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Saha R, Assouline B, Mason G, Douiri A, Summers C, Shankar-Har M. The Impact of Sample Size Misestimations on the Interpretation of ARDS Trials: Systematic Review and Meta-analysis. Chest 2022; 162:1048-1062. [PMID: 35643115 DOI: 10.1016/j.chest.2022.05.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 04/06/2022] [Accepted: 05/04/2022] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Indeterminate randomized controlled trials (RCTs) in ARDS may arise from sample size misspecification, leading to abandonment of efficacious therapies. RESEARCH QUESTIONS If evidence exists for sample size misspecification in ARDS RCTs, has this led to rejection of potentially beneficial therapies? Does evidence exist for prognostic enrichment in RCTs using mortality as a primary outcome? STUDY DESIGN AND METHODS We identified 150 ARDS RCTs commencing recruitment after the 1994 American European Consensus Conference ARDS definition and published before October 31, 2020. We examined predicted-observed sample size, predicted-observed control event rate (CER), predicted-observed average treatment effect (ATE), and the relationship between observed CER and observed ATE for RCTs with mortality and nonmortality primary outcome measures. To quantify the strength of evidence, we used Bayesian-averaged meta-analysis, trial sequential analysis, and Bayes factors. RESULTS Only 84 of 150 RCTs (56.0%) reported sample size estimations. In RCTs with mortality as the primary outcome, CER was overestimated in 16 of 28 RCTs (57.1%). To achieve predicted ATE, interventions needed to prevent 40.8% of all deaths, compared with the original prediction of 29.3%. Absolute reduction in mortality ≥ 10% was observed in 5 of 28 RCTs (17.9%), but predicted in 21 of 28 RCTs (75%). For RCTs with mortality as the primary outcome, no association was found between observed CER and observed ATE (pooled OR: β = -0.04; 95% credible interval, -0.18 to 0.09). We identified three interventions that are not currently standard of care with a Bayesian-averaged effect size of > 0.20 and moderate strength of existing evidence: corticosteroids, airway pressure release ventilation, and noninvasive ventilation. INTERPRETATION Reporting of sample size estimations was inconsistent in ARDS RCTs, and misspecification of CER and ATE was common. Prognostic enrichment strategies in ARDS RCTs based on all-cause mortality are unlikely to be successful. Bayesian methods can be used to prioritize interventions for future effectiveness RCTs.
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Affiliation(s)
- Rohit Saha
- Critical Care Centre, King's College London, London, United Kingdom; School of Immunology & Microbial Sciences, King's College London, London, United Kingdom
| | - Benjamin Assouline
- Service de Médecine Intensive Réanimation, Faculté de Médecine Sorbonne Université, Hôpital Pitié Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Georgina Mason
- Critical Care Centre, King's College London, London, United Kingdom
| | - Abdel Douiri
- School of Population Health & Environmental Sciences, King's College London, London, United Kingdom; National Institute for Health Research Comprehensive Biomedical Research Centre, Guy's and St. Thomas' NHS Foundation Trust, London, United Kingdom
| | - Charlotte Summers
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Manu Shankar-Har
- Centre for Inflammation Research, University of Edinburgh, Edinburgh, United Kingdom.
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Miller AG, Tan HL, Smith BJ, Rotta AT, Lee JH. The Physiological Basis of High-Frequency Oscillatory Ventilation and Current Evidence in Adults and Children: A Narrative Review. Front Physiol 2022; 13:813478. [PMID: 35557962 PMCID: PMC9087180 DOI: 10.3389/fphys.2022.813478] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 04/08/2022] [Indexed: 12/12/2022] Open
Abstract
High-frequency oscillatory ventilation (HFOV) is a type of invasive mechanical ventilation that employs supra-physiologic respiratory rates and low tidal volumes (VT) that approximate the anatomic deadspace. During HFOV, mean airway pressure is set and gas is then displaced towards and away from the patient through a piston. Carbon dioxide (CO2) is cleared based on the power (amplitude) setting and frequency, with lower frequencies resulting in higher VT and CO2 clearance. Airway pressure amplitude is significantly attenuated throughout the respiratory system and mechanical strain and stress on the alveoli are theoretically minimized. HFOV has been purported as a form of lung protective ventilation that minimizes volutrauma, atelectrauma, and biotrauma. Following two large randomized controlled trials showing no benefit and harm, respectively, HFOV has largely been abandoned in adults with ARDS. A multi-center clinical trial in children is ongoing. This article aims to review the physiologic rationale for the use of HFOV in patients with acute respiratory failure, summarize relevant bench and animal models, and discuss the potential use of HFOV as a primary and rescue mode in adults and children with severe respiratory failure.
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Affiliation(s)
- Andrew G Miller
- Duke University Medical Center, Respiratory Care Services, Durham, NC, United States
| | - Herng Lee Tan
- KK Women's and Children's Hospital, Children's Intensive Care Unit, Singapore, Singapore
| | - Brian J Smith
- University of California, Davis, Respiratory Care Services, Sacramento, CA, United States
| | - Alexandre T Rotta
- Duke University Medical Center, Division of Pediatric Critical Care Medicine, Durham, NC, United States
| | - Jan Hau Lee
- KK Women's and Children's Hospital, Children's Intensive Care Unit, Singapore, Singapore.,Duke-NUS Medical School, Singapore, Singapore
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Sanfilippo F, Palumbo GJ, Bignami E, Pavesi M, Ranucci M, Scolletta S, Pelosi P, Astuto M. Acute Respiratory Distress Syndrome in the Perioperative Period of Cardiac Surgery: Predictors, Diagnosis, Prognosis, Management Options, and Future Directions. J Cardiothorac Vasc Anesth 2022; 36:1169-1179. [PMID: 34030957 PMCID: PMC8141368 DOI: 10.1053/j.jvca.2021.04.024] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 04/08/2021] [Accepted: 04/16/2021] [Indexed: 12/13/2022]
Abstract
Acute respiratory distress syndrome (ARDS) after cardiac surgery is reported with a widely variable incidence (from 0.4%-8.1%). Cardiac surgery patients usually are affected by several comorbidities, and the development of ARDS significantly affects their prognosis. Herein, evidence regarding the current knowledge in the field of ARDS in cardiac surgery is summarized and is followed by a discussion on therapeutic strategies, with consideration of the peculiar aspects of ARDS after cardiac surgery. Prevention of lung injury during and after cardiac surgery remains pivotal. Blood product transfusions should be limited to minimize the risk, among others, of lung injury. Open lung ventilation strategy (ventilation during cardiopulmonary bypass, recruitment maneuvers, and the use of moderate positive end-expiratory pressure) has not shown clear benefits on clinical outcomes. Clinicians in the intraoperative and postoperative ventilatory settings carefully should consider the effect of mechanical ventilation on cardiac function (in particular the right ventricle). Driving pressure should be kept as low as possible, with low tidal volumes (on predicted body weight) and optimal positive end-expiratory pressure. Regarding the therapeutic options, management of ARDS after cardiac surgery challenges the common approach. For instance, prone positioning may not be easily applicable after cardiac surgery. In patients who develop ARDS after cardiac surgery, extracorporeal techniques may be a valid choice in experienced hands. The use of neuromuscular blockade and inhaled nitric oxide can be considered on a case-by-case basis, whereas the use of aggressive lung recruitment and oscillatory ventilation should be discouraged.
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Affiliation(s)
- Filippo Sanfilippo
- Department of Anaesthesia and Intensive Care, A.O.U. "Policlinico-San Marco", Catania, Italy.
| | | | - Elena Bignami
- Unit of Anesthesiology, Division of Critical Care and Pain Medicine, Department of Medicine and Surgery, University of Parma, Parma, Italy
| | - Marco Pavesi
- Department of Cardiovascular Anesthesia and Intensive Care, IRCCS Policlinico San Donato, San Donato Milanese, Milan, Italy
| | - Marco Ranucci
- Department of Cardiovascular Anesthesia and Intensive Care, IRCCS Policlinico San Donato, San Donato Milanese, Milan, Italy
| | - Sabino Scolletta
- Department of Urgency and Emergency, of Organ Transplantation, Anesthesia and Intensive Care, Siena University Hospital, Siena, Italy
| | - Paolo Pelosi
- Anesthesia and Intensive Care, San Martino Policlinico Hospital, IRCCS for Oncology and Neuroscience, Genoa, Italy,Department of Surgical Sciences and Integrated Diagnostics, University of Genoa, Genoa, Italy
| | - Marinella Astuto
- Department of Anaesthesia and Intensive Care, A.O.U. “Policlinico-San Marco”, Catania, Italy,Department of General Surgery and Medical-Surgical Specialties, Section of Anesthesia and Intensive Care, University of Catania, Catania, Italy
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Saha R, Assouline B, Mason G, Douiri A, Summers C, Shankar-Hari M. Impact of differences in acute respiratory distress syndrome randomised controlled trial inclusion and exclusion criteria: systematic review and meta-analysis. Br J Anaesth 2021; 127:85-101. [PMID: 33812666 PMCID: PMC9768208 DOI: 10.1016/j.bja.2021.02.027] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 01/31/2021] [Accepted: 02/21/2021] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Control-arm mortality varies between acute respiratory distress syndrome (ARDS) RCTs. METHODS We systematically reviewed ARDS RCTs that commenced recruitment after publication of the American-European Consensus (AECC) definition (MEDLINE, Embase, and Cochrane central register of controlled trials; January 1994 to October 2020). We assessed concordance of RCT inclusion criteria to ARDS consensus definitions and whether exclusion criteria are strongly or poorly justified. We estimated the proportion of between-trial difference in control-arm 28-day mortality explained by the inclusion criteria and RCT design characteristics using meta-regression. RESULTS A literature search identified 43 709 records. One hundred and fifty ARDS RCTs were included; 146/150 (97.3%) RCTs defined ARDS inclusion criteria using AECC/Berlin definitions. Deviations from consensus definitions, primarily aimed at improving ARDS diagnostic certainty, frequently related to duration of hypoxaemia (117/146; 80.1%). Exclusion criteria could be grouped by rationale for selection into strongly or poorly justified criteria. Common poorly justified exclusions included pregnancy related, age, and comorbidities (infectious/immunosuppression, hepatic, renal, and human immunodeficiency virus/acquired immunodeficiency syndrome). Control-arm 28-day mortality varied between ARDS RCTs (mean: 29.8% [95% confidence interval: 27.0-32.7%; I2=88.8%; τ2=0.02; P<0.01]), and differed significantly between RCTs with different Pao2:FiO2 ratio inclusion thresholds (26.6-39.9 kPa vs <26.6 kPa; P<0.01). In a meta-regression model, inclusion criteria and RCT design characteristics accounted for 30.6% of between-trial difference (P<0.01). CONCLUSIONS In most ARDS RCTs, consensus definitions are modified to use as inclusion criteria. Between-RCT mortality differences are mostly explained by the Pao2:FiO2 ratio threshold within the consensus definitions. An exclusion criteria framework can be applied when designing and reporting exclusion criteria in future ARDS RCTs.
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Affiliation(s)
- Rohit Saha
- Critical Care, King's College Hospital NHS Foundation Trust, London, UK
| | | | - Georgina Mason
- Critical Care, King's College Hospital NHS Foundation Trust, London, UK
| | - Abdel Douiri
- School of Population Health & Environmental Sciences, King's College London, London, UK,National Institute for Health Research Comprehensive Biomedical Research Centre, Guy's and St Thomas' NHS Foundation Trust, London, UK
| | | | - Manu Shankar-Hari
- Critical Care, Guy's and St Thomas' NHS Foundation Trust, London, UK,School of Immunology & Microbial Sciences, King's College London, London, UK,Corresponding author
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Yumoto T, Fujita T, Asaba S, Kanazawa S, Nishimatsu A, Yamanouchi H, Nakagawa S, Nagano O. Comparison of the ventilation characteristics in two adult oscillators: a lung model study. Intensive Care Med Exp 2019; 7:15. [PMID: 30868327 PMCID: PMC6419651 DOI: 10.1186/s40635-019-0229-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2018] [Accepted: 02/28/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Two recent large randomized controlled trials did not show the superiority of high-frequency oscillatory ventilation (HFOV) in adults with ARDS. These two trials had differing results, and possible causes could be the different oscillators used and their different settings, including inspiratory time % (IT%). The aims of this study were to obtain basic data about the ventilation characteristics in two adult oscillators and to elucidate the effect of the oscillator and IT% on ventilation efficiency. METHODS The Metran R100 or SensorMedics 3100B was connected to an original lung model internally equipped with a simulated bronchial tree. The actual stroke volume (aSV) was measured with a flow sensor placed at the Y-piece. Carbon dioxide (CO2) was continuously insufflated into the lung model ([Formula: see text]CO2), and the partial pressure of CO2 (PCO2) in the lung model was monitored. Alveolar ventilation ([Formula: see text]A; L/min) was estimated as [Formula: see text]CO2 divided by the stabilized value of PCO2. [Formula: see text]A was evaluated with several stroke volume settings in the R100 (IT = 50%) or several airway pressure amplitude settings in the 3100B (IT = 33%, 50%) at a frequency of 6 and 8 Hz, a mean airway pressure of 25 cmH2O, and a bias flow of 30 L/min. Assuming that [Formula: see text]A = frequencya × aSVb, values of a and b were determined. Ventilation efficiency was calculated as [Formula: see text]A divided by actual minute ventilation. RESULTS The relationship between aSV and [Formula: see text]A or ventilation efficiency were different depending on the oscillator and IT%. The values of a and b were 0 < a < 1 and 1 < b < 2 and were different for three conditions at both frequencies. [Formula: see text]A and ventilation efficiency were highest with R100 (IT = 50%) and lowest with 3100B (IT = 33%) for high aSV ranges at both frequencies. CONCLUSIONS In this lung model study, ventilation characteristics were different depending on the oscillator and IT%. Ventilation efficiency was highest with R100 (IT = 50%) and lowest with 3100B (IT = 33%) for high aSV ranges.
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Affiliation(s)
- Tetsuya Yumoto
- Advanced Emergency and Critical Care Medical Center, Okayama University Hospital, 2-5-1, Shikata-cho, Kita-ku, Okayama, 700-8558, Japan
| | - Takahisa Fujita
- Center for Innovative and Translational Medicine, Kochi University Medical School, 185-1, Kohasu, Oko-cho, Nankoku, Kochi, 783-8505, Japan
| | - Sunao Asaba
- Center for Innovative and Translational Medicine, Kochi University Medical School, 185-1, Kohasu, Oko-cho, Nankoku, Kochi, 783-8505, Japan
| | - Shunsuke Kanazawa
- Center for Innovative and Translational Medicine, Kochi University Medical School, 185-1, Kohasu, Oko-cho, Nankoku, Kochi, 783-8505, Japan
| | - Atsunori Nishimatsu
- Center for Innovative and Translational Medicine, Kochi University Medical School, 185-1, Kohasu, Oko-cho, Nankoku, Kochi, 783-8505, Japan
| | - Hideo Yamanouchi
- Department of Disaster and Emergency Medicine, Kochi University Medical School, 185-1, Kohasu, Oko-cho, Nankoku, Kochi, 783-8505, Japan
| | - Satoshi Nakagawa
- Department of Critical Care and Anesthesia, National Center for Child Health and Development, 2-10-1, Okura, Setagaya-ku, Tokyo, 157-8535, Japan
| | - Osamu Nagano
- Department of Disaster and Emergency Medicine, Kochi University Medical School, 185-1, Kohasu, Oko-cho, Nankoku, Kochi, 783-8505, Japan.
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Sklar MC, Fan E, Goligher EC. High-Frequency Oscillatory Ventilation in Adults With ARDS: Past, Present, and Future. Chest 2017; 152:1306-1317. [PMID: 28684287 DOI: 10.1016/j.chest.2017.06.025] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 05/29/2017] [Accepted: 06/16/2017] [Indexed: 01/12/2023] Open
Abstract
High-frequency oscillatory ventilation (HFOV) is a unique mode of mechanical ventilation that uses nonconventional gas exchange mechanisms to deliver ventilation at very low tidal volumes and high frequencies. The properties of HFOV make it a potentially ideal mode to prevent ventilator-induced lung injury in patients with ARDS. Despite a compelling physiological basis and promising experimental data, large randomized controlled trials have not detected an improvement in survival with the use of HFOV, and its use as an early lung-protective strategy in patients with ARDS may be harmful. Nevertheless, HFOV still has an important potential role in the management of refractory hypoxemia. Careful attention should be paid to right ventricular function and lung stress when applying HFOV. This review discusses the physiological principles, clinical evidence, practical applications, and future prospects for the use of HFOV in patients with ARDS.
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Affiliation(s)
- Michael C Sklar
- Department of Anesthesia, University of Toronto, Toronto, ON, Canada; Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, ON, Canada
| | - Eddy Fan
- Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, ON, Canada; Institute for Health Policy, Management, and Evaluation, University of Toronto, Toronto, ON, Canada; Division of Respirology, Department of Medicine, University Health Network and Mount Sinai Hospital, Toronto, ON, Canada
| | - Ewan C Goligher
- Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, ON, Canada; Division of Respirology, Department of Medicine, University Health Network and Mount Sinai Hospital, Toronto, ON, Canada.
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Cressoni M, Chiumello D. Transpulmonary pressure during high-frequency oscillation ventilation: Is it the culprit? Ann Intensive Care 2016; 6:86. [PMID: 27620876 PMCID: PMC5020035 DOI: 10.1186/s13613-016-0191-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Accepted: 08/31/2016] [Indexed: 11/12/2022] Open
Affiliation(s)
- M Cressoni
- Dipartimento di Fisiopatologia Medico Chirurgica e dei Trapianti, Università degli Studi di Milano, Milan, Italy
| | - Davide Chiumello
- Dipartimento di Scienze della Salute, Università degli Studi di Milano, Milan, Italy. .,Dipartimento di Emergenza-Urgenza, ASST Santi Paolo e Carlo, Milan, Italy.
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