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Spinelli E, Giani M, Slobod D, Pavlovsky B, di Pierro M, Crotti S, Lissoni A, Foti G, Grasselli G, Mauri T. Physiologic Effects of Extracorporeal Membrane Oxygenation in Patients with Severe Acute Respiratory Distress Syndrome. Am J Respir Crit Care Med 2024; 210:629-638. [PMID: 38526489 PMCID: PMC11389568 DOI: 10.1164/rccm.202309-1688oc] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 03/22/2024] [Indexed: 03/26/2024] Open
Abstract
Rationale: Blood flow rate affects mixed venous oxygenation (SvO2) during venovenous extracorporeal membrane oxygenation (ECMO), with possible effects on the pulmonary circulation and the right heart function. Objectives: To describe the physiologic effects of different levels of SvO2 obtained by changing ECMO blood flow in patients with severe acute respiratory distress syndrome receiving ECMO and controlled mechanical ventilation. Methods: Low (SvO2 target, 70-75%), intermediate (SvO2 target, 75-80%), and high (SvO2 target, >80%) ECMO blood flows were applied for 30 minutes in random order in 20 patients. Mechanical ventilation settings were left unchanged. The hemodynamic and pulmonary effects were assessed with pulmonary artery catheter and electrical impedance tomography. Measurements and Main Results: Cardiac output decreased from low to intermediate and to high blood flow/SvO2 (9.2 [6.2-10.9] vs. 8.3 [5.9-9.8] vs. 7.9 [6.5-9.1] L/min; P = 0.014), as well as mean pulmonary artery pressure (34 ± 6 vs. 31 ± 6 vs. 30 ± 5 mm Hg; P < 0.001) and right ventricular stroke work index (14.2 ± 4.4 vs. 12.2 ± 3.6 vs. 11.4 ± 3.2 g × m/beat/m2; P = 0.002). Cardiac output was inversely correlated with mixed venous and arterial Po2 values (R2 = 0.257; P = 0.031; and R2 = 0.324; P = 0.05). Pulmonary artery pressure was correlated with decreasing mixed venous Po2 (R2 = 0.29; P < 0.001) and with increasing cardiac output (R2 = 0.378; P < 0.007). Measures of [Formula: see text]/[Formula: see text] mismatch did not differ between the three steps. Conclusions: In patients with severe acute respiratory distress syndrome, increased ECMO blood flow rate resulting in higher SvO2 decreases pulmonary artery pressure, cardiac output, and right heart workload.
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Affiliation(s)
- Elena Spinelli
- Department of Anesthesia, Critical Care and Emergency, Institute for Scientific Research and Care Foundation Ca' Granda, Maggiore Policlinico Hospital, Milan, Italy
| | - Marco Giani
- Department of Emergency and Intensive Care, Institute for Scientific Research and Care Foundation San Gerardo dei Tintori, Monza, Italy
- Department of Emergency and Intensive Care, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico San Gerardo dei Tintori, Monza, Italy
| | - Douglas Slobod
- Department of Critical Care Medicine, McGill University, Montreal, Quebec, Canada
| | - Bertrand Pavlovsky
- Medical Intensive Care Unit, University Hospital of Angers, Angers, France; and
| | - Michela di Pierro
- Department of Emergency and Intensive Care, Institute for Scientific Research and Care Foundation San Gerardo dei Tintori, Monza, Italy
- Department of Emergency and Intensive Care, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico San Gerardo dei Tintori, Monza, Italy
| | - Stefania Crotti
- Department of Anesthesia, Critical Care and Emergency, Institute for Scientific Research and Care Foundation Ca' Granda, Maggiore Policlinico Hospital, Milan, Italy
| | - Alfredo Lissoni
- Department of Anesthesia, Critical Care and Emergency, Institute for Scientific Research and Care Foundation Ca' Granda, Maggiore Policlinico Hospital, Milan, Italy
| | - Giuseppe Foti
- Department of Emergency and Intensive Care, Institute for Scientific Research and Care Foundation San Gerardo dei Tintori, Monza, Italy
- Department of Emergency and Intensive Care, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico San Gerardo dei Tintori, Monza, Italy
| | - Giacomo Grasselli
- Department of Anesthesia, Critical Care and Emergency, Institute for Scientific Research and Care Foundation Ca' Granda, Maggiore Policlinico Hospital, Milan, Italy
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Tommaso Mauri
- Department of Anesthesia, Critical Care and Emergency, Institute for Scientific Research and Care Foundation Ca' Granda, Maggiore Policlinico Hospital, Milan, Italy
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
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Rehman TA, John K, Maslow A. Protective Lung Ventilation: What Do We Know?-"In An Investigation, Details Matter"-Jack Reacher TV Series. J Cardiothorac Vasc Anesth 2023; 37:2572-2576. [PMID: 37423839 PMCID: PMC10264327 DOI: 10.1053/j.jvca.2023.06.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Accepted: 06/11/2023] [Indexed: 07/11/2023]
Affiliation(s)
- T A Rehman
- Department of Anesthesiology, Beth Israel Deaconess Medical Center, Boston, MA
| | - K John
- Department of Anesthesiology, Rhode Island Hospital, Providence, RI
| | - A Maslow
- Department of Anesthesiology, Rhode Island Hospital, Providence, RI.
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Shah N, Katira BH. Role of cardiopulmonary interactions in development of ventilator-induced lung injury-Experimental evidence and clinical Implications. Front Physiol 2023; 14:1228476. [PMID: 37534365 PMCID: PMC10391157 DOI: 10.3389/fphys.2023.1228476] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 07/07/2023] [Indexed: 08/04/2023] Open
Abstract
Ventilator-induced lung injury (VILI) impacts outcomes in ARDS and optimization of ventilatory strategies improves survival. Decades of research has identified various mechanisms of VILI, largely focusing on airspace forces of plateau pressure, tidal volume and driving pressure. Experimental evidence indicates the role of adverse cardiopulmonary interaction during mechanical ventilation, contributing to VILI genesis mostly by modulating pulmonary vascular dynamics. Under passive mechanical ventilation, high transpulmonary pressure increases afterload on right heart while high pleural pressure reduces the RV preload. Together, they can result in swings of pulmonary vascular flow and pressure. Altered vascular flow and pressure result in increased vascular shearing and wall tension, in turn causing direct microvascular injury accompanied with permeability to water, proteins and cells. Moreover, abrupt decreases in airway pressure, may result in sudden overperfusion of the lung and result in similar microvascular injury, especially when the endothelium is stretched or primed at high positive end-expiratory pressure. Microvascular injury is universal in VILI models and presumed in the diagnosis of ARDS; preventing such microvascular injury can reduce VILI and impact outcomes in ARDS. Consequently, developing cardiovascular targets to reduce macro and microvascular stressors in the pulmonary circulation can potentially reduce VILI. This paper reviews the role of cardiopulmonary interaction in VILI genesis.
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Yuan JL, Kang K, Li B, Lu J, Miao MR, Kang X, Zhang JQ, Zhang W. The Effects of Sevoflurane vs. Propofol for Inflammatory Responses in Patients Undergoing Lung Resection: A Meta-Analysis of Randomized Controlled Trials. Front Surg 2021; 8:692734. [PMID: 34277696 PMCID: PMC8282814 DOI: 10.3389/fsurg.2021.692734] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Accepted: 05/31/2021] [Indexed: 01/14/2023] Open
Abstract
Objective: Inflammatory cytokines are increased during one-lung ventilation in patients undergoing lung resection, and this increase can be fatal. Propofol and sevoflurane are the main anesthetics used for these patients. Unfortunately, there is no consensus on the best choice of an anesthetic agent concerning an inflammatory response in patients undergoing lung resection. This meta-analysis aimed to compare the effects of propofol and sevoflurane on the inflammatory response in patients undergoing lung resection. Methods: We searched electronic databases to identify randomized controlled trials comparing the effects of different anesthetics (sevoflurane vs. propofol) on the inflammatory response. The primary outcome concerned the concentration of systemic inflammatory cytokines. The secondary outcomes concerned the concentrations of inflammatory cytokines in the bronchoalveolar lavage (BAL) fluid from the dependent and independent lung. Random effects analysis of the meta-analyses were performed to synthesize the evidence and to assess the concentrations of inflammatory factors in the sevoflurane and propofol groups. Results: Eight trials involving 488 participants undergoing lung resection with one-lung ventilation were included. There was no significant difference in the concentrations of systemic interleukin (IL)-6, IL-10, or tumor necrosis factor α between the sevoflurane and propofol groups. Compared with the propofol group, BAL levels of IL-6 in the dependent ventilated lung were decreased in the sevoflurane group (three trials, 256 participants; standardized mean difference [SMD], −0.51; 95% confidence interval [CI], −0.90 to −0.11; p = 0.01; I2 = 46%). The BAL levels of IL-6 in the independent ventilated lung were also decreased by sevoflurane (four trials, 362 participants; SMD, −0.70; 95% [CI], −0.93 to −0.47; p < 0.00001; I2 = 0%). Conclusions: There was no difference in the systemic inflammatory response between the sevoflurane and propofol groups. However, compared with propofol, sevoflurane can reduce the local alveolar inflammatory response. Additional research is necessary to confirm whether the inflammatory response is direct or indirect.
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Affiliation(s)
- Jing-Li Yuan
- Department of Anesthesiology and Perioperative Medicine, Henan University People's Hospital, Henan Provincial People's Hospital, Zhengzhou, China
| | - Kang Kang
- Department of Anesthesiology and Perioperative Medicine, Henan University People's Hospital, Henan Provincial People's Hospital, Zhengzhou, China
| | - Bing Li
- Department of Anesthesiology and Perioperative Medicine, Henan University People's Hospital, Henan Provincial People's Hospital, Zhengzhou, China
| | - Jie Lu
- Department of Health Statistics, School of Public Health, Zhengzhou University, Zhengzhou, China
| | - Meng-Rong Miao
- Department of Anesthesiology and Perioperative Medicine, Henan University People's Hospital, Henan Provincial People's Hospital, Zhengzhou, China
| | - Xia Kang
- Department of Anesthesiology and Perioperative Medicine, Zhengzhou University People's Hospital, Henan Provincial People's Hospital, Zhengzhou, China
| | - Jia-Qiang Zhang
- Department of Anesthesiology and Perioperative Medicine, Henan University People's Hospital, Henan Provincial People's Hospital, Zhengzhou, China
| | - Wei Zhang
- Department of Anesthesiology and Perioperative Medicine, Henan University People's Hospital, Henan Provincial People's Hospital, Zhengzhou, China
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Comparative effects of neurally adjusted ventilatory assist and variable pressure support on lung and diaphragmatic function in a model of acute respiratory distress syndrome: A randomised animal study. Eur J Anaesthesiol 2021; 38:32-40. [PMID: 32657806 DOI: 10.1097/eja.0000000000001261] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
BACKGROUND Variable assisted mechanical ventilation has been shown to improve lung function and reduce lung injury. However, differences between extrinsic and intrinsic variability are unknown. OBJECTIVE To investigate the effects of neurally adjusted ventilatory assist (NAVA, intrinsic variability), variable pressure support ventilation (Noisy PSV, extrinsic variability) and conventional pressure-controlled ventilation (PCV) on lung and diaphragmatic function and damage in experimental acute respiratory distress syndrome (ARDS). DESIGN Randomised controlled animal study. SETTING University Hospital Research Facility. SUBJECTS A total of 24 juvenile female pigs. INTERVENTIONS ARDS was induced by repetitive lung lavage and injurious ventilation. Animals were randomly assigned to 24 h of either: 1) NAVA, 2) Noisy PSV or 3) PCV (n=8 per group). Mechanical ventilation settings followed the ARDS Network recommendations. MEASUREMENTS The primary outcome was histological lung damage. Secondary outcomes were respiratory variables and patterns, subject-ventilator asynchrony (SVA), pulmonary and diaphragmatic biomarkers, as well as diaphragmatic muscle atrophy and myosin isotypes. RESULTS Global alveolar damage did not differ between groups, but NAVA resulted in less interstitial oedema in dorsal lung regions than Noisy PSV. Gas exchange and SVA incidence did not differ between groups. Compared with Noisy PSV, NAVA generated higher coefficients of variation of tidal volume and respiratory rate. During NAVA, only 40.4% of breaths were triggered by the electrical diaphragm signal. The IL-8 concentration in lung tissue was lower after NAVA compared with PCV and Noisy PSV, whereas Noisy PSV yielded lower type III procollagen mRNA expression than NAVA and PCV. Diaphragmatic muscle fibre diameters were smaller after PCV compared with assisted modes, whereas expression of myosin isotypes did not differ between groups. CONCLUSION Noisy PSV and NAVA did not reduce global lung injury compared with PCV but affected different biomarkers and attenuated diaphragmatic atrophy. NAVA increased the respiratory variability; however, NAVA yielded a similar SVA incidence as Noisy PSV. TRIAL REGISTRATION This trial was registered and approved by the Landesdirektion Dresden, Germany (AZ 24-9168.11-1/2012-2).
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Bhattacharjee I, Das A, Collin M, Aly H. Predicting outcomes of mechanically ventilated premature infants using respiratory severity score. J Matern Fetal Neonatal Med 2020; 35:4620-4627. [PMID: 33280479 DOI: 10.1080/14767058.2020.1858277] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND Extremely low birth weight (ELBW) infants have significant morbidities and higher mortality. The major morbidities are bronchopulmonary dysplasia (BPD), intraventricular hemorrhage (IVH) and retinopathy of prematurity (ROP). Release of proinflammatory cytokines has been implicated in the development of systemic inflammation that contributes to BPD aND ROP. Also, cumulative oxygen exposure in the first 3 days of life and use of mechanical ventilation was associated with 3-fold increase in severe IVH. Therefore, early ventilation and oxygenation may contribute significantly to morbidities in ELBW infants. Respiratory severity score (RSS), a product of Mean airway pressure (MAP) and FiO2, is a steady-state noninvasive assessment tool useful in infants to monitor the severity of respiratory failure. We used RSS, in the first 3 days of life of ELBW infants, to predict neonatal morbidities and mortality. STUDY DESIGN In a single-center retrospective cohort study in an urban setting, convenience sampling of ELBW infants meeting the study criteria who were mechanically ventilated at birth for the first 3 days of life were included. Time-weighted average RSS was plotted on receiver-operating characteristic (ROC) curve in the first 3 days of life to predict outcomes. Sensitivity, specificity, positive predictive value, negative predictive value and likelihood ratios were calculated. RESULTS A total of 69 infants qualified for the study. RSS in the first 3 days significantly predicted the composite outcome of death, ROP, IVH or BPD with an area under the curve (AUC) of 0.82 (p < 0.001). Individually, RSS predicted death, severe ROP and IVH with an AUC of 0.86, 0.77 and 0.71 respectively; but did not predict severe BPD (AUC 0.61). RSS was more sensitive and specific than each of its component; FiO2 and MAP. Weighted RSS in the first 3 days had high-negative predictive value of 98.1% for death between 7 days and 36 weeks, 94.6% for ROP and 91.7% for IVH. CONCLUSIONS This study is the first to show that RSS in the first 3 days of life is a good predictor of composite neonatal outcomes: severe IVH, BPD, ROP, or mortality. Early RSS had a high positive predictive value for the composite outcome of morbidities/mortality and a high specificity for mortality, ROP, and IVH individually.
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Affiliation(s)
| | - Anirudha Das
- Department of Neonatology, Cleveland Clinic Children's Hospital, Cleveland, OH, USA
| | - Marc Collin
- Department of Neonatology, MetroHealth Medical Center, Cleveland, OH, USA
| | - Hany Aly
- Department of Neonatology, Cleveland Clinic Children's Hospital, Cleveland, OH, USA
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7
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Serpa Neto A, Juffermans NP, Hemmes SNT, Barbas CSV, Beiderlinden M, Biehl M, Fernandez-Bustamante A, Futier E, Gajic O, Jaber S, Kozian A, Licker M, Lin WQ, Memtsoudis SG, Miranda DR, Moine P, Paparella D, Ranieri M, Scavonetto F, Schilling T, Selmo G, Severgnini P, Sprung J, Sundar S, Talmor D, Treschan T, Unzueta C, Weingarten TN, Wolthuis EK, Wrigge H, de Abreu MG, Pelosi P, Schultz MJ. Interaction between peri-operative blood transfusion, tidal volume, airway pressure and postoperative ARDS: an individual patient data meta-analysis. ANNALS OF TRANSLATIONAL MEDICINE 2018; 6:23. [PMID: 29430440 DOI: 10.21037/atm.2018.01.16] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Background Transfusion of blood products and mechanical ventilation with injurious settings are considered risk factors for postoperative lung injury in surgical Patients. Methods A systematic review and individual patient data meta-analysis was done to determine the independent effects of peri-operative transfusion of blood products, intra-operative tidal volume and airway pressure in adult patients undergoing mechanical ventilation for general surgery, as well as their interactions on the occurrence of postoperative acute respiratory distress syndrome (ARDS). Observational studies and randomized trials were identified by a systematic search of MEDLINE, CINAHL, Web of Science, and CENTRAL and screened for inclusion into a meta-analysis. Individual patient data were obtained from the corresponding authors. Patients were stratified according to whether they received transfusion in the peri-operative period [red blood cell concentrates (RBC) and/or fresh frozen plasma (FFP)], tidal volume size [≤7 mL/kg predicted body weight (PBW), 7-10 and >10 mL/kg PBW] and airway pressure level used during surgery (≤15, 15-20 and >20 cmH2O). The primary outcome was development of postoperative ARDS. Results Seventeen investigations were included (3,659 patients). Postoperative ARDS occurred in 40 (7.2%) patients who received at least one blood product compared to 40 patients (2.5%) who did not [adjusted hazard ratio (HR), 2.32; 95% confidence interval (CI), 1.25-4.33; P=0.008]. Incidence of postoperative ARDS was highest in patients ventilated with tidal volumes of >10 mL/kg PBW and having airway pressures of >20 cmH2O receiving both RBC and FFP, and lowest in patients ventilated with tidal volume of ≤7 mL/kg PBW and having airway pressures of ≤15 cmH2O with no transfusion. There was a significant interaction between transfusion and airway pressure level (P=0.002) on the risk of postoperative ARDS. Conclusions Peri-operative transfusion of blood products is associated with an increased risk of postoperative ARDS, which seems more dependent on airway pressure than tidal volume size.
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Affiliation(s)
- Ary Serpa Neto
- Department of Intensive Care, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.,Program of Post-Graduation, Research and Innovation, Faculdade de Medicina do ABC, São Paulo, Brazil.,Department of Critical Care Medicine, Hospital Israelita Albert Einstein, São Paulo, Brazil
| | - Nicole P Juffermans
- Department of Intensive Care, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Sabrine N T Hemmes
- Department of Intensive Care, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Carmen S V Barbas
- Department of Critical Care Medicine, Hospital Israelita Albert Einstein, São Paulo, Brazil
| | - Martin Beiderlinden
- Department of Anaesthesiology, Düsseldorf University Hospital, Düsseldorf, Germany.,Department of Anaesthesiology, Marienhospital Osnabrück, Osnabrück, Germany
| | - Michelle Biehl
- Division of Pulmonary and Critical Care Medicine, Mayo Clinic, Rochester, MN, USA
| | | | - Emmanuel Futier
- Department of Anesthesiology and Critical Care Medicine, Estaing University Hospital, Clermont-Ferrand, France
| | - Ognjen Gajic
- Division of Pulmonary and Critical Care Medicine, Mayo Clinic, Rochester, MN, USA
| | - Samir Jaber
- Department of Critical Care Medicine and Anesthesiology (SAR B), Saint Eloi University Hospital, Montpellier, France
| | - Alf Kozian
- Department of Anesthesiology and Intensive Care Medicine, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany
| | - Marc Licker
- Department of Anaesthesiology, Pharmacology and Intensive Care, Faculty of Medicine, University Hospital of Geneva, Geneva, Switzerland
| | - Wen-Qian Lin
- State Key Laboratory of Oncology of South China, Sun Yat-sen University Cancer Center, Guangzhou 510060, China
| | - Stavros G Memtsoudis
- Department of Anesthesiology, Hospital for Special Surgery, Weill Medical College of Cornell University, New York, USA
| | | | - Pierre Moine
- Department of Anesthesiology, University of Colorado, Aurora, Colorado, USA
| | - Domenico Paparella
- Division of Cardiac Surgery, Department of Emergency and Organ Transplant (D.E.T.O.), University of Bari Aldo Moro, Bari, Italy
| | - Marco Ranieri
- Department of Anesthesia and Intensive Care Medicine, Sapienza University of Rome, Policlinico Umberto I Hospital, Rome, Italy
| | - Federica Scavonetto
- Department of Anesthesiology and Anesthesia Clinical Research Unit, Mayo Clinic College of Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | - Thomas Schilling
- Department of Anesthesiology and Intensive Care Medicine, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany
| | - Gabriele Selmo
- Department of Environment, Health and Safety, University of Insubria, Varese, Italy
| | - Paolo Severgnini
- Department of Environment, Health and Safety, University of Insubria, Varese, Italy
| | - Juraj Sprung
- Department of Anesthesiology and Anesthesia Clinical Research Unit, Mayo Clinic College of Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | - Sugantha Sundar
- Department of Anesthesia, Critical Care and Pain Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, USA
| | - Daniel Talmor
- Department of Anesthesia, Critical Care and Pain Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, USA
| | - Tanja Treschan
- Department of Anaesthesiology, Düsseldorf University Hospital, Düsseldorf, Germany
| | - Carmen Unzueta
- Department of Anaesthesiology and Intensive Care, Hospital de Sant Pau, Barcelona, Spain
| | - Toby N Weingarten
- Department of Anesthesiology and Anesthesia Clinical Research Unit, Mayo Clinic College of Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | - Esther K Wolthuis
- Department of Intensive Care, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Hermann Wrigge
- Department Anesthesiology and Intensive Care Medicine, University of Leipzig, Leipzig, Germany
| | - Marcelo Gama de Abreu
- Department of Anesthesiology and Intensive Care Medicine, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Paolo Pelosi
- Department of Surgical Sciences and Integrated Diagnostics, IRCCS San Martino IST University of Genoa, Genoa, Italy
| | - Marcus J Schultz
- Department of Intensive Care, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.,Laboratory of Experimental Intensive Care and Anesthesiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
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Katira BH, Giesinger RE, Engelberts D, Zabini D, Kornecki A, Otulakowski G, Yoshida T, Kuebler WM, McNamara PJ, Connelly KA, Kavanagh BP. Adverse Heart-Lung Interactions in Ventilator-induced Lung Injury. Am J Respir Crit Care Med 2017; 196:1411-1421. [PMID: 28795839 DOI: 10.1164/rccm.201611-2268oc] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
RATIONALE In the original 1974 in vivo study of ventilator-induced lung injury, Webb and Tierney reported that high Vt with zero positive end-expiratory pressure caused overwhelming lung injury, subsequently shown by others to be due to lung shear stress. OBJECTIVES To reproduce the lung injury and edema examined in the Webb and Tierney study and to investigate the underlying mechanism thereof. METHODS Sprague-Dawley rats weighing approximately 400 g received mechanical ventilation for 60 minutes according to the protocol of Webb and Tierney (airway pressures of 14/0, 30/0, 45/10, 45/0 cm H2O). Additional series of experiments (20 min in duration to ensure all animals survived) were studied to assess permeability (n = 4 per group), echocardiography (n = 4 per group), and right and left ventricular pressure (n = 5 and n = 4 per group, respectively). MEASUREMENTS AND MAIN RESULTS The original Webb and Tierney results were replicated in terms of lung/body weight ratio (45/0 > 45/10 ≈ 30/0 ≈ 14/0; P < 0.05) and histology. In 45/0, pulmonary edema was overt and rapid, with survival less than 30 minutes. In 45/0 (but not 45/10), there was an increase in microvascular permeability, cyclical abolition of preload, and progressive dilation of the right ventricle. Although left ventricular end-diastolic pressure decreased in 45/10, it increased in 45/0. CONCLUSIONS In a classic model of ventilator-induced lung injury, high peak pressure (and zero positive end-expiratory pressure) causes respiratory swings (obliteration during inspiration) in right ventricular filling and pulmonary perfusion, ultimately resulting in right ventricular failure and dilation. Pulmonary edema was due to increased permeability, which was augmented by a modest (approximately 40%) increase in hydrostatic pressure. The lung injury and acute cor pulmonale is likely due to pulmonary microvascular injury, the mechanism of which is uncertain, but which may be due to cyclic interruption and exaggeration of pulmonary blood flow.
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Affiliation(s)
- Bhushan H Katira
- 1 The Research Institute.,2 Department of Critical Care Medicine.,3 Interdepartmental Division of Critical Care Medicine
| | | | | | - Diana Zabini
- 5 Keenan Research Centre for Biomedical Sciences, St. Michael's Hospital, Toronto, Ontario, Canada; and
| | - Alik Kornecki
- 6 Department of Pediatrics, London Health Sciences Centre, London, Ontario, Canada
| | | | - Takeshi Yoshida
- 1 The Research Institute.,2 Department of Critical Care Medicine.,3 Interdepartmental Division of Critical Care Medicine
| | - Wolfgang M Kuebler
- 7 Department of Surgery, and.,8 Department of Physiology, University of Toronto, Toronto, Ontario, Canada.,5 Keenan Research Centre for Biomedical Sciences, St. Michael's Hospital, Toronto, Ontario, Canada; and
| | | | - Kim A Connelly
- 5 Keenan Research Centre for Biomedical Sciences, St. Michael's Hospital, Toronto, Ontario, Canada; and
| | - Brian P Kavanagh
- 1 The Research Institute.,2 Department of Critical Care Medicine.,9 Department of Anesthesia, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.,3 Interdepartmental Division of Critical Care Medicine.,8 Department of Physiology, University of Toronto, Toronto, Ontario, Canada
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9
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The Effects of Prone Position Ventilation on Experimental Mild Acute Lung Injury Induced by Intraperitoneal Lipopolysaccharide Injection in Rats. Lung 2016; 194:193-9. [PMID: 26912235 DOI: 10.1007/s00408-016-9853-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Accepted: 02/05/2016] [Indexed: 02/04/2023]
Abstract
INTRODUCTION The benefits of prone position ventilation are well demonstrated in the severe forms of acute respiratory distress syndrome, but not in the milder forms. We investigated the effects of prone position on arterial blood gases, lung inflammation, and histology in an experimental mild acute lung injury (ALI) model. METHODS ALI was induced in Wistar rats by intraperitoneal Escherichia coli lipopolysaccharide (LPS, 5 mg/kg). After 24 h, the animals with PaO2/FIO2 between 200 and 300 mmHg were randomized into 2 groups: prone position (n = 6) and supine position (n = 6). Both groups were compared with a control group (n = 5) that was ventilated in the supine position. All of the groups were ventilated for 1 h with volume-controlled ventilation mode (tidal volume = 6 ml/kg, respiratory rate = 80 breaths/min, positive end-expiratory pressure = 5 cmH2O, inspired oxygen fraction = 1) RESULTS: Significantly higher lung injury scores were observed in the LPS-supine group compared to the LPS-prone and control groups (0.32 ± 0.03; 0.17 ± 0.03 and 0.13 ± 0.04, respectively) (p < 0.001), mainly due to a higher neutrophil infiltration level in the interstitial space and more proteinaceous debris that filled the airspaces. Similar differences were observed when the gravity-dependent lung regions and non-dependent lung regions were analyzed separately (p < 0.05). The BAL neutrophil content was also higher in the LPS-supine group compared to the LPS-prone and control groups (p < 0.05). There were no significant differences in the wet/dry ratio and gas exchange levels. CONCLUSIONS In this experimental extrapulmonary mild ALI model, prone position ventilation for 1 h, when compared with supine position ventilation, was associated with lower lung inflammation and injury.
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Effects of ultraprotective ventilation, extracorporeal carbon dioxide removal, and spontaneous breathing on lung morphofunction and inflammation in experimental severe acute respiratory distress syndrome. Anesthesiology 2015; 122:631-46. [PMID: 25371037 DOI: 10.1097/aln.0000000000000504] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
BACKGROUND To investigate the role of ultraprotective mechanical ventilation (UP-MV) and extracorporeal carbon dioxide removal with and without spontaneous breathing (SB) to improve respiratory function and lung protection in experimental severe acute respiratory distress syndrome. METHODS Severe acute respiratory distress syndrome was induced by saline lung lavage and mechanical ventilation (MV) with higher tidal volume (VT) in 28 anesthetized pigs (32.8 to 52.5 kg). Animals (n = 7 per group) were randomly assigned to 6 h of MV (airway pressure release ventilation) with: (1) conventional P-MV with VT ≈6 ml/kg (P-MVcontr); (2) UP-MV with VT ≈3 ml/kg (UP-MVcontr); (3) UP-MV with VT ≈3 ml/kg and SB (UP-MVspont); and (4) UP-MV with VT ≈3 ml/kg and pressure supported SB (UP-MVPS). In UP-MV groups, extracorporeal carbon dioxide removal was used. RESULTS The authors found that: (1) UP-MVcontr reduced diffuse alveolar damage score in dorsal lung zones (median[interquartile]) (12.0 [7.0 to 16.8] vs. 22.5 [13.8 to 40.8]), but worsened oxygenation and intrapulmonary shunt, compared to P-MVcontr; (2) UP-MVspont and UP-MVPS improved oxygenation and intrapulmonary shunt, and redistributed ventilation towards dorsal areas, as compared to UP-MVcontr; (3) compared to P-MVcontr, UP-MVcontr and UP-MVspont, UP-MVPS yielded higher levels of tumor necrosis factor-α (6.9 [6.5 to 10.1] vs. 2.8 [2.2 to 3.0], 3.6 [3.0 to 4.7] and 4.0 [2.8 to 4.4] pg/mg, respectively) and interleukin-8 (216.8 [113.5 to 343.5] vs. 59.8 [45.3 to 66.7], 37.6 [18.8 to 52.0], and 59.5 [36.1 to 79.7] pg/mg, respectively) in dorsal lung zones. CONCLUSIONS In this model of severe acute respiratory distress syndrome, MV with VT ≈3 ml/kg and extracorporeal carbon dioxide removal without SB slightly reduced lung histologic damage, but not inflammation, as compared to MV with VT = 4 to 6 ml/kg. During UP-MV, pressure supported SB increased lung inflammation.
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Modulation of stress versus time product during mechanical ventilation influences inflammation as well as alveolar epithelial and endothelial response in rats. Anesthesiology 2015; 122:106-16. [PMID: 25141026 DOI: 10.1097/aln.0000000000000415] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
BACKGROUND Mechanical ventilation can lead to lung biotrauma when mechanical stress exceeds safety thresholds. The authors investigated whether the duration of mechanical stress, that is, the impact of a stress versus time product (STP), influences biotrauma. The authors hypothesized that higher STP levels are associated with increased inflammation and with alveolar epithelial and endothelial cell injury. METHODS In 46 rats, Escherichia coli lipopolysaccharide (acute lung inflammation) or saline (control) was administered intratracheally. Both groups were protectively ventilated with inspiratory-to-expiratory ratios 1:2, 1:1, or 2:1 (n = 12 each), corresponding to low, middle, and high STP levels (STPlow, STPmid, and STPhigh, respectively). The remaining 10 animals were not mechanically ventilated. RESULTS In animals with mild acute lung inflammation, but not in controls: (1) messenger RNA expression of interleukin-6 was higher in STPhigh (28.1 ± 13.6; mean ± SD) and STPlow (28.9 ± 16.0) versus STPmid (7.4 ± 7.5) (P < 0.05); (2) expression of the receptor for advanced glycation end-products was increased in STPhigh (3.6 ± 1.6) versus STPlow (2.3 ± 1.1) (P < 0.05); (3) alveolar edema was decreased in STPmid (0 [0 to 0]; median, Q1 to Q3) compared with STPhigh (0.8 [0.6 to 1]) (P < 0.05); and (4) expressions of vascular cell adhesion molecule-1 and intercellular adhesion molecule-1 were higher in STPlow (3.0 ± 1.8) versus STPhigh (1.2 ± 0.5) and STPmid (1.4 ± 0.7) (P < 0.05), respectively. CONCLUSIONS In the mild acute lung inflammation model used herein, mechanical ventilation with inspiratory-to-expiratory of 1:1 (STPmid) minimized lung damage, whereas STPhigh increased the gene expression of biological markers associated with inflammation and alveolar epithelial cell injury and STPlow increased markers of endothelial cell damage.
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Protective Ventilatory Approaches to One-Lung Ventilation: More than Reduction of Tidal Volume. CURRENT ANESTHESIOLOGY REPORTS 2014. [DOI: 10.1007/s40140-014-0057-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Gattinoni L, Taccone P, Carlesso E, Marini JJ. Prone position in acute respiratory distress syndrome. Rationale, indications, and limits. Am J Respir Crit Care Med 2014; 188:1286-93. [PMID: 24134414 DOI: 10.1164/rccm.201308-1532ci] [Citation(s) in RCA: 268] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
In the prone position, computed tomography scan densities redistribute from dorsal to ventral as the dorsal region tends to reexpand while the ventral zone tends to collapse. Although gravitational influence is similar in both positions, dorsal recruitment usually prevails over ventral derecruitment, because of the need for the lung and its confining chest wall to conform to the same volume. The final result of proning is that the overall lung inflation is more homogeneous from dorsal to ventral than in the supine position, with more homogeneously distributed stress and strain. As the distribution of perfusion remains nearly constant in both postures, proning usually improves oxygenation. Animal experiments clearly show that prone positioning delays or prevents ventilation-induced lung injury, likely due in large part to more homogeneously distributed stress and strain. Over the last 15 years, five major trials have been conducted to compare the prone and supine positions in acute respiratory distress syndrome, regarding survival advantage. The sequence of trials enrolled patients who were progressively more hypoxemic; exposure to the prone position was extended from 8 to 17 hours/day, and lung-protective ventilation was more rigorously applied. Single-patient and meta-analyses drawing from the four major trials showed significant survival benefit in patients with PaO2/FiO2 lower than 100. The latest PROSEVA (Proning Severe ARDS Patients) trial confirmed these benefits in a formal randomized study. The bulk of data indicates that in severe acute respiratory distress syndrome, carefully performed prone positioning offers an absolute survival advantage of 10-17%, making this intervention highly recommended in this specific population subset.
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Affiliation(s)
- Luciano Gattinoni
- 1 Dipartimento di Fisiopatologia Medico-Chirurgica e dei Trapianti, Fondazione IRCCS Ca' Granda-Ospedale Maggiore Policlinico, Università degli Studi di Milano, Milan, Italy
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Hedenstierna G, Rothen HU. Respiratory function during anesthesia: effects on gas exchange. Compr Physiol 2013; 2:69-96. [PMID: 23728971 DOI: 10.1002/cphy.c080111] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Anaesthesia causes a respiratory impairment, whether the patient is breathing spontaneously or is ventilated mechanically. This impairment impedes the matching of alveolar ventilation and perfusion and thus the oxygenation of arterial blood. A triggering factor is loss of muscle tone that causes a fall in the resting lung volume, functional residual capacity. This fall promotes airway closure and gas adsorption, leading eventually to alveolar collapse, that is, atelectasis. The higher the oxygen concentration, the faster will the gas be adsorbed and the aleveoli collapse. Preoxygenation is a major cause of atelectasis and continuing use of high oxygen concentration maintains or increases the lung collapse, that typically is 10% or more of the lung tissue. It can exceed 25% to 40%. Perfusion of the atelectasis causes shunt and cyclic airway closure causes regions with low ventilation/perfusion ratios, that add to impaired oxygenation. Ventilation with positive end-expiratory pressure reduces the atelectasis but oxygenation need not improve, because of shift of blood flow down the lung to any remaining atelectatic tissue. Inflation of the lung to an airway pressure of 40 cmH2O recruits almost all collapsed lung and the lung remains open if ventilation is with moderate oxygen concentration (< 40%) but recollapses within a few minutes if ventilation is with 100% oxygen. Severe obesity increases the lung collapse and obstructive lung disease and one-lung anesthesia increase the mismatch of ventilation and perfusion. CO2 pneumoperitoneum increases atelectasis formation but not shunt, likely explained by enhanced hypoxic pulmonary vasoconstriction by CO2. Atelectasis may persist in the postoperative period and contribute to pneumonia.
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Affiliation(s)
- Göran Hedenstierna
- Department of Medical Sciences, Clinical Physiology, Uppsala University Hospital, Uppsala, Sweden.
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Xia J, Sun B, He H, Zhang H, Wang C, Zhan Q. Effect of spontaneous breathing on ventilator-induced lung injury in mechanically ventilated healthy rabbits: a randomized, controlled, experimental study. Crit Care 2011; 15:R244. [PMID: 22018091 PMCID: PMC3334795 DOI: 10.1186/cc10502] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2011] [Revised: 08/09/2011] [Accepted: 10/21/2011] [Indexed: 11/10/2022] Open
Abstract
INTRODUCTION Ventilator-induced lung injury (VILI), one of the most serious complications of mechanical ventilation (MV), can impact patients' clinical prognoses. Compared to control ventilation, preserving spontaneous breathing can improve many physiological features in ventilated patients, such as gas distribution, cardiac performance, and ventilation-perfusion matching. However, the effect of spontaneous breathing on VILI is unknown. The goal of this study was to compare the effects of spontaneous breathing and control ventilation on lung injury in mechanically-ventilated healthy rabbits. METHODS Sixteen healthy New Zealand white rabbits were randomly placed into a spontaneous breathing group (SB Group) and a control ventilation group (CV Group). Both groups were ventilated for eight hours using biphasic positive airway pressure (BIPAP) with similar ventilator parameters: inspiration pressure (PI) resulting in a tidal volume (VT) of 10 to 15 ml/kg, inspiratory-to-expiratory ratio of 1:1, positive end-expiration pressure (PEEP) of 2 cmH₂O, and FiO₂ of 0.5. Inflammatory markers in blood serum, lung homogenates and bronchoalveolar lavage fluid (BALF), total protein levels in BALF, mRNA expressions of selected cytokines in lung tissue, and lung injury histopathology scores were determined. RESULTS Animals remained hemodynamically stable throughout the entire experiment. After eight hours of MV, compared to the CV Group, the SB Group had lower PaCO₂ values and ratios of dead space to tidal volume, and higher lung compliance. The levels of cytokines in blood serum and BALF in both groups were similar, but spontaneous breathing led to significantly lower cytokine mRNA expressions in lung tissues and lower lung injury histological scores. CONCLUSIONS Preserving spontaneous breathing can not only improve ventilatory function, but can also attenuate selected markers of VILI in the mechanically-ventilated healthy lung.
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Affiliation(s)
- Jingen Xia
- Department of Respiratory and Critical Care Medicine, Beijing Institute of Respiratory Medicine, Beijing Chao-Yang Hospital, Capital Medical University, 8 Gongren Tiyuchang South Road, Beijing, 100020, PR China
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Kapetanakis T, Siempos II, Metaxas EI, Kopterides P, Agrogiannis G, Patsouris E, Lazaris AC, Stravodimos KG, Roussos C, Armaganidis A. Metabolic acidosis may be as protective as hypercapnic acidosis in an ex-vivo model of severe ventilator-induced lung injury: a pilot study. BMC Anesthesiol 2011; 11:8. [PMID: 21486492 PMCID: PMC3087686 DOI: 10.1186/1471-2253-11-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2010] [Accepted: 04/13/2011] [Indexed: 11/10/2022] Open
Abstract
Background There is mounting experimental evidence that hypercapnic acidosis protects against lung injury. However, it is unclear if acidosis per se rather than hypercapnia is responsible for this beneficial effect. Therefore, we sought to evaluate the effects of hypercapnic (respiratory) versus normocapnic (metabolic) acidosis in an ex vivo model of ventilator-induced lung injury (VILI). Methods Sixty New Zealand white rabbit ventilated and perfused heart-lung preparations were used. Six study groups were evaluated. Respiratory acidosis (RA), metabolic acidosis (MA) and normocapnic-normoxic (Control - C) groups were randomized into high and low peak inspiratory pressures, respectively. Each preparation was ventilated for 1 hour according to a standardized ventilation protocol. Lung injury was evaluated by means of pulmonary edema formation (weight gain), changes in ultrafiltration coefficient, mean pulmonary artery pressure changes as well as histological alterations. Results HPC group gained significantly greater weight than HPMA, HPRA and all three LP groups (P = 0.024), while no difference was observed between HPMA and HPRA groups regarding weight gain. Neither group differ on ultrafiltration coefficient. HPMA group experienced greater increase in the mean pulmonary artery pressure at 20 min (P = 0.0276) and 40 min (P = 0.0012) compared with all other groups. Histology scores were significantly greater in HP vs. LP groups (p < 0.001). Conclusions In our experimental VILI model both metabolic acidosis and hypercapnic acidosis attenuated VILI-induced pulmonary edema implying a mechanism other than possible synergistic effects of acidosis with CO2 for VILI attenuation.
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Affiliation(s)
- Theodoros Kapetanakis
- "G, P, Livanos and M, Simou" Laboratories, "Evangelismos" General Hospital, University of Athens Medical School, Athens, Greece.
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Pressure support improves oxygenation and lung protection compared to pressure-controlled ventilation and is further improved by random variation of pressure support*. Crit Care Med 2011; 39:746-55. [DOI: 10.1097/ccm.0b013e318206bda6] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Kozian A, Schilling T, Röcken C, Breitling C, Hachenberg T, Hedenstierna G. Increased Alveolar Damage After Mechanical Ventilation in a Porcine Model of Thoracic Surgery. J Cardiothorac Vasc Anesth 2010; 24:617-23. [DOI: 10.1053/j.jvca.2009.09.016] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2009] [Indexed: 11/11/2022]
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Saddy F, Oliveira GP, Garcia CSNB, Nardelli LM, Rzezinski AF, Ornellas DS, Morales MM, Capelozzi VL, Pelosi P, Rocco PRM. Assisted ventilation modes reduce the expression of lung inflammatory and fibrogenic mediators in a model of mild acute lung injury. Intensive Care Med 2010; 36:1417-26. [PMID: 20333356 DOI: 10.1007/s00134-010-1808-6] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2009] [Accepted: 12/06/2009] [Indexed: 01/09/2023]
Abstract
PURPOSE The goal of the study was to compare the effects of different assisted ventilation modes with pressure controlled ventilation (PCV) on lung histology, arterial blood gases, inflammatory and fibrogenic mediators in experimental acute lung injury (ALI). METHODS Paraquat-induced ALI rats were studied. At 24 h, animals were anaesthetised and further randomized as follows (n = 6/group): (1) pressure controlled ventilation mode (PCV) with tidal volume (V (T)) = 6 ml/kg and inspiratory to expiratory ratio (I:E) = 1:2; (2) three assisted ventilation modes: (a) assist-pressure controlled ventilation (APCV1:2) with I:E = 1:2, (b) APCV1:1 with I:E = 1:1; and (c) biphasic positive airway pressure and pressure support ventilation (BiVent + PSV), and (3) spontaneous breathing without PEEP in air. PCV, APCV1:1, and APCV1:2 were set with P (insp) = 10 cmH(2)O and PEEP = 5 cmH(2)O. BiVent + PSV was set with two levels of CPAP [inspiratory pressure (P (High) = 10 cmH(2)O) and positive end-expiratory pressure (P (Low) = 5 cmH(2)O)] and inspiratory/expiratory times: T (High) = 0.3 s and T (Low) = 0.3 s. PSV was set as follows: 2 cmH(2)O above P (High) and 7 cmH(2)O above P (Low). All rats were mechanically ventilated in air and PEEP = 5 cmH(2)O for 1 h. RESULTS Assisted ventilation modes led to better functional improvement and less lung injury compared to PCV. APCV1:1 and BiVent + PSV presented similar oxygenation levels, which were higher than in APCV1:2. Bivent + PSV led to less alveolar epithelium injury and lower expression of tumour necrosis factor-alpha, interleukin-6, and type III procollagen. CONCLUSIONS In this experimental ALI model, assisted ventilation modes presented greater beneficial effects on respiratory function and a reduction in lung injury compared to PCV. Among assisted ventilation modes, Bi-Vent + PSV demonstrated better functional results with less lung damage and expression of inflammatory mediators.
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Affiliation(s)
- Felipe Saddy
- Laboratory of Pulmonary Investigation, Carlos Chagas Filho Institute of Biophysics-CCS, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
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Effects of vascular flow and PEEP in a multiple hit model of lung injury in isolated perfused rabbit lungs. ACTA ACUST UNITED AC 2008; 65:147-53. [PMID: 18580520 DOI: 10.1097/ta.0b013e31813e0904] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND High vascular flow aggravates lung damage in animal models of ventilator-induced lung injury. Positive end-expiratory pressure (PEEP) can attenuate ventilator-induced lung injury, but its continued effectiveness in the setting of antecedent lung injury is unclear. The objective of the present study was to evaluate whether the application of PEEP diminishes lung injury induced by concurrent high vascular flow and high alveolar pressures in normal lungs and in a preinjury lung model. METHODS Two series of experiments were performed. Fifteen sets of isolated rabbit lungs were randomized into three groups (n = 5): low vascular flow/low PEEP; high vascular flow/low PEEP, and high vascular flow/high PEEP. Subsequently, the same protocol was applied in an additional 15 sets of isolated rabbit lungs in which oleic acid was added to the vascular perfusate to produce mild to moderate lung injury. All lungs were ventilated with peak airway pressure of 30 cm H2O for 30 minutes. Outcome measures included frequency of gross structural failure, pulmonary hemorrhage, edema formation, changes in static compliance, pulmonary vascular resistance, and pulmonary ultrafiltration coefficient. RESULTS In the context of high vascular flow, application of a moderate level of PEEP reduced pulmonary rupture, edema formation, and lung hemorrhage. The protective effects of PEEP were not observed in lungs concurrently injured with oleic acid. CONCLUSIONS Under these experimental conditions, PEEP attenuates lung injury in the setting of high vascular flow. The protective effect of PEEP is lost in a two-hit model of lung injury.
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López-Aguilar J, Piacentini E, Villagrá A, Murias G, Pascotto S, Saenz-Valiente A, Fernández-Segoviano P, Hotchkiss JR, Blanch L. Contributions of vascular flow and pulmonary capillary pressure to ventilator-induced lung injury. Crit Care Med 2006; 34:1106-12. [PMID: 16484897 DOI: 10.1097/01.ccm.0000205757.66971.da] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To evaluate the influence of vascular flow on ventilator-induced lung injury independent of vascular pressures. DESIGN Laboratory study. SETTING Hospital laboratory. SUBJECTS Thirty-two New Zealand White rabbits. INTERVENTIONS Thirty-two isolated perfused rabbit lungs were allocated into four groups: low flow/low pulmonary capillary pressure; high flow/high pulmonary capillary pressure; low flow/high pulmonary capillary pressure, and high flow/low pulmonary capillary pressure. All lungs were ventilated with peak airway pressure 30 cm H2O and positive end-expiratory pressure 5 cm H2O for 30 mins. MEASUREMENTS AND MAIN RESULTS Outcome measures included frequency of gross structural failure (pulmonary rupture), pulmonary hemorrhage, edema formation, changes in lung compliance, pulmonary vascular resistance, and pulmonary ultrafiltration coefficient. Lungs exposed to high pulmonary vascular flow ruptured more frequently, displayed more hemorrhage, developed more edema, suffered larger decreases in compliance, and had larger increases in vascular resistance than lungs exposed to low vascular flows (p < .05 for each pairwise comparison between groups). CONCLUSIONS These findings suggest that high pulmonary vascular flows might exacerbate ventilator-induced lung injury independent of their effects on pulmonary vascular pressures.
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Affiliation(s)
- Josefina López-Aguilar
- Critical Care Center, Hospital de Sabadell, Institut Universitari Parc Taulí, Universitat Autónoma de Barcelona, Esfera UAB, Spain
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Broccard A. Prone position, high-frequency oscillatory ventilation, and Hippocrates in acute respiratory distress syndrome. Crit Care Med 2005; 33:2407-8. [PMID: 16215399 DOI: 10.1097/01.ccm.0000182888.94728.3a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Chugh K, Sachdev A, Agarwal S. Comparision of two ventilation modes and their clinical implications in sick children. Indian J Crit Care Med 2005. [DOI: 10.4103/0972-5229.19760] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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Papazian L, Gainnier M, Marin V, Donati S, Arnal JM, Demory D, Roch A, Forel JM, Bongrand P, Brégeon F, Sainty JM. Comparison of prone positioning and high-frequency oscillatory ventilation in patients with acute respiratory distress syndrome*. Crit Care Med 2005; 33:2162-71. [PMID: 16215365 DOI: 10.1097/01.ccm.0000181298.05474.2b] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
OBJECTIVE Both prone position and high-frequency oscillatory ventilation (HFOV) have the potential to facilitate lung recruitment, and their combined use could thus be synergetic on gas exchange. Keeping the lung open could also potentially be lung protective. The aim of this study was to compare physiologic and proinflammatory effects of HFOV, prone positioning, or their combination in severe acute respiratory distress syndrome (ARDS). DESIGN : Prospective, comparative randomized study. SETTING A medical intensive care unit. PATIENTS Thirty-nine ARDS patients with a Pao2/Fio2 ratio <150 mm Hg at positive end-expiratory pressure > or =5 cm H2O. INTERVENTIONS After 12 hrs on conventional lung-protective mechanical ventilation (tidal volume 6 mL/kg of ideal body weight, plateau pressure not exceeding the upper inflection point, and a maximum of 35 cm H2O; supine-CV), 39 patients were randomized to receive one of the following 12-hr periods: conventional lung-protective mechanical ventilation in prone position (prone-CV), HFOV in supine position (supine-HFOV), or HFOV in prone position (prone-HFOV). MEASUREMENTS AND MAIN RESULTS Prone-CV (from 138 +/- 58 mm Hg to 217 +/- 110 mm Hg, p < .0001) and prone-HFOV (from 126 +/- 40 mm Hg to 227 +/- 64 mm Hg, p < 0.0001) improved the Pao2/Fio2 ratio whereas supine-HFOV did not alter the Pao2/Fio2 ratio (from 134 +/- 57 mm Hg to 138 +/- 48 mm Hg). The oxygenation index ({mean airway pressure x Fio2 x 100}/Pao2) decreased in the prone-CV and prone-HFOV groups and was lower than in the supine-HFOV group. Interleukin-8 increased significantly in the bronchoalveolar lavage fluid (BALF) in supine-HFOV and prone-HFOV groups compared with prone-CV and supine-CV. Neutrophil counts were higher in the supine-HFOV group than in the prone-CV group. CONCLUSIONS Although HFOV in the supine position does not improve oxygenation or lung inflammation, the prone position increases oxygenation and reduces lung inflammation in ARDS patients. Prone-HFOV produced similar improvement in oxygenation like prone-CV but was associated with higher BALF indexes of inflammation. In contrast, supine-HFOV did not improve gas exchange and was associated with enhanced lung inflammation.
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Affiliation(s)
- Laurent Papazian
- Service de Réanimation Médicale, Hôpital Sainte-Marguerite, Faculté de Médecine de Marseille, Université de la Méditerranée, Marseille, France
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Schilling T, Kozian A, Huth C, Bühling F, Kretzschmar M, Welte T, Hachenberg T. The Pulmonary Immune Effects of Mechanical Ventilation in Patients Undergoing Thoracic Surgery. Anesth Analg 2005; 101:957-965. [PMID: 16192502 DOI: 10.1213/01.ane.0000172112.02902.77] [Citation(s) in RCA: 171] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
UNLABELLED Mechanical ventilation (MV) may induce an inflammatory alveolar response. One-lung ventilation (OLV) with tidal volumes (Vt) as used during two-lung ventilation is a suggested algorithm but may impose mechanical stress of the dependent lung and potentially aggravate alveolar mediator release. We studied whether ventilation with different Vt modifies pulmonary immune function, hemodynamics, and gas exchange. Thirty-two patients undergoing open thoracic surgery were randomized to receive either MV with Vt = 10 mL/kg (n = 16) or Vt = 5 mL/kg (n = 16) adjusted to normal Pa(CO2) during and after OLV. Fiberoptic bronchoalveolar lavage of the ventilated lung was performed, and cells, protein, tumor necrosis factor (TNF)-alpha, interleukin (IL)-8, soluble intercellular adhesion molecule (sICAM)-1, IL-10, and elastase were determined in the bronchoalveolar lavage. Data were analyzed by parametric or nonparametric tests, as indicated. In all patients, an increase of proinflammatory variables was found. The time courses of intra-alveolar cells, protein, albumin, IL-8, elastase, and IL-10 did not differ between the groups after OLV and postoperatively. TNF-alpha (8.4 versus 5.0 microg/mL) and sICAM-1 (52.7 versus 27.5 microg/mL) concentrations were significantly smaller after OLV with Vt = 5 mL/kg. These results indicate that MV may induce epithelial damage and a proinflammatory response in the ventilated lung. Reduction of tidal volume during OLV may reduce alveolar concentrations of TNF-alpha and of sICAM-1. IMPLICATIONS Reductions of tidal volume, with subsequently decreased peak airway pressures, may reduce some alveolar inflammatory responses seen with mechanical ventilation.
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Affiliation(s)
- Thomas Schilling
- *Department of Anesthesiology and Intensive Care Medicine, †Department of Cardiovascular and Thoracic Surgery, ‡Institute of Immunology, and §Department of Cardiology, Angiology, and Pneumology, Otto-von-Guericke-University, Magdeburg, Germany
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Broccard AF, Feihl F, Vannay C, Markert M, Hotchkiss J, Schaller MD. Effects of L-NAME and inhaled nitric oxide on ventilator-induced lung injury in isolated, perfused rabbit lungs. Crit Care Med 2004; 32:1872-8. [PMID: 15343015 DOI: 10.1097/01.ccm.0000139605.38527.1b] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To determine whether nitric oxide (NO) might modulate ventilator-induced lung injury. DESIGN Randomized prospective animal study. SETTING Animal research laboratory in a university hospital. SUBJECTS Isolated, perfused rabbit heart-lung preparation. INTERVENTIONS Thirty-six isolated, perfused rabbit lungs were randomized into six groups (n = 6) and ventilated using pressure-controlled ventilation for two consecutive periods (T1 and T2). Peak alveolar pressure during pressure-controlled ventilation was 20 cm H2O at T1 and was subsequently (T2) either reduced to 15 cm H2O in the three low-pressure control groups (Cx) or increased to 25 cm H2O in the three high-pressure groups (Px). In the control and high-pressure groups, NO concentration was increased to approximately equal to 20 ppm (inhaled NO groups: CNO, PNO), reduced by NO synthase inhibition (L-NAME groups: CL-Name, PL-Name), or not manipulated (groups CE, PE). MEASUREMENTS AND MAIN RESULTS Changes in ultrafiltration coefficients (deltaKf [vascular permeability index: g.min(-1).cm H2O(-1).100 g(-1)]), bronchoalveolar lavage fluid 8-isoprostane, and NOx (nitrate + nitrite) concentrations were the measures examined. Neither L-NAME nor inhaled NO altered lung permeability in the setting of low peak alveolar pressure (control groups). In contrast, L-NAME virtually abolished the change in permeability (deltaKf: PL-Name (0.10 +/- 0.03) vs. PNO [1.75 +/- 1.10] and PE [0.37 +/- 0.11; p <.05]) and the increase in bronchoalveolar lavage 8-isoprostane concentration induced by high-pressure ventilation. Although inhaled NO was associated with the largest change in permeability, no significant difference between the PE and PL-NAME groups was observed. The change in permeability (deltaKf) correlated with bronchoalveolar lavage NOx (r2 =.6; p <.001). CONCLUSIONS L-NAME may attenuate ventilator-induced microvascular leak and lipid peroxidation and NO may contribute to the development of ventilator-induced lung injury. Measurement of NO metabolites in the bronchoalveolar lavage may afford a means to monitor lung injury induced by mechanical stress.
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Affiliation(s)
- Alain F Broccard
- University of Minnesota, Pulmonary and Critical Care Division, Regions Hospital, St. Paul, MN, USA
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Simonson DA, Adams AB, Wright LA, Dries DJ, Hotchkiss JR, Marini JJ. Effects of ventilatory pattern on experimental lung injury caused by high airway pressure. Crit Care Med 2004; 32:781-6. [PMID: 15090962 DOI: 10.1097/01.ccm.0000114825.03249.62] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To determine the influence of clinician-adjustable ventilator settings on the development of ventilator-induced lung injury, as assessed by changes in gas exchange (Pao2), compliance, functional residual capacity, and wet weight to dry weight ratio. DESIGN Randomized in vivo rabbit study. SETTING Hospital research laboratory. SUBJECTS Forty-four anesthetized, mechanically ventilated adult rabbits. INTERVENTIONS Ventilation for 2 hrs with pressure control ventilation at 45 cm H2O, Fio2 = 0.6, and randomization to one of five ventilatory strategies using combinations of positive end-expiratory pressure (3 or 12 cm H2O), inspiratory time (0.45, 1.0, or 2.0 secs), and frequency (9 or 23/min). MEASUREMENTS AND MAIN RESULTS Among the ventilator strategies applied, PEEP at 12 cm H2O (elevated positive end-expiratory pressure) and inspiratory time at 0.45 secs (reduced inspiratory time) best preserved Pao2 (p <.003) and compliance (p <.035). During injury development, two consistent changes were observed: Tidal volume increased, and airway pressure waveform was transformed by extending the time to attain target pressure. CONCLUSIONS In this preclinical model, lung injury was attenuated by decreasing inspiratory time. As lung injury occurred, tidal volume increased and airway pressure waveform changed.
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Affiliation(s)
- Dana A Simonson
- Department of Pulmonary and Critical Care Medicine, Regions Hospital/HealthPartners and University of Minnesota Medical School, USA
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Marini JJ, Hotchkiss JR, Broccard AF. Bench-to-bedside review: microvascular and airspace linkage in ventilator-induced lung injury. Crit Care 2003; 7:435-44. [PMID: 14624683 PMCID: PMC374383 DOI: 10.1186/cc2392] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Experimental and clinical evidence point strongly toward the potential for microvascular stresses to influence the severity and expression of ventilator associated lung injury. Intense microvascular stresses not only influence edema but predispose to structural failure of the gas-blood barrier, possibly with adverse consequences for the lung and for extrapulmonary organs. Taking measures to lower vascular stress may offer a logical, but as yet unproven, extension of a lung-protective strategy for life support in ARDS.
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Affiliation(s)
- John J Marini
- Professor, University of Minnesota, Regions Hospital, St Paul, Minnesota, USA.
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Reper P, Van Bos R, Van Loey K, Van Laeke P, Vanderkelen A. High frequency percussive ventilation in burn patients: hemodynamics and gas exchange. Burns 2003; 29:603-8. [PMID: 12927989 DOI: 10.1016/s0305-4179(03)00068-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
High frequency percussive ventilation (HFPV) is a recent ventilatory mode, which combines conventional cycles with high frequency percussions. HFPV was initially instituted as salvage therapy after acute respiratory failure following smoke inhalation injury achieving in each case a dramatic improvement of blood oxygenation, PaCO(2) and ventilatory pressures. This study investigates the influence of HFPV on hesmodynamics, blood oxygenation and ventilatory parameters in eight stable ICU burn patients requiring artificial ventilatory support during a postoperative period following traumatic injury. Periods of 2h were analysed receiving conventional ventilation and HFPV with a high frequency of 400 and 800 cycles/min. Hemodynamic data were not significantly modified; peak inspiratory pressure was significantly lower under HFPV but mean airway pressure was unchanged. Blood oxygenation and CO(2) elimination were significantly improved under HFPV. No side effects were noted. These observations suggest that HFPV could improve pulmonary gas exchanges under lower peak pressures and without hemodynamic compromise. HFPV could represent an interesting alternative open lung strategy method to improve alveolar recruitment.
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Affiliation(s)
- P Reper
- Critical Care Department, Queen Astrid Military Hospital, Bruinstreet, 1, 1120 B-, Brussels, Belgium.
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Gama de Abreu M, Heintz M, Heller A, Széchényi R, Albrecht DM, Koch T. One-Lung Ventilation with High Tidal Volumes and Zero Positive End-Expiratory Pressure Is Injurious in the Isolated Rabbit Lung Model. Anesth Analg 2003. [DOI: 10.1213/00000539-200301000-00045] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Bendjelid K, Canet E, Gasche Y, Andre-Fouet X, Revel D, Janier M. Slaughterhouse blood as a perfusate for studying myocardial function under ischemic conditions. Braz J Med Biol Res 2003; 36:39-44. [PMID: 12532225 DOI: 10.1590/s0100-879x2003000100006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Metabolic studies using the in vitro non-recirculating blood-perfused isolated heart model require large volumes of blood. The present study was designed to determine whether heterologous pig blood collected from a slaughterhouse can be used as perfusate for isolated pig hearts perfused under aerobic and constant reduced flow conditions. Eight isolated working pig hearts perfused for 90 min at a constant flow of 1.5 ml g(-1) min(-1) with non-recirculated blood diluted with Krebs-Henseleit bicarbonate buffer at a hematocrit of 23% were compared to eight hearts subjected to the same protocol but perfused only with Krebs-Henseleit bicarbonate buffer solution. Hearts were paced at 100 bpm and subjected to aerobic perfusion at 38 degrees C. Hearts were weighed before perfusion and at the end of the experiment and the results are reported as percent weight gain (mean +/- SD). Comparisons between groups were performed by the Student t-test (P<0.05). After 90 min of perfusion with modified Krebs-Henseleit, perfused hearts presented a larger weight gain than blood-perfused hearts (39.34 +/- 9.27 vs 23.13 +/- 5.42%, P = 0.003). Left ventricular end-diastolic pressure was higher in the modified Krebs-Henseleit-perfused group than in the blood group (2.8 +/- 0.4 vs 2.3 +/- 0.3 mmHg, respectively, P = 0.01). We conclude that heterologous blood perfusion, by preserving a more physiological myocardial water content, is a better perfusion fluid than modified Krebs-Henseleit solution for quantitative studies of myocardial metabolism and heart function under ischemic conditions.
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Affiliation(s)
- K Bendjelid
- Medical Research Centre with Positron Emission (CERMEP), Lyon, France
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Gama de Abreu M, Heintz M, Heller A, Széchényi R, Albrecht DM, Koch T. One-lung ventilation with high tidal volumes and zero positive end-expiratory pressure is injurious in the isolated rabbit lung model. Anesth Analg 2003; 96:220-8, table of contents. [PMID: 12505956 DOI: 10.1097/00000539-200301000-00045] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
UNLABELLED We tested the hypothesis that one-lung ventilation (OLV) with high tidal volumes (VT) and zero positive end-expiratory pressure (PEEP) may lead to ventilator-induced lung injury. In an isolated, perfused rabbit lung model, VT and PEEP were set to avoid lung collapse and overdistension in both lungs, resulting in a straight pressure-time (P-vs-t) curve during constant flow. Animals were randomized to (a) nonprotective OLV (left lung) (n = 6), with VT values as high as before randomization and zero PEEP; (b) protective OLV (left lung) (n = 6), with 50% reduction of VT and maintenance of PEEP as before randomization; and (c) control group (n = 6), with ventilation of two lungs as before randomization. The nonprotective OLV was associated with significantly smaller degrees of collapse and overdistension in the ventilated lung (P < 0.001). Peak inspiratory pressure values were higher in the nonprotective OLV group (P < 0.001) and increased progressively throughout the observation period (P < 0.01). The mean pulmonary artery pressure and lung weight gain values, as well as the concentration of thromboxane B(2), were comparatively higher in the nonprotective OLV group (P < 0.05). A ventilatory strategy with VT values as high as those used in the clinical setting and zero PEEP leads to ventilator-induced lung injury in this model of OLV, but this can be minimized with VT and PEEP values set to avoid lung overdistension and collapse. IMPLICATIONS One-lung ventilation with high tidal volumes and zero positive end-expiratory pressure (PEEP) is injurious in the isolated rabbit lung model. A ventilatory strategy with tidal volumes and PEEP set to avoid lung overdistension and collapse minimizes lung injury during one-lung ventilation in this model.
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Affiliation(s)
- Marcelo Gama de Abreu
- Clinic of Anesthesiology and Intensive Care Medicine, University Clinic Carl Gustav Carus, Technical University Dresden, Germany.
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Broccard AF, Vannay C, Feihl F, Schaller MD. Impact of low pulmonary vascular pressure on ventilator-induced lung injury. Crit Care Med 2002; 30:2183-90. [PMID: 12394942 DOI: 10.1097/00003246-200210000-00002] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
OBJECTIVE To study the impact of low pulmonary vascular pressure on ventilator-induced lung injury. DESIGN Randomized prospective animal study. SUBJECTS Isolated perfused rabbit heart-lung preparation. SETTINGS Animal research laboratory in a university hospital. INTERVENTIONS Twenty isolated sets of normal lungs were perfused (constant flow, 0.3 L/min; left atrial pressure, 6 mm Hg), ventilated for 20 min (pressure control ventilation, 15 cm H2O; baseline period), and then randomized into three groups. Group A (control, n = 7) was perfused and ventilated as previously described during three consecutive 20-min periods. In group B (high airway pressure/normal left atrial pressure, n = 7), pressure control ventilation was 20, 25, and 30 cm H2O during each period. Group C (high airway pressure/low left atrial pressure, n = 6) was ventilated as group B but, in contrast to groups A and B, left atrial pressure was reduced to 1 mm Hg. MEASUREMENTS AND MAIN RESULTS The rate of edema formation (WGR, weight gain per minute normalized for initial lung weight) and the ultrafiltration coefficient (Kf) were measured during and after each period and their changes from baseline [DeltaWGR (edema formation index) and DeltaKf (vascular permeability index)] calculated to compare groups. The incidence and timing of vascular failure were compared. Vascular failure was considered to be present if all the following conditions were met: pulmonary hypertension, accelerated weight gain, and occurrence of fluid leak from the lungs. At the end of the study, DeltaWGR (g.g.min(-1)) was higher in group C (0.54 +/- 0.17) than in groups B (0.08 +/- 0.04) and A (0.00 +/- 0.01; p<.05), as well as in group B compared with A (p <.05). Similar differences between groups (p <.05) were found for DeltaK (g x min(-1) x cm H2O(-1) x 100 g(-1)): C, 7.24 +/- 2.36; B, 1.40 +/- 0.49; A, 0.01 +/- 0.03. Vascular failure was not observed in groups A and B but occurred in all but one preparation in group C (p <.05; C vs. A and B). CONCLUSION Reducing left atrial pressure results in more severe ventilator-induced lung injury. These results suggest that lung blood volume modulates cyclic tidal lung stress.
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Affiliation(s)
- Alain F Broccard
- Division of Intensive Care, Department of Medicine, University Hospital, Lausanne, Switzerland
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Mols G, Hermle G, Fries G, Benzing A, Lichtwarck-Aschoff M, Geiger K, Guttmann J. Different strategies to keep the lung open: a study in isolated perfused rabbit lungs. Crit Care Med 2002; 30:1598-604. [PMID: 12130985 DOI: 10.1097/00003246-200207000-00033] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
OBJECTIVE Atelectatic alveoli can be recruited or kept open either by sustained inflation maneuvers or by positive end-expiratory pressure (PEEP). Little is known about potential interactions between both approaches. Especially, it is not known whether the recruiting effect of sustained inflation maneuvers is maintained in combination with a low PEEP, as suggested recently. In an attempt to answer this question, we combined sustained inflation maneuvers with either high or low PEEP. Both approaches were compared with a strategy likely to result in alveolar atelectasis and with another ensuring adequate alveolar recruitment by adjustment of PEEP alone. DESIGN Randomized block design. SETTING Laboratory. SUBJECTS Isolated perfused rabbit lungs (n = 28). INTERVENTIONS The lungs were ventilated with a tidal volume of 8 mL/kg. After stabilization, the lungs were randomized to one of four ventilatory strategies, which then were followed for 120 mins: a) PEEP 1 cm H2O (PEEP1, negative control); b) PEEP 1 cm H2O and 30 sec-sustained inflations (20 cm H2O) every 30 mins (SI-1); c) PEEP 3 cm H2O combined with sustained inflations (SI-3); and d) PEEP repeatedly adjusted following a previously established strategy ensuring full alveolar recruitment (DYN, positive control). MEASUREMENTS AND MAIN RESULTS Distribution of ventilation and perfusion (Va/Q distribution) was analyzed by the multiple inert gas elimination technique. Volume-dependent compliance within the tidal volume was determined by using the slice method. Shunt and Va/Q mismatch significantly differed between SI-1 and SI-3, indicating full alveolar recruitment only in the latter. Data of SI-1 did not differ substantially from those of PEEP1, and data obtained in SI-3 were similar to those of DYN. CONCLUSIONS First, enduring alveolar recruitment by sustained inflation maneuvers is only possible when the alveoli are stabilized thereafter by sufficient PEEP. Second, a ventilation strategy that uses repeated sustained inflations on a comparably high PEEP may not be superior to adequate adjustment of PEEP alone.
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Affiliation(s)
- Georg Mols
- Department of Anesthesiology and Critical Care Medicine, University of Freiburg, Germany
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Broccard AF, Hotchkiss JR, Vannay C, Markert M, Sauty A, Feihl F, Schaller MD. Protective effects of hypercapnic acidosis on ventilator-induced lung injury. Am J Respir Crit Care Med 2001; 164:802-6. [PMID: 11549536 DOI: 10.1164/ajrccm.164.5.2007060] [Citation(s) in RCA: 130] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
To investigate whether respiratory acidosis modulates ventilator-induced lung injury (VILI), we perfused (constant flow) 21 isolated sets of normal rabbit lungs, ventilated them for 20 min (pressure controlled ventilation [PCV] = 15 cm H(2)O) (Baseline) with an inspired CO(2) fraction adjusted for the partial pressure of CO(2) in the perfusate (PCO(2) approximately equal to 40 mm Hg), and then randomized them into three groups. Group A (control: n = 7) was ventilated with PCV = 15 cm H(2)O for three consecutive 20-min periods (T1, T2, T3). In Group B (high PCV/normocapnia; n = 7), PCV was given at 20 (T1), 25 (T2), and 30 (T3) cm H(2)O. The targeted PCO(2) was 40 mm Hg in Groups A and B. Group C (high PCV/hypercapnia; n = 7) was ventilated in the same way as Group B, but the targeted PCO(2) was approximately equal to 70 to 100 mm Hg. The changes (from Baseline to T3) in weight gain (Delta WG: g) and in the ultrafiltration coefficient (Delta K(f) = gr/min/ cm H(2)O/100g) and the protein and hemoglobin concentrations in bronchoalveolar lavage fluid (BALF) were used to assess injury. Group B experienced a significantly greater Delta WG (14.85 +/- 5.49 [mean +/- SEM] g) and Delta K(f) (1.40 +/- 0.49 g/min/cm H(2)O/100 g) than did either Group A (Delta WG = 0.70 +/- 0.43; Delta K(f) = 0.01 +/- 0.03) or Group C (Delta WG = 5.27 +/- 2.03 g; Delta K(f) = 0.25 +/- 0.12 g/min/cm H(2)O/ 100 g). BALF protein and hemoglobin concentrations (g/L) were higher in Group B (11.98 +/- 3.78 g/L and 1.82 +/- 0.40 g/L, respectively) than in Group A (2.92 +/- 0.75 g/L and 0.38 +/- 0.15 g/L) or Group C (5.71 +/- 1.88 g/L and 1.19 +/- 0.32 g/L). We conclude that respiratory acidosis decreases the severity of VILI in this model.
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Affiliation(s)
- A F Broccard
- Division of Intensive Care, Department of Internal Medicine, University Hospital (CHUV), Lausanne, Switzerland.
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Hotchkiss JR, Blanch L, Naveira A, Adams AB, Carter C, Olson DA, Leo PH, Marini JJ. Relative roles of vascular and airspace pressures in ventilator-induced lung injury. Crit Care Med 2001; 29:1593-8. [PMID: 11505134 DOI: 10.1097/00003246-200108000-00016] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To determine whether elevations in pulmonary vascular pressure induced by mechanical ventilation are more injurious than elevations of pulmonary vascular pressure of similar magnitude occurring in the absence of mechanical ventilation. DESIGN Prospective comparative laboratory investigation. SETTING University research laboratory. SUBJECTS Male New Zealand white rabbits. INTERVENTIONS Three groups of isolated, perfused rabbit lungs were exposed to cyclic elevation of pulmonary artery pressures arising from either intermittent positive pressure mechanical ventilation or from pulsatile perfusion of lungs held motionless by continuous positive airway pressure. Peak, mean, and nadir pulmonary artery pressures and mean airway pressure were matched between groups (35, 27.4 +/- 0.74, and 20.8 +/- 1.5 mm Hg, and 17.7 +/- 0.22 cm H2O, respectively). MEASUREMENTS AND MAIN RESULTS Lungs exposed to elevated pulmonary artery pressures attributable to intermittent positive pressure mechanical ventilation formed more edema (6.8 +/- 1.3 vs. 1.1 +/- 0.9 g/g of lung), displayed more perivascular (61 +/- 26 vs. 15 +/- 13 vessels) and alveolar hemorrhage (76 +/- 11% vs. 26 +/- 18% of alveoli), and underwent larger fractional declines in static compliance (88 +/- 4.4% vs. 48 +/- 25.1% decline) than lungs exposed to similar peak and mean pulmonary artery pressures in the absence of tidal positive pressure ventilation. CONCLUSIONS Isolated phasic elevations of pulmonary artery pressure may cause less damage than those occurring during intermittent positive pressure mechanical ventilation, suggesting that cyclic changes in perivascular pressure surrounding extra-alveolar vessels may be important in the genesis of ventilator-induced lung injury.
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Affiliation(s)
- J R Hotchkiss
- Department of Pulmonary and Critical Care Medicine, Regions Hospital, University of Minnesota, St. Paul, MN, USA
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Cellular effects of ventilator-induced lung injury. Curr Opin Crit Care 2000. [DOI: 10.1097/00075198-200002000-00010] [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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