital, Brisbane, QLD, Australia
- Prince Charles Hospital Northside Clinical Unit, Faculty of Medicine, University of Queensland, Brisbane, QLD, Australia
- Uniting Care Hospitals, Intensive Care Units St Andrew's War Memorial Hospital and The Wesley Hospital, Brisbane, QLD, Australia
- Wesley Medical Research, Brisbane, QLD, Australia
- Queensland University of Technology, Brisbane, QLD, Australia
| | - Alessandro Protti
- Department of Biomedical Sciences, Humanitas University, Pieve Emanuele, Milan, Italy
- Department of Anesthesia and Intensive Care Units, IRCCS Humanitas Research Hospital, Rozzano, Milan, Italy
| | - Alessandro Santini
- Department of Anesthesia and Intensive Care Units, IRCCS Humanitas Research Hospital, Rozzano, Milan, Italy
| | - Massimo Cressoni
- Unit of Radiology, IRCCS, Policlinico San Donato, San Donato Milanese, Milan, Italy
| | - Mattia Busana
- Department of Anesthesiology, University Medical Center Göttingen, Göttingen, Germany
| | - Onnen Moerer
- Department of Anesthesiology, University Medical Center Göttingen, Göttingen, Germany
| | - Luigi Camporota
- Department of Adult Critical Care Guy's & St Thomas' NHS Foundation Trust, London, UK
- Centre for Human & Applied Physiological Sciences, School of Basic & Medical Biosciences, King's College London, London, UK
| | - Luciano Gattinoni
- Department of Anesthesiology, University Medical Center Göttingen, Göttingen, Germany.
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Al-Khalisy H, Nieman GF, Kollisch-Singule M, Andrews P, Camporota L, Shiber J, Manougian T, Satalin J, Blair S, Ghosh A, Herrmann J, Kaczka DW, Gaver DP, Bates JHT, Habashi NM. Time-Controlled Adaptive Ventilation (TCAV): a personalized strategy for lung protection. Respir Res 2024; 25:37. [PMID: 38238778 PMCID: PMC10797864 DOI: 10.1186/s12931-023-02615-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Accepted: 11/25/2023] [Indexed: 01/22/2024] Open
Abstract
Acute respiratory distress syndrome (ARDS) alters the dynamics of lung inflation during mechanical ventilation. Repetitive alveolar collapse and expansion (RACE) predisposes the lung to ventilator-induced lung injury (VILI). Two broad approaches are currently used to minimize VILI: (1) low tidal volume (LVT) with low-moderate positive end-expiratory pressure (PEEP); and (2) open lung approach (OLA). The LVT approach attempts to protect already open lung tissue from overdistension, while simultaneously resting collapsed tissue by excluding it from the cycle of mechanical ventilation. By contrast, the OLA attempts to reinflate potentially recruitable lung, usually over a period of seconds to minutes using higher PEEP used to prevent progressive loss of end-expiratory lung volume (EELV) and RACE. However, even with these protective strategies, clinical studies have shown that ARDS-related mortality remains unacceptably high with a scarcity of effective interventions over the last two decades. One of the main limitations these varied interventions demonstrate to benefit is the observed clinical and pathologic heterogeneity in ARDS. We have developed an alternative ventilation strategy known as the Time Controlled Adaptive Ventilation (TCAV) method of applying the Airway Pressure Release Ventilation (APRV) mode, which takes advantage of the heterogeneous time- and pressure-dependent collapse and reopening of lung units. The TCAV method is a closed-loop system where the expiratory duration personalizes VT and EELV. Personalization of TCAV is informed and tuned with changes in respiratory system compliance (CRS) measured by the slope of the expiratory flow curve during passive exhalation. Two potentially beneficial features of TCAV are: (i) the expiratory duration is personalized to a given patient's lung physiology, which promotes alveolar stabilization by halting the progressive collapse of alveoli, thereby minimizing the time for the reopened lung to collapse again in the next expiration, and (ii) an extended inspiratory phase at a fixed inflation pressure after alveolar stabilization gradually reopens a small amount of tissue with each breath. Subsequently, densely collapsed regions are slowly ratcheted open over a period of hours, or even days. Thus, TCAV has the potential to minimize VILI, reducing ARDS-related morbidity and mortality.
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Affiliation(s)
| | - Gary F Nieman
- SUNY Upstate Medical University, 750 E. Adams St., Syracuse, NY, 13210, USA
| | | | - Penny Andrews
- R Adams Cowley Shock Trauma Center, University of Maryland Medical Center, Baltimore, MD, USA
| | - Luigi Camporota
- Health Centre for Human and Applied Physiological Sciences, Guy's and St Thomas' NHS Foundation Trust, London, UK
| | - Joseph Shiber
- University of Florida College of Medicine, Jacksonville, FL, USA
| | | | - Joshua Satalin
- SUNY Upstate Medical University, 750 E. Adams St., Syracuse, NY, 13210, USA.
| | - Sarah Blair
- SUNY Upstate Medical University, 750 E. Adams St., Syracuse, NY, 13210, USA
| | - Auyon Ghosh
- SUNY Upstate Medical University, 750 E. Adams St., Syracuse, NY, 13210, USA
| | | | | | | | | | - Nader M Habashi
- R Adams Cowley Shock Trauma Center, University of Maryland Medical Center, Baltimore, MD, USA
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Shaikh FAR, Ramaswamy KN, Chirla DK, Venkataraman ST, Kneyber MCJ. Mechanical power and normalized mechanical power in pediatric acute respiratory distress syndrome. Front Pediatr 2024; 12:1293639. [PMID: 38298612 PMCID: PMC10829106 DOI: 10.3389/fped.2024.1293639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Accepted: 01/03/2024] [Indexed: 02/02/2024] Open
Abstract
Background Mechanical power (MP) refers to the energy transmitted over time to the respiratory system and serves as a unifying determinant of ventilator-induced lung injury. MP normalization is required to account for developmental changes in children. We sought to examine the relationship between mechanical energy (MEBW), MP normalized to body weight (MPBW), and MP normalized to respiratory compliance (MPCRS) concerning the severity and outcomes of pediatric acute respiratory distress syndrome (pARDS). Method In this retrospective study, children aged 1 month to 18 years diagnosed with pARDS who underwent pressure-control ventilation for at least 24 h between January 2017 and September 2020 were enrolled. We calculated MP using Becher's equation. Multivariable logistic regression analysis adjusted for age, pediatric organ dysfunction score, and oxygenation index (OI) was performed to determine the independent association of MP and its derivatives 24 h after diagnosing pARDS with 28-day mortality. The association was also studied for 28 ventilator-free days (VFD-28) and the severity of pARDS in terms of OI. Results Out of 246 admitted with pARDS, 185 were eligible, with an overall mortality of 43.7%. Non-survivors exhibited higher severity of illness, as evidenced by higher values of MP, MPBW, and MEBW. Multivariable logistic regression analysis showed that only MEBW but not MP, MPBW, or MPCRS at 24 h was independently associated with mortality [adjusted OR: 1.072 (1.002-1.147), p = 0.044]. However, after adjusting for the type of pARDS, MEBW was not independently associated with mortality [adjusted OR: 1.061 (0.992-1.136), p = 0.085]. After adjusting for malnutrition, only MP at 24 h was found to be independently associated. Only MPCRS at 1-4 and 24 h but not MP, MPBW, or MEBW at 24 h of diagnosing pARDS was significantly correlated with VFD-28. Conclusions Normalization of MP is better related to outcomes and severity of pARDS than non-normalized MP. Malnutrition can be a significant confounding factor in resource-limited settings.
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Affiliation(s)
- Farhan A. R. Shaikh
- Department of Pediatric Intensive Care, Rainbow Children’s Hospital, Hyderabad, India
| | - Karthik N. Ramaswamy
- Department of Pediatric Intensive Care, Rainbow Children’s Hospital, Chennai, India
| | - Dinesh K. Chirla
- Department of Pediatric Intensive Care, Rainbow Children’s Hospital, Hyderabad, India
| | - Shekhar T. Venkataraman
- Departments of Critical Care Medicine and Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Martin C. J. Kneyber
- Division of Paediatric Critical Care Medicine, Department of Paediatrics, Beatrix Children’s Hospital, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
- Critical Care, Anaesthesiology, Peri-Operative & Emergency Medicine (CAPE), University of Groningen, Groningen, Netherlands
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da Silva AL, Bessa CM, Rocha NN, Carvalho EB, Magalhaes RF, Capelozzi VL, Robba C, Pelosi P, Samary CS, Rocco PRM, Silva PL. Pressure-support compared with pressure-controlled ventilation mitigates lung and brain injury in experimental acute ischemic stroke in rats. Intensive Care Med Exp 2023; 11:93. [PMID: 38102452 PMCID: PMC10724101 DOI: 10.1186/s40635-023-00580-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Accepted: 12/08/2023] [Indexed: 12/17/2023] Open
Abstract
BACKGROUND We aimed to evaluate the pulmonary and cerebral effects of low-tidal volume ventilation in pressure-support (PSV) and pressure-controlled (PCV) modes at two PEEP levels in acute ischemic stroke (AIS). METHODS In this randomized experimental study, AIS was induced by thermocoagulation in 30 healthy male Wistar rats. After 24 h, AIS animals were randomly assigned to PSV or PCV with VT = 6 mL/kg and PEEP = 2 cmH2O (PSV-PEEP2 and PCV-PEEP2) or PEEP = 5 cmH2O (PSV-PEEP5 and PCV-PEEP5) for 2 h. Lung mechanics, arterial blood gases, and echocardiography were evaluated before and after the experiment. Lungs and brain tissue were removed for histologic and molecular biology analysis. The primary endpoint was diffuse alveolar damage (DAD) score; secondary endpoints included brain histology and brain and lung molecular biology markers. RESULTS In lungs, DAD was lower with PSV-PEEP5 than PCV-PEEP5 (p < 0.001); interleukin (IL)-1β was lower with PSV-PEEP2 than PCV-PEEP2 (p = 0.016) and PSV-PEEP5 than PCV-PEEP5 (p = 0.046); zonula occludens-1 (ZO-1) was lower in PCV-PEEP5 than PCV-PEEP2 (p = 0.042). In brain, necrosis, hemorrhage, neuropil edema, and CD45 + microglia were lower in PSV than PCV animals at PEEP = 2 cmH2O (p = 0.036, p = 0.025, p = 0.018, p = 0.011, respectively) and PEEP = 5 cmH2O (p = 0.003, p = 0.003, p = 0.007, p = 0.003, respectively); IL-1β was lower while ZO-1 was higher in PSV-PEEP2 than PCV-PEEP2 (p = 0.009, p = 0.007, respectively), suggesting blood-brain barrier integrity. Claudin-5 was higher in PSV-PEEP2 than PSV-PEEP5 (p = 0.036). CONCLUSION In experimental AIS, PSV compared with PCV reduced lung and brain injury. Lung ZO-1 reduced in PCV with PEEP = 2 versus PEEP = 5 cmH2O, while brain claudin-5 increased in PSV with PEEP = 2 versus PEEP = 5 cmH2O.
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Affiliation(s)
- Adriana L da Silva
- Laboratory of Pulmonary Investigation, Centro de Ciências da Saúde, Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Avenida Carlos Chagas Filho, S/N, Bloco G-014, Ilha Do Fundão, Rio de Janeiro, RJ, 21941-902, Brazil
| | - Camila M Bessa
- Laboratory of Pulmonary Investigation, Centro de Ciências da Saúde, Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Avenida Carlos Chagas Filho, S/N, Bloco G-014, Ilha Do Fundão, Rio de Janeiro, RJ, 21941-902, Brazil
| | - Nazareth N Rocha
- Laboratory of Pulmonary Investigation, Centro de Ciências da Saúde, Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Avenida Carlos Chagas Filho, S/N, Bloco G-014, Ilha Do Fundão, Rio de Janeiro, RJ, 21941-902, Brazil
- Department of Physiology and Pharmacology, Biomedical Institute, Fluminense Federal University, Rio de Janeiro, Brazil
| | - Eduardo B Carvalho
- Laboratory of Pulmonary Investigation, Centro de Ciências da Saúde, Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Avenida Carlos Chagas Filho, S/N, Bloco G-014, Ilha Do Fundão, Rio de Janeiro, RJ, 21941-902, Brazil
| | - Raquel F Magalhaes
- Laboratory of Pulmonary Investigation, Centro de Ciências da Saúde, Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Avenida Carlos Chagas Filho, S/N, Bloco G-014, Ilha Do Fundão, Rio de Janeiro, RJ, 21941-902, Brazil
| | - Vera L Capelozzi
- Department of Pathology, Faculty of Medicine, University of São Paulo, São Paulo, Brazil
| | - Chiara Robba
- Department of Surgical Sciences and Integrated Diagnostics (DISC), University of Genoa, Genoa, Italy
- Anesthesia and Critical Care, San Martino Policlinico Hospital, IRCCS for Oncology and Neurosciences, Genoa, Italy
| | - Paolo Pelosi
- Department of Surgical Sciences and Integrated Diagnostics (DISC), University of Genoa, Genoa, Italy
- Anesthesia and Critical Care, San Martino Policlinico Hospital, IRCCS for Oncology and Neurosciences, Genoa, Italy
| | - Cynthia S Samary
- Laboratory of Pulmonary Investigation, Centro de Ciências da Saúde, Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Avenida Carlos Chagas Filho, S/N, Bloco G-014, Ilha Do Fundão, Rio de Janeiro, RJ, 21941-902, Brazil
- Department of Cardiorespiratory and Musculoskeletal Physiotherapy, Faculty of Physiotherapy, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Patricia R M Rocco
- Laboratory of Pulmonary Investigation, Centro de Ciências da Saúde, Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Avenida Carlos Chagas Filho, S/N, Bloco G-014, Ilha Do Fundão, Rio de Janeiro, RJ, 21941-902, Brazil
| | - Pedro L Silva
- Laboratory of Pulmonary Investigation, Centro de Ciências da Saúde, Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Avenida Carlos Chagas Filho, S/N, Bloco G-014, Ilha Do Fundão, Rio de Janeiro, RJ, 21941-902, Brazil.
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Chen H, Chen ZZ, Gong SR, Yu RG. Visualizing the dynamic mechanical power and time burden of mechanical ventilation patients: an analysis of the MIMIC-IV database. J Intensive Care 2023; 11:58. [PMID: 38031184 PMCID: PMC10685677 DOI: 10.1186/s40560-023-00709-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Accepted: 11/23/2023] [Indexed: 12/01/2023] Open
Abstract
BACKGROUND Limiting driving pressure and mechanical power is associated with reduced mortality risk in both patients with and without acute respiratory distress syndrome. However, it is still poorly understood how the intensity of mechanical ventilation and its corresponding duration impact the risk of mortality. METHODS Critically ill patients who received mechanical ventilation were identified from the Medical Information Mart for Intensive Care (MIMIC)-IV database. A visualization method was developed by calculating the odds ratio of survival for all combinations of ventilation duration and intensity to assess the relationship between the intensity and duration of mechanical ventilation and the mortality risk. RESULTS A total of 6251 patients were included. The color-coded plot demonstrates the intuitive concept that episodes of higher dynamic mechanical power can only be tolerated for shorter durations. The three fitting contour lines represent 0%, 10%, and 20% increments in the mortality risk, respectively, and exhibit an exponential pattern: higher dynamic mechanical power is associated with an increased mortality risk with shorter exposure durations. CONCLUSIONS Cumulative exposure to higher intensities and/or longer duration of mechanical ventilation is associated with worse outcomes. Considering both the intensity and duration of mechanical ventilation may help evaluate patient outcomes and guide adjustments in mechanical ventilation to minimize harmful exposure.
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Affiliation(s)
- Han Chen
- The Third Department of Critical Care Medicine, Shengli Clinical Medical College of Fujian Medical University, Fujian Provincial Hospital, Fujian Provincial Center for Critical Care Medicine, Fujian Provincial Key Laboratory of Critical Care Medicine, Dongjie 134, Gulou District, Fuzhou, Fujian, China
| | - Zhi-Zhong Chen
- General Product Center, Fujian Foxit Software Development, Joint Stock Co. Ltd., Building 5, Area G, Fuzhou Software Park, No. 89 Software Avenue, Gulou District, Fuzhou, Fujian, China
| | - Shu-Rong Gong
- The Third Department of Critical Care Medicine, Shengli Clinical Medical College of Fujian Medical University, Fujian Provincial Hospital, Fujian Provincial Center for Critical Care Medicine, Fujian Provincial Key Laboratory of Critical Care Medicine, Dongjie 134, Gulou District, Fuzhou, Fujian, China
| | - Rong-Guo Yu
- The Third Department of Critical Care Medicine, Shengli Clinical Medical College of Fujian Medical University, Fujian Provincial Hospital, Fujian Provincial Center for Critical Care Medicine, Fujian Provincial Key Laboratory of Critical Care Medicine, Dongjie 134, Gulou District, Fuzhou, Fujian, China.
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Thornton LT, Marini JJ. Optimized ventilation power to avoid VILI. J Intensive Care 2023; 11:57. [PMID: 37986109 PMCID: PMC10658809 DOI: 10.1186/s40560-023-00706-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 11/09/2023] [Indexed: 11/22/2023] Open
Abstract
The effort to minimize VILI risk must be multi-pronged. The need to adequately ventilate, a key determinant of hazardous power, is reduced by judicious permissive hypercapnia, reduction of innate oxygen demand, and by prone body positioning that promotes both efficient pulmonary gas exchange and homogenous distributions of local stress. Modifiable ventilator-related determinants of lung protection include reductions of tidal volume, plateau pressure, driving pressure, PEEP, inspiratory flow amplitude and profile (using longer inspiration to expiration ratios), and ventilation frequency. Underappreciated conditional cofactors of importance to modulate the impact of local specific power may include lower vascular pressures and blood flows. Employed together, these measures modulate ventilation power with the intent to avoid VILI while achieving clinically acceptable targets for pulmonary gas exchange.
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Affiliation(s)
- Lauren T Thornton
- Department of Pulmonary and Critical Care Medicine, University of Minnesota, Minneapolis/St Paul, MN, USA
| | - John J Marini
- Department of Pulmonary and Critical Care Medicine, University of Minnesota, Minneapolis/St Paul, MN, USA.
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Mälberg J, Marchesi S, Spangler D, Hadziosmanovic N, Smekal D, Rubertsson S. Continuous chest compressions are associated with higher peak inspiratory pressures when compared to 30:2 in an experimental cardiac arrest model. Intensive Care Med Exp 2023; 11:75. [PMID: 37938394 PMCID: PMC10632261 DOI: 10.1186/s40635-023-00559-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Accepted: 10/30/2023] [Indexed: 11/09/2023] Open
Abstract
BACKGROUND Ventilation during cardiopulmonary resuscitation (CPR) has long been a part of the standard treatment during cardiac arrests. Ventilation is usually given either during continuous chest compressions (CCC) or during a short pause after every 30 chest compressions (30:2). There is limited knowledge of how ventilation is delivered if it effects the hemodynamics and if it plays a role in the occurrence of lung injuries. The aim of this study was to compare ventilation parameters, hemodynamics, blood gases and lung injuries during experimental CPR given with CCC and 30:2 in a porcine model. METHODS Sixteen pigs weighing approximately 33 kg were randomized to either receive CPR with CCC or 30:2. Ventricular fibrillation was induced by passing an electrical current through the heart. CPR was started after 3 min and given for 20 min. Chest compressions were provided mechanically with a chest compression device and ventilations were delivered manually with a self-inflating bag and 12 l/min of oxygen. During the experiment, ventilation parameters and hemodynamics were sampled continuously, and arterial blood gases were taken every five minutes. After euthanasia and cessation of CPR, the lungs and heart were removed in block and visually examined followed by sampling of lung tissue which were examined using microscopy. RESULTS In the CCC group and the 30:2 group, peak inspiratory pressure (PIP) was 58.6 and 35.1 cmH2O (p < 0.001), minute volume (MV) 2189.6 and 1267.1 ml (p < 0.001), peak expired carbon dioxide (PECO2) 28.6 and 39.4 mmHg (p = 0.020), partial pressure of carbon dioxide (PaCO2) 50.2 and 61.1 mmHg (p = 0.013) and pH 7.3 and 7.2 (p = 0.029), respectively. Central venous pressure (CVP) decreased more over time in the 30:2 group (p = 0.023). All lungs were injured, but there were no differences between the groups. CONCLUSIONS Ventilation during CCC resulted in a higher PIP, MV and pH and lower PECO2 and PaCO2, showing that ventilation mode during CPR can affect ventilation parameters and blood gases.
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Affiliation(s)
- Johan Mälberg
- Department of Surgical Sciences-Anesthesia and Intensive Care, Uppsala University, Uppsala, Sweden.
| | - Silvia Marchesi
- Division of Intensive- and Perioperative Care, Skåne University Hospital, Malmö, Sweden
| | - Douglas Spangler
- Department of Surgical Sciences-Anesthesia and Intensive Care, Uppsala University, Uppsala, Sweden
| | | | - David Smekal
- Department of Surgical Sciences-Anesthesia and Intensive Care, Uppsala University, Uppsala, Sweden
| | - Sten Rubertsson
- Department of Surgical Sciences-Anesthesia and Intensive Care, Uppsala University, Uppsala, Sweden
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10
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Cruces P, Moreno D, Reveco S, Ramirez Y, Díaz F. Plateau Pressure and Driving Pressure in Volume- and Pressure-Controlled Ventilation: Comparison of Frictional and Viscoelastic Resistive Components in Pediatric Acute Respiratory Distress Syndrome. Pediatr Crit Care Med 2023; 24:750-759. [PMID: 37260322 DOI: 10.1097/pcc.0000000000003291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
OBJECTIVES To examine frictional, viscoelastic, and elastic resistive components, as well threshold pressures, during volume-controlled ventilation (VCV) and pressure-controlled ventilation (PCV) in pediatric patients with acute respiratory distress syndrome (ARDS). DESIGN Prospective cohort study. SETTING Seven-bed PICU, Hospital El Carmen de Maipú, Chile. PATIENTS Eighteen mechanically ventilated patients less than or equal to 15 years old undergoing neuromuscular blockade as part of management for ARDS. INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS All patients were in VCV mode during measurement of pulmonary mechanics, including: the first pressure drop (P1) upon reaching zero flow during the inspiratory hold, peak inspiratory pressure (PIP), plateau pressure (P PLAT ), and total positive end-expiratory pressure (tPEEP). We calculated the components of the working pressure, as defined by the following: frictional resistive = PIP-P1; viscoelastic resistive = P1-P PLAT ; purely elastic = driving pressure (ΔP) = P PLAT -tPEEP; and threshold = intrinsic PEEP. The procedures and calculations were repeated on PCV, keeping the same tidal volume and inspiratory time. Measurements in VCV were considered the gold standard. We performed Spearman correlation and Bland-Altman analysis. The median (interquartile range [IQR]) for patient age was 5 months (2-17 mo). Tidal volume was 5.7 mL/kg (5.3-6.1 mL/kg), PIP cm H 2 O 26 (23-27 cm H 2 O), P1 23 cm H 2 O (21-26 cm H 2 O), P PLAT 19 cm H 2 O (17-22 cm H 2 O), tPEEP 9 cm H 2 O (8-9 cm H 2 O), and ΔP 11 cm H 2 O (9-13 cm H 2 O) in VCV mode at baseline. There was a robust correlation (rho > 0.8) and agreement between frictional resistive, elastic, and threshold components of working pressure in both modes but not for the viscoelastic resistive component. The purely frictional resistive component was negligible. Median peak inspiratory flow with decelerating-flow was 21 (IQR, 15-26) and squared-shaped flow was 7 L/min (IQR, 6-10 L/min) ( p < 0.001). CONCLUSIONS P PLAT , ΔP, and tPEEP can guide clinical decisions independent of the ventilatory mode. The modest purely frictional resistive component emphasizes the relevance of maintaining the same safety limits, regardless of the selected ventilatory mode. Therefore, peak inspiratory flow should be studied as a mechanism of ventilator-induced lung injury in pediatric ARDS.
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Affiliation(s)
- Pablo Cruces
- Departamento de Pediatría, Unidad de Paciente Crítico Pediátrico, Hospital El Carmen de Maipú, Santiago, Chile
- Centro de Investigación de Medicina Veterinaria, Escuela de Medicina Veterinaria, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, Chile
- Red Colaborativa Pediátrica de Latinoamérica (LARed Network), Montevideo, Uruguay
- Unidad de Investigación y Epidemiología Clínica, Escuela de Medicina, Universidad Finis Terrae, Santiago, Chile
| | - Diego Moreno
- Departamento de Pediatría, Unidad de Paciente Crítico Pediátrico, Hospital El Carmen de Maipú, Santiago, Chile
| | - Sonia Reveco
- Departamento de Pediatría, Unidad de Paciente Crítico Pediátrico, Hospital El Carmen de Maipú, Santiago, Chile
| | - Yenny Ramirez
- Departamento de Pediatría, Unidad de Paciente Crítico Pediátrico, Hospital El Carmen de Maipú, Santiago, Chile
| | - Franco Díaz
- Departamento de Pediatría, Unidad de Paciente Crítico Pediátrico, Hospital El Carmen de Maipú, Santiago, Chile
- Red Colaborativa Pediátrica de Latinoamérica (LARed Network), Montevideo, Uruguay
- Unidad de Investigación y Epidemiología Clínica, Escuela de Medicina, Universidad Finis Terrae, Santiago, Chile
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11
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Buiteman-Kruizinga LA, van Meenen DMP, Bos LDJ, van der Heiden PLJ, Paulus F, Schultz MJ. A closed-loop ventilation mode that targets the lowest work and force of breathing reduces the transpulmonary driving pressure in patients with moderate-to-severe ARDS. Intensive Care Med Exp 2023; 11:42. [PMID: 37442844 DOI: 10.1186/s40635-023-00527-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 06/01/2023] [Indexed: 07/15/2023] Open
Abstract
INTRODUCTION The driving pressure (ΔP) has an independent association with outcome in patients with acute respiratory distress syndrome (ARDS). INTELLiVENT-Adaptive Support Ventilation (ASV) is a closed-loop mode of ventilation that targets the lowest work and force of breathing. AIM To compare transpulmonary and respiratory system ΔP between closed-loop ventilation and conventional pressure controlled ventilation in patients with moderate-to-severe ARDS. METHODS Single-center randomized cross-over clinical trial in patients in the early phase of ARDS. Patients were randomly assigned to start with a 4-h period of closed-loop ventilation or conventional ventilation, after which the alternate ventilation mode was selected. The primary outcome was the transpulmonary ΔP; secondary outcomes included respiratory system ΔP, and other key parameters of ventilation. RESULTS Thirteen patients were included, and all had fully analyzable data sets. Compared to conventional ventilation, with closed-loop ventilation the median transpulmonary ΔP with was lower (7.0 [5.0-10.0] vs. 10.0 [8.0-11.0] cmH2O, mean difference - 2.5 [95% CI - 2.6 to - 2.1] cmH2O; P = 0.0001). Inspiratory transpulmonary pressure and the respiratory rate were also lower. Tidal volume, however, was higher with closed-loop ventilation, but stayed below generally accepted safety cutoffs in the majority of patients. CONCLUSIONS In this small physiological study, when compared to conventional pressure controlled ventilation INTELLiVENT-ASV reduced the transpulmonary ΔP in patients in the early phase of moderate-to-severe ARDS. This closed-loop ventilation mode also led to a lower inspiratory transpulmonary pressure and a lower respiratory rate, thereby reducing the intensity of ventilation. Trial registration Clinicaltrials.gov, NCT03211494, July 7, 2017. https://clinicaltrials.gov/ct2/show/NCT03211494?term=airdrop&draw=2&rank=1 .
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Affiliation(s)
- Laura A Buiteman-Kruizinga
- Department of Intensive Care, Reinier de Graaf Hospital, Delft, The Netherlands.
- Department of Intensive Care, Amsterdam University Medical Centers, Location 'AMC', Amsterdam, The Netherlands.
| | - David M P van Meenen
- Department of Intensive Care, Amsterdam University Medical Centers, Location 'AMC', Amsterdam, The Netherlands
- Department of Anesthesia, Amsterdam University Medical Centers, Location 'AMC', Amsterdam, The Netherlands
| | - Lieuwe D J Bos
- Department of Intensive Care, Amsterdam University Medical Centers, Location 'AMC', Amsterdam, The Netherlands
- Department of Respiratory Medicine, Amsterdam University Medical Centers, Location 'AMC', Amsterdam, The Netherlands
| | | | - Frederique Paulus
- Department of Intensive Care, Amsterdam University Medical Centers, Location 'AMC', Amsterdam, The Netherlands
- ACHIEVE, Centre of Applied Research, Faculty of Health, Amsterdam University of Applied Sciences, Amsterdam, The Netherlands
| | - Marcus J Schultz
- Department of Intensive Care, Amsterdam University Medical Centers, Location 'AMC', Amsterdam, The Netherlands
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Mahidol University, Bangkok, Thailand
- Nuffield Department of Medicine, University of Oxford, Oxford, UK
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12
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Nieman GF, Kaczka DW, Andrews PL, Ghosh A, Al-Khalisy H, Camporota L, Satalin J, Herrmann J, Habashi NM. First Stabilize and then Gradually Recruit: A Paradigm Shift in Protective Mechanical Ventilation for Acute Lung Injury. J Clin Med 2023; 12:4633. [PMID: 37510748 PMCID: PMC10380509 DOI: 10.3390/jcm12144633] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 06/15/2023] [Accepted: 06/21/2023] [Indexed: 07/30/2023] Open
Abstract
Acute respiratory distress syndrome (ARDS) is associated with a heterogeneous pattern of injury throughout the lung parenchyma that alters regional alveolar opening and collapse time constants. Such heterogeneity leads to atelectasis and repetitive alveolar collapse and expansion (RACE). The net effect is a progressive loss of lung volume with secondary ventilator-induced lung injury (VILI). Previous concepts of ARDS pathophysiology envisioned a two-compartment system: a small amount of normally aerated lung tissue in the non-dependent regions (termed "baby lung"); and a collapsed and edematous tissue in dependent regions. Based on such compartmentalization, two protective ventilation strategies have been developed: (1) a "protective lung approach" (PLA), designed to reduce overdistension in the remaining aerated compartment using a low tidal volume; and (2) an "open lung approach" (OLA), which first attempts to open the collapsed lung tissue over a short time frame (seconds or minutes) with an initial recruitment maneuver, and then stabilize newly recruited tissue using titrated positive end-expiratory pressure (PEEP). A more recent understanding of ARDS pathophysiology identifies regional alveolar instability and collapse (i.e., hidden micro-atelectasis) in both lung compartments as a primary VILI mechanism. Based on this understanding, we propose an alternative strategy to ventilating the injured lung, which we term a "stabilize lung approach" (SLA). The SLA is designed to immediately stabilize the lung and reduce RACE while gradually reopening collapsed tissue over hours or days. At the core of SLA is time-controlled adaptive ventilation (TCAV), a method to adjust the parameters of the airway pressure release ventilation (APRV) modality. Since the acutely injured lung at any given airway pressure requires more time for alveolar recruitment and less time for alveolar collapse, SLA adjusts inspiratory and expiratory durations and inflation pressure levels. The TCAV method SLA reverses the open first and stabilize second OLA method by: (i) immediately stabilizing lung tissue using a very brief exhalation time (≤0.5 s), so that alveoli simply do not have sufficient time to collapse. The exhalation duration is personalized and adaptive to individual respiratory mechanical properties (i.e., elastic recoil); and (ii) gradually recruiting collapsed lung tissue using an inflate and brake ratchet combined with an extended inspiratory duration (4-6 s) method. Translational animal studies, clinical statistical analysis, and case reports support the use of TCAV as an efficacious lung protective strategy.
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Affiliation(s)
- Gary F. Nieman
- Department of Surgery, Upstate Medical University, Syracuse, NY 13210, USA;
| | - David W. Kaczka
- Departments of Anesthesia, Radiology and Biomedical Engineering, University of Iowa, Iowa City, IA 52242, USA
| | - Penny L. Andrews
- Department of Medicine, R Adams Cowley Shock Trauma Center, University of Maryland Medical Center, Baltimore, MD 21201, USA
| | - Auyon Ghosh
- Department of Medicine, Upstate Medical University, Syracuse, NY 13210, USA
| | - Hassan Al-Khalisy
- Brody School of Medicine, Department of Internal Medicine, East Carolina University, Greenville, NC 27834, USA
| | - Luigi Camporota
- Department of Adult Critical Care, Guy’s and St Thomas’ NHS Foundation Trust, King’s Partners, St Thomas’ Hospital, London SE1 7EH, UK
| | - Joshua Satalin
- Department of Surgery, Upstate Medical University, Syracuse, NY 13210, USA;
| | - Jacob Herrmann
- Department of Biomedical Engineering, University of Iowa, Iowa City, IA 52242, USA
| | - Nader M. Habashi
- Department of Medicine, R Adams Cowley Shock Trauma Center, University of Maryland Medical Center, Baltimore, MD 21201, USA
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13
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Grieco DL, Russo A, Anzellotti GM, Romanò B, Bongiovanni F, Dell'Anna AM, Mauti L, Cascarano L, Gallotta V, Rosà T, Varone F, Menga LS, Polidori L, D'Indinosante M, Cappuccio S, Galletta C, Tortorella L, Costantini B, Gueli Alletti S, Sollazzi L, Scambia G, Antonelli M. Lung-protective ventilation during Trendelenburg pneumoperitoneum surgery: A randomized clinical trial. J Clin Anesth 2023; 85:111037. [PMID: 36495775 DOI: 10.1016/j.jclinane.2022.111037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 10/31/2022] [Accepted: 12/01/2022] [Indexed: 12/12/2022]
Abstract
Study objective To assess the effects of a protective ventilation strategy during Trendelenburg pneumoperitoneum surgery on postoperative oxygenation. DESIGNS Parallel-group, randomized trial. SETTING Operating room of a university hospital, Italy. PATIENTS Morbidly obese patients undergoing Trendelenburg pneumoperitoneum gynaecological surgery. INTERVENTIONS Participants were randomized to standard (SV: tidal volume = 10 ml/kg of predicted body weight, PEEP = 5 cmH2O) or protective (PV: tidal volume = 6 ml/kg of predicted body weight, PEEP = 10 cmH2O, recruitment maneuvers) ventilation during anesthesia. MEASUREMENTS Primary outcome was PaO2/FiO2 one hour after extubation. Secondary outcomes included day-1 PaO2/FiO2, day-2 respiratory function and intraoperative respiratory/lung mechanics, assessed through esophageal manometry, end-expiratory lung volume (EELV) measurement and pressure-volume curves. MAIN RESULTS Sixty patients were analyzed (31 in SV group, 29 in PV group). Median [IqR] tidal volume was 350 ml [300-360] in PV group and 525 [500-575] in SV group. Median PaO2/FiO2 one hour after extubation was 280 mmHg [246-364] in PV group vs. 298 [250-343] in SV group (p = 0.64). Day-1 PaO2/FiO2, day-2 forced vital capacity, FEV-1 and Tiffenau Index were not different between groups (all p > 0.10). Intraoperatively, 59% of patients showed complete airway closure during pneumoperitoneum, without difference between groups: median airway opening pressure was 17 cmH2O. In PV group, airway and transpulmonary driving pressure were lower (12 ± 5 cmH2O vs. 17 ± 7, p < 0.001; 9 ± 4 vs. 13 ± 7, p < 0.001), PaCO2 and respiratory rate were higher (48 ± 8 mmHg vs. 42 ± 12, p < 0.001; 23 ± 5 breaths/min vs. 16 ± 4, p < 0.001). Intraoperative EELV was similar between PV and SV group (1193 ± 258 ml vs. 1207 ± 368, p = 0.80); ratio of tidal volume to EELV was lower in PV group (0.45 ± 0.12 vs. 0.32 ± 0.09, p < 0.001). CONCLUSIONS In obese patients undergoing Trendelenburg pneumoperitoneum surgery, PV did not improve postoperative oxygenation nor day-2 respiratory function. PV was associated with intraoperative respiratory mechanics indicating less injurious ventilation. The high prevalence of complete airway closure may have affected study results. TRIAL REGISTRATION Prospectively registered on http://clinicaltrials.govNCT03157479 on May 17th, 2017.
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Affiliation(s)
- Domenico Luca Grieco
- Department of Anesthesiology and Intensive Care Medicine, Catholic University of The Sacred Heart, Rome, Italy; Anesthesia, Emergency and Intensive Care Medicine, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy.
| | - Andrea Russo
- Department of Anesthesiology and Intensive Care Medicine, Catholic University of The Sacred Heart, Rome, Italy; Anesthesia, Emergency and Intensive Care Medicine, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
| | - Gian Marco Anzellotti
- Department of Anesthesiology and Intensive Care Medicine, Catholic University of The Sacred Heart, Rome, Italy; Anesthesia, Emergency and Intensive Care Medicine, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
| | - Bruno Romanò
- Department of Anesthesiology and Intensive Care Medicine, Catholic University of The Sacred Heart, Rome, Italy; Anesthesia, Emergency and Intensive Care Medicine, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
| | - Filippo Bongiovanni
- Department of Anesthesiology and Intensive Care Medicine, Catholic University of The Sacred Heart, Rome, Italy; Anesthesia, Emergency and Intensive Care Medicine, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
| | - Antonio M Dell'Anna
- Department of Anesthesiology and Intensive Care Medicine, Catholic University of The Sacred Heart, Rome, Italy; Anesthesia, Emergency and Intensive Care Medicine, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
| | - Luigi Mauti
- Department of Internal medicine, Catholic University of The Sacred Heart, Rome, Italy; Respiratory Medicine, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
| | - Laura Cascarano
- Department of Anesthesiology and Intensive Care Medicine, Catholic University of The Sacred Heart, Rome, Italy; Anesthesia, Emergency and Intensive Care Medicine, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
| | - Valerio Gallotta
- Department of Obstetrics and Gynecology, Catholic University of The Sacred Heart, Rome, Italy; Gynecologic Oncology, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
| | - Tommaso Rosà
- Department of Anesthesiology and Intensive Care Medicine, Catholic University of The Sacred Heart, Rome, Italy; Anesthesia, Emergency and Intensive Care Medicine, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
| | - Francesco Varone
- Department of Internal medicine, Catholic University of The Sacred Heart, Rome, Italy; Respiratory Medicine, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
| | - Luca S Menga
- Department of Anesthesiology and Intensive Care Medicine, Catholic University of The Sacred Heart, Rome, Italy; Anesthesia, Emergency and Intensive Care Medicine, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
| | - Lorenzo Polidori
- Department of Anesthesiology and Intensive Care Medicine, Catholic University of The Sacred Heart, Rome, Italy; Anesthesia, Emergency and Intensive Care Medicine, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
| | - Marco D'Indinosante
- Department of Obstetrics and Gynecology, Catholic University of The Sacred Heart, Rome, Italy; Gynecologic Oncology, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
| | - Serena Cappuccio
- Department of Obstetrics and Gynecology, Catholic University of The Sacred Heart, Rome, Italy; Gynecologic Oncology, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
| | - Claudia Galletta
- Department of Anesthesiology and Intensive Care Medicine, Catholic University of The Sacred Heart, Rome, Italy; Anesthesia, Emergency and Intensive Care Medicine, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
| | - Lucia Tortorella
- Department of Obstetrics and Gynecology, Catholic University of The Sacred Heart, Rome, Italy; Gynecologic Oncology, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
| | - Barbara Costantini
- Department of Obstetrics and Gynecology, Catholic University of The Sacred Heart, Rome, Italy; Gynecologic Oncology, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
| | - Salvatore Gueli Alletti
- Department of Obstetrics and Gynecology, Catholic University of The Sacred Heart, Rome, Italy; Gynecologic Oncology, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
| | - Liliana Sollazzi
- Department of Anesthesiology and Intensive Care Medicine, Catholic University of The Sacred Heart, Rome, Italy; Anesthesia, Emergency and Intensive Care Medicine, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
| | - Giovanni Scambia
- Department of Obstetrics and Gynecology, Catholic University of The Sacred Heart, Rome, Italy; Gynecologic Oncology, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
| | - Massimo Antonelli
- Department of Anesthesiology and Intensive Care Medicine, Catholic University of The Sacred Heart, Rome, Italy; Anesthesia, Emergency and Intensive Care Medicine, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
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14
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Abstract
Advanced respiratory monitoring involves several mini- or noninvasive tools, applicable at bedside, focused on assessing lung aeration and morphology, lung recruitment and overdistention, ventilation-perfusion distribution, inspiratory effort, respiratory drive, respiratory muscle contraction, and patient-ventilator asynchrony, in dealing with acute respiratory failure. Compared to a conventional approach, advanced respiratory monitoring has the potential to provide more insights into the pathologic modifications of lung aeration induced by the underlying disease, follow the response to therapies, and support clinicians in setting up a respiratory support strategy aimed at protecting the lung and respiratory muscles. Thus, in the clinical management of the acute respiratory failure, advanced respiratory monitoring could play a key role when a therapeutic strategy, relying on individualization of the treatments, is adopted.
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15
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16
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Nieman G, Kollisch-Singule M, Ramcharran H, Satalin J, Blair S, Gatto LA, Andrews P, Ghosh A, Kaczka DW, Gaver D, Bates J, Habashi NM. Unshrinking the baby lung to calm the VILI vortex. Crit Care 2022; 26:242. [PMID: 35934707 PMCID: PMC9357329 DOI: 10.1186/s13054-022-04105-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 07/12/2022] [Indexed: 02/07/2023] Open
Abstract
A hallmark of ARDS is progressive shrinking of the ‘baby lung,’ now referred to as the ventilator-induced lung injury (VILI) ‘vortex.’ Reducing the risk of the VILI vortex is the goal of current ventilation strategies; unfortunately, this goal has not been achieved nor has mortality been reduced. However, the temporal aspects of a mechanical breath have not been considered. A brief expiration prevents alveolar collapse, and an extended inspiration can recruit the atelectatic lung over hours. Time-controlled adaptive ventilation (TCAV) is a novel ventilator approach to achieve these goals, since it considers many of the temporal aspects of dynamic lung mechanics.
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Affiliation(s)
- Gary Nieman
- Department of Surgery, SUNY Upstate Medical Center, SUNY Upstate, 750 East Adams St., Syracuse, NY, 13210, USA
| | - Michaela Kollisch-Singule
- Department of Surgery, SUNY Upstate Medical Center, SUNY Upstate, 750 East Adams St., Syracuse, NY, 13210, USA
| | - Harry Ramcharran
- Department of Surgery, SUNY Upstate Medical Center, SUNY Upstate, 750 East Adams St., Syracuse, NY, 13210, USA
| | - Joshua Satalin
- Department of Surgery, SUNY Upstate Medical Center, SUNY Upstate, 750 East Adams St., Syracuse, NY, 13210, USA.
| | - Sarah Blair
- Department of Surgery, SUNY Upstate Medical Center, SUNY Upstate, 750 East Adams St., Syracuse, NY, 13210, USA
| | - Louis A Gatto
- Department of Surgery, SUNY Upstate Medical Center, SUNY Upstate, 750 East Adams St., Syracuse, NY, 13210, USA
| | - Penny Andrews
- Department of Medicine, University of Maryland, Baltimore, MD, USA
| | - Auyon Ghosh
- Department of Surgery, SUNY Upstate Medical Center, SUNY Upstate, 750 East Adams St., Syracuse, NY, 13210, USA
| | - David W Kaczka
- Departments of Anesthesia, Biomedical Engineering, and Radiology, University of Iowa, Iowa City, IA, USA
| | - Donald Gaver
- Department of Biomedical Engineering, Tulane University, New Orleans, LA, USA
| | - Jason Bates
- Department of Medicine, University of Vermont, Burlington, VT, USA
| | - Nader M Habashi
- Department of Medicine, University of Maryland, Baltimore, MD, USA
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17
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Grieco DL, Costa ELV, Nolan JP. The importance of ventilator settings and respiratory mechanics in patients resuscitated from cardiac arrest. Intensive Care Med 2022; 48:1056-1058. [PMID: 35776161 DOI: 10.1007/s00134-022-06779-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 06/02/2022] [Indexed: 12/26/2022]
Affiliation(s)
- Domenico L Grieco
- Department of Emergency, Intensive Care Medicine and Anesthesia, Fondazione 'Policlinico Universitario A. Gemelli' IRCCS, L.go F. Vito, 00168, Rome, Italy. .,Department of Anesthesiology and Intensive Care Medicine, Catholic University of The Sacred Heart, L.go F. Vito, 00168, Rome, Italy.
| | - Eduardo L V Costa
- Laboratório de Pneumologia LIM-09, Disciplina de Pneumologia, Heart Institute (Incor), Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, Sao Paulo, Brazil.,Research and Education Institute, Hospital Sírio-Libanes, Sao Paulo, Brazil
| | - Jerry P Nolan
- Warwick Clinical Trials Unit, Warwick Medical School, University of Warwick, Coventry, UK.,Department of Anesthesia and Intensive Care Medicine, Royal United Hospital Bath, Bath, UK
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18
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Lung aeration and volumes following alveolar recruitment maneuvers with three airway pressures in healthy anesthetized and mechanically ventilated Beagle dogs. Vet Anaesth Analg 2022; 49:443-451. [DOI: 10.1016/j.vaa.2022.06.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 06/21/2022] [Accepted: 06/24/2022] [Indexed: 01/17/2023]
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19
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Worku E, Brodie D, Ling RR, Ramanathan K, Combes A, Shekar K. Venovenous extracorporeal CO 2 removal to support ultraprotective ventilation in moderate-severe acute respiratory distress syndrome: A systematic review and meta-analysis of the literature. Perfusion 2022:2676591221096225. [PMID: 35656595 DOI: 10.1177/02676591221096225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
BACKGROUND A strategy that limits tidal volumes and inspiratory pressures, improves outcomes in patients with the acute respiratory distress syndrome (ARDS). Extracorporeal carbon dioxide removal (ECCO2R) may facilitate ultra-protective ventilation. We conducted a systematic review and meta-analysis to evaluate the efficacy and safety of venovenous ECCO2R in supporting ultra-protective ventilation in moderate-to-severe ARDS. METHODS MEDLINE and EMBASE were interrogated for studies (2000-2021) reporting venovenous ECCO2R use in patients with moderate-to-severe ARDS. Studies reporting ≥10 adult patients in English language journals were included. Ventilatory parameters after 24 h of initiating ECCO2R, device characteristics, and safety outcomes were collected. The primary outcome measure was the change in driving pressure at 24 h of ECCO2R therapy in relation to baseline. Secondary outcomes included change in tidal volume, gas exchange, and safety data. RESULTS Ten studies reporting 421 patients (PaO2:FiO2 141.03 mmHg) were included. Extracorporeal blood flow rates ranged from 0.35-1.5 L/min. Random effects modelling indicated a 3.56 cmH2O reduction (95%-CI: 3.22-3.91) in driving pressure from baseline (p < .001) and a 1.89 mL/kg (95%-CI: 1.75-2.02, p < .001) reduction in tidal volume. Oxygenation, respiratory rate and PEEP remained unchanged. No significant interactions between driving pressure reduction and baseline driving pressure, partial pressure of arterial carbon dioxide or PaO2:FiO2 ratio were identified in metaregression analysis. Bleeding and haemolysis were the commonest complications of therapy. CONCLUSIONS Venovenous ECCO2R permitted significant reductions in ∆P in patients with moderate-to-severe ARDS. Heterogeneity amongst studies and devices, a paucity of randomised controlled trials, and variable safety reporting calls for standardisation of outcome reporting. Prospective evaluation of optimal device operation and anticoagulation in high quality studies is required before further recommendations can be made.
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Affiliation(s)
- Elliott Worku
- Adult Intensive Care Services, 67567The Prince Charles Hospital, Metro North Hospital and Health Service, Brisbane, QLD, Australia
- University of Queensland, Brisbane, QLD, Australia
| | - Daniel Brodie
- Department of Medicine, 12294Columbia University College of Physicians and Surgeons, NY, USA
- Center for Acute Respiratory Failure, 25065New York-Presbyterian Hospital, NY, USA
| | - Ryan Ruiyang Ling
- Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Kollengode Ramanathan
- Yong Loo Lin School of Medicine, National University of Singapore, Singapore
- Cardiothoracic Intensive Care Unit, 375583National University Heart Centre, National University Hospital, Singapore
| | - Alain Combes
- Sorbonne Université, Institute of Cardiometabolism and Nutrition, Paris, France
- Medical Intensive Care Unit, Assistance Publique-Hôpitaux de Paris, 26933Pitié-Salpêtrière Hospital, Paris, France
| | - Kiran Shekar
- Adult Intensive Care Services, 67567The Prince Charles Hospital, Metro North Hospital and Health Service, Brisbane, QLD, Australia
- University of Queensland, Brisbane, QLD, Australia
- Queensland University of Technology, Brisbane and Bond University, Gold Coast, QLD, Australia
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20
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Rezoagli E, Laffey JG, Bellani G. Monitoring Lung Injury Severity and Ventilation Intensity during Mechanical Ventilation. Semin Respir Crit Care Med 2022; 43:346-368. [PMID: 35896391 DOI: 10.1055/s-0042-1748917] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
Acute respiratory distress syndrome (ARDS) is a severe form of respiratory failure burden by high hospital mortality. No specific pharmacologic treatment is currently available and its ventilatory management is a key strategy to allow reparative and regenerative lung tissue processes. Unfortunately, a poor management of mechanical ventilation can induce ventilation induced lung injury (VILI) caused by physical and biological forces which are at play. Different parameters have been described over the years to assess lung injury severity and facilitate optimization of mechanical ventilation. Indices of lung injury severity include variables related to gas exchange abnormalities, ventilatory setting and respiratory mechanics, ventilation intensity, and the presence of lung hyperinflation versus derecruitment. Recently, specific indexes have been proposed to quantify the stress and the strain released over time using more comprehensive algorithms of calculation such as the mechanical power, and the interaction between driving pressure (DP) and respiratory rate (RR) in the novel DP multiplied by four plus RR [(4 × DP) + RR] index. These new parameters introduce the concept of ventilation intensity as contributing factor of VILI. Ventilation intensity should be taken into account to optimize protective mechanical ventilation strategies, with the aim to reduce intensity to the lowest level required to maintain gas exchange to reduce the potential for VILI. This is further gaining relevance in the current era of phenotyping and enrichment strategies in ARDS.
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Affiliation(s)
- Emanuele Rezoagli
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy.,Department of Emergency and Intensive Care, San Gerardo University Hospital, Monza, Italy
| | - John G Laffey
- School of Medicine, National University of Ireland, Galway, Ireland.,Department of Anaesthesia and Intensive Care Medicine, Galway University Hospitals, Saolta University Hospital Group, Galway, Ireland.,Lung Biology Group, Regenerative Medicine Institute (REMEDI) at CÚRAM Centre for Research in Medical Devices, National University of Ireland Galway, Galway, Ireland
| | - Giacomo Bellani
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy.,Department of Emergency and Intensive Care, San Gerardo University Hospital, Monza, Italy
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21
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Crooke PS, Gattinoni L, Michalik M, Marini JJ. Intracycle power distribution in a heterogeneous multi-compartmental mathematical model: possible links to strain and VILI. Intensive Care Med Exp 2022; 10:21. [PMID: 35641652 PMCID: PMC9156592 DOI: 10.1186/s40635-022-00447-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2022] [Accepted: 05/12/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Repeated expenditure of energy and its generation of damaging strain are required to injure the lung by ventilation (VILI). Mathematical modeling of passively inflated, single-compartment lungs with uniform parameters for resistance and compliance indicates that standard clinical modes (flow patterns) differ impressively with respect to the timing and intensity of energy delivery-the intracycle power (ICP) that determines parenchymal stress and strain. Although measures of elastic ICP may accurately characterize instantaneous rates of global energy delivery, how the ICP component delivered to a compartment affects the VILI-linked variable of strain is determined by compartmental mechanics, compartmental size and mode of gas delivery. We extended our one-compartment model of ICP to a multi-compartment setting that varied those characteristics. MAIN FINDINGS The primary findings of this model/simulation indicate that: (1) the strain and strain rate experienced within a modeled compartment are nonlinear functions of delivered energy and power, respectively; (2) for a given combination of flow profile and tidal volume, resting compartmental volumes influence their resulting maximal strains in response to breath delivery; (3) flow profile is a key determinant of the maximal strain as well as maximal strain rate experienced within a multi-compartment lung. By implication, different clinician-selected flow profiles not only influence the timing of power delivery, but also spatially distribute the attendant strains of expansion among compartments with diverse mechanical properties. Importantly, the contours and magnitudes of the compartmental ICP, strain, and strain rate curves are not congruent; strain and strain rate do not necessarily follow the compartmental ICP, and the hierarchy of amplitudes among compartments for these variables may not coincide. CONCLUSIONS Different flow patterns impact how strain and strain rate develop as compartmental volume crests to its final value. Notably, as inflation proceeds, strain rate may rise or fall even as total strain, a monotonic function of volume, steadily (and predictably) rises. Which flow pattern serves best to minimize the maximal strain rate and VILI risk experienced within any sector, therefore, may strongly depend on the nature and heterogeneity of the mechanical properties of the injured lung.
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Affiliation(s)
- Philip S. Crooke
- Department of Mathematics, Vanderbilt University, Nashville, TN USA
| | - Luciano Gattinoni
- Department of Anesthesiology and Intensive Care, Gottingen University, Gottingen, Germany
| | - Michael Michalik
- Department of Medicine, University of Minnesota, Minneapolis, St. Paul, MN USA
| | - John J. Marini
- Pulmonary and Critical Care Medicine, Regions Hospital, University of Minnesota, MS 11203B, 640 Jackson St., Minneapolis, St. Paul, MN 55101-2595 USA
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22
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Dries DJ, Perry JF, Tawfik PN. A Rationale for Safe Ventilation with Inhalation Injury: An Editorial Review. J Burn Care Res 2022; 43:irac061. [PMID: 35511894 DOI: 10.1093/jbcr/irac061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Indexed: 11/14/2022]
Abstract
Lung injury from smoke inhalation manifests as airway and parenchymal damage, at times leading to the acute respiratory distress syndrome. From the beginning of this millennium, the approach to mechanical ventilation in the patient with ARDS was based on reduction of tidal volume to 6 milliliters/kilogram of ideal body weight, maintaining a ceiling of plateau pressure, and titration of driving pressure (plateau pressure minus PEEP). Beyond these broad constraints, there is little specification for the mechanics of ventilator settings, consideration of the metabolic impact of the disease process on the patient, or interaction of patient disease and ventilator settings. Various studies suggest that inhomogeneity of lung injury, which increases the risk of regional lung trauma from mechanical ventilation, may be found in the patient with smoke inhalation. We now appreciate that energy transfer principles may affect optimal ventilator management and come into play in damaged heterogenous lungs. Mechanical ventilation in the patient with inhalation injury should consider various factors. Self-injurious respiratory demand by the patient can be reduced using analgesia and sedation. Dynamic factors beginning with rate management can reduce the incidence of potentially damaging ventilation. Moreover, preclinical study is underway to examine the flow of gas based on the ventilator mode selected, which may also be a factor triggering regional lung injury.
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Affiliation(s)
| | - John F Perry
- Chair of Trauma Surgery University of Minnesota, U.S.A
| | - Pierre N Tawfik
- Fellow Pulmonary and Critical Care Medicine University of Minnesota, U.S.A
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23
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Fernandes MVS, Rocha NN, Felix NS, Rodrigues GC, Silva LHA, Coelho MS, Fonseca ACF, Teixeira ACGM, Capelozzi VL, Pelosi P, Silva PL, Marini JJ, Rocco PRM. A more gradual positive end-expiratory pressure increase reduces lung damage and improves cardiac function in experimental acute respiratory distress syndrome. J Appl Physiol (1985) 2022; 132:375-387. [PMID: 34941443 DOI: 10.1152/japplphysiol.00613.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 12/17/2021] [Indexed: 11/22/2022] Open
Abstract
Increases in positive end-expiratory pressure (PEEP) or recruitment maneuvers may increase stress in lung parenchyma, extracellular matrix, and lung vessels; however, adaptative responses may occur. We evaluated the effects of PEEP on lung damage and cardiac function when increased abruptly, gradually, or more gradually in experimental mild/moderate acute respiratory distress syndrome (ARDS) induced by Escherichia coli lipopolysaccharide intratracheally. After 24 h, Wistar rats (n = 48) were randomly assigned to four mechanical ventilation strategies according to PEEP levels: 1) 3 cmH2O for 2 h (control); 2) 3 cmH2O for 1 h followed by an abrupt increase to 9 cmH2O for 1 h (no adaptation time); 3) 3 cmH2O for 30 min followed by a gradual increase to 9 cmH2O over 30 min then kept constant for 1 h (shorter adaptation time); and 4) more gradual increase in PEEP from 3 cmH2O to 9 cmH2O over 1 h and kept constant thereafter (longer adaptation time). At the end of the experiment, oxygenation improved in the shorter and longer adaptation time groups compared with the no-adaptation and control groups. Diffuse alveolar damage and expressions of interleukin-6, club cell protein-16, vascular cell adhesion molecule-1, amphiregulin, decorin, and syndecan were higher in no adaptation time compared with other groups. Pulmonary arterial pressure was lower in longer adaptation time than in no adaptation (P = 0.002) and shorter adaptation time (P = 0.025) groups. In this model, gradually increasing PEEP limited lung damage and release of biomarkers associated with lung epithelial/endothelial cell and extracellular matrix damage, as well as the PEEP-associated increase in pulmonary arterial pressure.NEW & NOTEWORTHY In a rat model of Escherichia coli lipopolysaccharide-induced mild/moderate acute respiratory distress syndrome, a gradual PEEP increase (shorter adaptation time) effectively mitigated histological lung injury and biomarker release associated with lung inflammation, damage to epithelial cells, endothelial cells, and the extracellular matrix compared with an abrupt increase in PEEP. A more gradual PEEP increase (longer adaptation time) decreased lung damage, pulmonary vessel compression, and pulmonary arterial pressure.
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Affiliation(s)
- Marcos V S Fernandes
- Laboratory of Pulmonary Investigation, Carlos Chagas Filho Biophysics Institute, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Nazareth N Rocha
- Laboratory of Pulmonary Investigation, Carlos Chagas Filho Biophysics Institute, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
- Department of Physiology and Pharmacology, Biomedical Institute, Fluminense Federal University, Niteroi, Brazil
| | - Nathane S Felix
- Laboratory of Pulmonary Investigation, Carlos Chagas Filho Biophysics Institute, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Gisele C Rodrigues
- Laboratory of Pulmonary Investigation, Carlos Chagas Filho Biophysics Institute, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Luísa H A Silva
- Laboratory of Pulmonary Investigation, Carlos Chagas Filho Biophysics Institute, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Mariana S Coelho
- Laboratory of Pulmonary Investigation, Carlos Chagas Filho Biophysics Institute, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Ana Carolina F Fonseca
- Laboratory of Pulmonary Investigation, Carlos Chagas Filho Biophysics Institute, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Ana Carolina G M Teixeira
- Laboratory of Pulmonary Investigation, Carlos Chagas Filho Biophysics Institute, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Vera L Capelozzi
- Department of Pathology, School of Medicine, University of São Paulo, São Paulo, Brazil
| | - Paolo Pelosi
- Department of Surgical Sciences and Integrated Diagnostics, University of Genoa, Genoa, Italy
- San Martino Policlinico Hospital, IRCCS for Oncology and Neurosciences, Genoa, Italy
| | - Pedro L Silva
- Laboratory of Pulmonary Investigation, Carlos Chagas Filho Biophysics Institute, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - John J Marini
- Regions Hospital and University of Minnesota, Minneapolis/Saint Paul, Minnesota
| | - Patricia R M Rocco
- Laboratory of Pulmonary Investigation, Carlos Chagas Filho Biophysics Institute, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
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24
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Bhalla AK, Klein MJ, Modesto I Alapont V, Emeriaud G, Kneyber MCJ, Medina A, Cruces P, Diaz F, Takeuchi M, Maddux AB, Mourani PM, Camilo C, White BR, Yehya N, Pappachan J, Di Nardo M, Shein S, Newth C, Khemani R. Mechanical power in pediatric acute respiratory distress syndrome: a PARDIE study. Crit Care 2022; 26:2. [PMID: 34980228 PMCID: PMC8722295 DOI: 10.1186/s13054-021-03853-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 12/01/2021] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND Mechanical power is a composite variable for energy transmitted to the respiratory system over time that may better capture risk for ventilator-induced lung injury than individual ventilator management components. We sought to evaluate if mechanical ventilation management with a high mechanical power is associated with fewer ventilator-free days (VFD) in children with pediatric acute respiratory distress syndrome (PARDS). METHODS Retrospective analysis of a prospective observational international cohort study. RESULTS There were 306 children from 55 pediatric intensive care units included. High mechanical power was associated with younger age, higher oxygenation index, a comorbid condition of bronchopulmonary dysplasia, higher tidal volume, higher delta pressure (peak inspiratory pressure-positive end-expiratory pressure), and higher respiratory rate. Higher mechanical power was associated with fewer 28-day VFD after controlling for confounding variables (per 0.1 J·min-1·Kg-1 Subdistribution Hazard Ratio (SHR) 0.93 (0.87, 0.98), p = 0.013). Higher mechanical power was not associated with higher intensive care unit mortality in multivariable analysis in the entire cohort (per 0.1 J·min-1·Kg-1 OR 1.12 [0.94, 1.32], p = 0.20). But was associated with higher mortality when excluding children who died due to neurologic reasons (per 0.1 J·min-1·Kg-1 OR 1.22 [1.01, 1.46], p = 0.036). In subgroup analyses by age, the association between higher mechanical power and fewer 28-day VFD remained only in children < 2-years-old (per 0.1 J·min-1·Kg-1 SHR 0.89 (0.82, 0.96), p = 0.005). Younger children were managed with lower tidal volume, higher delta pressure, higher respiratory rate, lower positive end-expiratory pressure, and higher PCO2 than older children. No individual ventilator management component mediated the effect of mechanical power on 28-day VFD. CONCLUSIONS Higher mechanical power is associated with fewer 28-day VFDs in children with PARDS. This association is strongest in children < 2-years-old in whom there are notable differences in mechanical ventilation management. While further validation is needed, these data highlight that ventilator management is associated with outcome in children with PARDS, and there may be subgroups of children with higher potential benefit from strategies to improve lung-protective ventilation. TAKE HOME MESSAGE Higher mechanical power is associated with fewer 28-day ventilator-free days in children with pediatric acute respiratory distress syndrome. This association is strongest in children <2-years-old in whom there are notable differences in mechanical ventilation management.
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Affiliation(s)
- Anoopindar K. Bhalla
- grid.239546.f0000 0001 2153 6013Department of Anesthesiology and Critical Care Medicine, Children’s Hospital Los Angeles, Los Angeles, CA USA ,grid.42505.360000 0001 2156 6853Department of Pediatrics, Keck School of Medicine, University of Southern California, Los Angeles, CA USA
| | - Margaret J. Klein
- grid.239546.f0000 0001 2153 6013Department of Anesthesiology and Critical Care Medicine, Children’s Hospital Los Angeles, Los Angeles, CA USA
| | - Vicent Modesto I Alapont
- grid.84393.350000 0001 0360 9602University and Polytechnic Hospital La Fe Valencia, Valencia, Spain
| | - Guillaume Emeriaud
- grid.14848.310000 0001 2292 3357Pediatric Intensive Care Unit, CHU Sainte-Justine, Department of Pediatrics, Université de Montréal, Montreal, Canada
| | - Martin C. J. Kneyber
- grid.4830.f0000 0004 0407 1981Division of Paediatric Critical Care Medicine, Department of Paediatrics, University Medical Center Groningen, Beatrix Children’s Hospital, University of Groningen, Groningen, The Netherlands ,grid.4830.f0000 0004 0407 1981Critical Care, Anaesthesiology, Peri-Operative & Emergency Medicine (CAPE), University of Groningen, Groningen, The Netherlands
| | - Alberto Medina
- grid.411052.30000 0001 2176 9028Hospital Universitario Central de Asturias, Oviedo, Spain
| | - Pablo Cruces
- grid.412848.30000 0001 2156 804XCentro de Investigación de Medicina Veterinaria, Escuela de Medicina Veterinaria, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, Chile ,Departamento de Pediatría, Unidad de Paciente Crítico Pediátrico, Hospital El Carmen de Maipú, Santiago, Chile
| | - Franco Diaz
- grid.412187.90000 0000 9631 4901Instituto de Ciencias e Innovación ed Medicina (ICIM), Universidad del Desarrollo, Santiago, Chile ,Hospital Clínico La Florida, Santiago, Chile
| | - Muneyuki Takeuchi
- grid.416629.e0000 0004 0377 2137Department of Intensive Care Medicine, Osaka Women’s and Children’s Hospital, Osaka, Japan
| | - Aline B. Maddux
- grid.430503.10000 0001 0703 675XPediatric Critical Care, University of Colorado School of Medicine, Aurora, CO USA ,grid.413957.d0000 0001 0690 7621Children’s Hospital Colorado, Aurora, CO USA
| | - Peter M. Mourani
- grid.241054.60000 0004 4687 1637Arkansas Children’s Hospital, University of Arkansas for Medical Sciences, Little Rock, AR USA
| | - Cristina Camilo
- grid.411265.50000 0001 2295 9747PICU, Hospital de Santa Maria – CHULN, Lisbon, Portugal
| | - Benjamin R. White
- grid.29857.310000 0001 2097 4281Penn State Health Children’s Hospital, Hershey, PA USA
| | - Nadir Yehya
- grid.239552.a0000 0001 0680 8770Department of Anesthesiology and Critical Care Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA USA
| | - John Pappachan
- grid.430506.4Paediatric Intensive Care Unit, University Hospital Southampton NHS Foundation Trust, Southampton, UK ,grid.5491.90000 0004 1936 9297Faculty of Medicine, University of Southampton, Southampton, UK
| | - Matteo Di Nardo
- grid.414125.70000 0001 0727 6809Pediatric Intensive Care Unit, Children’s Hospital Bambino Gesù, IRCCS, Rome, Italy
| | - Steven Shein
- grid.415629.d0000 0004 0418 9947Division of Pediatric Critical Care Medicine, Rainbow Babies and Children’s Hospital, Cleveland, OH USA
| | - Christopher Newth
- grid.239546.f0000 0001 2153 6013Department of Anesthesiology and Critical Care Medicine, Children’s Hospital Los Angeles, Los Angeles, CA USA ,grid.42505.360000 0001 2156 6853Department of Pediatrics, Keck School of Medicine, University of Southern California, Los Angeles, CA USA
| | - Robinder Khemani
- grid.239546.f0000 0001 2153 6013Department of Anesthesiology and Critical Care Medicine, Children’s Hospital Los Angeles, Los Angeles, CA USA ,grid.42505.360000 0001 2156 6853Department of Pediatrics, Keck School of Medicine, University of Southern California, Los Angeles, CA USA
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25
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Paudel R, Trinkle CA, Waters CM, Robinson LE, Cassity E, Sturgill JL, Broaddus R, Morris PE. Mechanical Power: A New Concept in Mechanical Ventilation. Am J Med Sci 2021; 362:537-545. [PMID: 34597688 PMCID: PMC8688297 DOI: 10.1016/j.amjms.2021.09.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 07/26/2021] [Accepted: 09/24/2021] [Indexed: 11/22/2022]
Abstract
Mechanical ventilation is a potentially life-saving therapy for patients with acute lung injury, but the ventilator itself may cause lung injury. Ventilator-induced lung injury (VILI) is sometimes an unfortunate consequence of mechanical ventilation. It is not clear however how best to minimize VILI through adjustment of various parameters including tidal volume, plateau pressure, driving pressure, and positive end expiratory pressure (PEEP). No single parameter provides a clear indication for onset of lung injury attributable exclusively to the ventilator. There is currently interest in quantifying how static and dynamic parameters contribute to VILI. One concept that has emerged is the consideration of the amount of energy transferred from the ventilator to the respiratory system per unit time, which can be quantified as mechanical power. This review article reports on recent literature in this emerging field and future roles for mechanical power assessments in prospective studies.
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Affiliation(s)
- Robin Paudel
- Division of Pulmonary, Critical Care, and Sleep Medicine, Mayo Clinic Health System, Franciscan Healthcare in La Crosse, La Crosse, WI, USA.
| | - Christine A Trinkle
- Department of Mechanical Engineering, University of Kentucky College of Engineering, Lexington, KY, USA
| | - Christopher M Waters
- Department of Physiology, University of Kentucky College of Medicine, Lexington, KY, USA
| | | | - Evan Cassity
- Division of Pulmonary, Critical Care, and Sleep Medicine, University of Kentucky College of Medicine, Lexington, KY, USA
| | - Jamie L Sturgill
- Division of Pulmonary, Critical Care, and Sleep Medicine, University of Kentucky College of Medicine, Lexington, KY, USA
| | - Richard Broaddus
- Division of Pulmonary, Critical Care, and Sleep Medicine, University of Kentucky College of Medicine, Lexington, KY, USA
| | - Peter E Morris
- Division of Pulmonary, Critical Care, and Sleep Medicine, University of Kentucky College of Medicine, Lexington, KY, USA
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26
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Marini JJ, Crooke PS, Tawfik P, Chatburn RL, Dries DJ, Gattinoni L. Intracycle power and ventilation mode as potential contributors to ventilator-induced lung injury. Intensive Care Med Exp 2021; 9:55. [PMID: 34719749 PMCID: PMC8557972 DOI: 10.1186/s40635-021-00420-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Accepted: 10/07/2021] [Indexed: 11/23/2022] Open
Abstract
Background High rates of inflation energy delivery coupled with transpulmonary tidal pressures of sufficient magnitude may augment the risk of damage to vulnerable, stress-focused units within a mechanically heterogeneous lung. Apart from flow amplitude, the clinician-selected flow waveform, a relatively neglected dimension of inflation power, may distribute inflation energy of each inflation cycle non-uniformly among alveoli with different mechanical properties over the domains of time and space. In this initial step in modeling intracycle power distribution, our primary objective was to develop a mathematical model of global intracycle inflation power that uses clinician-measurable inputs to allow comparisons of instantaneous ICP profiles among the flow modes commonly encountered in clinical practice: constant, linearly decelerating, exponentially decelerating (pressure control), and spontaneous (sinusoidal). Methods We first tested the predictions of our mathematical model of passive inflation with the actual physical performance of a mechanical ventilator–lung system that simulated ventilation to three types of patients: normal, severe ARDS, and severe airflow obstruction. After verification, model predictions were then generated for 5000 ‘virtual ARDS patients’. Holding constant the tidal volume and inflation time between modes, the validated model then varied the flow profile and quantitated the resulting intensity and timing of potentially damaging ‘elastic’ energy and intracycle power (pressure–flow product) developed in response to random combinations of machine settings and severity levels for ARDS. Results Our modeling indicates that while the varied flow patterns ultimately deliver similar total amounts of alveolar energy during each breath, they differ profoundly regarding the potentially damaging pattern with which that energy distributes over time during inflation. Pressure control imposed relatively high maximal intracycle power. Conclusions Flow amplitude and waveform may be relatively neglected and modifiable determinants of VILI risk when ventilating ARDS. Supplementary Information The online version contains supplementary material available at 10.1186/s40635-021-00420-9.
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Affiliation(s)
- John J Marini
- Pulmonary and Critical Care Medicine, University of Minnesota and Regions Hospital, Minneapolis/St. Paul, MN, 55101, USA. .,Regions Hospital, MS-11203B, 640 Jackson St, St. Paul, MN, 55101, USA.
| | - Philip S Crooke
- Department of Mathematics, Vanderbilt University, Nashville, TN, USA
| | - Pierre Tawfik
- Pulmonary and Critical Care Medicine, University of Minnesota and Regions Hospital, Minneapolis/St. Paul, MN, 55101, USA
| | - Robert L Chatburn
- Department of Medicine and Respiratory Institute, Cleveland Clinic, Cleveland, OH, USA
| | - David J Dries
- Pulmonary and Critical Care Medicine, University of Minnesota and Regions Hospital, Minneapolis/St. Paul, MN, 55101, USA
| | - Luciano Gattinoni
- Department of Anesthesiology, Intensive Care and Emergency Medicine, Medical University of Göttingen, Göttingen, Germany
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27
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Chiumello D, Meli A, Pozzi T, Lucenteforte M, Simili P, Sterchele E, Coppola S. Different Inspiratory Flow Waveform during Volume-Controlled Ventilation in ARDS Patients. J Clin Med 2021; 10:jcm10204756. [PMID: 34682881 PMCID: PMC8540057 DOI: 10.3390/jcm10204756] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 09/30/2021] [Accepted: 10/12/2021] [Indexed: 11/16/2022] Open
Abstract
The most used types of mechanical ventilation are volume- and pressure-controlled ventilation, respectively characterized by a square and a decelerating flow waveform. Nowadays, the clinical utility of different inspiratory flow waveforms remains unclear. The aim of this study was to assess the effects of four different inspiratory flow waveforms in ARDS patients. Twenty-eight ARDS patients (PaO2/FiO2 182 ± 40 and PEEP 11.3 ± 2.5 cmH2O) were ventilated in volume-controlled ventilation with four inspiratory flow waveforms: square (SQ), decelerating (DE), sinusoidal (SIN), and trunk descending (TDE). After 30 min in each condition, partitioned respiratory mechanics and gas exchange were collected. The inspiratory peak flow was higher in the DE waveform compared to the other three waveforms, and in SIN compared to the SQ and TDE waveforms, respectively. The mean inspiratory flow was higher in the DE and SIN waveforms compared with TDE and SQ. The inspiratory peak pressure was higher in the SIN and SQ compared to the TDE waveform. Partitioned elastance was similar in the four groups; mechanical power was lower in the TDE waveform, while PaCO2 in DE. No major effect on oxygenation was found. The explored flow waveforms did not provide relevant changes in oxygenation and respiratory mechanics.
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Affiliation(s)
- Davide Chiumello
- Department of Anesthesia and Intensive Care, ASST Santi Paolo e Carlo, San Paolo University Hospital, Via Di Rudini 9, 20142 Milan, Italy;
- Department of Health Sciences, University of Milan, 20142 Milan, Italy; (T.P.); (M.L.); (P.S.); (E.S.)
- Coordinated Research Center on Respiratory Failure, University of Milan, 20142 Milan, Italy
- Correspondence:
| | - Andrea Meli
- Department of Anesthesia, Intensive Care and Emergency, Fondazione IRCCS Ca’ Granda Hospital Maggiore Policlinico, Via F. Sforza 35, 20122 Milan, Italy;
| | - Tommaso Pozzi
- Department of Health Sciences, University of Milan, 20142 Milan, Italy; (T.P.); (M.L.); (P.S.); (E.S.)
| | - Manuela Lucenteforte
- Department of Health Sciences, University of Milan, 20142 Milan, Italy; (T.P.); (M.L.); (P.S.); (E.S.)
| | - Paolo Simili
- Department of Health Sciences, University of Milan, 20142 Milan, Italy; (T.P.); (M.L.); (P.S.); (E.S.)
| | - Elda Sterchele
- Department of Health Sciences, University of Milan, 20142 Milan, Italy; (T.P.); (M.L.); (P.S.); (E.S.)
| | - Silvia Coppola
- Department of Anesthesia and Intensive Care, ASST Santi Paolo e Carlo, San Paolo University Hospital, Via Di Rudini 9, 20142 Milan, Italy;
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Guérin C, Bayat S, Noury N, Cour M, Argaud L, Louis B, Terzi N. Regional lung viscoelastic properties in supine and prone position in a porcine model of acute respiratory distress syndrome. J Appl Physiol (1985) 2021; 131:15-25. [PMID: 33982595 DOI: 10.1152/japplphysiol.00104.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Regional viscoelastic properties of thoracic tissues in acute respiratory distress syndrome (ARDS) and their change with position and positive end-expiratory pressure (PEEP) are unknown. In an experimental porcine ARDS, dorsal and ventral lung (R2,L and E2,L) and chest wall (R2,cw and E2,cw) viscoelastic resistive (R) and elastic (E) parameters were measured at 20, 15, 10, and 5 cmH2O PEEP in supine and prone position. E2 and R2 were obtained by fitting the decay of pressure after end-inspiratory occlusion to the equation: Pviscmax (t) =R2 e-t/τ2, where t is the length of occlusion and τ2 time constant. E2 was equal to R2/τ2. R2,cw and E2,cw were measured from esophageal, dorsal, and ventral pleural pressures. Global R2,L and E2,L were obtained from the global transpulmonary pressure (airway pressure-esophageal pressure), and regional R2,L and E2,L from the dorsal and ventral airway pressure-pleural pressure difference. Lung ventilation was measured by electrical impedance tomography (EIT). Global R2,cw and E2,cw did not change with PEEP or position. Global R2,L [median(Q1-Q3)] was 37.1 (11.0-65.1), 5.1 (4.3-5.5), 12.1 (8.4-19.5), and 41.0 (26.6-53.5) cmH2O/L/s in supine, and 15.3 (9.1-41.9), 7.9 (5.7-11.0), 8.0 (5.1-12.1), and 12.9 (6.4-19.4) cmH2O/L in prone from 20 to 5 cmH2O PEEP (P = 0.06 for PEEP and P = 0.06 for position). Dorsal R2,L significantly and positively correlated with the amount of collapse measured with EIT. Global and regional lung and chest wall viscoelastic parameters can be described by a simple rheological model. Regional E2 and R2 were uninfluenced by PEEP and position except for PEEP on dorsal E2,L and position on dorsal E2,cw.NEW & NOTEWORTHY In a porcine model of acute respiratory distress syndrome, data were successfully fitted to a rheological model of the nonlinear behavior of viscoelastic properties of lung and chest wall at different positive end-expiratory pressure (PEEP) in the supine and prone position. Prone position tended to decrease lung viscoelastic resistive component. PEEP had a significant effect on dorsal lung viscoelastic elastance. Finally, lung viscoelastic resistance correlated with the amount of lung collapse assessed by electrical impedance tomography.
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Affiliation(s)
- Claude Guérin
- Médecine Intensive-Réanimation, Groupement Hospitalier Centre, Hôpital Edouard Herriot, Lyon, France.,Université de Lyon, Lyon, France.,Laboratoire d'explorations fonctionnelles respiratoires, CHU Grenoble-Alpes, Grenoble, France
| | - Sam Bayat
- Laboratoire d'explorations fonctionnelles respiratoires, CHU Grenoble-Alpes, Grenoble, France.,INSERM UA7 STROBE, Grenoble, France.,Université de Grenoble, Grenoble, France
| | | | - Martin Cour
- Médecine Intensive-Réanimation, Groupement Hospitalier Centre, Hôpital Edouard Herriot, Lyon, France.,Université de Lyon, Lyon, France
| | - Laurent Argaud
- Médecine Intensive-Réanimation, Groupement Hospitalier Centre, Hôpital Edouard Herriot, Lyon, France.,Université de Lyon, Lyon, France
| | - Bruno Louis
- Laboratoire d'explorations fonctionnelles respiratoires, CHU Grenoble-Alpes, Grenoble, France
| | - Nicolas Terzi
- Université de Grenoble, Grenoble, France.,Médecine intensive-Réanimation, CHU Grenoble-Alpes, Grenoble, France.,INSERM U1042, Grenoble, France
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Abstract
Mechanical power of ventilation, currently defined as the energy delivered from the ventilator to the respiratory system over a period of time, has been recognized as a promising indicator to evaluate ventilator-induced lung injury and predict the prognosis of ventilated critically ill patients. Mechanical power can be accurately measured by the geometric method, while simplified equations allow an easy estimation of mechanical power at the bedside. There may exist a safety threshold of mechanical power above which lung injury is inevitable, and the assessment of mechanical power might be helpful to determine whether the extracorporeal respiratory support is needed in patients with acute respiratory distress syndrome. It should be noted that relatively low mechanical power does not exclude the possibility of lung injury. Lung size and inhomogeneity should also be taken into consideration. Problems regarding the safety limits of mechanical power and contribution of each component to lung injury have not been determined yet. Whether mechanical power-directed lung-protective ventilation strategy could improve clinical outcomes also needs further investigation. Therefore, this review discusses the algorithms, clinical relevance, optimization, and future directions of mechanical power in critically ill patients.
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Kaczka DW. Oscillatory ventilation redux: alternative perspectives on ventilator-induced lung injury in the acute respiratory distress syndrome. CURRENT OPINION IN PHYSIOLOGY 2021; 21:36-43. [PMID: 33898903 PMCID: PMC8056876 DOI: 10.1016/j.cophys.2021.03.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
For patients with the acute respiratory distress syndrome (ARDS), ventilation strategies that limit end-expiratory derecruitment and end-inspiratory overdistension are the only interventions to have significantly reduced the morbidity and mortality. For this reason, the use of high-frequency oscillatory ventilation (HFOV) was considered to be an ideal protective strategy, given its reliance on very low tidal volumes cycled at very high rates. However, results from clinical trials in adults with ARDS have demonstrated that HFOV does not improve clinical outcomes. Recent experimental and computational studies have shown that oscillation of a mechanically heterogeneous lung with multiple simultaneous frequencies can reduce parenchymal strain, improve gas exchange, and maintain lung recruitment at lower distending pressures compared to traditional ‘single-frequency’ HFOV. This review will discuss the theoretical rationale for the use of multiple oscillatory frequencies in ARDS, as well as the mechanisms by which it may reduce the risk for ventilator-induced lung injury.
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Affiliation(s)
- David W Kaczka
- Department of Anesthesia, University of Iowa, Iowa City, IA, USA.,Roy J. Carver Department of Biomedical Engineering, University of Iowa, Iowa City, IA, USA.,Department of Radiology, University of Iowa, Iowa City, IA, USA
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Wittenstein J, Scharffenberg M, Ran X, Keller D, Michler P, Tauer S, Theilen R, Kiss T, Bluth T, Koch T, Gama de Abreu M, Huhle R. Comparative effects of flow vs. volume-controlled one-lung ventilation on gas exchange and respiratory system mechanics in pigs. Intensive Care Med Exp 2020; 8:24. [PMID: 33336305 PMCID: PMC7746431 DOI: 10.1186/s40635-020-00308-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 05/21/2020] [Indexed: 01/23/2023] Open
Abstract
Background Flow-controlled ventilation (FCV) allows expiratory flow control, reducing the collapse of the airways during expiration. The performance of FCV during one-lung ventilation (OLV) under intravascular normo- and hypovolaemia is currently unknown. In this explorative study, we hypothesised that OLV with FCV improves PaO2 and reduces mechanical power compared to volume-controlled ventilation (VCV). Sixteen juvenile pigs were randomly assigned to one of two groups: (1) intravascular normovolaemia (n = 8) and (2) intravascular hypovolaemia (n = 8). To mimic inflammation due to major thoracic surgery, a thoracotomy was performed, and 0.5 μg/kg/h lipopolysaccharides from Escherichia coli continuously administered intravenously. Animals were randomly assigned to OLV with one of two sequences (60 min per mode): (1) VCV–FCV or (2) FCV–VCV. Variables of gas exchange, haemodynamics and respiratory signals were collected 20, 40 and 60 min after initiation of OLV with each mechanical ventilation mode. The distribution of ventilation was determined using electrical impedance tomography (EIT). Results Oxygenation did not differ significantly between modes (P = 0.881). In the normovolaemia group, the corrected expired minute volume (P = 0.022) and positive end-expiratory pressure (PEEP) were lower during FCV than VCV. The minute volume (P ≤ 0.001), respiratory rate (P ≤ 0.001), total PEEP (P ≤ 0.001), resistance of the respiratory system (P ≤ 0.001), mechanical power (P ≤ 0.001) and resistive mechanical power (P ≤ 0.001) were lower during FCV than VCV irrespective of the volaemia status. The distribution of ventilation did not differ between both ventilation modes (P = 0.103). Conclusions In a model of OLV in normo- and hypovolemic pigs, mechanical power was lower during FCV compared to VCV, without significant differences in oxygenation. Furthermore, the efficacy of ventilation was higher during FCV compared to VCV during normovolaemia.
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Affiliation(s)
- Jakob Wittenstein
- Pulmonary Engineering Group, Dept. of Anaesthesiology and Intensive Care Medicine, University Hospital Carl Gustav Carus at Technische Universität Dresden, Fetscherstrasse 74, 01307, Dresden, Germany
| | - Martin Scharffenberg
- Pulmonary Engineering Group, Dept. of Anaesthesiology and Intensive Care Medicine, University Hospital Carl Gustav Carus at Technische Universität Dresden, Fetscherstrasse 74, 01307, Dresden, Germany
| | - Xi Ran
- Pulmonary Engineering Group, Dept. of Anaesthesiology and Intensive Care Medicine, University Hospital Carl Gustav Carus at Technische Universität Dresden, Fetscherstrasse 74, 01307, Dresden, Germany
| | - Diana Keller
- Pulmonary Engineering Group, Dept. of Anaesthesiology and Intensive Care Medicine, University Hospital Carl Gustav Carus at Technische Universität Dresden, Fetscherstrasse 74, 01307, Dresden, Germany
| | - Pia Michler
- Pulmonary Engineering Group, Dept. of Anaesthesiology and Intensive Care Medicine, University Hospital Carl Gustav Carus at Technische Universität Dresden, Fetscherstrasse 74, 01307, Dresden, Germany
| | - Sebastian Tauer
- Pulmonary Engineering Group, Dept. of Anaesthesiology and Intensive Care Medicine, University Hospital Carl Gustav Carus at Technische Universität Dresden, Fetscherstrasse 74, 01307, Dresden, Germany
| | - Raphael Theilen
- Pulmonary Engineering Group, Dept. of Anaesthesiology and Intensive Care Medicine, University Hospital Carl Gustav Carus at Technische Universität Dresden, Fetscherstrasse 74, 01307, Dresden, Germany
| | - Thomas Kiss
- Pulmonary Engineering Group, Dept. of Anaesthesiology and Intensive Care Medicine, University Hospital Carl Gustav Carus at Technische Universität Dresden, Fetscherstrasse 74, 01307, Dresden, Germany
| | - Thomas Bluth
- Pulmonary Engineering Group, Dept. of Anaesthesiology and Intensive Care Medicine, University Hospital Carl Gustav Carus at Technische Universität Dresden, Fetscherstrasse 74, 01307, Dresden, Germany
| | - Thea Koch
- Pulmonary Engineering Group, Dept. of Anaesthesiology and Intensive Care Medicine, University Hospital Carl Gustav Carus at Technische Universität Dresden, Fetscherstrasse 74, 01307, Dresden, Germany
| | - Marcelo Gama de Abreu
- Pulmonary Engineering Group, Dept. of Anaesthesiology and Intensive Care Medicine, University Hospital Carl Gustav Carus at Technische Universität Dresden, Fetscherstrasse 74, 01307, Dresden, Germany.
| | - Robert Huhle
- Pulmonary Engineering Group, Dept. of Anaesthesiology and Intensive Care Medicine, University Hospital Carl Gustav Carus at Technische Universität Dresden, Fetscherstrasse 74, 01307, Dresden, Germany
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Mathanlal T, Israel Nazarious M, Mantas-Nakhai R, Zorzano MP, Martin-Torres J. ATMO-vent: An adapted breathing atmosphere for COVID-19 patients. HARDWAREX 2020; 8:e00145. [PMID: 33015423 PMCID: PMC7518965 DOI: 10.1016/j.ohx.2020.e00145] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 09/16/2020] [Accepted: 09/16/2020] [Indexed: 06/11/2023]
Abstract
The ongoing worldwide pandemic of coronavirus disease 2019 (COVID-19), has been one of the most significant challenges to humankind in centuries. The extremely contagious nature of the SARS-CoV-2 virus has put forth an immense pressure on the health sector. In order to mitigate the stress on the healthcare systems especially to battle the crisis of mechanical ventilators, we have designed a modular, and robust DIY ventilator, ATMO-Vent (Atmospheric Mixture Optimization Ventilator) which can be fully mounted within two days by two operators. The ATMO-Vent has been designed using low-cost, robust, Commercial Off The Shelf (COTS) components, with many features comparable to a full-fledged ventilator. ATMO-Vent has been designed based on the United Kingdom Medicines & Healthcare products Regulatory Agency (UK-MHRA) guidelines for Rapidly Manufactured Ventilator System (RMVS), yet is scalable to the specific requirements of different countries. ATMO-Vent is capable of adjusting the Fraction of Inspiratory Oxygen (FiO2) levels, Tidal Volume (TV), frequency of breaths, Inspiratory/Expiratory ratio (I/E), Peak Inspiratory Pressure (PIP) and Positive End-Expiratory Pressure (PEEP). ATMO-Vent can operate in two modes - Continuous Mandatory Ventilation (CMV) using Volume-Controlled Ventilation (VCV) and in Assisted Control (AC) mode with pressure triggered by the patient. ATMO-Vent has undergone rigorous testing and qualifies under Class B Electric and Magnetic Compatibility (EMC) requirements of EN 55,011 CISPR 11 standards.
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Affiliation(s)
- Thasshwin Mathanlal
- Group of Atmospheric Science, Department of Computer Science, Electrical and Space Engineering, Luleå, University of Technology, Luleå 97 187, Sweden
| | - Miracle Israel Nazarious
- Group of Atmospheric Science, Department of Computer Science, Electrical and Space Engineering, Luleå, University of Technology, Luleå 97 187, Sweden
| | - Roberto Mantas-Nakhai
- Group of Atmospheric Science, Department of Computer Science, Electrical and Space Engineering, Luleå, University of Technology, Luleå 97 187, Sweden
| | - Maria-Paz Zorzano
- Group of Atmospheric Science, Department of Computer Science, Electrical and Space Engineering, Luleå, University of Technology, Luleå 97 187, Sweden
- Centro de Astrobiología (CSIC-INTA), Torrejon de Ardoz, 28850 Madrid, Spain
- School of Geosciences, University of Aberdeen, Meston Building, King's College, Aberdeen AB24 3UE, UK
| | - Javier Martin-Torres
- Group of Atmospheric Science, Department of Computer Science, Electrical and Space Engineering, Luleå, University of Technology, Luleå 97 187, Sweden
- Instituto Andaluz de Ciencias de la Tierra (CSIC-UGR), 18100 Granada, Spain
- School of Geosciences, University of Aberdeen, Meston Building, King's College, Aberdeen AB24 3UE, UK
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Chi Y, He H, Long Y. A simple method of mechanical power calculation: using mean airway pressure to replace plateau pressure. J Clin Monit Comput 2020; 35:1139-1147. [PMID: 32780353 DOI: 10.1007/s10877-020-00575-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Accepted: 08/04/2020] [Indexed: 12/30/2022]
Abstract
The reference method for mechanical power (MP) calculation proposed by Gattinoni et al. is based on plateau pressure (Pplat) which needs an inspiratory hold. This study aims to introduce and validate a simple surrogate for MP calculation without any intervention in ventilated patients with or without acute respiratory distress syndrome (ARDS). The introduced equation is as:[Formula: see text]where Pmean is mean airway pressure, VE is minute ventilation, PEEP is positive end-expiratory pressure, and Te/Ti is expiratory-to-inspiratory ratio. 50 patients with ARDS and 50 post-operative patients without ARDS were enrolled. Pmean-derived MP and reference MP were obtained at the inspiratory plateau time (Tplat) of 0 and 0.5 s (s). When Tplat was adjusted from 0 to 0.5 s, higher Pmean [non-ARDS cases: 9.3 (8.8-9.9) cmH2O versus 8.2 (7.9-8.8) cmH2O, P < 0.001; ARDS cases: 14 (13-16) cmH2O versus 13 (11-14) cmH2O, P < 0.001] and shorter Te/Ti [non-ARDS cases: 1.4 (1.2-1.7) versus 2.4 (2.0-3.0), P < 0.001; ARDS cases: 1.3 (1.2-1.5) versus 2.5 (2.3-2.9), P < 0.001] were found. At both Tplat levels, the Pmean-derived MP correlated well with the reference MP both in patients with or without ARDS (non-ARDS: slopes = 1.05, 0.94, R2 = 0.95, 0.93, bias + 0.76, + 0.51; ARDS: slopes = 1.03, 0.95, R2 = 0.96, 0.96, bias + 0.97, + 0.78. P < 0.0001 for all). In patients with or without ARDS, Pmean-derived MP allows rapid and dynamic estimation of mechanical power without any intervention at the bedside.
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Affiliation(s)
- Yi Chi
- Department of Critical Care Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, 1 Shuaifuyuan, Dongcheng District, Beijing, China
| | - Huaiwu He
- Department of Critical Care Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, 1 Shuaifuyuan, Dongcheng District, Beijing, China
| | - Yun Long
- Department of Critical Care Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, 1 Shuaifuyuan, Dongcheng District, Beijing, China.
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Hurtado DE, Erranz B, Lillo F, Sarabia-Vallejos M, Iturrieta P, Morales F, Blaha K, Medina T, Diaz F, Cruces P. Progression of regional lung strain and heterogeneity in lung injury: assessing the evolution under spontaneous breathing and mechanical ventilation. Ann Intensive Care 2020; 10:107. [PMID: 32761387 PMCID: PMC7407426 DOI: 10.1186/s13613-020-00725-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Accepted: 07/30/2020] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Protective mechanical ventilation (MV) aims at limiting global lung deformation and has been associated with better clinical outcomes in acute respiratory distress syndrome (ARDS) patients. In ARDS lungs without MV support, the mechanisms and evolution of lung tissue deformation remain understudied. In this work, we quantify the progression and heterogeneity of regional strain in injured lungs under spontaneous breathing and under MV. METHODS Lung injury was induced by lung lavage in murine subjects, followed by 3 h of spontaneous breathing (SB-group) or 3 h of low Vt mechanical ventilation (MV-group). Micro-CT images were acquired in all subjects at the beginning and at the end of the ventilation stage following induction of lung injury. Regional strain, strain progression and strain heterogeneity were computed from image-based biomechanical analysis. Three-dimensional regional strain maps were constructed, from which a region-of-interest (ROI) analysis was performed for the regional strain, the strain progression, and the strain heterogeneity. RESULTS After 3 h of ventilation, regional strain levels were significantly higher in 43.7% of the ROIs in the SB-group. Significant increase in regional strain was found in 1.2% of the ROIs in the MV-group. Progression of regional strain was found in 100% of the ROIs in the SB-group, whereas the MV-group displayed strain progression in 1.2% of the ROIs. Progression in regional strain heterogeneity was found in 23.4% of the ROIs in the SB-group, while the MV-group resulted in 4.7% of the ROIs showing significant changes. Deformation progression is concurrent with an increase of non-aerated compartment in SB-group (from 13.3% ± 1.6% to 37.5% ± 3.1%), being higher in ventral regions of the lung. CONCLUSIONS Spontaneous breathing in lung injury promotes regional strain and strain heterogeneity progression. In contrast, low Vt MV prevents regional strain and heterogeneity progression in injured lungs.
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Affiliation(s)
- Daniel E Hurtado
- Department of Structural and Geotechnical Engineering, School of Engineering Pontificia, Universidad Católica de Chile, Santiago, Chile.,Institute for Biological and Medical Engineering, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile.,Millennium Nucleus for Cardiovascular Magnetic Resonance, Santiago, Chile
| | - Benjamín Erranz
- Centro de Medicina Regenerativa, Facultad de Medicina Clínica Alemana, Universidad del Desarrollo, Santiago, Chile
| | - Felipe Lillo
- Centro de Investigación de Medicina Veterinaria, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, Chile
| | - Mauricio Sarabia-Vallejos
- Department of Structural and Geotechnical Engineering, School of Engineering Pontificia, Universidad Católica de Chile, Santiago, Chile
| | - Pablo Iturrieta
- Department of Structural and Geotechnical Engineering, School of Engineering Pontificia, Universidad Católica de Chile, Santiago, Chile
| | - Felipe Morales
- Centro de Investigación de Medicina Veterinaria, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, Chile
| | - Katherine Blaha
- Pediatric Critical Care Unit, Clínica Alemana de Santiago, Santiago, Chile
| | - Tania Medina
- Pediatric Intensive Care Unit, Hospital El Carmen de Maipú, Santiago, Chile
| | - Franco Diaz
- Centro de Medicina Regenerativa, Facultad de Medicina Clínica Alemana, Universidad del Desarrollo, Santiago, Chile.,Pediatric Critical Care Unit, Clínica Alemana de Santiago, Santiago, Chile
| | - Pablo Cruces
- Centro de Investigación de Medicina Veterinaria, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, Chile. .,Pediatric Intensive Care Unit, Hospital El Carmen de Maipú, Santiago, Chile.
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Abstract
OBJECTIVES To examine the potentially modifiable drivers that injure and heal the "baby lung" of acute respiratory distress syndrome and describe a rational clinical approach to favor benefit. DATA SOURCES Published experimental studies and clinical papers that address varied aspects of ventilator-induced lung injury pathogenesis and its consequences. STUDY SELECTION Published information relevant to the novel hypothesis of progressive lung vulnerability and to the biophysical responses of lung injury and repair. DATA EXTRACTION None. DATA SYNTHESIS In acute respiratory distress syndrome, the reduced size and capacity for gas exchange of the functioning "baby lung" imply loss of ventilatory capability that dwindles in proportion to severity of lung injury. Concentrating the entire ventilation workload and increasing perfusion to these already overtaxed units accentuates their potential for progressive injury. Unlike static airspace pressures, which, in theory, apply universally to aerated structures of all dimensions, the components of tidal inflation that relate to power (which include frequency and flow) progressively intensify their tissue-stressing effects on parenchyma and microvasculature as the ventilated compartment shrinks further, especially during the first phase of the evolving injury. This "ventilator-induced lung injury vortex" of the shrinking baby lung is opposed by reactive, adaptive, and reparative processes. In this context, relatively little attention has been paid to the evolving interactions between lung injury and response and to the timing of interventions that worsen, limit or reverse a potentially accelerating ventilator-induced lung injury process. Although universal and modifiable drivers hold the potential to progressively injure the functional lung units of acute respiratory distress syndrome in a positive feedback cycle, measures can be taken to interrupt that process and encourage growth and healing of the "baby lung" of severe acute respiratory distress syndrome.
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Affiliation(s)
- John J Marini
- University of Minnesota and Regions Hospital, Minneapolis/St. Paul, MN
| | - Luciano Gattinoni
- Department of Anesthesiology, Intensive Care and Emergency Medicine, Medical University of Göttingen, Göttingen, Germany
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Abstract
This review focuses on the use of veno-venous extracorporeal membrane oxygenation for respiratory failure across all blood flow ranges. Starting with a short overview of historical development, aspects of the physiology of gas exchange (i.e., oxygenation and decarboxylation) during extracorporeal circulation are discussed. The mechanisms of phenomena such as recirculation and shunt playing an important role in daily clinical practice are explained.Treatment of refractory and symptomatic hypoxemic respiratory failure (e.g., acute respiratory distress syndrome [ARDS]) currently represents the main indication for high-flow veno-venous-extracorporeal membrane oxygenation. On the other hand, lower-flow extracorporeal carbon dioxide removal might potentially help to avoid or attenuate ventilator-induced lung injury by allowing reduction of the energy load (i.e., driving pressure, mechanical power) transmitted to the lungs during mechanical ventilation or spontaneous ventilation. In the latter context, extracorporeal carbon dioxide removal plays an emerging role in the treatment of chronic obstructive pulmonary disease patients during acute exacerbations. Both applications of extracorporeal lung support raise important ethical considerations, such as likelihood of ultimate futility and end-of-life decision-making. The review concludes with a brief overview of potential technical developments and persistent challenges.
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Does Iso-mechanical Power Lead to Iso-lung Damage?: An Experimental Study in a Porcine Model. Anesthesiology 2020; 132:1126-1137. [PMID: 32032095 DOI: 10.1097/aln.0000000000003189] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Excessive tidal volume, respiratory rate, and positive end-expiratory pressure (PEEP) are all potential causes of ventilator-induced lung injury, and all contribute to a single variable: the mechanical power. The authors aimed to determine whether high tidal volume or high respiratory rate or high PEEP at iso-mechanical power produce similar or different ventilator-induced lung injury. METHODS Three ventilatory strategies-high tidal volume (twice baseline functional residual capacity), high respiratory rate (40 bpm), and high PEEP (25 cm H2O)-were each applied at two levels of mechanical power (15 and 30 J/min) for 48 h in six groups of seven healthy female piglets (weight: 24.2 ± 2.0 kg, mean ± SD). RESULTS At iso-mechanical power, the high tidal volume groups immediately and sharply increased plateau, driving pressure, stress, and strain, which all further deteriorated with time. In high respiratory rate groups, they changed minimally at the beginning, but steadily increased during the 48 h. In contrast, after a sudden huge increase, they decreased with time in the high PEEP groups. End-experiment specific lung elastance was 6.5 ± 1.7 cm H2O in high tidal volume groups, 10.1 ± 3.9 cm H2O in high respiratory rate groups, and 4.5 ± 0.9 cm H2O in high PEEP groups. Functional residual capacity decreased and extravascular lung water increased similarly in these three categories. Lung weight, wet-to-dry ratio, and histologic scores were similar, regardless of ventilatory strategies and power levels. However, the alveolar edema score was higher in the low power groups. High PEEP had the greatest impact on hemodynamics, leading to increased need for fluids. Adverse events (early mortality and pneumothorax) also occurred more frequently in the high PEEP groups. CONCLUSIONS Different ventilatory strategies, delivered at iso-power, led to similar anatomical lung injury. The different systemic consequences of high PEEP underline that ventilator-induced lung injury must be evaluated in the context of the whole body.
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Chiumello D, Gotti M, Guanziroli M, Formenti P, Umbrello M, Pasticci I, Mistraletti G, Busana M. Bedside calculation of mechanical power during volume- and pressure-controlled mechanical ventilation. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2020; 24:417. [PMID: 32653011 PMCID: PMC7351639 DOI: 10.1186/s13054-020-03116-w] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Accepted: 06/29/2020] [Indexed: 12/15/2022]
Abstract
Background Mechanical power (MP) is the energy delivered to the respiratory system over time during mechanical ventilation. Our aim was to compare the currently available methods to calculate MP during volume- and pressure-controlled ventilation, comparing different equations with the geometric reference method, to understand whether the easier to use surrogate formulas were suitable for the everyday clinical practice. This would warrant a more widespread use of mechanical power to promote lung protection. Methods Forty respiratory failure patients, sedated and paralyzed for clinical reasons, were ventilated in volume-controlled ventilation, at two inspiratory flows (30 and 60 L/min), and pressure-controlled ventilation with a similar tidal volume. Mechanical power was computed both with the geometric method, as the area between the inspiratory limb of the airway pressure and the volume, and with two algebraic methods, a comprehensive and a surrogate formula. Results The bias between the MP computed by the geometric method and by the comprehensive algebraic method during volume-controlled ventilation was respectively 0.053 (0.77, − 0.81) J/min and − 0.4 (0.70, − 1.50) J/min at low and high flows (r2 = 0.96 and 0.97, p < 0.01). The MP measured and computed by the two methods were highly correlated (r2 = 0.95 and 0.94, p < 0.01) with a bias of − 0.0074 (0.91, − 0.93) and − 1.0 (0.45, − 2.52) J/min at high-low flows. During pressure-controlled ventilation, the bias between the MP measured and the one calculated with the comprehensive and simplified methods was correlated (r2 = 0.81, 0.94, p < 0.01) with mean differences of − 0.001 (2.05, − 2.05) and − 0.81 (2.11, − 0.48) J/min. Conclusions Both for volume-controlled and pressure-controlled ventilation, the surrogate formulas approximate the reference method well enough to warrant their use in the everyday clinical practice. Given that these formulas require nothing more than the variables already displayed by the intensive care ventilator, a more widespread use of mechanical power should be encouraged to promote lung protection against ventilator-induced lung injury.
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Affiliation(s)
- Davide Chiumello
- SC Anestesia e Rianimazione, Ospedale San Paolo - Polo Universitario, ASST Santi Paolo e Carlo, Via Di Rudinì, 8, 20142, Milan, Italy. .,Dipartimento di Scienze della Salute, Università degli Studi di Milano, Milan, Italy. .,Centro Ricerca Coordinata di Insufficienza Respiratoria, Milan, Italy.
| | - Miriam Gotti
- SC Anestesia e Rianimazione, Ospedale San Paolo - Polo Universitario, ASST Santi Paolo e Carlo, Via Di Rudinì, 8, 20142, Milan, Italy
| | - Mariateresa Guanziroli
- SC Anestesia e Rianimazione, Ospedale San Paolo - Polo Universitario, ASST Santi Paolo e Carlo, Via Di Rudinì, 8, 20142, Milan, Italy.,Dipartimento di Scienze della Salute, Università degli Studi di Milano, Milan, Italy
| | - Paolo Formenti
- SC Anestesia e Rianimazione, Ospedale San Paolo - Polo Universitario, ASST Santi Paolo e Carlo, Via Di Rudinì, 8, 20142, Milan, Italy
| | - Michele Umbrello
- SC Anestesia e Rianimazione, Ospedale San Paolo - Polo Universitario, ASST Santi Paolo e Carlo, Via Di Rudinì, 8, 20142, Milan, Italy
| | - Iacopo Pasticci
- SC Anestesia e Rianimazione, Ospedale San Paolo - Polo Universitario, ASST Santi Paolo e Carlo, Via Di Rudinì, 8, 20142, Milan, Italy.,Dipartimento di Scienze della Salute, Università degli Studi di Milano, Milan, Italy
| | - Giovanni Mistraletti
- SC Anestesia e Rianimazione, Ospedale San Paolo - Polo Universitario, ASST Santi Paolo e Carlo, Via Di Rudinì, 8, 20142, Milan, Italy.,Dipartimento di Fisiopatologia Medica Chirurgica e dei Trapianti, Università degli Studi di Milano, Milan, Italy
| | - Mattia Busana
- Department of Anesthesiology, Emergency and Intensive Care Medicine, University of Göttingen, Göttingen, Germany
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High-Frequency Oscillatory Ventilation and Ventilator-Induced Lung Injury: Size Does Matter. Crit Care Med 2020; 48:e66-e73. [PMID: 31634232 DOI: 10.1097/ccm.0000000000004073] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES The theoretical basis for minimizing tidal volume during high-frequency oscillatory ventilation may not be appropriate when lung tissue stretch occurs heterogeneously and/or rapidly. The objective of this study was to assess the extent to which increased ventilation heterogeneity may contribute to ventilator-induced lung injury during high-frequency oscillatory ventilation in adults compared with neonates on the basis of lung size, using a computational model of human lungs. DESIGN Computational modeling study. SETTING Research laboratory. SUBJECTS High-fidelity, 3D computational models of human lungs, scaled to various sizes representative of neonates, children, and adults, with varying injury severity. All models were generated from one thoracic CT image of a healthy adult male. INTERVENTIONS Oscillatory ventilation was simulated in each lung model at frequencies ranging from 0.2 to 40 Hz. Sinusoidal flow oscillations were delivered at the airway opening of each model and distributed through the lungs according to regional parenchymal mechanics. MEASUREMENTS AND MAIN RESULTS Acinar flow heterogeneity was assessed by the coefficient of variation in flow magnitudes across all acini in each model. High-frequency oscillatory ventilation simulations demonstrated increasing heterogeneity of regional parenchymal flow with increasing lung size, with decreasing ratio of deadspace to total acinar volume, and with increasing frequency above lung corner frequency and resonant frequency. Potential for resonant amplification was greatest in injured adult-sized lungs with higher regional quality factors indicating the presence of underdamped lung regions. CONCLUSIONS The potential for ventilator-induced lung injury during high-frequency oscillatory ventilation is enhanced at frequencies above lung corner frequency or resonant frequency despite reduced tidal volumes, especially in adults, due to regional amplification of heterogeneous flow. Measurements of corner frequency and resonant frequency should be considered during high-frequency oscillatory ventilation management.
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Marini JJ, Rocco PRM, Gattinoni L. Static and Dynamic Contributors to Ventilator-induced Lung Injury in Clinical Practice. Pressure, Energy, and Power. Am J Respir Crit Care Med 2020; 201:767-774. [PMID: 31665612 PMCID: PMC7124710 DOI: 10.1164/rccm.201908-1545ci] [Citation(s) in RCA: 120] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Ventilation is inherently a dynamic process. The present-day clinical practice of concentrating on the static inflation characteristics of the individual tidal cycle (plateau pressure, positive end-expiratory pressure, and their difference [driving pressure, the ratio of Vt to compliance]) does not take into account key factors shown experimentally to influence ventilator-induced lung injury (VILI). These include rate of airway pressure change (influenced by flow amplitude, inspiratory time fraction, and inspiratory inflation contour) and cycling frequency. Energy must be expended to cause injury, and the product of applied stress and resulting strain determines the energy delivered to the lungs per breathing cycle. Understanding the principles of VILI energetics may provide valuable insights and guidance to intensivists for safer clinical practice. In this interpretive review, we highlight that the injuring potential of the inflation pattern depends upon tissue vulnerability, the number of intolerable high-energy cycles applied in unit time (mechanical power), and the duration of that exposure. Yet, as attractive as this energy/power hypothesis for encapsulating the drivers of VILI may be for clinical applications, we acknowledge that even these all-inclusive and measurable ergonomic parameters (energy per cycle and power) are still too bluntly defined to pinpoint the precise biophysical link between ventilation strategy and tissue injury.
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Affiliation(s)
- John J Marini
- University of Minnesota and Regions Hospital, Minneapolis/St. Paul, Minnesota
| | - Patricia R M Rocco
- Laboratory of Pulmonary Investigation, Carlos Chagas Filho Biophysics Institute, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil; and
| | - Luciano Gattinoni
- Department of Anaesthesiology, Emergency and Intensive Care Medicine, University of Göttingen, Göttingen, Germany
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Abstract
BACKGROUND This study hypothesized that, in experimental mild acute respiratory distress syndrome, lung damage caused by high tidal volume (VT) could be attenuated if VT increased slowly enough to progressively reduce mechanical heterogeneity and to allow the epithelial and endothelial cells, as well as the extracellular matrix of the lung to adapt. For this purpose, different strategies of approaching maximal VT were tested. METHODS Sixty-four Wistar rats received Escherichia coli lipopolysaccharide intratracheally. After 24 h, animals were randomly assigned to receive mechanical ventilation with VT = 6 ml/kg for 2 h (control); VT = 6 ml/kg during hour 1 followed by an abrupt increase to VT = 22 ml/kg during hour 2 (no adaptation time); VT = 6 ml/kg during the first 30 min followed by a gradual VT increase up to 22 ml/kg for 30 min, then constant VT = 22 ml/kg during hour 2 (shorter adaptation time); and a more gradual VT increase, from 6 to 22 ml/kg during hour 1 followed by VT = 22 ml/kg during hour 2 (longer adaptation time). All animals were ventilated with positive end-expiratory pressure of 3 cm H2O. Nonventilated animals were used for molecular biology analysis. RESULTS At 2 h, diffuse alveolar damage score and heterogeneity index were greater in the longer adaptation time group than in the control and shorter adaptation time animals. Gene expression of interleukin-6 favored the shorter (median [interquartile range], 12.4 [9.1-17.8]) adaptation time compared with longer (76.7 [20.8 to 95.4]; P = 0.02) and no adaptation (65.5 [18.1 to 129.4]) time (P = 0.02) strategies. Amphiregulin, metalloproteinase-9, club cell secretory protein-16, and syndecan showed similar behavior. CONCLUSIONS In experimental mild acute respiratory distress syndrome, lung damage in the shorter adaptation time group compared with the no adaptation time group was attenuated in a time-dependent fashion by preemptive adaptation of the alveolar epithelial cells and extracellular matrix. Extending the adaptation period increased cumulative power and did not prevent lung damage, because it may have exposed animals to injurious strain earlier and for a longer time, thereby negating any adaptive benefit.
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Herrmann J, Gerard SE, Shao W, Hawley ML, Reinhardt JM, Christensen GE, Hoffman EA, Kaczka DW. Quantifying Regional Lung Deformation Using Four-Dimensional Computed Tomography: A Comparison of Conventional and Oscillatory Ventilation. Front Physiol 2020; 11:14. [PMID: 32153417 PMCID: PMC7044245 DOI: 10.3389/fphys.2020.00014] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 01/13/2020] [Indexed: 01/14/2023] Open
Abstract
Mechanical ventilation strategies that reduce the heterogeneity of regional lung stress and strain may reduce the risk of ventilator-induced lung injury (VILI). In this study, we used registration of four-dimensional computed tomographic (4DCT) images to assess regional lung aeration and deformation in 10 pigs under baseline conditions and following acute lung injury induced with oleic acid. CT images were obtained via dynamic axial imaging (Siemens SOMATOM Force) during conventional pressure-controlled mechanical ventilation (CMV), as well as high-frequency and multi-frequency oscillatory ventilation modalities (HFOV and MFOV, respectively). Our results demonstrate that oscillatory modalities reduce intratidal strain throughout the lung in comparison to conventional ventilation, as well as the spatial gradients of dynamic strain along the dorsal-ventral axis. Harmonic distortion of parenchymal deformation was observed during HFOV with a single discrete sinusoid delivered at the airway opening, suggesting inherent mechanical nonlinearity of the lung tissues. MFOV may therefore provide improved lung-protective ventilation by reducing strain magnitudes and spatial gradients of strain compared to either CMV or HFOV.
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Affiliation(s)
- Jacob Herrmann
- Roy J. Carver Department of Biomedical Engineering, University of Iowa, Iowa City, IA, United States.,Department of Anesthesia, University of Iowa, Iowa City, IA, United States.,OscillaVent, Inc., Iowa City, IA, United States
| | - Sarah E Gerard
- Roy J. Carver Department of Biomedical Engineering, University of Iowa, Iowa City, IA, United States
| | - Wei Shao
- Department of Electrical and Computer Engineering, University of Iowa, Iowa City, IA, United States
| | | | - Joseph M Reinhardt
- Roy J. Carver Department of Biomedical Engineering, University of Iowa, Iowa City, IA, United States.,Department of Radiology, University of Iowa, Iowa City, IA, United States
| | - Gary E Christensen
- Department of Electrical and Computer Engineering, University of Iowa, Iowa City, IA, United States.,Department of Radiation Oncology, University of Iowa, Iowa City, IA, United States
| | - Eric A Hoffman
- Roy J. Carver Department of Biomedical Engineering, University of Iowa, Iowa City, IA, United States.,Department of Radiology, University of Iowa, Iowa City, IA, United States.,Department of Internal Medicine, University of Iowa, Iowa City, IA, United States
| | - David W Kaczka
- Roy J. Carver Department of Biomedical Engineering, University of Iowa, Iowa City, IA, United States.,Department of Anesthesia, University of Iowa, Iowa City, IA, United States.,OscillaVent, Inc., Iowa City, IA, United States.,Department of Radiology, University of Iowa, Iowa City, IA, United States
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Which component of mechanical power is most important in causing VILI? CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2020; 24:39. [PMID: 32024538 PMCID: PMC7003372 DOI: 10.1186/s13054-020-2747-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 01/20/2020] [Indexed: 12/11/2022]
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Chiumello D, Froio S, Mistraletti G, Formenti P, Bolgiaghi L, Cammaroto A, Umbrello M, Coppola S. Gas exchange, specific lung elastance and mechanical power in the early and persistent ARDS. J Crit Care 2020; 55:42-47. [DOI: 10.1016/j.jcrc.2019.09.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 09/16/2019] [Accepted: 09/23/2019] [Indexed: 02/01/2023]
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Bersten AD, Krupa M, Griggs K, Dixon DL. Reduced Surfactant Contributes to Increased Lung Stiffness Induced by Rapid Inspiratory Flow. Lung 2020; 198:43-52. [PMID: 31915922 DOI: 10.1007/s00408-019-00317-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Accepted: 12/24/2019] [Indexed: 10/25/2022]
Abstract
INTRODUCTION The mechanism of fast inspiratory flow rate (VI') induced lung injury is unclear. As fast VI' increases hysteresis, a measure of surface tension at the air-liquid interface, surfactant release or function may be important. This experimental study examines the contribution of impaired surfactant release or function to dynamic-VILI. METHODS Isolated perfused lungs from male Sprague Dawley rats were randomly allocated to four groups: a long or short inspiratory time (Ti = 0.5 s; slow VI' or Ti = 0.1 s; fast VI') at PEEP of 2 or 10 cmH2O. Tidal volume was constant (7 ml/kg), with f = 60 breath/min. Forced impedance mechanics (tissue elastance (Htis), tissue resistance (Gtis) and airway resistance (Raw) were measured at 30, 60 and 90 min following which the lung was lavaged for surfactant phospholipids (PL) and disaturated PL (DSP). RESULTS Fast VI' resulted in a stiffer lung. Concurrently, PL and DSP were decreased in both tubular myelin rich and poor fractions. Phospholipid decreases were similar with PEEP. In a subsequent cohort, laser confocal microscopy-based assessment demonstrated increased cellular injury with increased VI' at both 30 and 90 min ventilation. CONCLUSION Rapid VI' may contribute to ventilator induced lung injury (VILI) through reduced surfactant release and/or more rapid reuptake despite unchanged tidal stretch.
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Affiliation(s)
- Andrew D Bersten
- Intensive and Critical Care Unit, Flinders Medical Centre, Adelaide, SA, Australia.,Department of Critical Care Medicine, College of Medicine and Public Health, Flinders University, Adelaide, SA, 5001, Australia
| | - Malgorzata Krupa
- Department of Critical Care Medicine, College of Medicine and Public Health, Flinders University, Adelaide, SA, 5001, Australia
| | - Kim Griggs
- Department of Critical Care Medicine, College of Medicine and Public Health, Flinders University, Adelaide, SA, 5001, Australia
| | - Dani-Louise Dixon
- Intensive and Critical Care Unit, Flinders Medical Centre, Adelaide, SA, Australia. .,Department of Critical Care Medicine, College of Medicine and Public Health, Flinders University, Adelaide, SA, 5001, Australia.
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Risk factors for the development of acute respiratory distress syndrome in mechanically ventilated adults in Peru: a multicenter observational study. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2019; 23:398. [PMID: 31810487 PMCID: PMC6898929 DOI: 10.1186/s13054-019-2646-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Accepted: 10/09/2019] [Indexed: 12/29/2022]
Abstract
Background Clinical and epidemiological differences between acute respiratory distress syndrome (ARDS) that presents at the initiation of mechanical ventilation [MV] (ARDS at MV onset) and that which develops during the course of MV (ARDS after MV onset) are not well understood. We conducted an observational study in five Peruvian ICUs to characterize differences between ARDS at MV onset and after MV onset and identify risk factors for the development of ARDS after MV onset. Methods We consecutively enrolled critically ill patients with acute respiratory failure requiring at least 24 h of mechanical ventilation and followed them prospectively during the first 28 days and compared baseline characteristics and clinical outcomes by ARDS status. Results We enrolled 1657 participants on MV (mean age 60.0 years, 55% males) of whom 334 (20.2%) had ARDS at MV onset and 180 (10.9%) developed ARDS after MV onset. Average tidal volume at the initiation of MV was 8.7 mL/kg of predicted body weight (PBW) for participants with ARDS at MV onset, 8.6 mL/kg PBW for those who developed ARDS after MV onset, and 8.5 mL/kg PBW for those who never developed ARDS (p = 0.23). Overall, 90-day mortality was 56% and 55% for ARDS after MV onset and ARDS at MV onset, respectively, as compared to 46% among those who never developed ARDS (p < 0.01). Adults with ARDS had a higher body mass index (BMI) than those without ARDS (27.3 vs 26.5 kg/m2, p < 0.01). Higher peak pressure (adjusted interquartile OR = 1.51, 95% CI 1.21–1.88), higher mean airway pressure (adjusted interquartile OR = 1.41, 95% CI 1.13–1.76), and higher positive end-expiratory pressure (adjusted interquartile OR = 1.29, 95% CI 1.10–1.50) at MV onset were associated with a higher odds of developing ARDS after MV onset. Conclusions In this study of mechanically ventilated patients, 31% of study participants had ARDS at some point during their ICU stay. Optimal lung-protective ventilation was not used in a majority of patients. Patients with ARDS after MV onset had a similar 90-day mortality as those with ARDS at MV onset. Higher airway pressures at MV onset, higher PEEP, and higher BMI were associated with the development of ARDS after MV onset.
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Giosa L, Busana M, Pasticci I, Bonifazi M, Macrì MM, Romitti F, Vassalli F, Chiumello D, Quintel M, Marini JJ, Gattinoni L. Mechanical power at a glance: a simple surrogate for volume-controlled ventilation. Intensive Care Med Exp 2019; 7:61. [PMID: 31773328 PMCID: PMC6879677 DOI: 10.1186/s40635-019-0276-8] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 10/16/2019] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Mechanical power is a summary variable including all the components which can possibly cause VILI (pressures, volume, flow, respiratory rate). Since the complexity of its mathematical computation is one of the major factors that delay its clinical use, we propose here a simple and easy to remember equation to estimate mechanical power under volume-controlled ventilation: [Formula: see text] where the mechanical power is expressed in Joules/minute, the minute ventilation (VE) in liters/minute, the inspiratory flow (F) in liters/minute, and peak pressure and positive end-expiratory pressure (PEEP) in centimeter of water. All the components of this equation are continuously displayed by any ventilator under volume-controlled ventilation without the need for clinician intervention. To test the accuracy of this new equation, we compared it with the reference formula of mechanical power that we proposed for volume-controlled ventilation in the past. The comparisons were made in a cohort of mechanically ventilated pigs (485 observations) and in a cohort of ICU patients (265 observations). RESULTS Both in pigs and in ICU patients, the correlation between our equation and the reference one was close to the identity. Indeed, the R2 ranged from 0.97 to 0.99 and the Bland-Altman showed small biases (ranging from + 0.35 to - 0.53 J/min) and proportional errors (ranging from + 0.02 to - 0.05). CONCLUSIONS Our new equation of mechanical power for volume-controlled ventilation represents a simple and accurate alternative to the more complex ones available to date. This equation does not need any clinical intervention on the ventilator (such as an inspiratory hold) and could be easily implemented in the software of any ventilator in volume-controlled mode. This would allow the clinician to have an estimation of mechanical power at a simple glance and thus increase the clinical consciousness of this variable which is still far from being used at the bedside. Our equation carries the same limitations of all other formulas of mechanical power, the most important of which, as far as it concerns VILI prevention, are the lack of normalization and its application to the whole respiratory system (including the chest wall) and not only to the lung parenchyma.
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Affiliation(s)
- Lorenzo Giosa
- Departement of Anesthesiology, Emergency and Intensive Care Medicine, University of Göttingen, Göttingen, Germany
| | - Mattia Busana
- Departement of Anesthesiology, Emergency and Intensive Care Medicine, University of Göttingen, Göttingen, Germany
| | - Iacopo Pasticci
- Departement of Anesthesiology, Emergency and Intensive Care Medicine, University of Göttingen, Göttingen, Germany
| | - Matteo Bonifazi
- Departement of Anesthesiology, Emergency and Intensive Care Medicine, University of Göttingen, Göttingen, Germany
| | - Matteo Maria Macrì
- Departement of Anesthesiology, Emergency and Intensive Care Medicine, University of Göttingen, Göttingen, Germany
| | - Federica Romitti
- Departement of Anesthesiology, Emergency and Intensive Care Medicine, University of Göttingen, Göttingen, Germany
| | - Francesco Vassalli
- Departement of Anesthesiology, Emergency and Intensive Care Medicine, University of Göttingen, Göttingen, Germany
| | - Davide Chiumello
- SC Anestesia e Rianimazione, Ospedale San Paolo - Polo Universitario, ASST Santi Paolo e Carlo, Milan, Italy
- Dipartimento di Scienze Biomediche per la Salute, Centro Ricerca Coordinato di Insufficienza Respiratoria, Università degli Studi di Milano, Milan, Italy
| | - Michael Quintel
- Departement of Anesthesiology, Emergency and Intensive Care Medicine, University of Göttingen, Göttingen, Germany
| | - J J Marini
- University of Minnesota and Regions Hospital, Minneapolis/St. Paul, MN, USA
| | - Luciano Gattinoni
- Departement of Anesthesiology, Emergency and Intensive Care Medicine, University of Göttingen, Göttingen, Germany.
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Effects of inspiratory flow on lung stress, pendelluft, and ventilation heterogeneity in ARDS: a physiological study. Crit Care 2019; 23:369. [PMID: 31752952 PMCID: PMC6873770 DOI: 10.1186/s13054-019-2641-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Accepted: 10/09/2019] [Indexed: 11/10/2022] Open
Abstract
Background High inspiratory flow might damage the lungs by mechanisms not fully understood yet. We hypothesized that increasing inspiratory flow would increase lung stress, ventilation heterogeneity, and pendelluft in ARDS patients undergoing volume-controlled ventilation with constant tidal volume and that higher PEEP levels would reduce this phenomenon. Methods Ten ARDS patients were studied during protective volume-controlled ventilation. Three inspiratory flows (400, 800, and 1200 ml/s) and two PEEP levels (5 and 15 cmH2O) were applied in random order to each patient. Airway and esophageal pressures were recorded, end-inspiratory and end-expiratory holds were performed, and ventilation distribution was measured with electrical impedance tomography. Peak and plateau airway and transpulmonary pressures were recorded, together with the airway and transpulmonary pressure corresponding to the first point of zero end-inspiratory flow (P1). Ventilation heterogeneity was measured by the EIT-based global inhomogeneity (GI) index. Pendelluft was measured as the absolute difference between pixel-level inflation measured at plateau pressure minus P1. Results Plateau airway and transpulmonary pressure was not affected by inspiratory flow, while P1 increased at increasing inspiratory flow. The difference between P1 and plateau pressure was higher at higher flows at both PEEP levels (p < 0.001). While higher PEEP reduced heterogeneity of ventilation, higher inspiratory flow increased GI (p = 0.05), irrespective of the PEEP level. Finally, gas volume undergoing pendelluft was larger at higher inspiratory flow (p < 0.001), while PEEP had no effect. Conclusions The present exploratory analysis suggests that higher inspiratory flow increases additional inspiratory pressure, heterogeneity of ventilation, and pendelluft while PEEP has negligible effects on these flow-dependent phenomena. The clinical significance of these findings needs to be further clarified.
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Abstract
BACKGROUND Positive end-expiratory pressure is usually considered protective against ventilation-induced lung injury by reducing atelectrauma and improving lung homogeneity. However, positive end-expiratory pressure, together with tidal volume, gas flow, and respiratory rate, contributes to the mechanical power required to ventilate the lung. This study aimed at investigating the effects of increasing mechanical power by selectively modifying its positive end-expiratory pressure component. METHODS Thirty-six healthy piglets (23.3 ± 2.3 kg) were ventilated prone for 50 h at 30 breaths/min and with a tidal volume equal to functional residual capacity. Positive end-expiratory pressure levels (0, 4, 7, 11, 14, and 18 cm H2O) were applied to six groups of six animals. Respiratory, gas exchange, and hemodynamic variables were recorded every 6 h. Lung weight and wet-to-dry ratio were measured, and histologic samples were collected. RESULTS Lung mechanical power was similar at 0 (8.8 ± 3.8 J/min), 4 (8.9 ± 4.4 J/min), and 7 (9.6 ± 4.3 J/min) cm H2O positive end-expiratory pressure, and it linearly increased thereafter from 15.5 ± 3.6 J/min (positive end-expiratory pressure, 11 cm H2O) to 18.7 ± 6 J/min (positive end-expiratory pressure, 14 cm H2O) and 22 ± 6.1 J/min (positive end-expiratory pressure, 18 cm H2O). Lung elastances, vascular congestion, atelectasis, inflammation, and septal rupture decreased from zero end-expiratory pressure to 4 to 7 cm H2O (P < 0.0001) and increased progressively at higher positive end-expiratory pressure. At these higher positive end-expiratory pressure levels, striking hemodynamic impairment and death manifested (mortality 0% at positive end-expiratory pressure 0 to 11 cm H2O, 33% at 14 cm H2O, and 50% at 18 cm H2O positive end-expiratory pressure). From zero end-expiratory pressure to 18 cm H2O, mean pulmonary arterial pressure (from 19.7 ± 5.3 to 32.2 ± 9.2 mmHg), fluid administration (from 537 ± 403 to 2043 ± 930 ml), and noradrenaline infusion (0.04 ± 0.09 to 0.34 ± 0.31 μg · kg(-1) · min(-1)) progressively increased (P < 0.0001). Lung weight and lung wet-to-dry ratios were not significantly different across the groups. The lung mechanical power level that best discriminated between more versus less severe damage was 13 ± 1 J/min. CONCLUSIONS Less than 7 cm H2O positive end-expiratory pressure reduced atelectrauma encountered at zero end-expiratory pressure. Above a defined power threshold, sustained positive end-expiratory pressure contributed to potentially lethal lung damage and hemodynamic impairment.
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Affiliation(s)
- John J Marini
- Division of Pulmonary and Critical Care Medicine, Regions Hospital, University of Minnesota, MS11203B, 640 Jackson St., Minneapolis/ St. Paul, MN, USA.
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