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Hamlington KL, Smith BJ, Dunn CM, Charlebois CM, Roy GS, Bates JHT. Linking lung function to structural damage of alveolar epithelium in ventilator-induced lung injury. Respir Physiol Neurobiol 2018; 255:22-29. [PMID: 29742448 DOI: 10.1016/j.resp.2018.05.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 05/02/2018] [Accepted: 05/05/2018] [Indexed: 12/21/2022]
Abstract
Understanding how the mechanisms of ventilator-induced lung injury (VILI), namely atelectrauma and volutrauma, contribute to the failure of the blood-gas barrier and subsequent intrusion of edematous fluid into the airspace is essential for the design of mechanical ventilation strategies that minimize VILI. We ventilated mice with different combinations of tidal volume and positive end-expiratory pressure (PEEP) and linked degradation in lung function measurements to injury of the alveolar epithelium observed via scanning electron microscopy. Ventilating with both high inspiratory plateau pressure and zero PEEP was necessary to cause derangements in lung function as well as visually apparent physical damage to the alveolar epithelium of initially healthy mice. In particular, the epithelial injury was tightly associated with indicators of alveolar collapse. These results support the hypothesis that mechanical damage to the epithelium during VILI is at least partially attributed to atelectrauma-induced damage of alveolar type I epithelial cells.
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Affiliation(s)
- Katharine L Hamlington
- Department of Medicine, University of Vermont Larner College of Medicine, Burlington, VT 05405, USA.
| | - Bradford J Smith
- Department of Medicine, University of Vermont Larner College of Medicine, Burlington, VT 05405, USA.
| | - Celia M Dunn
- Department of Medicine, University of Vermont Larner College of Medicine, Burlington, VT 05405, USA
| | - Chantel M Charlebois
- Department of Medicine, University of Vermont Larner College of Medicine, Burlington, VT 05405, USA
| | - Gregory S Roy
- Department of Medicine, University of Vermont Larner College of Medicine, Burlington, VT 05405, USA
| | - Jason H T Bates
- Department of Medicine, University of Vermont Larner College of Medicine, Burlington, VT 05405, USA.
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Pourfathi M, Cereda M, Chatterjee S, Xin Y, Kadlecek S, Duncan I, Hamedani H, Siddiqui S, Profka H, Ehrich J, Ruppert K, Rizi RR. Lung Metabolism and Inflammation during Mechanical Ventilation; An Imaging Approach. Sci Rep 2018; 8:3525. [PMID: 29476083 PMCID: PMC5824838 DOI: 10.1038/s41598-018-21901-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Accepted: 02/13/2018] [Indexed: 12/20/2022] Open
Abstract
Acute respiratory distress syndrome (ARDS) is a major cause of mortality in critically ill patients. Patients are currently managed by protective ventilation and alveolar recruitment using positive-end expiratory pressure (PEEP). However, the PEEP's effect on both pulmonary metabolism and regional inflammation is poorly understood. Here, we demonstrate the effect of PEEP on pulmonary anaerobic metabolism in mechanically ventilated injured rats, using hyperpolarized carbon-13 imaging. Pulmonary lactate-to-pyruvate ratio was measured in 21 rats; 14 rats received intratracheal instillation of hydrochloric-acid, while 7 rats received sham saline. 1 hour after acid/saline instillation, PEEP was lowered to 0 cmH2O in 7 injured rats (ZEEP group) and in all sham rats; PEEP was continued in the remaining 7 injured rats (PEEP group). Pulmonary compliance, oxygen saturation, histological injury scores, ICAM-1 expression and myeloperoxidase expression were measured. Lactate-to-pyruvate ratio progressively increased in the dependent lung during mechanical ventilation at ZEEP (p < 0.001), but remained unchanged in PEEP and sham rats. Lactate-to-pyruvate ratio was correlated with hyaline membrane deposition (r = 0.612), edema severity (r = 0.663), ICAM-1 (r = 0.782) and myeloperoxidase expressions (r = 0.817). Anaerobic pulmonary metabolism increases during lung injury progression and is contained by PEEP. Pulmonary lactate-to-pyruvate ratio may indicate in-vivo neutrophil activity due to atelectasis.
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Affiliation(s)
- Mehrdad Pourfathi
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
- Department Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Maurizio Cereda
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, PA, USA
| | - Shampa Chatterjee
- Department of Physiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Yi Xin
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Stephen Kadlecek
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Ian Duncan
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Hooman Hamedani
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Sarmad Siddiqui
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Harrilla Profka
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Jason Ehrich
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Kai Ruppert
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Rahim R Rizi
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA.
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Abstract
Sepsis is the main cause of close to 70% of all cases of acute respiratory distress syndromes (ARDS). In addition, sepsis increases susceptibility to ventilator-induced lung injury. Therefore, the development of a ventilatory strategy that can achieve adequate oxygenation without injuring the lungs is highly sought after for patients with acute infection and represents an important therapeutic window to improve patient care. Suboptimal ventilatory settings cannot only harm the lung, but may also contribute to the cascade of organ failure in sepsis due to organ crosstalk.Despite the prominent role of sepsis as a cause for lung injury, most of the studies that addressed mechanical ventilation strategies in ARDS did not specifically assess sepsis-related ARDS patients. Consequently, most of the recommendations regarding mechanical ventilation in sepsis patients are derived from ARDS trials that included multiple clinical diagnoses. While there have been important improvements in general ventilatory management that should apply to all critically ill patients, sepsis-related lung injury might still have particularities that could influence bedside management.After revisiting the interplay between sepsis and ventilation-induced lung injury, this review will reappraise the evidence for the major components of the lung protective ventilation strategy, emphasizing the particularities of sepsis-related acute lung injury.
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Nieman GF, Satalin J, Andrews P, Aiash H, Habashi NM, Gatto LA. Personalizing mechanical ventilation according to physiologic parameters to stabilize alveoli and minimize ventilator induced lung injury (VILI). Intensive Care Med Exp 2017; 5:8. [PMID: 28150228 PMCID: PMC5289131 DOI: 10.1186/s40635-017-0121-x] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Accepted: 01/26/2017] [Indexed: 12/15/2022] Open
Abstract
It has been shown that mechanical ventilation in patients with, or at high-risk for, the development of acute respiratory distress syndrome (ARDS) can be a double-edged sword. If the mechanical breath is improperly set, it can amplify the lung injury associated with ARDS, causing a secondary ventilator-induced lung injury (VILI). Conversely, the mechanical breath can be adjusted to minimize VILI, which can reduce ARDS mortality. The current standard of care ventilation strategy to minimize VILI attempts to reduce alveolar over-distension and recruitment-derecruitment (R/D) by lowering tidal volume (Vt) to 6 cc/kg combined with adjusting positive-end expiratory pressure (PEEP) based on a sliding scale directed by changes in oxygenation. Thus, Vt is often but not always set as a "one-size-fits-all" approach and although PEEP is often set arbitrarily at 5 cmH2O, it may be personalized according to changes in a physiologic parameter, most often to oxygenation. However, there is evidence that oxygenation as a method to optimize PEEP is not congruent with the PEEP levels necessary to maintain an open and stable lung. Thus, optimal PEEP might not be personalized to the lung pathology of an individual patient using oxygenation as the physiologic feedback system. Multiple methods of personalizing PEEP have been tested and include dead space, lung compliance, lung stress and strain, ventilation patterns using computed tomography (CT) or electrical impedance tomography (EIT), inflection points on the pressure/volume curve (P/V), and the slope of the expiratory flow curve using airway pressure release ventilation (APRV). Although many studies have shown that personalizing PEEP is possible, there is no consensus as to the optimal technique. This review will assess various methods used to personalize PEEP, directed by physiologic parameters, necessary to adaptively adjust ventilator settings with progressive changes in lung pathophysiology.
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Affiliation(s)
- Gary F. Nieman
- Department of Surgery, SUNY Upstate Medical University, Syracuse, NY USA
| | - Joshua Satalin
- Department of Surgery, SUNY Upstate Medical University, Syracuse, NY USA
- Cardiopulmonary Critical Care Lab, Department of Surgery, Upstate Medical University, 750 East Adams Street, Syracuse, NY 13210 USA
| | | | - Hani Aiash
- Department of Surgery, SUNY Upstate Medical University, Syracuse, NY USA
| | - Nader M. Habashi
- Department of Trauma Critical Care Medicine, R Adams Cowley Shock Trauma Center, University of Maryland, Baltimore, MD USA
| | - Louis A. Gatto
- Biological Sciences Department, Biological Sciences Department, SUNY Cortland, Cortland, NY USA
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Mauri T, Lazzeri M, Bellani G, Zanella A, Grasselli G. Respiratory mechanics to understand ARDS and guide mechanical ventilation. Physiol Meas 2017; 38:R280-H303. [PMID: 28967868 DOI: 10.1088/1361-6579/aa9052] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
OBJECTIVE As precision medicine is becoming a standard of care in selecting tailored rather than average treatments, physiological measurements might represent the first step in applying personalized therapy in the intensive care unit (ICU). A systematic assessment of respiratory mechanics in patients with the acute respiratory distress syndrome (ARDS) could represent a step in this direction, for two main reasons. Approach and Main results: On the one hand, respiratory mechanics are a powerful physiological method to understand the severity of this syndrome in each single patient. Decreased respiratory system compliance, for example, is associated with low end expiratory lung volume and more severe lung injury. On the other hand, respiratory mechanics might guide protective mechanical ventilation settings. Improved gravitationally dependent regional lung compliance could support the selection of positive end-expiratory pressure and maximize alveolar recruitment. Moreover, the association between driving airway pressure and mortality in ARDS patients potentially underlines the importance of sizing tidal volume on respiratory system compliance rather than on predicted body weight. SIGNIFICANCE The present review article aims to describe the main alterations of respiratory mechanics in ARDS as a potent bedside tool to understand severity and guide mechanical ventilation settings, thus representing a readily available clinical resource for ICU physicians.
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Affiliation(s)
- Tommaso Mauri
- Department of Pathophysiology and Transplantation, University of Milan, Via Festa del Perdono 7, 20122 Milan, Italy. Department of Anesthesia, Critical Care and Emergency, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Via F. Sforza 35, 20122 Milan, Italy
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Varghese J, Kutty S, Bisselou Moukagna KS, Craft M, Abdullah I, Hammel JM. Five-year experience with immediate extubation after arterial switch operations for transposition of great arteries. Eur J Cardiothorac Surg 2017; 51:728-734. [PMID: 28199509 DOI: 10.1093/ejcts/ezw424] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Accepted: 11/30/2016] [Indexed: 11/12/2022] Open
Abstract
Objectives We sought to identify preoperative, intraoperative and anatomical factors associated with immediate extubation (IE) after arterial switch operation for d-transposition of great arteries (dTGA). Methods This was a single-centre retrospective study performed from 1 January 2010 to 30 June 2015. IE was defined as successful extubation in the operating room (OR). Univariate/bivariate regression of preoperative, intraoperative and anatomical variables was used to determine associations with IE. Results Of 32 patients in the dTGA spectrum (age at operation 6 days), 18 (56%) underwent IE. Twelve (71%) of the 17 patients with an intact ventricular septum and 6 (43%) of the 14 patients with ventricular septal defect (VSD) underwent IE, whereas none of the patients with double outlet right ventricle or aortic arch obstruction ( n = 4) did. Patients who had cardiopulmonary bypass time (CPB) >173 min ( P = 0.01), lowest temperature on CPB (T min) ≤ 30.4°C ( P = 0.04) and aortic cross-clamp time >86 min ( P = 0.04) were more likely to be left intubated at the end of the procedure. There was no significant difference in patient's chronological age, gestational age, post-conceptual age, weight, coronary anatomy or prevalence of VSD between those who did and did not undergo IE. There was a median increase in intensive care unit (ICU) length of stay (LOS) by 1 day (33%, P = 0.03) and ICU costs by $12 338 (15%, P = 0.06) in non-IE patients. The OR turnover time ( P = 0.09) and reintubation rate ( P = 1) at 24 h post-extubation did not differ between those who did and did not have IE. There was no myocardial dysfunction evident on predismissal echocardiography in either group. Conclusions In this cohort of infants, post repair for TGA, 56% were extubated immediately in the OR. Greater CPB and cross-clamp times and T min ≤ 30.4°C were associated with a lesser likelihood of IE. IE was associated with shorter ICU length of stay.
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Affiliation(s)
- Joby Varghese
- Department of Pediatric Anesthesia, Children's Hospital and Medical Center, University of Nebraska Medical Center College of Medicine, Omaha, NE, USA
| | - Shelby Kutty
- Department of Pediatric Anesthesia, Children's Hospital and Medical Center, University of Nebraska Medical Center College of Medicine, Omaha, NE, USA
| | - Karl Stessy Bisselou Moukagna
- Department of Pediatric Anesthesia, Children's Hospital and Medical Center, University of Nebraska Medical Center College of Medicine, Omaha, NE, USA
| | - Mary Craft
- Department of Pediatric Anesthesia, Children's Hospital and Medical Center, University of Nebraska Medical Center College of Medicine, Omaha, NE, USA
| | - Ibrahim Abdullah
- Department of Pediatric Anesthesia, Children's Hospital and Medical Center, University of Nebraska Medical Center College of Medicine, Omaha, NE, USA
| | - James M Hammel
- Department of Pediatric Anesthesia, Children's Hospital and Medical Center, University of Nebraska Medical Center College of Medicine, Omaha, NE, USA
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Henderson WR, Chen L, Amato MBP, Brochard LJ. Fifty Years of Research in ARDS. Respiratory Mechanics in Acute Respiratory Distress Syndrome. Am J Respir Crit Care Med 2017; 196:822-833. [PMID: 28306327 DOI: 10.1164/rccm.201612-2495ci] [Citation(s) in RCA: 119] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Acute respiratory distress syndrome is a multifactorial lung injury that continues to be associated with high levels of morbidity and mortality. Mechanical ventilation, although lifesaving, is associated with new iatrogenic injury. Current best practice involves the use of small Vt, low plateau and driving pressures, and high levels of positive end-expiratory pressure. Collectively, these interventions are termed "lung-protective ventilation." Recent investigations suggest that individualized measurements of pulmonary mechanical variables rather than population-based ventilation prescriptions may be used to set the ventilator with the potential to improve outcomes beyond those achieved with standard lung protective ventilation. This review outlines the measurement and application of clinically applicable pulmonary mechanical concepts, such as plateau pressures, driving pressure, transpulmonary pressures, stress index, and measurement of strain. In addition, the concept of the "baby lung" and the utility of dynamic in addition to static measures of pulmonary mechanical variables are discussed.
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Affiliation(s)
- William R Henderson
- 1 Division of Critical Care Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Lu Chen
- 2 Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, Ontario, Canada.,3 Keenan Research Centre, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario, Canada; and
| | - Marcelo B P Amato
- 4 Cardio-Pulmonary Department, Pulmonary Division, Heart Institute (Incor), University of São Paulo, São Paulo, Brazil
| | - Laurent J Brochard
- 2 Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, Ontario, Canada.,3 Keenan Research Centre, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario, Canada; and
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59
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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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60
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Comparative Effects of Volutrauma and Atelectrauma on Lung Inflammation in Experimental Acute Respiratory Distress Syndrome. Crit Care Med 2017; 44:e854-65. [PMID: 27035236 DOI: 10.1097/ccm.0000000000001721] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Volutrauma and atelectrauma promote ventilator-induced lung injury, but their relative contribution to inflammation in ventilator-induced lung injury is not well established. The aim of this study was to determine the impact of volutrauma and atelectrauma on the distribution of lung inflammation in experimental acute respiratory distress syndrome. DESIGN Laboratory investigation. SETTING University-hospital research facility. SUBJECTS Ten pigs (five per group; 34.7-49.9 kg) INTERVENTIONS : Animals were anesthetized and intubated, and saline lung lavage was performed. Lungs were separated with a double-lumen tube. Following lung recruitment and decremental positive end-expiratory pressure trial, animals were randomly assigned to 4 hours of ventilation of the left (ventilator-induced lung injury) lung with tidal volume of approximately 3 mL/kg and 1) high positive end-expiratory pressure set above the level where dynamic compliance increased more than 5% during positive end-expiratory pressure trial (volutrauma); or 2) low positive end-expiratory pressure to achieve driving pressure comparable with volutrauma (atelectrauma). The right (control) lung was kept on continuous positive airway pressure of 20 cm H2O, and CO2 was partially removed extracorporeally. MEASUREMENTS AND MAIN RESULTS Regional lung aeration, specific [F]fluorodeoxyglucose uptake rate, and perfusion were assessed using computed and positron emission tomography. Volutrauma yielded higher [F]fluorodeoxyglucose uptake rate in the ventilated lung compared with atelectrauma (median [interquartile range], 0.017 [0.014-0.025] vs 0.013 min [0.010-0.014 min]; p < 0.01), mainly in central lung regions. Volutrauma yielded higher [F]fluorodeoxyglucose uptake rate in ventilator-induced lung injury versus control lung (0.017 [0.014-0.025] vs 0.011 min [0.010-0.016 min]; p < 0.05), whereas atelectrauma did not. Volutrauma decreased blood fraction at similar perfusion and increased normally as well as hyperaerated lung compartments and tidal hyperaeration. Atelectrauma yielded higher poorly and nonaerated lung compartments, and tidal recruitment. Driving pressure increased in atelectrauma. CONCLUSIONS In this model of acute respiratory distress syndrome, volutrauma promoted higher lung inflammation than atelectrauma at comparable low tidal volume and lower driving pressure, suggesting that static stress and strain are major determinants of ventilator-induced lung injury.
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Differential Effects of Intraoperative Positive End-expiratory Pressure (PEEP) on Respiratory Outcome in Major Abdominal Surgery Versus Craniotomy. Ann Surg 2017; 264:362-369. [PMID: 26496082 DOI: 10.1097/sla.0000000000001499] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
OBJECTIVES In this study, we examined whether (1) positive end-expiratory pressure (PEEP) has a protective effect on the risk of major postoperative respiratory complications in a cohort of patients undergoing major abdominal surgeries and craniotomies, and (2) the effect of PEEP is differed by surgery type. BACKGROUND Protective mechanical ventilation with lower tidal volumes and PEEP reduces compounded postoperative complications after abdominal surgery. However, data regarding the use of intraoperative PEEP is conflicting. METHODS In this observational study, we included 5915 major abdominal surgery patients and 5063 craniotomy patients. Analysis was performed using multivariable logistic regression. The primary outcome was a composite of major postoperative respiratory complications (respiratory failure, reintubation, pulmonary edema, and pneumonia) within 3 days of surgery. RESULTS Within the entire study population (major abdominal surgeries and craniotomies), we found an association between application of PEEP ≥5 cmH2O and a decreased risk of postoperative respiratory complications compared with PEEP <5 cmH2O. Application of PEEP >5 cmH2O was associated with a significant lower odds of respiratory complications in patients undergoing major abdominal surgery (odds ratio 0.53, 95% confidence interval 0.39 - 0.72), effects that translated to deceased hospital length of stay [median hospital length of stay : 6 days (4-9 days), incidence rate ratios for each additional day: 0.91 (0.84 - 0.98)], whereas PEEP >5 cmH2O was not significantly associated with reduced odds of respiratory complications or hospital length of stay in patients undergoing craniotomy. CONCLUSIONS The protective effects of PEEP are procedure specific with meaningful effects observed in patients undergoing major abdominal surgery. Our data suggest that default mechanical ventilator settings should include PEEP of 5-10 cmH2O during major abdominal surgery.
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Spatial patterns and frequency distributions of regional deformation in the healthy human lung. Biomech Model Mechanobiol 2017; 16:1413-1423. [DOI: 10.1007/s10237-017-0895-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2016] [Accepted: 03/09/2017] [Indexed: 12/31/2022]
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63
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Pourfathi M, Xin Y, Kadlecek SJ, Cereda MF, Profka H, Hamedani H, Siddiqui SM, Ruppert K, Drachman NA, Rajaei JN, Rizi RR. In vivo imaging of the progression of acute lung injury using hyperpolarized [1- 13 C] pyruvate. Magn Reson Med 2017; 78:2106-2115. [PMID: 28074497 DOI: 10.1002/mrm.26604] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Revised: 11/29/2016] [Accepted: 12/20/2016] [Indexed: 12/19/2022]
Abstract
PURPOSE To investigate pulmonary metabolic alterations during progression of acute lung injury. METHODS Using hyperpolarized [1-13 C] pyruvate imaging, we measured pulmonary lactate and pyruvate in 15 ventilated rats 1, 2, and 4 h after initiation of mechanical ventilation. Lung compliance was used as a marker for injury progression. 5 untreated rats were used as controls; 5 rats (injured-1) received 1 ml/kg and another 5 rats (injured-2) received 2 ml/kg hydrochloric acid (pH 1.25) in the trachea at 70 min. RESULTS The mean lactate-to-pyruvate ratio of the injured-1 cohort was 0.15 ± 0.02 and 0.15 ± 0.03 at baseline and 1 h after the injury, and significantly increased from the baseline value 3 h after the injury to 0.23 ± 0.02 (P = 0.002). The mean lactate-to-pyruvate ratio of the injured-2 cohort decreased from 0.14 ± 0.03 at baseline to 0.08 ± 0.02 1 h after the injury and further decreased to 0.07 ± 0.02 (P = 0.08) 3 h after injury. No significant change was observed in the control group. Compliance in both injured groups decreased significantly after the injury (P < 0.01). CONCLUSIONS Our findings suggest that in severe cases of lung injury, edema and hyperperfusion in the injured lung tissue may complicate interpretation of the pulmonary lactate-to-pyruvate ratio as a marker of inflammation. However, combining the lactate-to-pyruvate ratio with pulmonary compliance provides more insight into the progression of the injury and its severity. Magn Reson Med 78:2106-2115, 2017. © 2017 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Mehrdad Pourfathi
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Yi Xin
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Stephen J Kadlecek
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Maurizio F Cereda
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Harrilla Profka
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Hooman Hamedani
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Sarmad M Siddiqui
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Kai Ruppert
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Nicholas A Drachman
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Jennia N Rajaei
- School of Medicine, Stanford University, Stanford, California, USA
| | - Rahim R Rizi
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Paula LF, Wellman TJ, Winkler T, Spieth PM, Güldner A, Venegas JG, Gama de Abreu M, Carvalho AR, Vidal Melo MF. Regional tidal lung strain in mechanically ventilated normal lungs. J Appl Physiol (1985) 2016; 121:1335-1347. [PMID: 27445302 PMCID: PMC5206384 DOI: 10.1152/japplphysiol.00861.2015] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 07/05/2016] [Indexed: 01/12/2023] Open
Abstract
Parenchymal strain is a key determinant of lung injury produced by mechanical ventilation. However, imaging estimates of volumetric tidal strain (ε = regional tidal volume/reference volume) present substantial conceptual differences in reference volume computation and consideration of tidally recruited lung. We compared current and new methods to estimate tidal volumetric strains with computed tomography, and quantified the effect of tidal volume (VT) and positive end-expiratory pressure (PEEP) on strain estimates. Eight supine pigs were ventilated with VT = 6 and 12 ml/kg and PEEP = 0, 6, and 12 cmH2O. End-expiratory and end-inspiratory scans were analyzed in eight regions of interest along the ventral-dorsal axis. Regional reference volumes were computed at end-expiration (with/without correction of regional VT for intratidal recruitment) and at resting lung volume (PEEP = 0) corrected for intratidal and PEEP-derived recruitment. All strain estimates demonstrated vertical heterogeneity with the largest tidal strains in middependent regions (P < 0.01). Maximal strains for distinct estimates occurred at different lung regions and were differently affected by VT-PEEP conditions. Values consistent with lung injury and inflammation were reached regionally, even when global measurements were below critical levels. Strains increased with VT and were larger in middependent than in nondependent lung regions. PEEP reduced tidal-strain estimates referenced to end-expiratory lung volumes, although it did not affect strains referenced to resting lung volume. These estimates of tidal strains in normal lungs point to middependent lung regions as those at risk for ventilator-induced lung injury. The different conditions and topography at which maximal strain estimates occur allow for testing the importance of each estimate for lung injury.
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Affiliation(s)
- Luis Felipe Paula
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts
- Laboratory of Respiration Physiology, Carlos Chagas Filho Biophysics Institute, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Tyler J Wellman
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts
| | - Tilo Winkler
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts
| | - Peter M Spieth
- Pulmonary Engineering Group, Department of Anesthesiology and Intensive Care Therapy, University Hospital Carl Gustav Carus, Dresden, Germany; and
| | - Andreas Güldner
- Pulmonary Engineering Group, Department of Anesthesiology and Intensive Care Therapy, University Hospital Carl Gustav Carus, Dresden, Germany; and
| | - Jose G Venegas
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts
| | - Marcelo Gama de Abreu
- Pulmonary Engineering Group, Department of Anesthesiology and Intensive Care Therapy, University Hospital Carl Gustav Carus, Dresden, Germany; and
| | - Alysson R Carvalho
- Laboratory of Respiration Physiology, Carlos Chagas Filho Biophysics Institute, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
- Pulmonary Engineering Group, Department of Anesthesiology and Intensive Care Therapy, University Hospital Carl Gustav Carus, Dresden, Germany; and
- Laboratory of Pulmonary Engineering, Alberto Luiz Coimbra Institute of Post-Graduation and Research in Engineering, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Marcos F Vidal Melo
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts;
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Wellman TJ, de Prost N, Tucci M, Winkler T, Baron RM, Filipczak P, Raby B, Chu JH, Harris RS, Musch G, Dos Reis Falcao LF, Capelozzi V, Venegas JG, Vidal Melo MF. Lung Metabolic Activation as an Early Biomarker of Acute Respiratory Distress Syndrome and Local Gene Expression Heterogeneity. Anesthesiology 2016; 125:992-1004. [PMID: 27611185 PMCID: PMC5096592 DOI: 10.1097/aln.0000000000001334] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
BACKGROUND Acute respiratory distress syndrome (ARDS) is an inflammatory condition comprising diffuse lung edema and alveolar damage. ARDS frequently results from regional injury mechanisms. However, it is unknown whether detectable inflammation precedes lung edema and opacification and whether topographically differential gene expression consistent with heterogeneous injury occurs in early ARDS. The authors aimed to determine the temporal relationship between pulmonary metabolic activation and density in a large animal model of early ARDS and to assess gene expression in differentially activated regions. METHODS The authors produced ARDS in sheep with intravenous lipopolysaccharide (10 ng ⋅ kg ⋅ h) and mechanical ventilation for 20 h. Using positron emission tomography, the authors assessed regional cellular metabolic activation with 2-deoxy-2-[(18)F]fluoro-D-glucose, perfusion and ventilation with NN-saline, and aeration using transmission scans. Species-specific microarray technology was used to assess regional gene expression. RESULTS Metabolic activation preceded detectable increases in lung density (as required for clinical diagnosis) and correlated with subsequent histologic injury, suggesting its predictive value for severity of disease progression. Local time courses of metabolic activation varied, with highly perfused and less aerated dependent lung regions activated earlier than nondependent regions. These regions of distinct metabolic trajectories demonstrated differential gene expression for known and potential novel candidates for ARDS pathogenesis. CONCLUSIONS Heterogeneous lung metabolic activation precedes increases in lung density in the development of ARDS due to endotoxemia and mechanical ventilation. Local differential gene expression occurs in these early stages and reveals molecular pathways relevant to ARDS biology and of potential use as treatment targets.
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Affiliation(s)
- Tyler J Wellman
- From the Departments of Anesthesia, Critical Care and Pain Medicine (T.J.W., M.T., T.W., G.M., L.F.d.R.F., J.G.V., M.F.V.M.) and Medicine (Pulmonary and Critical Care; R.S.H.), Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts; Medical Intensive Care Unit, Hôpital Henri Mondor, Assistance Publique - Hôpitaux de Paris, Créteil, France (N.d.P.); Department of Medicine (Pulmonary and Critical Care) (R.M.B., P.F.) and Channing Laboratory (B.R., J.-h.C.), Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts; and Laboratory of Histomorphometry and Lung Genomics, University of Sao Paulo, Sao Paulo, Brazil (V.C.)
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Abstract
Prevention of ventilator-induced lung injury (VILI) can attenuate multiorgan failure and improve survival in at-risk patients. Clinically significant VILI occurs from volutrauma, barotrauma, atelectrauma, biotrauma, and shear strain. Differences in regional mechanics are important in VILI pathogenesis. Several interventions are available to protect against VILI. However, most patients at risk of lung injury do not develop VILI. VILI occurs most readily in patients with concomitant physiologic insults. VILI prevention strategies must balance risk of lung injury with untoward side effects from the preventive effort, and may be most effective when targeted to subsets of patients at increased risk.
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End-Expiratory Lung Volume in Patients with Acute Respiratory Distress Syndrome: A Time Course Analysis. Lung 2016; 194:527-34. [PMID: 27169535 DOI: 10.1007/s00408-016-9892-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 05/02/2016] [Indexed: 10/21/2022]
Abstract
PURPOSE Lung injury can be caused by ventilation and non-physiological lung stress (transpulmonary pressure) and strain [inflated volume over functional residual capacity ratio (FRC)]. FRC is severely decreased in patients with acute respiratory distress syndrome (ARDS). End-expiratory lung volume (EELV) is FRC plus lung volume increased by the applied positive end-expiratory pressure (PEEP). Measurement using the modified nitrogen multiple breath washout technique may help titrating PEEP during ARDS and allow determining dynamic lung strain (tidal volume over EELV) in patients ventilated with PEEP. In this observational study, we measured EELV for up to seven consecutive days in patients with ARDS at different PEEP levels. RESULTS Thirty sedated patients with ARDS (10 mild, 14 moderate, 6 severe) underwent decremental PEEP testing (20, 15, 10, 5 cm H2O) for up to 7 days after inclusion. At all PEEP levels examined, over a period of 7 days the measured absolute EELVs showed no significant change over time [PEEP 20 cm H2O 2464 ml at day 1 vs. 2144 ml at day 7 (p = 0.78), PEEP 15 cm H2O 2226 ml vs. 1990 ml (p = 0.36), PEEP 10 1835 ml vs. 1858 ml (p = 0.76) and PEEP 5 cm H2O 1487 ml vs. 1612 ml (p = 0.37)]. In relation to the predicted body weight (pbw), no significant change in EELV/kg pbw over time could be detected either at any PEEP level or over time [PEEP 20 36 ml/kg pbw at day 1 vs. 33 ml/kg pbw at day 7 (p = 0.66); PEEP 15 33 vs. 29 ml/kg pbw (p = 0.32); PEEP 10 27 vs. 27 ml/kg pbw (p = 0.70) and PEEP 5 22 vs. 24 ml/kg pbw (p = 0.70)]. Oxygenation significantly improved over time from PaO2/FiO2 of 169 mmHg at day 1 to 199 mmHg at day 7 (p < 0.01). CONCLUSIONS EELV did not change significantly for up to 7 days in patients with ARDS. By contrast, PaO2/FiO2 improved significantly. Bedside measurement of EELV may be a novel approach to individualise lung-protective ventilation on the basis of calculation of dynamic strain as the ratio of VT to EELV.
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Pesenti A, Musch G, Lichtenstein D, Mojoli F, Amato MBP, Cinnella G, Gattinoni L, Quintel M. Imaging in acute respiratory distress syndrome. Intensive Care Med 2016; 42:686-698. [DOI: 10.1007/s00134-016-4328-1] [Citation(s) in RCA: 88] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 03/11/2016] [Indexed: 11/30/2022]
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Retamal J, Sörensen J, Lubberink M, Suarez-Sipmann F, Borges JB, Feinstein R, Jalkanen S, Antoni G, Hedenstierna G, Roivainen A, Larsson A, Velikyan I. Feasibility of (68)Ga-labeled Siglec-9 peptide for the imaging of acute lung inflammation: a pilot study in a porcine model of acute respiratory distress syndrome. AMERICAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING 2016; 6:18-31. [PMID: 27069763 PMCID: PMC4749502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Accepted: 12/04/2015] [Indexed: 06/05/2023]
Abstract
There is an unmet need for noninvasive, specific and quantitative imaging of inherent inflammatory activity. Vascular adhesion protein-1 (VAP-1) translocates to the luminal surface of endothelial cells upon inflammatory challenge. We hypothesized that in a porcine model of acute respiratory distress syndrome (ARDS), positron emission tomography (PET) with sialic acid-binding immunoglobulin-like lectin 9 (Siglec-9) based imaging agent targeting VAP-1 would allow quantification of regional pulmonary inflammation. ARDS was induced by lung lavages and injurious mechanical ventilation. Hemodynamics, respiratory system compliance (Crs) and blood gases were monitored. Dynamic examination using [(15)O]water PET-CT (10 min) was followed by dynamic (90 min) and whole-body examination using VAP-1 targeting (68)Ga-labeled 1,4,7,10-tetraaza cyclododecane-1,4,7-tris-acetic acid-10-ethylene glycol-conjugated Siglec-9 motif peptide ([(68)Ga]Ga-DOTA-Siglec-9). The animals received an anti-VAP-1 antibody for post-mortem immunohistochemistry assay of VAP-1 receptors. Tissue samples were collected post-mortem for the radioactivity uptake, histology and immunohistochemistry assessment. Marked reduction of oxygenation and Crs, and higher degree of inflammation were observed in ARDS animals. [(68)Ga]Ga-DOTA-Siglec-9 PET showed significant uptake in lungs, kidneys and urinary bladder. Normalization of the net uptake rate (Ki) for the tissue perfusion resulted in 4-fold higher uptake rate of [(68)Ga]Ga-DOTA-Siglec-9 in the ARDS lungs. Immunohistochemistry showed positive VAP-1 signal in the injured lungs. Detection of pulmonary inflammation associated with a porcine model of ARDS was possible with [(68)Ga]Ga-DOTA-Siglec-9 PET when using kinetic modeling and normalization for tissue perfusion.
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Affiliation(s)
- Jaime Retamal
- Department of Surgical Sciences, Hedenstierna laboratory, Uppsala UniversityUppsala, Sweden
- Departament de Medicina Intensiva, Pontificia Universidad Católica de ChileSantiago, Chile
| | - Jens Sörensen
- Department of Surgical Sciences, Section of Nuclear Medicine and PET, Uppsala UniversityUppsala, Sweden
| | - Mark Lubberink
- Department of Surgical Sciences, Section of Nuclear Medicine and PET, Uppsala UniversityUppsala, Sweden
| | - Fernando Suarez-Sipmann
- Department of Surgical Sciences, Hedenstierna laboratory, Uppsala UniversityUppsala, Sweden
- CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos IIIMadrid, Spain
| | - João Batista Borges
- Department of Surgical Sciences, Hedenstierna laboratory, Uppsala UniversityUppsala, Sweden
- Pulmonary Divison, Heart Institute (Incor) Hospital das Clínicas da Faculdade de Medicina da Universidade de São PauloBrazil
| | | | - Sirpa Jalkanen
- MediCity Research Laboratory, Department of Medical Microbiology and Immunology, University of TurkuTurku, Finland
| | - Gunnar Antoni
- Department of Medicinal Chemistry, Uppsala UniversityUppsala, Sweden
| | - Göran Hedenstierna
- Department of Surgical Sciences, Hedenstierna laboratory, Uppsala UniversityUppsala, Sweden
| | - Anne Roivainen
- Turku PET Centre, University of Turku and Turku University HospitalTurku, Finland
- Turku Center for Disease Modelling, University of TurkuFurku, Finland
| | - Anders Larsson
- Department of Surgical Sciences, Hedenstierna laboratory, Uppsala UniversityUppsala, Sweden
| | - Irina Velikyan
- Department of Surgical Sciences, Section of Nuclear Medicine and PET, Uppsala UniversityUppsala, Sweden
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Abstract
BACKGROUND During mechanical ventilation, stress and strain may be locally multiplied in an inhomogeneous lung. The authors investigated whether, in healthy lungs, during high pressure/volume ventilation, injury begins at the interface of naturally inhomogeneous structures as visceral pleura, bronchi, vessels, and alveoli. The authors wished also to characterize the nature of the lesions (collapse vs. consolidation). METHODS Twelve piglets were ventilated with strain greater than 2.5 (tidal volume/end-expiratory lung volume) until whole lung edema developed. At least every 3 h, the authors acquired end-expiratory/end-inspiratory computed tomography scans to identify the site and the number of new lesions. Lung inhomogeneities and recruitability were quantified. RESULTS The first new densities developed after 8.4 ± 6.3 h (mean ± SD), and their number increased exponentially up to 15 ± 12 h. Afterward, they merged into full lung edema. A median of 61% (interquartile range, 57 to 76) of the lesions appeared in subpleural regions, 19% (interquartile range, 11 to 23) were peribronchial, and 19% (interquartile range, 6 to 25) were parenchymal (P < 0.0001). All the new densities were fully recruitable. Lung elastance and gas exchange deteriorated significantly after 18 ± 11 h, whereas lung edema developed after 20 ± 11 h. CONCLUSIONS Most of the computed tomography scan new densities developed in nonhomogeneous lung regions. The damage in this model was primarily located in the interstitial space, causing alveolar collapse and consequent high recruitability.
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Intraoperative protective mechanical ventilation for prevention of postoperative pulmonary complications: a comprehensive review of the role of tidal volume, positive end-expiratory pressure, and lung recruitment maneuvers. Anesthesiology 2015; 123:692-713. [PMID: 26120769 DOI: 10.1097/aln.0000000000000754] [Citation(s) in RCA: 249] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Postoperative pulmonary complications are associated with increased morbidity, length of hospital stay, and mortality after major surgery. Intraoperative lung-protective mechanical ventilation has the potential to reduce the incidence of postoperative pulmonary complications. This review discusses the relevant literature on definition and methods to predict the occurrence of postoperative pulmonary complication, the pathophysiology of ventilator-induced lung injury with emphasis on the noninjured lung, and protective ventilation strategies, including the respective roles of tidal volumes, positive end-expiratory pressure, and recruitment maneuvers. The authors propose an algorithm for protective intraoperative mechanical ventilation based on evidence from recent randomized controlled trials.
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Hedenstierna G. Small Tidal Volumes, Positive End-expiratory Pressure, and Lung Recruitment Maneuvers during Anesthesia. Anesthesiology 2015; 123:501-3. [DOI: 10.1097/aln.0000000000000755] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- Göran Hedenstierna
- From the Department of Medical Sciences, Clinical Physiology, University Hospital, Uppsala, Sweden
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Effects of Sigh on Regional Lung Strain and Ventilation Heterogeneity in Acute Respiratory Failure Patients Undergoing Assisted Mechanical Ventilation*. Crit Care Med 2015; 43:1823-31. [DOI: 10.1097/ccm.0000000000001083] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Ladha K, Vidal Melo MF, McLean DJ, Wanderer JP, Grabitz SD, Kurth T, Eikermann M. Intraoperative protective mechanical ventilation and risk of postoperative respiratory complications: hospital based registry study. BMJ 2015; 351:h3646. [PMID: 26174419 PMCID: PMC4501577 DOI: 10.1136/bmj.h3646] [Citation(s) in RCA: 195] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
OBJECTIVE To evaluate the effects of intraoperative protective ventilation on major postoperative respiratory complications and to define safe intraoperative mechanical ventilator settings that do not translate into an increased risk of postoperative respiratory complications. DESIGN Hospital based registry study. SETTING Academic tertiary care hospital and two affiliated community hospitals in Massachusetts, United States. PARTICIPANTS 69,265 consecutively enrolled patients over the age of 18 who underwent a non-cardiac surgical procedure between January 2007 and August 2014 and required general anesthesia with endotracheal intubation. INTERVENTIONS Protective ventilation, defined as a median positive end expiratory pressure (PEEP) of 5 cmH2O or more, a median tidal volume of less than 10 mL/kg of predicted body weight, and a median plateau pressure of less than 30 cmH2O. MAIN OUTCOME MEASURE Composite outcome of major respiratory complications, including pulmonary edema, respiratory failure, pneumonia, and re-intubation. RESULTS Of the 69,265 enrolled patients 34,800 (50.2%) received protective ventilation and 34,465 (49.8%) received non-protective ventilation intraoperatively. Protective ventilation was associated with a decreased risk of postoperative respiratory complications in multivariable regression (adjusted odds ratio 0.90, 95% confidence interval 0.82 to 0.98, P=0.013). The results were similar in the propensity score matched cohort (odds ratio 0.89, 95% confidence interval 0.83 to 0.97, P=0.004). A PEEP of 5 cmH2O and median plateau pressures of 16 cmH2O or less were associated with the lowest risk of postoperative respiratory complications. CONCLUSIONS Intraoperative protective ventilation was associated with a decreased risk of postoperative respiratory complications. A PEEP of 5 cmH2O and a plateau pressure of 16 cmH2O or less were identified as protective mechanical ventilator settings. These findings suggest that protective thresholds differ for intraoperative ventilation in patients with normal lungs compared with those used for patients with acute lung injury.
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Affiliation(s)
- Karim Ladha
- Department of Anesthesia, Critical Care, Pain Medicine, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Marcos F Vidal Melo
- Department of Anesthesia, Critical Care, Pain Medicine, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Duncan J McLean
- Department of Anesthesia, Critical Care, Pain Medicine, Massachusetts General Hospital, Boston, MA 02114, USA
| | | | - Stephanie D Grabitz
- Department of Anesthesia, Critical Care, Pain Medicine, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Tobias Kurth
- INSERM Research Center for Epidemiology and Biostatistics (U897)-Team Neuroepidemiology, Bordeaux, France College of Health Sciences, University of Bordeaux, Bordeaux, France Division of Preventive Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Matthias Eikermann
- Department of Anesthesia, Critical Care, Pain Medicine, Massachusetts General Hospital, Boston, MA 02114, USA Essen-Duisburg University, Essen, Germany
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Wellman TJ, Winkler T, Vidal Melo MF. Modeling of Tracer Transport Delays for Improved Quantification of Regional Pulmonary ¹⁸F-FDG Kinetics, Vascular Transit Times, and Perfusion. Ann Biomed Eng 2015; 43:2722-34. [PMID: 25940652 DOI: 10.1007/s10439-015-1327-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Accepted: 04/20/2015] [Indexed: 10/23/2022]
Abstract
¹⁸F-FDG-PET is increasingly used to assess pulmonary inflammatory cell activity. However, current models of pulmonary ¹⁸F-FDG kinetics do not account for delays in ¹⁸F-FDG transport between the plasma sampling site and the lungs. We developed a three-compartment model of ¹⁸F-FDG kinetics that includes a delay between the right heart and the local capillary blood pool, and used this model to estimate regional pulmonary perfusion. We acquired dynamic ¹⁸F-FDG scans in 12 mechanically ventilated sheep divided into control and lung injury groups (n = 6 each). The model was fit to tracer kinetics in three isogravitational regions-of-interest to estimate regional lung transport delays and regional perfusion. ¹³NN bolus infusion scans were acquired during a period of apnea to measure regional perfusion using an established reference method. The delayed input function model improved description of ¹⁸F-FDG kinetics (lower Akaike Information Criterion) in 98% of studied regions. Local transport delays ranged from 2.0 to 13.6 s, averaging 6.4 ± 2.9 s, and were highest in non-dependent regions. Estimates of regional perfusion derived from model parameters were highly correlated with perfusion measurements based on ¹³NN-PET (R² = 0.92, p < 0.001). By incorporating local vascular transports delays, this model of pulmonary ¹⁸F-FDG kinetics allows for simultaneous assessment of regional lung perfusion, transit times, and inflammation.
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Affiliation(s)
- Tyler J Wellman
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, 55 Fruit St, Boston, MA, 02114, USA
| | - Tilo Winkler
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, 55 Fruit St, Boston, MA, 02114, USA
| | - Marcos F Vidal Melo
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, 55 Fruit St, Boston, MA, 02114, USA.
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Hedenstierna G, Edmark L, Perchiazzi G. Postoperative lung complications: have multicentre studies been of any help? Br J Anaesth 2015; 114:541-3. [DOI: 10.1093/bja/aeu343] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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78
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Wanderer JP, Ehrenfeld JM, Epstein RH, Kor DJ, Bartz RR, Fernandez-Bustamante A, Vidal Melo MF, Blum JM. Temporal trends and current practice patterns for intraoperative ventilation at U.S. academic medical centers: a retrospective study. BMC Anesthesiol 2015; 15:40. [PMID: 25852301 PMCID: PMC4387596 DOI: 10.1186/s12871-015-0010-3] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2014] [Accepted: 02/21/2015] [Indexed: 01/11/2023] Open
Abstract
Background Lung protective ventilation strategies utilizing lower tidal volumes per predicted body weight (PBW) and positive end-expiratory pressure (PEEP) have been suggested to be beneficial in a variety of surgical populations. Recent clinical studies have used control groups ventilated with high tidal volumes without PEEP based on the assumption that this reflects current clinical practice. We hypothesized that ventilation strategies have changed over time, that most anesthetics in U.S. academic medical centers are currently performed with lower tidal volumes, and that most receive PEEP. Methods Intraoperative data were pooled for adults undergoing general anesthesia with tracheal intubation. Median tidal volumes per kilogram of PBW were categorized as > 10, 8–10 and < 8 mL per kg of PBW. The percentages of cases in 2013 that were performed with median tidal volumes < 8 mL per kg of PBW and PEEP were determined. As a secondary analysis, a proportional odds model using institution, year, height, weight and gender determined the relative associations of these factors using categorical and interquartile odds ratios. Results 295,540 cases were analyzed from 5 institutions over a period of 10 years. In 2013, 59.3% of cases used median tidal volumes < 8 mL per kg of PBW, 83.3% used PEEP, and 51.0% used both. Of those cases with PEEP, 60.9% used a median pressure of ≥ 5 cmH2O. Predictors of lower categories of tidal volumes included height (odds ratio (OR) 10.83, 95% confidence interval [10.50, 11.16]), institution (lowest OR 0.98 [0.96, 1.00], highest OR 9.63 [9.41, 9.86]), year (lowest OR 1.32 [1.21, 1.44], highest OR 6.31 [5.84, 6.82]), male gender (OR 1.10 [1.07, 1.12]), and weight (OR 0.30 [0.29, 0.31]). Conclusion Most general anesthetics with tracheal intubation at the institutions surveyed are currently performed with a median tidal volume < 8 mL per kg of PBW, most are managed with PEEP of ≥ 5 cmH2O and approximately half utilize both. Given the diversity of the institutions included, this is likely reflective of practice in U.S. academic medical centers. The utilization of higher tidal volumes without PEEP in control groups for clinical research studies should be reconsidered. Electronic supplementary material The online version of this article (doi:10.1186/s12871-015-0010-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jonathan P Wanderer
- Departments of Anesthesiology and Biomedical Informatics, Vanderbilt University, The Vanderbilt Clinic, 1301 Medical Center Drive, Suite 4648, Nashville, TN USA
| | - Jesse M Ehrenfeld
- Departments of Anesthesiology, Biomedical Informatics, Health Policy and Surgery, Vanderbilt University, Nashville, TN USA
| | - Richard H Epstein
- Department of Anesthesiology, Sidney Kimmel College of Medicine at Thomas Jefferson University, Philadelphia, PA USA
| | - Daryl J Kor
- Department of Anesthesiology, Mayo Clinic, Rochester, MN USA
| | - Raquel R Bartz
- Department of Anesthesiology, Duke University School of Medicine, Durham, NC USA
| | | | - Marcos F Vidal Melo
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, MA USA
| | - James M Blum
- Department of Anesthesiology, Emory University Hospital, Atlanta, GA USA
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Influence of Inspiration to Expiration Ratio on Cyclic Recruitment and Derecruitment of Atelectasis in a Saline Lavage Model of Acute Respiratory Distress Syndrome*. Crit Care Med 2015; 43:e65-74. [DOI: 10.1097/ccm.0000000000000788] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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80
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Ortiz VE, Vidal-Melo MF, Walsh JL. Strategies for managing oxygenation in obese patients undergoing laparoscopic surgery. Surg Obes Relat Dis 2014; 11:721-8. [PMID: 25863532 DOI: 10.1016/j.soard.2014.11.021] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Revised: 10/29/2014] [Accepted: 11/27/2014] [Indexed: 12/17/2022]
Abstract
The worldwide trend toward increasing body mass index (BMI) has caused the anesthetic management of overweight, obese, and severely obese patients to become common. The increase in oxygen demand coupled with the anatomic and physiologic changes associated with excess adipose tissue make maintenance of oxygenation a major challenge during induction, maintenance and recovery from general anesthesia. It is crucial for anesthesiologists, surgeons and perioperative healthcare providers alike to have a thorough understanding of the impact of airway management and mechanical ventilation on the respiratory care of the obese in the immediate perioperative setting. In this manuscript we aim to discuss the consequences of obesity, particularly abdominal obesity, on respiratory physiology and provide suggestions on intraoperative ventilatory strategies to maintain oxygenation in the severely obese patient undergoing pneumoperitoneum.
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Affiliation(s)
- Vilma E Ortiz
- Massachusetts General Hospital, Department of Anesthesia, Critical Care & Pain Medicine, Boston, Massachusetts.
| | - Marcos F Vidal-Melo
- Massachusetts General Hospital, Department of Anesthesia, Critical Care & Pain Medicine, Boston, Massachusetts
| | - John L Walsh
- Massachusetts General Hospital, Department of Anesthesia, Critical Care & Pain Medicine, Boston, Massachusetts
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81
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de Prost N, Feng Y, Wellman T, Tucci MR, Costa EL, Musch G, Winkler T, Harris RS, Venegas JG, Chao W, Vidal Melo MF. 18F-FDG kinetics parameters depend on the mechanism of injury in early experimental acute respiratory distress syndrome. J Nucl Med 2014; 55:1871-7. [PMID: 25286924 DOI: 10.2967/jnumed.114.140962] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
UNLABELLED PET with (18)F-FDG allows for noninvasive assessment of regional lung metabolism reflective of neutrophilic inflammation. This study aimed at determining during early acute lung injury whether local (18)F-FDG phosphorylation rate and volume of distribution were sensitive to the initial regional inflammatory response and whether they depended on the mechanism of injury: endotoxemia and surfactant depletion. METHODS Twelve sheep underwent homogeneous unilateral surfactant depletion (alveolar lavage) and were mechanically ventilated for 4 h (positive end-expiratory pressure, 10 cm H2O; plateau pressure, 30 cm H2O) while receiving intravenous endotoxin (lipopolysaccharide-positive [LPS+] group; n = 6) or not (lipopolysaccharide-negative group; n = 6). (18)F-FDG PET emission scans were then acquired. (18)F-FDG phosphorylation rate and distribution volume were calculated with a 4-compartment model. Lung tissue expression of inflammatory cytokines was measured using real-time quantitative reverse transcription polymerase chain reaction. RESULTS (18)F-FDG uptake increased in LPS+ (P = 0.012) and in surfactant-depleted sheep (P < 0.001). These increases were topographically heterogeneous, predominantly in dependent lung regions, and without interaction between alveolar lavage and LPS. The increase of (18)F-FDG uptake in the LPS+ group was related both to increases in the (18)F-FDG phosphorylation rate (P < 0.05) and to distribution volume (P < 0.01). (18)F-FDG distribution volume increased with infiltrating neutrophils (P < 0.001) and phosphorylation rate with the regional expression of IL-1β (P = 0.026), IL-8 (P = 0.011), and IL-10 (P = 0.023). CONCLUSION Noninvasive (18)F-FDG PET-derived parameters represent histologic and gene expression markers of early lung injury. Pulmonary metabolism assessed with (18)F-FDG PET depends on the mechanism of injury and appears to be additive for endotoxemia and surfactant depletion. (18)F-FDG PET may be a valuable imaging biomarker of early lung injury.
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Affiliation(s)
- Nicolas de Prost
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts Medical Intensive Care Unit, Hôpital Henri Mondor, Assistance Publique-Hôpitaux de Paris, Créteil, France
| | - Yan Feng
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| | - Tyler Wellman
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts Department of Biomedical Engineering, Boston University, Boston, Massachusetts
| | - Mauro R Tucci
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts Pulmonary Division, Cardio-pulmonary Department, Heart Institute (Incor), University of São Paulo, São Paulo, Brazil; and
| | - Eduardo L Costa
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts Pulmonary Division, Cardio-pulmonary Department, Heart Institute (Incor), University of São Paulo, São Paulo, Brazil; and
| | - Guido Musch
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| | - Tilo Winkler
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| | - R Scott Harris
- Department of Medicine (Pulmonary and Critical Care Unit), Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| | - Jose G Venegas
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| | - Wei Chao
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| | - Marcos F Vidal Melo
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
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Regional lung strain and the metabolic signature of injury*. Crit Care Med 2014; 42:1745-6. [PMID: 24933059 DOI: 10.1097/ccm.0000000000000383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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