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Hysteresis and Lung Recruitment in Acute Respiratory Distress Syndrome Patients: A CT Scan Study. Crit Care Med 2021; 48:1494-1502. [PMID: 32897667 DOI: 10.1097/ccm.0000000000004518] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
OBJECTIVES Hysteresis of the respiratory system pressure-volume curve is related to alveolar surface forces, lung stress relaxation, and tidal reexpansion/collapse. Hysteresis has been suggested as a means of assessing lung recruitment. The objective of this study was to determine the relationship between hysteresis, mechanical characteristics of the respiratory system, and lung recruitment assessed by a CT scan in mechanically ventilated acute respiratory distress syndrome patients. DESIGN Prospective observational study. SETTING General ICU of a university hospital. PATIENTS Twenty-five consecutive sedated and paralyzed patients with acute respiratory distress syndrome (age 64 ± 15 yr, body mass index 26 ± 6 kg/m, PaO2/FIO2 147 ± 42, and positive end-expiratory pressure 9.3 ± 1.4 cm H2O) were enrolled. INTERVENTIONS A low-flow inflation and deflation pressure-volume curve (5-45 cm H2O) and a sustained inflation recruitment maneuver (45 cm H2O for 30 s) were performed. A lung CT scan was performed during breath-holding pressure at 5 cm H2O and during the recruitment maneuver at 45 cm H2O. MEASUREMENTS AND MAIN RESULTS Lung recruitment was computed as the difference in noninflated tissue and in gas volume measured at 5 and at 45 cm H2O. Hysteresis was calculated as the ratio of the area enclosed by the pressure-volume curve and expressed as the hysteresis ratio. Hysteresis was correlated with respiratory system compliance computed at 5 cm H2O and the lung gas volume entering the lung during inflation of the pressure-volume curve (R = 0.749, p < 0.001 and R = 0.851, p < 0.001). The hysteresis ratio was related to both lung tissue and gas recruitment (R = 0.266, p = 0.008, R = 0.357, p = 0.002, respectively). Receiver operating characteristic analysis showed that the optimal cutoff value to predict lung tissue recruitment for the hysteresis ratio was 28% (area under the receiver operating characteristic curve, 0.80; 95% CI, 0.62-0.98), with sensitivity and specificity of 0.75 and 0.77, respectively. CONCLUSIONS Hysteresis of the respiratory system computed by low-flow pressure-volume curve is related to the anatomical lung characteristics and has an acceptable accuracy to predict lung recruitment.
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Fernandez-Bustamante A, Sprung J, Parker RA, Bartels K, Weingarten TN, Kosour C, Thompson BT, Vidal Melo MF. Individualized PEEP to optimise respiratory mechanics during abdominal surgery: a pilot randomised controlled trial. Br J Anaesth 2020; 125:383-392. [PMID: 32682559 DOI: 10.1016/j.bja.2020.06.030] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 05/24/2020] [Accepted: 06/10/2020] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Higher intraoperative driving pressures (ΔP) are associated with increased postoperative pulmonary complications (PPC). We hypothesised that dynamic adjustment of PEEP throughout abdominal surgery reduces ΔP, maintains positive end-expiratory transpulmonary pressures (Ptp_ee) and increases respiratory system static compliance (Crs) with PEEP levels that are variable between and within patients. METHODS In a prospective multicentre pilot study, adults at moderate/high risk for PPC undergoing elective abdominal surgery were randomised to one of three ventilation protocols: (1) PEEP≤2 cm H2O, compared with periodic recruitment manoeuvres followed by individualised PEEP to either optimise respiratory system compliance (PEEPmaxCrs) or maintain positive end-expiratory transpulmonary pressure (PEEPPtp_ee). The composite primary outcome included intraoperative ΔP, Ptp_ee, Crs, and PEEP values (median (interquartile range) and coefficients of variation [CVPEEP]). RESULTS Thirty-seven patients (48.6% female; age range: 47-73 yr) were assigned to control (PEEP≤2 cm H2O; n=13), PEEPmaxCrs (n=16), or PEEPPtp_ee (n=8) groups. The PEEPPtp_ee intervention could not be delivered in two patients. Subjects assigned to PEEPmaxCrs had lower ΔP (median8 cm H2O [7-10]), compared with the control group (12 cm H2O [10-15]; P=0.006). PEEPmaxCrs was also associated with higher Ptp_ee (2.0 cm H2O [-0.7 to 4.5] vs controls: -8.3 cm H2O [-13.0 to -4.0]; P≤0.001) and higher Crs (47.7 ml cm H2O [43.2-68.8] vs controls: 39.0 ml cm H2O [32.9-43.4]; P=0.009). Individualised PEEP (PEEPmaxCrs and PEEPPtp_ee combined) varied widely (median: 10 cm H2O [8-15]; CVPEEP=0.24 [0.14-0.35]), both between, and within, subjects throughout surgery. CONCLUSIONS This pilot study suggests that individualised PEEP management strategies applied during abdominal surgery reduce driving pressure, maintain positive Ptp_ee and increase static compliance. The wide range of PEEP observed suggests that an individualised approach is required to optimise respiratory mechanics during abdominal surgery. CLINICAL TRIAL REGISTRATION NCT02671721.
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Affiliation(s)
- Ana Fernandez-Bustamante
- Department of Anesthesiology, University of Colorado School of Medicine, Aurora, CO, USA; Webb-Waring Center, University of Colorado School of Medicine, Aurora, CO, USA.
| | - Juraj Sprung
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, USA
| | - Robert A Parker
- Department of Medicine, Biostatistics Center, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Karsten Bartels
- Department of Anesthesiology, University of Colorado School of Medicine, Aurora, CO, USA
| | - Toby N Weingarten
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, USA
| | - Carolina Kosour
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - B Taylor Thompson
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Marcos F Vidal Melo
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
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The dawn of physiological closed-loop ventilation-a review. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2020; 24:121. [PMID: 32223754 PMCID: PMC7104522 DOI: 10.1186/s13054-020-2810-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 02/25/2020] [Indexed: 01/06/2023]
Abstract
The level of automation in mechanical ventilation has been steadily increasing over the last few decades. There has recently been renewed interest in physiological closed-loop control of ventilation. The development of these systems has followed a similar path to that of manual clinical ventilation, starting with ensuring optimal gas exchange and shifting to the prevention of ventilator-induced lung injury. Systems currently aim to encompass both aspects, and early commercial systems are appearing. These developments remain unknown to many clinicians and, hence, limit their adoption into the clinical environment. This review shows the evolution of the physiological closed-loop control of mechanical ventilation.
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Kaku S, Nguyen CD, Htet NN, Tutera D, Barr J, Paintal HS, Kuschner WG. Acute Respiratory Distress Syndrome: Etiology, Pathogenesis, and Summary on Management. J Intensive Care Med 2019; 35:723-737. [DOI: 10.1177/0885066619855021] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The acute respiratory distress syndrome (ARDS) has multiple causes and is characterized by acute lung inflammation and increased pulmonary vascular permeability, leading to hypoxemic respiratory failure and bilateral pulmonary radiographic opacities. The acute respiratory distress syndrome is associated with substantial morbidity and mortality, and effective treatment strategies are limited. This review presents the current state of the literature regarding the etiology, pathogenesis, and management strategies for ARDS.
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Affiliation(s)
- Shawn Kaku
- Department of Anesthesiology, Perioperative, and Pain Medicine, Stanford University School of Medicine, Stanford, CA, USA
- Authors have contributed equally
| | - Christopher D. Nguyen
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA
- Authors have contributed equally
| | - Natalie N. Htet
- Department of Anesthesiology, Perioperative, and Pain Medicine, Stanford University School of Medicine, Stanford, CA, USA
- Authors have contributed equally
| | - Dominic Tutera
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Juliana Barr
- Department of Anesthesiology, Perioperative, and Pain Medicine, Stanford University School of Medicine, Stanford, CA, USA
- Veterans Affairs Palo Alto Health Care System, Palo Alto, CA, USA
| | - Harman S. Paintal
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA
- Veterans Affairs Palo Alto Health Care System, Palo Alto, CA, USA
| | - Ware G. Kuschner
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA
- Veterans Affairs Palo Alto Health Care System, Palo Alto, CA, USA
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Baedorf Kassis E, Loring SH, Talmor D. Should we titrate peep based on end-expiratory transpulmonary pressure?-yes. ANNALS OF TRANSLATIONAL MEDICINE 2018; 6:390. [PMID: 30460264 DOI: 10.21037/atm.2018.06.35] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Ventilator management of patients with acute respiratory distress syndrome (ARDS) has been characterized by implementation of basic physiology principles by minimizing harmful distending pressures and preventing lung derecruitment. Such strategies have led to significant improvements in outcomes. Positive end expiratory pressure (PEEP) is an important part of a lung protective strategy but there is no standardized method to set PEEP level. With widely varying types of lung injury, body habitus and pulmonary mechanics, the use of esophageal manometry has become important for personalization and optimization of mechanical ventilation in patients with ARDS. Esophageal manometry estimates pleural pressures, and can be used to differentiate the chest wall and lung (transpulmonary) contributions to the total respiratory system mechanics. Elevated pleural pressures may result in negative transpulmonary pressures at end expiration, leading to lung collapse. Measuring the esophageal pressures and adjusting PEEP to make transpulmonary pressures positive can decrease atelectasis, derecruitment of lung, and cyclical opening and closing of airways and alveoli, thus optimizing lung mechanics and oxygenation. Although there is some spatial and positional artifact, esophageal pressures in numerous animal and human studies in healthy, obese and critically ill patients appear to be a good estimate for the "effective" pleural pressure. Multiple studies have illustrated the benefit of using esophageal pressures to titrate PEEP in patients with obesity and with ARDS. Esophageal pressure monitoring provides a window into the unique physiology of a patient and helps improve clinical decision making at the bedside.
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Affiliation(s)
- Elias Baedorf Kassis
- Division of Pulmonary and Critical Care, Beth Israel Deaconess Medical Center and Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Stephen H Loring
- Department of Anesthesia, Critical Care and Pain Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - Daniel Talmor
- Department of Anesthesia, Critical Care and Pain Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
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Esophageal pressure: research or clinical tool? Med Klin Intensivmed Notfmed 2017; 113:13-20. [PMID: 29134245 DOI: 10.1007/s00063-017-0372-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Accepted: 10/09/2017] [Indexed: 10/18/2022]
Abstract
Esophageal manometry has traditionally been utilized for respiratory physiology research, but clinicians have recently found numerous applications within the intensive care unit. Esophageal pressure (PEs) is a surrogate for pleural pressures (PPl), and the difference between airway pressure (PAO) and PEs provides a good estimate for the pressure across the lung also known as the transpulmonary pressure (PL). Differentiating the effects of mechanical ventilation and spontaneous breathing on the respiratory system, chest wall, and across the lung allows for improved personalization in clinical decision making. Measuring PL in acute respiratory distress syndrome (ARDS) may help set positive end expiratory pressure (PEEP) to prevent derecruitment and atelectrauma, while assuring peak pressures do not cause over distension during tidal breathing and recruitment maneuvers. Monitoring PEs allows improved insight into patient-ventilator interactions and may help in decisions to adjust sedation and paralytics to correct dyssynchrony. Intrinsic PEEP (auto-PEEP) may be monitored using esophageal manometry, which may also improve patient comfort and synchrony with the ventilator. Finally, during weaning, PEs may be used to better predict weaning success and allow for rapid intervention during failure. Improved consistency in definition and terminology and further outcomes research is needed to encourage more widespread adoption; however, with clear clinical benefit and increased ease of use, it appears time to reintroduce basic physiology into personalized ventilator management in the intensive care unit.
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Abstract
The main goals of assessing respiratory system mechanical function are to evaluate the lung function through a variety of methods and to detect early signs of abnormalities that could affect the patient's outcomes. In ventilated patients, it has become increasingly important to recognize whether respiratory function has improved or deteriorated, whether the ventilator settings match the patient's demand, and whether the selection of ventilator parameters follows a lung-protective strategy. Ventilator graphics, esophageal pressure, intra-abdominal pressure, and electric impedance tomography are some of the best-known monitoring tools to obtain measurements and adequately evaluate the respiratory system mechanical function.
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Pan C, Chen L, Zhang YH, Liu W, Urbino R, Ranieri VM, Qiu HB, Yang Y. Physiological Correlation of Airway Pressure and Transpulmonary Pressure Stress Index on Respiratory Mechanics in Acute Respiratory Failure. Chin Med J (Engl) 2017; 129:1652-7. [PMID: 27411451 PMCID: PMC4960953 DOI: 10.4103/0366-6999.185855] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
BACKGROUND Stress index at post-recruitment maneuvers could be a method of positive end-expiratory pressure (PEEP) titration in acute respiratory distress syndrome (ARDS) patients. However, airway pressure (Paw) stress index may not reflect lung mechanics in the patients with high chest wall elastance. This study was to evaluate the Pawstress index on lung mechanics and the correlation between Pawstress index and transpulmonary pressure (PL) stress index in acute respiratory failure (ARF) patients. METHODS Twenty-four ARF patients with mechanical ventilation (MV) were consecutively recruited from July 2011 to April 2013 in Zhongda Hospital, Nanjing, China and Ospedale S. Giovanni Battista-Molinette Hospital, Turin, Italy. All patients underwent MV with volume control (tidal volume 6 ml/kg) for 20 min. PEEP was set according to the ARDSnet study protocol. The patients were divided into two groups according to the chest wall elastance/respiratory system elastance ratio. The high elastance group (H group, n = 14) had a ratio ≥30%, and the low elastance group (L group, n = 10) had a ratio <30%. Respiratory elastance, gas-exchange, Pawstress index, and PLstress index were measured. Student's t-test, regression analysis, and Bland-Altman analysis were used for statistical analysis. RESULTS Pneumonia was the major cause of respiratory failure (71.0%). Compared with the L group, PEEP was lower in the H group (5.7 ± 1.7 cmH2O vs. 9.0 ± 2.3 cmH2O, P < 0.01). Compared with the H group, lung elastance was higher (20.0 ± 7.8 cmH2O/L vs. 11.6 ± 3.6 cmH2O/L, P < 0.01), and stress was higher in the L group (7.0 ± 1.9 vs. 4.9 ± 1.9, P = 0.02). A linear relationship was observed between the Pawstress index and the PLstress index in H group (R2 = 0.56, P < 0.01) and L group (R2 = 0.85, P < 0.01). CONCLUSION In the ARF patients with MV, Pawstress index can substitute for PLto guide ventilator settings. TRIAL REGISTRATION ClinicalTrials.gov NCT02196870 (https://clinicaltrials.gov/ct2/show/NCT02196870).
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Affiliation(s)
- Chun Pan
- Department of Critical Care Medicine, Zhongda Hospital, Medical School, Southeast University, Nanjing, Jiangsu 210009, China
| | - Lu Chen
- Department of Critical Care Medicine, Beijing Tiantan Hospital, Capital Medical University, Beijing 100050, China
| | - Yun-Hang Zhang
- Department of Critical Care Medicine, Zhongda Hospital, Medical School, Southeast University, Nanjing, Jiangsu 210009, China
| | - Wei Liu
- Department of Biopharmaceutics, School of Life Science and Technology, Chinese Pharmaceutical University, Nanjing, Jiangsu 210009, China
| | - Rosario Urbino
- Department of Anesthesiology and Critical Care Medicine, Ospedale S. Giovanni Battista-Molinette, Turin 10126, Italy
| | - V Marco Ranieri
- Department of Anesthesiology and Critical Care Medicine, Ospedale S. Giovanni Battista-Molinette, Turin 10126, Italy
| | - Hai-Bo Qiu
- Department of Critical Care Medicine, Zhongda Hospital, Medical School, Southeast University, Nanjing, Jiangsu 210009, China
| | - Yi Yang
- Department of Critical Care Medicine, Zhongda Hospital, Medical School, Southeast University, Nanjing, Jiangsu 210009, China
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Guérin C, Papazian L, Reignier J, Ayzac L, Loundou A, Forel JM. Effect of driving pressure on mortality in ARDS patients during lung protective mechanical ventilation in two randomized controlled trials. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2016; 20:384. [PMID: 27894328 PMCID: PMC5126997 DOI: 10.1186/s13054-016-1556-2] [Citation(s) in RCA: 136] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 11/02/2016] [Indexed: 12/15/2022]
Abstract
Background Driving pressure (ΔPrs) across the respiratory system is suggested as the strongest predictor of hospital mortality in patients with acute respiratory distress syndrome (ARDS). We wonder whether this result is related to the range of tidal volume (VT). Therefore, we investigated ΔPrs in two trials in which strict lung-protective mechanical ventilation was applied in ARDS. Our working hypothesis was that ΔPrs is a risk factor for mortality just like compliance (Crs) or plateau pressure (Pplat,rs) of the respiratory system. Methods We performed secondary analysis of data from 787 ARDS patients enrolled in two independent randomized controlled trials evaluating distinct adjunctive techniques while they were ventilated as in the low VT arm of the ARDSnet trial. For this study, we used VT, positive end-expiratory pressure (PEEP), Pplat,rs, Crs, ΔPrs, and respiratory rate recorded 24 hours after randomization, and compared them between survivors and nonsurvivors at day 90. Patients were followed for 90 days after inclusion. Cox proportional hazard modeling was used for mortality at day 90. If colinearity between ΔPrs, Crs, and Pplat,rs was verified, specific Cox models were used for each of them. Results Both trials enrolled 805 patients of whom 787 had day-1 data available, and 533 of these survived. In the univariate analysis, ΔPrs averaged 13.7 ± 3.7 and 12.8 ± 3.7 cmH2O (P = 0.002) in nonsurvivors and survivors, respectively. Colinearity between ΔPrs, Crs and Pplat,rs, which was expected as these variables are mathematically coupled, was statistically significant. Hazard ratios from the Cox models for day-90 mortality were 1.05 (1.02–1.08) (P = 0.005), 1.05 (1.01–1.08) (P = 0.008) and 0.985 (0.972–0.985) (P = 0.029) for ΔPrs, Pplat,rs and Crs, respectively. PEEP and VT were not associated with death in any model. Conclusions When ventilating patients with low VT, ΔPrs is a risk factor for death in ARDS patients, as is Pplat,rs or Crs. As our data originated from trials from which most ARDS patients were excluded due to strict inclusion and exclusion criteria, these findings must be validated in independent observational studies in patients ventilated with a lung protective strategy. Trial registration Clinicaltrials.gov NCT00299650. Registered 6 March 2006 for the Acurasys trial. Clinicaltrials.gov NCT00527813. Registered 10 September 2007 for the Proseva trial. Electronic supplementary material The online version of this article (doi:10.1186/s13054-016-1556-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Claude Guérin
- Réanimation Médicale Groupement Hospitalier Nord Hospices civils de Lyon, Lyon, France. .,Université de Lyon, 1 69100, Villeurbanne, France. .,Institut Mondor de Recherche Biomédicale, INSERM 955 Equipe 13, Créteil, France.
| | - Laurent Papazian
- Hôpitaux de Marseille Hôpital Nord Réanimation des Détresses Respiratoires et des Infections Sévères, Marseille, 13015, France.,Aix-Marseille University EA 3279 Research Unit Department of Public Health Medecine School University Marseille, Marseille, France.,URMITE UMR CNRS 7278, Marseille, 13005, France
| | | | - Louis Ayzac
- Centre de Coordination et de Lutte Contre les Infections Nosocomiales Sud-Est, Saint-Genis Laval, France
| | - Anderson Loundou
- Aix-Marseille University EA 3279 Research Unit Department of Public Health Medecine School University Marseille, Marseille, France
| | - Jean-Marie Forel
- Hôpitaux de Marseille Department of Research and Innovation Support Unit for clinical research and economic evaluation, Marseille, 13005, France
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