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Mojoli F, Pozzi M, Arisi E. Setting positive end-expiratory pressure: using the pressure-volume curve. Curr Opin Crit Care 2024; 30:35-42. [PMID: 38085871 DOI: 10.1097/mcc.0000000000001127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2024]
Abstract
PURPOSE OF REVIEW To discuss the role of pressure-volume curve (PV curve) in exploring elastic properties of the respiratory system and setting mechanical ventilator to reduce ventilator-induced lung injury. RECENT FINDINGS Nowadays, quasi-static PV curves and loops can be easily obtained and analyzed at the bedside without disconnection of the patient from the ventilator. It is shown that this tool can provide useful information to optimize ventilator setting. For example, PV curves can assess for patient's individual potential for lung recruitability and also evaluate the risk for lung injury of the ongoing mechanical ventilation setting. SUMMARY In conclusion, PV curve is an easily available bedside tool: its correct interpretation can be extremely valuable to enlighten potential for lung recruitability and select a high or low positive end-expiratory pressure (PEEP) strategy. Furthermore, recent studies have shown that PV curve can play a significant role in PEEP and driving pressure fine tuning: clinical studies are needed to prove whether this technique will improve outcome.
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Affiliation(s)
- Francesco Mojoli
- Department of Clinical-Surgical, Diagnostic and Pediatric Sciences, Unit of Anesthesia and Intensive Care, University of Pavia, Pavia, Italy
- Anesthesia and Intensive Care, Fondazione IRCCS Policlinico S. Matteo, Pavia, Italy
| | - Marco Pozzi
- Anesthesia and Intensive Care, Fondazione IRCCS Policlinico S. Matteo, Pavia, Italy
| | - Eric Arisi
- Anesthesia and Intensive Care, Fondazione IRCCS Policlinico S. Matteo, Pavia, Italy
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2
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Rezoagli E, Laffey JG, Bellani G. Monitoring Lung Injury Severity and Ventilation Intensity during Mechanical Ventilation. Semin Respir Crit Care Med 2022; 43:346-368. [PMID: 35896391 DOI: 10.1055/s-0042-1748917] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
Acute respiratory distress syndrome (ARDS) is a severe form of respiratory failure burden by high hospital mortality. No specific pharmacologic treatment is currently available and its ventilatory management is a key strategy to allow reparative and regenerative lung tissue processes. Unfortunately, a poor management of mechanical ventilation can induce ventilation induced lung injury (VILI) caused by physical and biological forces which are at play. Different parameters have been described over the years to assess lung injury severity and facilitate optimization of mechanical ventilation. Indices of lung injury severity include variables related to gas exchange abnormalities, ventilatory setting and respiratory mechanics, ventilation intensity, and the presence of lung hyperinflation versus derecruitment. Recently, specific indexes have been proposed to quantify the stress and the strain released over time using more comprehensive algorithms of calculation such as the mechanical power, and the interaction between driving pressure (DP) and respiratory rate (RR) in the novel DP multiplied by four plus RR [(4 × DP) + RR] index. These new parameters introduce the concept of ventilation intensity as contributing factor of VILI. Ventilation intensity should be taken into account to optimize protective mechanical ventilation strategies, with the aim to reduce intensity to the lowest level required to maintain gas exchange to reduce the potential for VILI. This is further gaining relevance in the current era of phenotyping and enrichment strategies in ARDS.
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Affiliation(s)
- Emanuele Rezoagli
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy.,Department of Emergency and Intensive Care, San Gerardo University Hospital, Monza, Italy
| | - John G Laffey
- School of Medicine, National University of Ireland, Galway, Ireland.,Department of Anaesthesia and Intensive Care Medicine, Galway University Hospitals, Saolta University Hospital Group, Galway, Ireland.,Lung Biology Group, Regenerative Medicine Institute (REMEDI) at CÚRAM Centre for Research in Medical Devices, National University of Ireland Galway, Galway, Ireland
| | - Giacomo Bellani
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy.,Department of Emergency and Intensive Care, San Gerardo University Hospital, Monza, Italy
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3
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Su L, Pan P, He H, Liu D, Long Y. PPV May Be a Starting Point to Achieve Circulatory Protective Mechanical Ventilation. Front Med (Lausanne) 2021; 8:745164. [PMID: 34926495 PMCID: PMC8674583 DOI: 10.3389/fmed.2021.745164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 10/20/2021] [Indexed: 11/16/2022] Open
Abstract
Pulse pressure variation (PPV) is a mandatory index for hemodynamic monitoring during mechanical ventilation. The changes in pleural pressure (Ppl) and transpulmonary pressure (PL) caused by mechanical ventilation are the basis for PPV and lead to the effect of blood flow. If the state of hypovolemia exists, the effect of the increased Ppl during mechanical ventilation on the right ventricular preload will mainly affect the cardiac output, resulting in a positive PPV. However, PL is more influenced by the change in alveolar pressure, which produces an increase in right heart overload, resulting in high PPV. In particular, if spontaneous breathing is strong, the transvascular pressure will be extremely high, which may lead to the promotion of alveolar flooding and increased RV flow. Asynchronous breathing and mediastinal swing may damage the pulmonary circulation and right heart function. Therefore, according to the principle of PPV, a high PPV can be incorporated into the whole respiratory treatment process to monitor the mechanical ventilation cycle damage/protection regardless of the controlled ventilation or spontaneous breathing. Through the monitoring of PPV, the circulation-protective ventilation can be guided at bedside in real time by PPV.
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Affiliation(s)
- Longxiang Su
- Department of Critical Care Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Pan Pan
- College of Pulmonary and Critical Care Medicine, Chinese PLA General Hospital, Beijing, China
| | - Huaiwu He
- Department of Critical Care Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Dawei Liu
- Department of Critical Care Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Yun Long
- Department of Critical Care Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
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4
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Santini A, Fumagalli J, Merrino A, Protti I, Paleari MC, Montoli M, Dondossola D, Gori F, Righi I, Rosso L, Gatti S, Pesenti A, Grasselli G, Zanella A. Evidence of Air Trapping During Ex Vivo Lung Perfusion: A Swine Experimental Lung Imaging and Mechanics Study. Transplant Proc 2020; 53:457-465. [PMID: 33339649 DOI: 10.1016/j.transproceed.2020.10.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 09/21/2020] [Accepted: 10/19/2020] [Indexed: 11/17/2022]
Abstract
Ex vivo lung perfusion (EVLP) allows the ventilation and perfusion of lungs to evaluate their viability for transplantation. The aim of this study is to compare the mechanical, morphologic and functional properties of lungs during EVLP with values obtained in vivo to guide a safe mechanical ventilation strategy. Lungs from 5 healthy pigs were studied in vivo and during 4 hours of EVLP. Lung compliance, airway resistance, gas exchange, and hemodynamic parameters were collected at positive end-expiratory pressure (PEEP) of 5 cm H2O. Computed tomography was performed at PEEP 0, PEEP 5, and total lung capacity (TLC). Lung pressure-volume (PV) curves were performed from PEEP 0 to TLC. Lung compliance decreased during EVLP (53 ± 5 mL/cm H2O vs 29 ± 7 mL/cm H2O, P < .05), and the PV curve showed a lower inflection point. Gas content (528 ± 118 mL vs 892 ± 402 mL at PEEP 0) and airway resistance (25 ± 5 vs 44 ± 9 cmH2O/L∗s-1, P < .05) were higher during EVLP. Alveolar dead space (5% ± 2% vs 17% ± 6%, P < .05) and intrapulmonary shunt (9% ± 2% vs 28% ± 13%, P < .05) increased ex vivo compared to in vivo, while the partial pressure of oxygen to inspired oxygen fraction ratio (PO2/FiO2) did not differ (468 ± 52 mm Hg vs 536 ± 14 mm Hg). In conclusion, during EVLP lungs show signs of air trapping and bronchoconstriction, resulting in low compliance and increased alveolar dead space. Intrapulmonary shunt is high despite oxygenation levels acceptable for transplantation.
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Affiliation(s)
- A Santini
- Dipartimento di Anestesia, Rianimazione ed Emergenza, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy; Dipartimento di Anestesia e Terapie Intensive, Humanitas Clinical and Research Center, IRCCS, Rozzano, Milan, Italy
| | - J Fumagalli
- Dipartimento di Anestesia, Rianimazione ed Emergenza, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - A Merrino
- Dipartimento di Fisiopatologia Medico-Chirurgica e dei Trapianti, Università degli Studi di Milano, Milan, Italy
| | - I Protti
- Dipartimento di Fisiopatologia Medico-Chirurgica e dei Trapianti, Università degli Studi di Milano, Milan, Italy
| | - M C Paleari
- Dipartimento di Fisiopatologia Medico-Chirurgica e dei Trapianti, Università degli Studi di Milano, Milan, Italy
| | - M Montoli
- Dipartimento di Chirurgia Toracica, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - D Dondossola
- Dipartimento di Fisiopatologia Medico-Chirurgica e dei Trapianti, Università degli Studi di Milano, Milan, Italy; Dipartimento di Chirurgia Generale e dei Trapianti di Fegato, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - F Gori
- Dipartimento di Anestesia, Rianimazione ed Emergenza, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - I Righi
- Dipartimento di Chirurgia Toracica, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - L Rosso
- Dipartimento di Chirurgia Toracica, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - S Gatti
- Centro di Ricerche Precliniche, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - A Pesenti
- Dipartimento di Anestesia, Rianimazione ed Emergenza, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy; Dipartimento di Fisiopatologia Medico-Chirurgica e dei Trapianti, Università degli Studi di Milano, Milan, Italy
| | - G Grasselli
- Dipartimento di Anestesia, Rianimazione ed Emergenza, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy; Dipartimento di Fisiopatologia Medico-Chirurgica e dei Trapianti, Università degli Studi di Milano, Milan, Italy
| | - A Zanella
- Dipartimento di Anestesia, Rianimazione ed Emergenza, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy; Dipartimento di Fisiopatologia Medico-Chirurgica e dei Trapianti, Università degli Studi di Milano, Milan, Italy.
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5
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Pellegrini M, Gudmundsson M, Bencze R, Segelsjö M, Freden F, Rylander C, Hedenstierna G, Larsson AS, Perchiazzi G. Expiratory Resistances Prevent Expiratory Diaphragm Contraction, Flow Limitation, and Lung Collapse. Am J Respir Crit Care Med 2020; 201:1218-1229. [PMID: 32150440 DOI: 10.1164/rccm.201909-1690oc] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Rationale: Tidal expiratory flow limitation (tidal-EFL) is not completely avoidable by applying positive end-expiratory pressure and may cause respiratory and hemodynamic complications in ventilated patients with lungs prone to collapse. During spontaneous breathing, expiratory diaphragmatic contraction counteracts tidal-EFL. We hypothesized that during both spontaneous breathing and controlled mechanical ventilation, external expiratory resistances reduce tidal-EFL.Objectives: To assess whether external expiratory resistances 1) affect expiratory diaphragmatic contraction during spontaneous breathing, 2) reduce expiratory flow and make lung compartments more homogeneous with more similar expiratory time constants, and 3) reduce tidal atelectasis, preventing hyperinflation.Methods: Three positive end-expiratory pressure levels and four external expiratory resistances were tested in 10 pigs after lung lavage. We analyzed expiratory diaphragmatic electric activity and respiratory mechanics. On the basis of computed tomography scans, four lung compartments-not inflated (atelectasis), poorly inflated, normally inflated, and hyperinflated-were defined.Measurements and Main Results: Consequently to additional external expiratory resistances, and mainly in lungs prone to collapse (at low positive end-expiratory pressure), 1) the expiratory transdiaphragmatic pressure decreased during spontaneous breathing by >10%, 2) expiratory flow was reduced and the expiratory time constants became more homogeneous, and 3) the amount of atelectasis at end-expiration decreased from 24% to 16% during spontaneous breathing and from 32% to 18% during controlled mechanical ventilation, without increasing hyperinflation.Conclusions: The expiratory modulation induced by external expiratory resistances preserves the positive effects of the expiratory brake while minimizing expiratory diaphragmatic contraction. External expiratory resistances optimize lung mechanics and limit tidal-EFL and tidal atelectasis, without increasing hyperinflation.
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Affiliation(s)
- Mariangela Pellegrini
- Department of Surgical Sciences and.,Central Intensive Care Unit, Department of Anesthesia, Operation, and Intensive Care and
| | - Magni Gudmundsson
- Department of Anesthesiology and Intensive Care Medicine, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Reka Bencze
- Department of Surgical Sciences and.,Central Intensive Care Unit, Department of Anesthesia, Operation, and Intensive Care and
| | - Monica Segelsjö
- Department of Radiology, Uppsala University Hospital, Uppsala, Sweden; and
| | - Filip Freden
- Department of Surgical Sciences and.,Central Intensive Care Unit, Department of Anesthesia, Operation, and Intensive Care and
| | - Christian Rylander
- Department of Anesthesiology and Intensive Care Medicine, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Göran Hedenstierna
- Department of Medical Sciences, Hedenstierna Laboratory, Uppsala University, Uppsala, Sweden
| | - Anders S Larsson
- Department of Surgical Sciences and.,Central Intensive Care Unit, Department of Anesthesia, Operation, and Intensive Care and
| | - Gaetano Perchiazzi
- Department of Surgical Sciences and.,Central Intensive Care Unit, Department of Anesthesia, Operation, and Intensive Care and
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6
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Koutsoukou A. Expiratory Flow Limitation and Airway Closure in Patients with Acute Respiratory Distress Syndrome. Am J Respir Crit Care Med 2019; 199:127-128. [PMID: 30256658 DOI: 10.1164/rccm.201807-1253le] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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7
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Shiba T, Takahashi M, Matsumoto T, Hori Y. Sleep-Disordered Breathing Is a Stronger Risk Factor for Proliferative Diabetic Retinopathy than Metabolic Syndrome and the Number of Its Individual Components. Semin Ophthalmol 2019; 34:59-65. [PMID: 30669924 DOI: 10.1080/08820538.2019.1569074] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
PURPOSE To evaluate whether the features of sleep-disordered breathing (SDB) are stronger independent factors for proliferative diabetic retinopathy (PDR) compared to the incidence of metabolic syndrome (MetS) and the number of its individual components. METHODS We studied a cross-sectional total of 132 patients with type 2 diabetes. Thirty-nine patients had non-proliferative diabetic retinopathy (NPDR) and 93 patients had PDR. Pulse oximetry was conducted, and the patients' mean oxygen saturation (mean SpO2%) and 4% oxygen desaturation index (4% ODI times/hour) were evaluated. We compared the SDB and MetS variables between the NPDR and PDR patients. A logistic regression analysis was used to determine the independent factors for the diagnosis of PDR. RESULTS The MetS diagnosis was made significantly more often in the PDR group (p = 0.04). The number of individual MetS components was significantly greater in the PDR group compared to the NPDR group (p = 0.01). The mean SpO2 of the NPDR group was not significantly different from that of the PDR group. The 4% ODI in the NPDR group was significantly lower than that in the PDR group (p = 0.01). The logistic regression analysis using the prevalence of MetS and the number of MetS components revealed that younger age and high 4%ODI value were independent factors contributing to the diagnosis of PDR. CONCLUSION Our findings confirmed that compared to MetS and the number of its individual components, SDB may be a factor contributing to the progression to PDR. However, further careful longitudinal validation studies are needed.
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Affiliation(s)
- Tomoaki Shiba
- a Department of Ophthalmology, School of Medicine , Toho University , Tokyo , Japan
| | - Mao Takahashi
- b Cardiovascular Center , Toho University Sakura Medical Center , Chiba , Japan
| | - Tadashi Matsumoto
- a Department of Ophthalmology, School of Medicine , Toho University , Tokyo , Japan
| | - Yuichi Hori
- a Department of Ophthalmology, School of Medicine , Toho University , Tokyo , Japan
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8
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Yonis H, Mortaza S, Baboi L, Mercat A, Guérin C. Expiratory Flow Limitation Assessment in Patients with Acute Respiratory Distress Syndrome. A Reappraisal. Am J Respir Crit Care Med 2018; 198:131-134. [DOI: 10.1164/rccm.201711-2326le] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Affiliation(s)
| | | | | | - Alain Mercat
- CHU LarreyAngers, France
- Université d’AngersAngers, France
| | - Claude Guérin
- Hospices Civils de LyonLyon, France
- Université de LyonLyon, Franceand
- INSERM 955Créteil, France
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9
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Junhasavasdikul D, Telias I, Grieco DL, Chen L, Gutierrez CM, Piraino T, Brochard L. Expiratory Flow Limitation During Mechanical Ventilation. Chest 2018; 154:948-962. [PMID: 29432712 DOI: 10.1016/j.chest.2018.01.046] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Revised: 01/27/2018] [Accepted: 01/30/2018] [Indexed: 12/13/2022] Open
Abstract
Expiratory flow limitation (EFL) is present when the flow cannot rise despite an increase in the expiratory driving pressure. The mechanisms of EFL are debated but are believed to be related to the collapsibility of small airways. In patients who are mechanically ventilated, EFL can exist during tidal ventilation, representing an extreme situation in which lung volume cannot decrease, regardless of the expiratory driving forces. It is a key factor for the generation of auto- or intrinsic positive end-expiratory pressure (PEEP) and requires specific management such as positioning and adjustment of external PEEP. EFL can be responsible for causing dyspnea and patient-ventilator dyssynchrony, and it is influenced by the fluid status of the patient. EFL frequently affects patients with COPD, obesity, and heart failure, as well as patients with ARDS, especially at low PEEP. EFL is, however, most often unrecognized in the clinical setting despite being associated with complications of mechanical ventilation and poor outcomes such as postoperative pulmonary complications, extubation failure, and possibly airway injury in ARDS. Therefore, prompt recognition might help the management of patients being mechanically ventilated who have EFL and could potentially influence outcome. EFL can be suspected by using different means, and this review summarizes the methods to specifically detect EFL during mechanical ventilation.
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Affiliation(s)
- Detajin Junhasavasdikul
- Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, ON, Canada; Keenan Research Centre, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, ON, Canada; Department of Medicine, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Irene Telias
- Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, ON, Canada; Keenan Research Centre, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, ON, Canada
| | - Domenico Luca Grieco
- Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, ON, Canada; Keenan Research Centre, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, ON, Canada; Department of Anesthesiology and Intensive Care Medicine, Catholic University of the Sacred Heart, Fondazione "Policlinico Universitario A. Gemelli," Rome, Italy
| | - Lu Chen
- Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, ON, Canada; Keenan Research Centre, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, ON, Canada
| | - Cinta Millan Gutierrez
- Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, ON, Canada; Critical Care Center, Parc Taulí Hospital Universitari, Institut d'Investigació i Innovació Parc Taulí (I3PT), Universitat Autònoma de Barcelona, Sabadell, Spain
| | - Thomas Piraino
- Department of Respiratory Therapy, St. Michael's Hospital, Toronto, ON, Canada; Department of Anesthesia, McMaster University, Hamilton, ON, Canada
| | - Laurent Brochard
- Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, ON, Canada; Keenan Research Centre, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, ON, Canada.
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10
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Chen L, Del Sorbo L, Grieco DL, Shklar O, Junhasavasdikul D, Telias I, Fan E, Brochard L. Airway Closure in Acute Respiratory Distress Syndrome: An Underestimated and Misinterpreted Phenomenon. Am J Respir Crit Care Med 2018; 197:132-136. [DOI: 10.1164/rccm.201702-0388le] [Citation(s) in RCA: 87] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Affiliation(s)
- Lu Chen
- University of TorontoToronto, Canada
- St. Michael’s HospitalToronto, Canada
| | - Lorenzo Del Sorbo
- University of TorontoToronto, Canada
- Toronto General HospitalToronto, Canada
| | - Domenico Luca Grieco
- University of TorontoToronto, Canada
- Catholic University of the Sacred HeartRome, Italyand
| | | | | | | | - Eddy Fan
- University of TorontoToronto, Canada
- Toronto General HospitalToronto, Canada
| | - Laurent Brochard
- University of TorontoToronto, Canada
- St. Michael’s HospitalToronto, Canada
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11
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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: 111] [Impact Index Per Article: 15.9] [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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12
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Vieillard-Baron A, Matthay M, Teboul JL, Bein T, Schultz M, Magder S, Marini JJ. Experts' opinion on management of hemodynamics in ARDS patients: focus on the effects of mechanical ventilation. Intensive Care Med 2016; 42:739-749. [PMID: 27038480 DOI: 10.1007/s00134-016-4326-3] [Citation(s) in RCA: 173] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Accepted: 03/11/2016] [Indexed: 02/06/2023]
Abstract
RATIONALE Acute respiratory distress syndrome (ARDS) is frequently associated with hemodynamic instability which appears as the main factor associated with mortality. Shock is driven by pulmonary hypertension, deleterious effects of mechanical ventilation (MV) on right ventricular (RV) function, and associated-sepsis. Hemodynamic effects of ventilation are due to changes in pleural pressure (Ppl) and changes in transpulmonary pressure (TP). TP affects RV afterload, whereas changes in Ppl affect venous return. Tidal forces and positive end-expiratory pressure (PEEP) increase pulmonary vascular resistance (PVR) in direct proportion to their effects on mean airway pressure (mPaw). The acutely injured lung has a reduced capacity to accommodate flowing blood and increases of blood flow accentuate fluid filtration. The dynamics of vascular pressure may contribute to ventilator-induced injury (VILI). In order to optimize perfusion, improve gas exchange, and minimize VILI risk, monitoring hemodynamics is important. RESULTS During passive ventilation pulse pressure variations are a predictor of fluid responsiveness when conditions to ensure its validity are observed, but may also reflect afterload effects of MV. Central venous pressure can be helpful to monitor the response of RV function to treatment. Echocardiography is suitable to visualize the RV and to detect acute cor pulmonale (ACP), which occurs in 20-25 % of cases. Inserting a pulmonary artery catheter may be useful to measure/calculate pulmonary artery pressure, pulmonary and systemic vascular resistance, and cardiac output. These last two indexes may be misleading, however, in cases of West zones 2 or 1 and tricuspid regurgitation associated with RV dilatation. Transpulmonary thermodilution may be useful to evaluate extravascular lung water and the pulmonary vascular permeability index. To ensure adequate intravascular volume is the first goal of hemodynamic support in patients with shock. The benefit and risk balance of fluid expansion has to be carefully evaluated since it may improve systemic perfusion but also may decrease ventilator-free days, increase pulmonary edema, and promote RV failure. ACP can be prevented or treated by applying RV protective MV (low driving pressure, limited hypercapnia, PEEP adapted to lung recruitability) and by prone positioning. In cases of shock that do not respond to intravascular fluid administration, norepinephrine infusion and vasodilators inhalation may improve RV function. Extracorporeal membrane oxygenation (ECMO) has the potential to be the cause of, as well as a remedy for, hemodynamic problems. Continuous thermodilution-based and pulse contour analysis-based cardiac output monitoring are not recommended in patients treated with ECMO, since the results are frequently inaccurate. Extracorporeal CO2 removal, which could have the capability to reduce hypercapnia/acidosis-induced ACP, cannot currently be recommended because of the lack of sufficient data.
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Affiliation(s)
- A Vieillard-Baron
- Intensive Care Unit, Section Thorax-Vascular Disease-Abdomen-Metabolism, Service de Réanimation, Assistance Publique-Hôpitaux de Paris, University Hospital Ambroise Paré, 9, avenue Charles de Gaulle, 92100, Boulogne-Billancourt, France. .,University of Versailles Saint-Quentin en Yvelines, Faculty of Medicine Paris Ile-de-France Ouest, 78280, Saint-Quentin en Yvelines, France. .,INSERM U-1018, CESP, Team 5 (EpReC, Renal and Cardiovascular Epidemiology), UVSQ, 94807, Villejuif, France.
| | - M Matthay
- Departments of Medicine and Anesthesia and the Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA, USA
| | - J L Teboul
- Assistance Publique-Hôpitaux de Paris, Hôpitaux universitaires Paris-Sud, Hôpital de Bicêtre, service de réanimation médicale, Le Kremlin-Bicêtre, France.,Université Paris-Sud, Faculté de médecine Paris-Sud, Inserm UMR S_999, Le Kremlin-Bicêtre, France
| | - T Bein
- Department of Anesthesia, Operative Intensive Care, University Hospital Regensburg, 93042, Regensburg, Germany
| | - M Schultz
- Laboratory of Experimental Intensive Care and Anesthesiology, Department of Intensive Care, Academic Medical Center, Amsterdam, The Netherlands
| | - S Magder
- Department of Critical Care, McGill University Health Centre (Glen Site Campus), Montreal, Canada
| | - J J Marini
- Departments of Pulmonary and Critical Care Medicine, University of Minnesota and Regions Hospital, Minneapolis/St. Paul, MN, USA
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Repessé X, Charron C, Vieillard-Baron A. Retentissement cardiovasculaire du décubitus ventral. MEDECINE INTENSIVE REANIMATION 2015. [DOI: 10.1007/s13546-015-1030-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Repessé X, Charron C, Vieillard-Baron A. Une approche moderne de la ventilation dans le syndrome de détresse respiratoire aiguë: laissez le ventricule droit respirer ! MEDECINE INTENSIVE REANIMATION 2014. [DOI: 10.1007/s13546-013-0822-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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Mekontso Dessap A, Boissier F. Effets hémodynamiques de la pression expiratoire positive. MEDECINE INTENSIVE REANIMATION 2012. [DOI: 10.1007/s13546-012-0448-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Charron C, Repesse X, Bouferrache K, Bodson L, Castro S, Page B, Jardin F, Vieillard-Baron A. PaCO2 and alveolar dead space are more relevant than PaO2/FiO2 ratio in monitoring the respiratory response to prone position in ARDS patients: a physiological study. Crit Care 2011; 15:R175. [PMID: 21791044 PMCID: PMC3387618 DOI: 10.1186/cc10324] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2011] [Revised: 06/28/2011] [Accepted: 07/25/2011] [Indexed: 11/18/2022] Open
Abstract
INTRODUCTION Our aims in this study were to report changes in the ratio of alveolar dead space to tidal volume (VDalv/VT) in the prone position (PP) and to test whether changes in partial pressure of arterial CO2 (PaCO2) may be more relevant than changes in the ratio of partial pressure of arterial O2 to fraction of inspired O2 (PaO2/FiO2) in defining the respiratory response to PP. We also aimed to validate a recently proposed method of estimation of the physiological dead space (VDphysiol/VT) without measurement of expired CO2. METHODS Thirteen patients with a PaO2/FiO2 ratio < 100 mmHg were included in the study. Plateau pressure (Pplat), positive end-expiratory pressure (PEEP), blood gas analysis and expiratory CO2 were recorded with patients in the supine position and after 3, 6, 9, 12 and 15 hours in the PP. Responders to PP were defined after 15 hours of PP either by an increase in PaO2/FiO2 ratio > 20 mmHg or by a decrease in PaCO2 > 2 mmHg. Estimated and measured VDphysiol/VT ratios were compared. RESULTS PP induced a decrease in Pplat, PaCO2 and VDalv/VT ratio and increases in PaO2/FiO2 ratios and compliance of the respiratory system (Crs). Maximal changes were observed after six to nine hours. Changes in VDalv/VT were correlated with changes in Crs, but not with changes in PaO2/FiO2 ratios. When the response was defined by PaO2/FiO2 ratio, no significant differences in Pplat, PaCO2 or VDalv/VT alterations between responders (n = 7) and nonresponders (n = 6) were observed. When the response was defined by PaCO2, four patients were differently classified, and responders (n = 7) had a greater decrease in VDalv/VT ratio and in Pplat and a greater increase in PaO2/FiO2 ratio and in Crs than nonresponders (n = 6). Estimated VDphysiol/VT ratios significantly underestimated measured VDphysiol/VT ratios (concordance correlation coefficient 0.19 (interquartile ranges 0.091 to 0.28)), whereas changes during PP were more reliable (concordance correlation coefficient 0.51 (0.32 to 0.66)). CONCLUSIONS PP induced a decrease in VDalv/VT ratio and an improvement in respiratory mechanics. The respiratory response to PP appeared more relevant when PaCO2 rather than the PaO2/FiO2 ratio was used. Estimated VDphysiol/VT ratios systematically underestimated measured VDphysiol/VT ratios.
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Affiliation(s)
- Cyril Charron
- Intensive Care Unit, Section Thorax-Vascular Disease-Abdomen-Metabolism, Ambroise Paré University Hospital, AP-HP, 9 Av Charles de Gaulle, F-92104 Boulogne-Billancourt Cedex, France
- Faculté de Paris Ile-de-France Ouest, Université de Versailles Saint Quentin en Yvelines, 9 boulevard d'Alembert, F-78280 Guyancourt, France
| | - Xavier Repesse
- Intensive Care Unit, Section Thorax-Vascular Disease-Abdomen-Metabolism, Ambroise Paré University Hospital, AP-HP, 9 Av Charles de Gaulle, F-92104 Boulogne-Billancourt Cedex, France
- Faculté de Paris Ile-de-France Ouest, Université de Versailles Saint Quentin en Yvelines, 9 boulevard d'Alembert, F-78280 Guyancourt, France
| | - Koceïla Bouferrache
- Intensive Care Unit, Section Thorax-Vascular Disease-Abdomen-Metabolism, Ambroise Paré University Hospital, AP-HP, 9 Av Charles de Gaulle, F-92104 Boulogne-Billancourt Cedex, France
- Faculté de Paris Ile-de-France Ouest, Université de Versailles Saint Quentin en Yvelines, 9 boulevard d'Alembert, F-78280 Guyancourt, France
| | - Laurent Bodson
- Intensive Care Unit, Section Thorax-Vascular Disease-Abdomen-Metabolism, Ambroise Paré University Hospital, AP-HP, 9 Av Charles de Gaulle, F-92104 Boulogne-Billancourt Cedex, France
- Faculté de Paris Ile-de-France Ouest, Université de Versailles Saint Quentin en Yvelines, 9 boulevard d'Alembert, F-78280 Guyancourt, France
| | - Samuel Castro
- Intensive Care Unit, Section Thorax-Vascular Disease-Abdomen-Metabolism, Ambroise Paré University Hospital, AP-HP, 9 Av Charles de Gaulle, F-92104 Boulogne-Billancourt Cedex, France
- Faculté de Paris Ile-de-France Ouest, Université de Versailles Saint Quentin en Yvelines, 9 boulevard d'Alembert, F-78280 Guyancourt, France
| | - Bernard Page
- Intensive Care Unit, Section Thorax-Vascular Disease-Abdomen-Metabolism, Ambroise Paré University Hospital, AP-HP, 9 Av Charles de Gaulle, F-92104 Boulogne-Billancourt Cedex, France
- Faculté de Paris Ile-de-France Ouest, Université de Versailles Saint Quentin en Yvelines, 9 boulevard d'Alembert, F-78280 Guyancourt, France
| | - François Jardin
- Intensive Care Unit, Section Thorax-Vascular Disease-Abdomen-Metabolism, Ambroise Paré University Hospital, AP-HP, 9 Av Charles de Gaulle, F-92104 Boulogne-Billancourt Cedex, France
- Faculté de Paris Ile-de-France Ouest, Université de Versailles Saint Quentin en Yvelines, 9 boulevard d'Alembert, F-78280 Guyancourt, France
| | - Antoine Vieillard-Baron
- Intensive Care Unit, Section Thorax-Vascular Disease-Abdomen-Metabolism, Ambroise Paré University Hospital, AP-HP, 9 Av Charles de Gaulle, F-92104 Boulogne-Billancourt Cedex, France
- Faculté de Paris Ile-de-France Ouest, Université de Versailles Saint Quentin en Yvelines, 9 boulevard d'Alembert, F-78280 Guyancourt, France
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Charron C, Bouferrache K, Caille V, Castro S, Aegerter P, Page B, Jardin F, Vieillard-Baron A. Routine prone positioning in patients with severe ARDS: feasibility and impact on prognosis. Intensive Care Med 2011; 37:785-90. [PMID: 21365313 DOI: 10.1007/s00134-011-2180-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Accepted: 01/10/2011] [Indexed: 10/18/2022]
Abstract
PURPOSE Since 1997, we have routinely used prone positioning (PP) in patients who have a PaO(2)/FiO(2) below 100 mmHg after 24-48 h of mechanical ventilation and who are ventilated using a low stretch ventilation strategy. We report here the characteristics and prognosis of this subgroup of patients with severe lung injury to illustrate the feasibility, role, and impact of routine PP in acute respiratory distress syndrome (ARDS). RESULTS A total of 218 patients were admitted because of ARDS between 1997 and 2009. Of these patients, 57 (26%) were positioned prone because of a PaO(2)/FiO(2) below 100 mmHg after 24-48 h of mechanical ventilation. Age was 51 ± 16 years, PaO(2)/FiO(2) 74 ± 19, and PaCO(2) 54 ± 10 mmHg. The lung injury score was 3.13 ± 0.15. Tidal volume was 7 ± 2 mL/kg, PEEP 5.6 ± 1.2 cmH(2)O, and plateau pressure 27 ± 3 cmH(2)O. Prone sessions lasted 18 h/day and 3.4 ± 1.1 sessions were required to obtain an FiO(2) below 60%. The 60-day mortality was 19% and death occurred after 12 ± 5 days. The ratio between observed and predicted mortality was 0.43. In patients with a PaO(2)/FiO(2) below 60 mmHg, the 60-day mortality was 28%. Logistic regression analysis showed that among the 218 patients, PP appeared to be protective with an odds ratio of 0.35 [0.16-0.79]. CONCLUSION We demonstrate the clinical feasibility of routine PP in patients with a PaO(2)/FiO(2) below 100 mmHg after 24-48 h and suggest that, when combined with a low stretch ventilation strategy, it is protective with a high survival rate.
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Affiliation(s)
- Cyril Charron
- University Hospital Ambroise Paré, Université de Versailles Saint Quentin en Yvelines, Boulogne, France
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Conti ML, Che MM, Boylan M, Sciuto AM, Gordon RK, Nambiar MP. Acute microinstillation inhalation exposure to sarin induces changes in respiratory dynamics and functions in guinea pigs. Int J Toxicol 2010; 28:436-47. [PMID: 19815847 DOI: 10.1177/1091581809344879] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
This study investigates the toxic effects of sarin on respiratory dynamics following microinstillation inhalation exposure in guinea pigs. Animals are exposed to sarin for 4 minutes, and respiratory functions are monitored at 4 hours and 24 hours by whole-body barometric plethysmography. Data show significant changes in respiratory dynamics and function following sarin exposure. An increase in respiratory frequency is observed at 4 hours post exposure compared with saline controls. Tidal volume and minute volume are also increased in sarin-exposed animals 4 hours after exposure. Peak inspiratory flow increases, whereas peak expiratory flow increases at 4 hours and is erratic following sarin exposure. Animals exposed to sarin show a significant decrease in expiratory time and inspiratory time. End-inspiratory pause is unchanged whereas end-expiratory pause is slightly decreased 24 hours after sarin exposure. These results indicate that inhalation exposure to sarin alters respiratory dynamics and function at 4 hours, with return to normal levels at 24 hours post exposure.
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Affiliation(s)
- Michele L Conti
- United States Army Medical Research Institute of Chemical Defense, Edgewood, MD, USA
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Mekontso Dessap A, Charron C, Devaquet J, Aboab J, Jardin F, Brochard L, Vieillard-Baron A. Impact of acute hypercapnia and augmented positive end-expiratory pressure on right ventricle function in severe acute respiratory distress syndrome. Intensive Care Med 2009; 35:1850-8. [PMID: 19652953 DOI: 10.1007/s00134-009-1569-2] [Citation(s) in RCA: 135] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2008] [Accepted: 05/23/2009] [Indexed: 01/13/2023]
Abstract
PURPOSE To evaluate the effects of acute hypercapnia induced by positive end-expiratory pressure (PEEP) variations at constant plateau pressure (P (plat)) in patients with severe acute respiratory distress syndrome (ARDS) on right ventricular (RV) function. METHODS Prospective observational study in two academic intensive care units enrolling 11 adults with severe ARDS (PaO(2)/FiO(2) <150 mmHg at PEEP >5 cmH(2)O). We compared three ventilatory strategies, each used for 1 h, with P (plat) at 22 (20-25) cmH(2)O: low PEEP (5.4 cmH(2)O) or high PEEP (11.0 cmH(2)O) with compensation of the tidal volume reduction by either a high respiratory rate (high PEEP/high rate) or instrumental dead space decrease (high PEEP/low rate). We assessed RV function (transesophageal echocardiography), alveolar dead space (expired CO(2)), and alveolar recruitment (pressure-volume curves). RESULTS Compared to low PEEP, PaO(2)/FiO(2) ratio and alveolar recruitment were increased with high PEEP. Alveolar dead space remained unchanged. Both high-PEEP strategies induced higher PaCO(2) levels [71 (60-94) and 75 (53-84), vs. 52 (43-68) mmHg] and lower pH values [7.17 (7.12-7.23) and 7.20 (7.16-7.25) vs. 7.30 (7.24-7.35)], as well as RV dilatation, LV deformation and a significant decrease in cardiac index. The decrease in stroke index tended to be negatively correlated to the increase in alveolar recruitment with high PEEP. CONCLUSIONS Acidosis and hypercapnia induced by tidal volume reduction and increase in PEEP at constant P (plat) were associated with impaired RV function and hemodynamics despite positive effects on oxygenation and alveolar recruitment ( ClinicalTrials.gov #NCT00236262).
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Affiliation(s)
- Armand Mekontso Dessap
- Medical Intensive Care Unit, Assistance Publique-Hôpitaux de Paris, Henri Mondor-Albert Chenevier Teaching Hospital, Créteil, France.
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Katos AM, Conti M, Moran TS, Chon TW, Gordon RK, Sciuto AM, Doctor BP, Nambiar MP. Acute microinstillation inhalation exposure to soman induces changes in respiratory dynamics and functions in guinea pigs. Inhal Toxicol 2009; 21:1-10. [DOI: 10.1080/08958370802331217] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Abstract
PURPOSE OF REVIEW Peripheral airways are less than 2 mm in diameter and comprise a relatively large cross-sectional area, which allows for slower, laminar airflow. They include both membranous bronchioles and gas exchange ducts, and have been referred to in the past as the 'quiet zone', partly because these structures were felt to contribute little to lung mechanics, and partly because they are difficult to study directly. RECENT FINDINGS Recent studies suggest that peripheral airway dysfunction plays a significant role in acute respiratory distress syndrome, which may be exacerbated by injurious mechanical ventilation strategies. The presence of elevated airways resistance, intrinsic positive end-expiratory pressure or a lower inflection point on a pressure-volume curve of the respiratory system may indicate presence of impaired peripheral airway function. In-vitro animal and human studies have begun to elucidate the signaling mechanisms responsible for stretch and shear mediated cellular injury. SUMMARY Understanding the pathophysiology of peripheral airway dysfunction in acute respiratory distress syndrome and mechanical ventilation continues to evolve. Greater insight into the signaling mechanisms involved in cellular injury and repair will lead to further alterations in mechanical ventilation strategies, and may lead to specific treatment options.
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Guérin C, Levrat A, Pontier S, Annat G. A study of experimental acute lung injury in pigs on zero end-expiratory pressure. Vet Anaesth Analg 2008; 35:122-31. [DOI: 10.1111/j.1467-2995.2007.00363.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Phenotypic heterogeneity in lung capillary and extra-alveolar endothelial cells. Increased extra-alveolar endothelial permeability is sufficient to decrease compliance. J Surg Res 2007; 143:70-7. [PMID: 17950075 DOI: 10.1016/j.jss.2007.03.047] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2007] [Revised: 02/20/2007] [Accepted: 03/05/2007] [Indexed: 12/21/2022]
Abstract
BACKGROUND In acute respiratory distress syndrome, pulmonary vascular permeability increases, causing intravascular fluid and protein to move into the lung's interstitium. The classic model describing the formation of pulmonary edema suggests that fluid crossing the capillary endothelium is drawn by negative interstitial pressure into the potential space surrounding extra-alveolar vessels and, as interstitial pressure builds, is forced into the alveolar air space. However, the validity of this model is challenged by animal models of acute lung injury in which extra-alveolar vessels are more permeable than capillaries under a variety of conditions. In the current study, we sought to determine whether extravascular fluid accumulation can be produced because of increased permeability of either the capillary or extra-alveolar endothelium, and whether different pathophysiology results from such site-specific increases in permeability. MATERIALS AND METHODS We perfused isolated lungs with either the plant alkaloid thapsigargin, which increases extra-alveolar endothelial permeability, or with 4alpha-phorbol 12, 13-didecanoate, which increases capillary endothelial permeability. RESULTS Both treatments produced equal increases in whole lung vascular permeability, but caused fluid accumulations in separate anatomical compartments. Light microscopy of isolated lungs showed that thapsigargin caused fluid cuffing of large vessels, while 4alpha-phorbol 12, 13-didecanoate caused alveolar flooding. Dynamic compliance was reduced in lungs with cuffing of large vessels, but not in lungs with alveolar flooding. CONCLUSIONS Phenotypic differences between vascular segments resulted in site-specific increases in permeability, which have different pathophysiological outcomes. Our findings suggest that insults leading to acute respiratory distress syndrome may increase permeability in extra-alveolar or capillary vascular segments, resulting in different pathophysiological sequela.
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Henzler D, Hochhausen N, Dembinski R, Orfao S, Rossaint R, Kuhlen R. Parameters derived from the pulmonary pressure volume curve, but not the pressure time curve, indicate recruitment in experimental lung injury. Anesth Analg 2007; 105:1072-8, table of contents. [PMID: 17898390 DOI: 10.1213/01.ane.0000278733.94863.09] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND In acute lung injury, ventilation avoiding tidal hyperinflation and tidal recruitment has been proposed to prevent ventilator-associated lung injury. Information about dynamic recruitment may be obtained from the characteristics of pressure-volume (PV) curves or the profile of pressure-time (Paw-t) curves. METHODS Six anesthetized pigs with lung lavage-induced acute lung injury were ventilated with lung-protective settings. We measured the effects of a standard recruitment maneuver on hysteresis area and ratio obtained from the PV curve and on the stress index obtained from the Paw-t curve and correlated this with aerated and nonaerated lung volumes as measured by multislice computed tomography. RESULTS Hysteresis area and ratio correlated with aerated lung volume (r = 0.886). The recruitment maneuver resulted in an increase in aerated (+12%) and a decrease (-18%) in nonaerated lung. Hysteresis area correlated with alveolar recruitment, represented by an increase in aerated lung (r = 0.886) and a decrease in nonaerated lung (r = -0.829) during tidal ventilation. The stress index was always >1 and indicated tidal hyperinflation only. Values did not change after the recruitment maneuver and did not correlate with any other lung volume. CONCLUSIONS Parameters derived from the PV curve may help in characterizing the lung aeration of the lung and in indicating recruitment. In the presence of lung-protective ventilator settings, the stress index derived from the Paw-t curve was not able to indicate recruitment.
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Affiliation(s)
- Dietrich Henzler
- Department of Anesthesiology, University Hospital, RWTH Aachen, Aachen, Germany.
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Jain M, Sznajder JI. Bench-to-bedside review: distal airways in acute respiratory distress syndrome. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2007; 11:206. [PMID: 17306039 PMCID: PMC2151900 DOI: 10.1186/cc5159] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Distal airways are less than 2 mm in diameter, comprising a relatively large cross-sectional area that allows for slower, laminar airflow. The airways include both membranous bronchioles and gas exchange ducts, and have been referred to in the past as the 'quiet zone', in part because these structures were felt to contribute little to lung mechanics and in part because they were difficult to study directly. More recent data suggest that distal airway dysfunction plays a significant role in acute respiratory distress syndrome. In addition, injurious mechanical ventilation strategies may contribute to distal airway dysfunction. The presence of elevated airway resistance, intrinsic positive end-expiratory pressure or a lower inflection point on a pressure–volume curve of the respiratory system may indicate the presence of impaired distal airway function. There are no proven specific treatments for distal airway dysfunction, and protective ventilation strategies to minimize distal airway injury may be the best therapeutic approach at this time.
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Affiliation(s)
- Manu Jain
- Division of Pulmonary and Critical Care, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
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Rezk PE, Graham JR, Moran TS, Gordon RK, Sciuto AM, Doctor BP, Nambiar MP. Acute toxic effects of nerve agent VX on respiratory dynamics and functions following microinsillation inhalation exposure in guinea pigs. Inhal Toxicol 2007; 19:291-302. [PMID: 17365032 DOI: 10.1080/08958370601069398] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Exposure to a chemical warfare nerve agent (CWNA) leads to severe respiratory distress, respiratory failure, or death if not treated. We investigated the toxic effects of nerve agent VX on the respiratory dynamics of guinea pigs following exposure to 90.4 mug/m3 of VX or saline by microinstillation inhalation technology for 10 min. Respiratory parameters were monitored by whole-body barometric plethysmography at 4, 24, and 48 h, 7 d, 18 d, and 4 wk after VX exposure. VX-exposed animals showed a significant decrease in the respiratory frequency (RF) at 24 and 48 h of recovery (p value .0329 and .0142, respectively) compared to the saline control. The tidal volume (TV) slightly increased in VX exposed animals at 24 and significantly at 48 h (p = .02) postexposure. Minute ventilation (MV) increased slightly at 4 h but was reduced at 24 h and remained unchanged at 48 h. Animals exposed to VX also showed an increase in expiratory (Te) and relaxation time (RT) at 24 and 48 h and a small reduction in inspiratory time (Ti) at 24 h. A significant increase in end expiratory pause (EEP) was observed at 48 h after VX exposure (p = .049). The pseudo lung resistance (Penh) was significantly increased at 4 h after VX exposure and remained slightly high even at 48 h. Time-course studies reveal that most of the altered respiratory dynamics returned to normal at 7 d after VX exposure except for EEP, which was high at 7 d and returned to normal at 18 d postexposure. After 1 mo, all the monitored respiratory parameters were within normal ranges. Bronchoalveolar lavage (BAL) 1 mo after exposure showed virtually no difference in protein levels, cholinesterase levels, cell number, and cell death in the exposed and control animals. These results indicate that sublethal concentrations of VX induce changes in respiratory dynamics and functions that over time return to normal levels.
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Affiliation(s)
- Peter E Rezk
- Department of Biochemical Pharmacology/Division of Biochemistry, Walter Reed Army Institute of Research, Silver Spring, Maryland, USA
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Nunes S, Valta P, Takala J. Changes in respiratory mechanics and gas exchange during the acute respiratory distress syndrome. Acta Anaesthesiol Scand 2006; 50:80-91. [PMID: 16451155 DOI: 10.1111/j.1399-6576.2005.00767.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
BACKGROUND The time course of impairment of respiratory mechanics and gas exchange in the acute respiratory distress syndrome (ARDS) remains poorly defined. We assessed the changes in respiratory mechanics and gas exchange during ARDS. We hypothesized that due to the changes in respiratory mechanics over time, ventilatory strategies based on rigid volume or pressure limits might fail to prevent overdistension throughout the disease process. METHODS Seventeen severe ARDS patients {PaO2/FiO2 10.1 (9.2-14.3) kPa; 76 (69-107) mmHg [median (25th-75th percentiles)] and bilateral infiltrates} were studied during the acute, intermediate, and late stages of ARDS (at 1-3, 4-6 and 7 days after diagnosis). Severity of lung injury, gas exchange, and hemodynamics were assessed. Pressure-volume (PV) curves of the respiratory system were obtained, and upper and lower inflection points (UIP, LIP) and recruitment were estimated. RESULTS (1) UIP decreased from early to established (intermediate and late) ARDS [30 (28-30) cmH2O, 27 (25-30) cmH2O and 25 (23-28) cmH2O (P=0.014)]; (2) oxygenation improved in survivors and in patients with non-pulmonary etiology in late ARDS, whereas all patients developed hypercapnia from early to established ARDS; and (3) dead-space ventilation and pulmonary shunt were larger in patients with pulmonary etiology during late ARDS. CONCLUSION We found a decrease in UIP from acute to established ARDS. If applied to our data, the inspiratory pressure limit advocated by the ARDSnet (30 cmH2O) would produce ventilation over the UIP, with a consequent increased risk of overdistension in 12%, 43% and 65% of our patients during the acute, intermediate and late phases of ARDS, respectively. Lung protective strategies based on fixed tidal volume or pressure limits may thus not fully avoid the risk of lung overdistension throughout ARDS.
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Affiliation(s)
- S Nunes
- Division of Intensive Care, Department of Anesthesiology and Intensive Care, Kuopio University Hospital, Kuopio, Finland.
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Henzler D, Pelosi P, Dembinski R, Ullmann A, Mahnken AH, Rossaint R, Kuhlen R. Respiratory compliance but not gas exchange correlates with changes in lung aeration after a recruitment maneuver: an experimental study in pigs with saline lavage lung injury. Crit Care 2005; 9:R471-82. [PMID: 16277708 PMCID: PMC1297611 DOI: 10.1186/cc3772] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2005] [Revised: 06/10/2005] [Accepted: 06/24/2005] [Indexed: 11/10/2022] Open
Abstract
INTRODUCTION Atelectasis is a common finding in acute lung injury, leading to increased shunt and hypoxemia. Current treatment strategies aim to recruit alveoli for gas exchange. Improvement in oxygenation is commonly used to detect recruitment, although the assumption that gas exchange parameters adequately represent the mechanical process of alveolar opening has not been proven so far. The aim of this study was to investigate whether commonly used measures of lung mechanics better detect lung tissue collapse and changes in lung aeration after a recruitment maneuver as compared to measures of gas exchange METHODS In eight anesthetized and mechanically ventilated pigs, acute lung injury was induced by saline lavage and a recruitment maneuver was performed by inflating the lungs three times with a pressure of 45 cmH2O for 40 s with a constant positive end-expiratory pressure of 10 cmH2O. The association of gas exchange and lung mechanics parameters with the amount and the changes in aerated and nonaerated lung volumes induced by this specific recruitment maneuver was investigated by multi slice CT scan analysis of the whole lung. RESULTS Nonaerated lung correlated with shunt fraction (r = 0.68) and respiratory system compliance (r = 0.59). The arterial partial oxygen pressure (PaO2) and the respiratory system compliance correlated with poorly aerated lung volume (r = 0.57 and 0.72, respectively). The recruitment maneuver caused a decrease in nonaerated lung volume, an increase in normally and poorly aerated lung, but no change in the distribution of a tidal breath to differently aerated lung volumes. The fractional changes in PaO2, arterial partial carbon dioxide pressure (PaCO2) and venous admixture after the recruitment maneuver did not correlate with the changes in lung volumes. Alveolar recruitment correlated only with changes in the plateau pressure (r = 0.89), respiratory system compliance (r = 0.82) and parameters obtained from the pressure-volume curve. CONCLUSION A recruitment maneuver by repeatedly hyperinflating the lungs led to an increase of poorly aerated and a decrease of nonaerated lung mainly. Changes in aerated and nonaerated lung volumes were adequately represented by respiratory compliance but not by changes in oxygenation or shunt.
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Affiliation(s)
- Dietrich Henzler
- Senior Anesthesiologist, Anesthesiology Department, University Hospital RWTH Aachen, Germany
| | - Paolo Pelosi
- Professor of Anesthesiology, Environment, Health and Safety Department, University of Insubria, Varese, Italy
| | - Rolf Dembinski
- Intensivist, Surgical Intensive Care Department, University Hospital RWTH Aachen, Germany
| | - Annette Ullmann
- Resident, Anesthesiology Department, University Hospital RWTH Aachen, Germany
| | - Andreas H Mahnken
- Department of Clinical Radiology, University Hospital RWTH Aachen, Germany
| | - Rolf Rossaint
- Professor of Anesthesiology, Anesthesiology Department, University Hospital RWTH Aachen, Germany
| | - Ralf Kuhlen
- Head, Surgical Intensive Care Department, University Hospital RWTH Aachen, Germany
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Pestaña D, Hernández-Gancedo C, Royo C, Pérez-Chrzanowska H, Criado A. Pressure-volume curve variations after a recruitment manoeuvre in acute lung injury/ARDS patients: implications for the understanding of the inflection points of the curve. Eur J Anaesthesiol 2005; 22:175-80. [PMID: 15852989 DOI: 10.1017/s0265021505000311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND OBJECTIVE Although the pressure-volume (P-V) curve has been proposed in the management of mechanically ventilated patients, its interpretation remains unclear. Our aim has been to study the variations of the P-V curve after a recruitment manoeuvre (RM). Our hypothesis was that the lower inflection point (LIP) represents the presence of compressive atelectases, so it should not change after lung recruitment, while the upper inflection point (UIP) reflects reabsorptive atelectases, and an effective recruitment should result in changes at this level. METHODS Two P-V curves (quasi-static method) separated by an RM (40 cmH2O, two consecutive manoeuvres) were plotted in 35 postoperative patients with criteria of acute lung injury/acute respiratory distress syndrome (ARDS). LIP, UIP and expiratory inflection point (EIP) were defined as the first point where the curve consistently starts to separate from the line. RESULTS One to six measurements were obtained per patient (73 procedures). Neither the lower nor the EIPs varied significantly after the RM (P = 0.11 and 0.35, respectively). An UIP was observed in 18 curves (25%) before the RM and disappeared on nine occasions after the recruitment. Similar results were obtained when first measurements only were analysed, and when the cause (pulmonary vs. extrapulmonary), severity of lung injury or duration of mechanical ventilation at first measurement were studied. CONCLUSIONS An RM does not modify the LIP significantly, but induces the disappearance of the UIP in 50% of the cases in which this point is found.
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Affiliation(s)
- D Pestaña
- Hospital Universitario La Paz, Servicio de Anestesia-Reanimación, Residencia General, Madrid, Spain.
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Vieillard-Baron A, Rabiller A, Chergui K, Peyrouset O, Page B, Beauchet A, Jardin F. Prone position improves mechanics and alveolar ventilation in acute respiratory distress syndrome. Intensive Care Med 2004; 31:220-6. [PMID: 15703898 DOI: 10.1007/s00134-004-2478-z] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2004] [Accepted: 09/15/2004] [Indexed: 10/26/2022]
Abstract
OBJECTIVE We tested the hypothesis that ventilation in the prone position might improve homogenization of tidal ventilation by reducing time-constant inequalities, and thus improving alveolar ventilation. We have recently reported in ARDS patients that these inequalities are responsible for the presence of a "slow compartment," excluded from tidal ventilation at supportive respiratory rate. DESIGN In 11 ARDS patients treated by ventilation in the prone position because of a major oxygenation impairment (PaO(2)/FIO(2)</=100 mm Hg) we studied mechanical and blood gas changes produced by a low PEEP (6+/-1 cm H(2)O), ventilation in the prone position, and the two combined. RESULTS Ventilation in the prone position significantly reduced the expiratory time constant from 1.98+/-0.53 s at baseline with ZEEP to 1.53+/-0.34 s, and significantly decreased PaCO(2) from 55+/-11 mm Hg at baseline with ZEEP to 50+/-7 mm Hg. This improvement in alveolar ventilation was accompanied by a significant improvement in respiratory system mechanics, and in arterial oxygenation, the latter being markedly increased by application of a low PEEP (PaO(2)/FIO(2) increasing from 64+/-19 mm Hg in supine position with ZEEP to 137+/-88 mm Hg in prone with a low PEEP). CONCLUSION In severely hypoxemic patients, prone position was able to improve alveolar ventilation significantly by reducing the expiratory time constant.
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Affiliation(s)
- Antoine Vieillard-Baron
- Medical Intensive Care Unit, University Hospital Ambroise Paré, Assistance Publique Hôpitaux de Paris, 9 avenue Charles de Gaulle, 92104, Boulogne Cedex, France
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Downie JM, Nam AJ, Simon BA. Pressure–Volume Curve Does Not Predict Steady-State Lung Volume in Canine Lavage Lung Injury. Am J Respir Crit Care Med 2004; 169:957-62. [PMID: 14764430 DOI: 10.1164/rccm.200305-614oc] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
To better understand strategies for recruiting and maintaining lung volume in acute lung injury, we examined relationships between steady-state lung volume and cumulative cyclic recruitment/derecruitment volume history and the quasi-static pressure-volume curve, in an animal saline lavage lung injury model. Small-volume tidal pressure-volume loops performed after inflation from functional residual capacity demonstrated incremental, cyclic recruitment only if the peak pressure achieved exceeded the pressure at which the compliance increased (Pflex) on the pressure-volume curve, whereas loops performed after deflation from total lung capacity remained close to the envelope deflation curve. Recruitment continued to occur up to and beyond a peak inspiratory airway pressure of 40 cm H(2)O, as demonstrated by both the tidal loops and by computed tomography-derived lung volume data. Tidal-specific compliance was relatively constant across positive end-expiratory pressure levels after inflation from functional residual capacity, but peaked at moderate positive end-expiratory pressure after deflation from total lung capacity, further demonstrating the effects of volume history and providing experimental validation of the recruitment models of Hickling (AJRCCM 2001;163:69-78). These results support the interpretation of Pflex as pressure threshold for recruitment, but otherwise do not suggest a role for the pressure-volume curve in predicting steady-state lung volume.
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Affiliation(s)
- John M Downie
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins Medical Institutions, Baltimore, Maryland, USA
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Nunes S, Uusaro A, Takala J. Pressure-volume relationships in acute lung injury: methodological and clinical implications. Acta Anaesthesiol Scand 2004; 48:278-86. [PMID: 14982559 DOI: 10.1111/j.0001-5172.2004.0313.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Pressure-volume relationships (PV curves) are the only available method for bedside monitoring of respiratory mechanics. Alveolar recruitment modifies the results obtained from the PV curves. We hypothesized that method-related differences may influence PV-curve guided ventilatory management. METHODS Twelve acute lung injury (ALI) patients [PaO2/FiO2 13.0 +/- 1.5 kPa (97.6 +/- 11.3 mmHg), bilateral pulmonary infiltrates] were studied. Two PV curves [one at variable, and another at constant level of positive end-expiratory pressure (PEEP)] were obtained from each patient using constant inspiratory flow and end-inspiratory and -expiratory occlusions. Upper and lower inflection points (UIP, LIP) were estimated. Recruitment due to PEEP and during inflation was assessed by respiratory inductive plethysmography (RIP). RESULTS (1) Pressure-volume curves at constant PEEP tended to provide higher LIP values compared with curves at variable PEEP (mean difference +/- SEM 5.1 +/- 1.9 cmH2O); and (2) recruitment occurred throughout the PV curve with no relationship with LIP or UIP. CONCLUSION Pressure-volume curves obtained using variable PEEP translate a different physiological reality and seem to be clinically more relevant than curves constructed at constant PEEP. If curves constructed at constant PEEP are used to set the ventilator, unnecessarily high PEEP levels may be used. Respiratory inductive plethysmography technology may be used for monitoring of recruitment at the bedside.
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Affiliation(s)
- S Nunes
- Division of Intensive Care, Department of Anesthesiology and Intensive Care, Kuopio University Hospital, Kuopio, Finland.
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Ruiz ferrón F, Rucabado aguilar L, Poala gallego M, Muñoz muñoz J, Brea salvago J, La rosa salas F, Morante valle A. Cambios en la auto-PEEP durante la ventilación mecánica relacionados con la frecuencia respiratoria según el análisis de la constante de tiempo. Med Intensiva 2004. [DOI: 10.1016/s0210-5691(04)70044-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Vieillard-Baron A, Prin S, Chergui K, Page B, Beauchet A, Jardin F. Early patterns of static pressure-volume loops in ARDS and their relations with PEEP-induced recruitment. Intensive Care Med 2003; 29:1929-35. [PMID: 12923622 DOI: 10.1007/s00134-003-1938-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2003] [Accepted: 07/10/2003] [Indexed: 11/29/2022]
Abstract
OBJECTIVE Evaluation of low-flow pressure-volume loop at the bedside in ARDS, as an aid to assess recruitment produced by PEEP. MATERIALS AND METHODS Low-flow pressure-volume loop at the bedside were obtained on the first day of respiratory support in 54 successive pulmonary ARDS patients (49 of whom had pneumonia) treated between April 1999 and June 2002. From the loop obtained at ZEEP, we determined manually the lower inflexion point (LIP). By superimposing the pressure-volume loop at ZEEP and at PEEP, we evaluated recruitment obtained at a constant elastic pressure of 20 cm H2O. RESULTS We observed two different types of loops, according to the pattern of the inflation limb. In type 1 (38 cases) the inflation limb was characterized by an inflexion zone, resulting from a progressive or a sudden improvement in compliance. In type 2 (16 patients) the inflation limb was virtually linear, without significant improvement in compliance during inflation, which remained particularly low (26+/-9 cm H2O). Use of a low PEEP (6+/-2 cm H2O) produced a substantial recruitment in type-1 patients (74+/-53 ml), which was marginally improved by a higher PEEP (89+/-54 ml). In type 2, recruitment produced by PEEP was significantly lower (48+/-26 ml, p=0.006). CONCLUSION Pressure-volume loop at bedside confirmed that a low PEEP was sufficient to obtain recruitment in ARDS. This study also individualized a group of pulmonary ARDS patients exhibiting a markedly reduced compliance, in whom recruitment obtained by PEEP was limited.
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Affiliation(s)
- Antoine Vieillard-Baron
- Medical Intensive Care Unit, University Hospital Ambroise Paré, Assistance Publique Hôpitaux de Paris, 9 avenue Charles de Gaulle, 92104, Boulogne Cedex, France
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Jardin F, Vieillard-Baron A. Right ventricular function and positive pressure ventilation in clinical practice: from hemodynamic subsets to respirator settings. Intensive Care Med 2003; 29:1426-34. [PMID: 12910335 DOI: 10.1007/s00134-003-1873-1] [Citation(s) in RCA: 111] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2003] [Accepted: 05/27/2003] [Indexed: 01/16/2023]
Affiliation(s)
- François Jardin
- Medical Intensive Care Unit, University Hospital Ambroise Paré, Assistance Publique Hôpitaux de Paris, 9 avenue Charles de Gaulle, 92104, Boulogne Cedex, France.
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Vieillard-Baron A, Jardin F. Right level of positive end-expiratory pressure in acute respiratory distress syndrome. Am J Respir Crit Care Med 2003; 167:1576; author reply 1576-7. [PMID: 12770857 DOI: 10.1164/ajrccm.167.11.952] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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38
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Maggiore SM, Lellouche F, Pigeot J, Taille S, Deye N, Durrmeyer X, Richard JC, Mancebo J, Lemaire F, Brochard L. Prevention of endotracheal suctioning-induced alveolar derecruitment in acute lung injury. Am J Respir Crit Care Med 2003; 167:1215-24. [PMID: 12615633 DOI: 10.1164/rccm.200203-195oc] [Citation(s) in RCA: 142] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
We studied endotracheal suctioning-induced alveolar derecruitment and its prevention in nine patients with acute lung injury. Changes in end-expiratory lung volume measured by inductive plethysmography, positive end-expiratory pressure-induced alveolar recruitment assessed by pressure-volume curves, oxygen saturation, and respiratory mechanics were recorded. Suctioning was performed after disconnection from the ventilator, through the swivel adapter of the catheter mount, with a closed system, and with the two latter techniques while performing recruitment maneuvers during suctioning (40 cm H2O pressure-supported breaths). End-expiratory lung volume after disconnection fell more than with all other techniques (-1,466 +/- 586, -733 +/- 406, -531 +/- 228, -168 +/- 176, and -284 +/- 317 ml after disconnection, through the swivel adapter, with the closed system, and with the two latter techniques with pressure-supported breaths, respectively, p < 0.001), and was not fully recovered 1 minute after suctioning. Recruitment decreased after disconnection and using the swivel adapter (-104 +/- 31 and -63 +/- 25 ml, respectively), was unchanged with the closed system (-1 +/- 10 ml), and increased when performing recruitment maneuvers during suctioning (71 +/- 37 and 60 +/- 30 ml) (p < 0.001). Changes in alveolar recruitment correlated with changes in lung volume (rho = 0.88, p < 0.001) and compliance (rho = 0.9, p < 0.001). Oxygenation paralleled lung volume changes. Suctioning-induced lung derecruitment in acute lung injury can be prevented by performing recruitment maneuvers during suctioning and minimized by avoiding disconnection.
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Affiliation(s)
- Salvatore M Maggiore
- Department of Anesthesiology and Intensive Care, Agostino Gemelli Teaching Hospital, Catholic University of the Sacred Heart, Rome, Italy
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Affiliation(s)
- Martin J Tobin
- Division of Pulmonary and Critical Care Medicine, Loyola University of Chicago Stritch School of Medicine and Hines Veterans Affairs Hospital, Hines, Illinois 60141, USA.
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40
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Vieillard-Baron A. Erratum. Am J Respir Crit Care Med 2002. [DOI: 10.1164/ajrccm.166.11.341a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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41
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Marini JJ. Auto-positive end-expiratory pressure and flow limitation in adult respiratory distress syndrome--intrinsically different? Crit Care Med 2002; 30:2140-1. [PMID: 12352054 DOI: 10.1097/00003246-200209000-00031] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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