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Background: Since publication of the 2012 Berlin definition of acute respiratory distress syndrome (ARDS), several developments have supported the need for an expansion of the definition, including the use of high-flow nasal oxygen, the expansion of the use of pulse oximetry in place of arterial blood gases, the use of ultrasound for chest imaging, and the need for applicability in resource-limited settings. Methods: A consensus conference of 32 critical care ARDS experts was convened, had six virtual meetings (June 2021 to March 2022), and subsequently obtained input from members of several critical care societies. The goal was to develop a definition that would 1 ) identify patients with the currently accepted conceptual framework for ARDS, 2 ) facilitate rapid ARDS diagnosis for clinical care and research, 3 ) be applicable in resource-limited settings, 4 ) be useful for testing specific therapies, and 5 ) be practical for communication to patients and caregivers. Results: The committee made four main recommendations: 1 ) include high-flow nasal oxygen with a minimum flow rate of ⩾30 L/min; 2 ) use Pa O 2 :Fi O 2  ⩽ 300 mm Hg or oxygen saturation as measured by pulse oximetry Sp O 2 :Fi O 2  ⩽ 315 (if oxygen saturation as measured by pulse oximetry is ⩽97%) to identify hypoxemia; 3 ) retain bilateral opacities for imaging criteria but add ultrasound as an imaging modality, especially in resource-limited areas; and 4 ) in resource-limited settings, do not require positive end-expiratory pressure, oxygen flow rate, or specific respiratory support devices. Conclusions: We propose a new global definition of ARDS that builds on the Berlin definition. The recommendations also identify areas for future research, including the need for prospective assessments of the feasibility, reliability, and prognostic validity of the proposed global definition.

Purpose: We sought to examine changes in acute respiratory distress syndrome (ARDS) management over a 12-year period of two successive randomized trials., Methods: Analyses included baseline data, from eligible patients, prior to influence of trial protocols, and daily study data, from randomized patients, of variables not determined by trial protocols. Mixed linear regressions examined changes in practice year-on-year., Results: A total of 2376 patients met the inclusion criteria. Over the 12-year period, baseline tidal volume index decreased (9.0 to 7.0 ml/kg, p < 0.001), plateau pressures decreased (30.8 to 29.0 cmH 2 O, p < 0.05), and baseline positive end-expiratory pressures increased (10.8 to 13.2 cmH 2 O, p < 0.001). Volume-controlled ventilation declined from 29.4 to 14.0% (p < 0.01). Use of corticosteroids increased (baseline: 7.7 to 30.3%; on study: 32.6 to 61.2%; both p < 0.001), as did neuromuscular blockade (baseline: 12.3 to 24.5%; on study: 55.5 to 70.0%; both p < 0.01). Inhaled nitric oxide use increased (24.9 to 65.8%, p < 0.05). We observed no significant change in prone positioning (16.2 to 18.9%, p = 0.70)., Conclusions: Clear trends were apparent in tidal volume, airway pressures, ventilator modes, adjuncts and rescue therapies. With the exception of prone positioning, and outside the context of rescue therapy, these trends appear consistent with the evolving literature on ARDS management., Competing Interests: Declaration of Competing Interest All the other authors declare no conflicts of interest., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Introduction: Severe acute respiratory distress syndrome (ARDS) has a high mortality, and there is limited knowledge about management of severe ARDS refractory to standard therapy. Early evidence suggests that therapeutic hypothermia (TH) could be a viable treatment for acute respiratory failure. We present 2 cases where TH was successfully used to manage refractory ARDS on extracorporeal membrane oxygenation (ECMO) and a review of the literature around TH and acute respiratory failure., Results: We present 2 cases of ARDS secondary to H1N1 influenza and human metapneumovirus. Both patients were treated with the current evidence-based therapy for ARDS. Venovenous ECMO was used in both patients for refractory hypoxemia. Therapeutic hypothermia was applied for 24 hours with improved oxygenation. We did a review of the literature summarizing 38 patients in 10 publications where TH was successfully utilized in the treatment of acute respiratory failure., Conclusion: Therapeutic hypothermia may be a viable salvage therapy for ARDS refractory to the current evidence-based therapy but needs further evaluation.

Immunosuppression predisposes the host to development of pulmonary infections, which can lead to respiratory failure and the development of acute respiratory distress syndrome (ARDS). There are multiple mechanisms by which a host can be immunosuppressed and each is associated with specific infectious pathogens. Early invasive diagnostic modalities such as fiber-optic bronchoscopy with bronchoalveolar lavage, transbronchial biopsy, and open lung biopsy are complementary to serologic and noninvasive studies and assist in rapidly establishing an accurate diagnosis, which allows initiation of appropriate therapy and may improve outcomes with relative safety., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Acute respiratory distress syndrome (ARDS) remains challenging to diagnose and manage. This article reviews the new definition of ARDS and the key findings of landmark studies over the last 5 years of prone-position ventilation, high-frequency oscillatory ventilation (HFOV), extracorporeal membrane oxygenation (ECMO), and neuromuscular blockade in patients with ARDS., (Copyright© 2014 The Cleveland Clinic Foundation.)

Background: Previous trials suggesting that high-frequency oscillatory ventilation (HFOV) reduced mortality among adults with the acute respiratory distress syndrome (ARDS) were limited by the use of outdated comparator ventilation strategies and small sample sizes., Methods: In a multicenter, randomized, controlled trial conducted at 39 intensive care units in five countries, we randomly assigned adults with new-onset, moderate-to-severe ARDS to HFOV targeting lung recruitment or to a control ventilation strategy targeting lung recruitment with the use of low tidal volumes and high positive end-expiratory pressure. The primary outcome was the rate of in-hospital death from any cause., Results: On the recommendation of the data monitoring committee, we stopped the trial after 548 of a planned 1200 patients had undergone randomization. The two study groups were well matched at baseline. The HFOV group underwent HFOV for a median of 3 days (interquartile range, 2 to 8); in addition, 34 of 273 patients (12%) in the control group received HFOV for refractory hypoxemia. In-hospital mortality was 47% in the HFOV group, as compared with 35% in the control group (relative risk of death with HFOV, 1.33; 95% confidence interval, 1.09 to 1.64; P=0.005). This finding was independent of baseline abnormalities in oxygenation or respiratory compliance. Patients in the HFOV group received higher doses of midazolam than did patients in the control group (199 mg per day [interquartile range, 100 to 382] vs. 141 mg per day [interquartile range, 68 to 240], P<0.001), and more patients in the HFOV group than in the control group received neuromuscular blockers (83% vs. 68%, P<0.001). In addition, more patients in the HFOV group received vasoactive drugs (91% vs. 84%, P=0.01) and received them for a longer period than did patients in the control group (5 days vs. 3 days, P=0.01)., Conclusions: In adults with moderate-to-severe ARDS, early application of HFOV, as compared with a ventilation strategy of low tidal volume and high positive end-expiratory pressure, does not reduce, and may increase, in-hospital mortality. (Funded by the Canadian Institutes of Health Research; Current Controlled Trials numbers, ISRCTN42992782 and ISRCTN87124254, and ClinicalTrials.gov numbers, NCT00474656 and NCT01506401.).

During the last 5 years, new randomized trials in critically ill patients have challenged a number of traditional treatment strategies in intensive care. The authors review eight studies that helped change their medical practices.

Objective: The use of sedatives, opioids, and neuromuscular blocking agents (NMBAs) may delay weaning and prolong intensive care unit length of stay. We hypothesized that in patients on higher positive end-expiratory pressure (PEEP), sedatives, opioids, and NMBAs are used in a higher proportion of patients and in higher doses and that the use of these medications is associated with prolongation of weaning and mortality., Design: Retrospective analysis., Setting: The ALVEOLI trial., Patients: Five hundred forty-nine patients with acute lung injury/acute respiratory distress syndrome (ALI/ARDS) who were enrolled in the ALVEOLI trial., Interventions: We analyzed prospectively collected data regarding the impact of sedatives, opioids, and NMBAs in ALI/ARDS patients on duration of mechanical ventilation, time to weaning landmarks, and mortality., Measurements and Main Results: Sedatives and opioids were used in >80% of the patients in similar proportion in the two groups. The use of sedatives and opioids, but not the use of NMBAs, was associated with longer time on mechanical ventilation and an increased time to achieve a 2-hr spontaneous breathing trial (p < .0001). Sedatives were also associated with increased time to achieve unassisted breathing. NMBAs were used for a short period of time, in a higher proportion of patients in the lower PEEP group, and for a longer time (0.23 days)., Conclusions: Sedatives and opioids use was similar in the higher and lower PEEP groups. The use of sedatives and opioids, but not NMBAs, was associated with a longer time to achieve important weaning landmarks.

The PAC provides a wealth of information about circulatory and respiratory systems and intravascular fluid volume over time. Specifically, the PAC allows measurement of central venous and pulmonary arterial pressure, pulmonary artery occlusion pressure, mixed venous blood gases, and indicator-dilution cardiac output. Based on these quantitative date, systemic and pulmonary vascular resistance can be derived. The PAC is frequently used in patients with ALI and ARDS, both to confirm the diagnosis and to optimize hemodynamic management. In this article, we review the evidence on the use of the PAC in patients with ALI/ARDS, paying particular attention to the recently published fluid and catheter treatment trial by the ARDS Clinical Trials Network.

Acute respiratory distress syndrome (ARDS) and acute lung injury (ALI) are clinical syndromes characterized by the sudden onset of severe hypoxemia and diffuse bilateral pulmonary infiltrates in the absence of left atrial hypertension. Although advances have been made in the understanding of the etiology, pathophysiology, and epidemiology of both entities, many questions remain regarding their incidence, diagnosis, and outcomes. This article reviews the currently used definition of ARDS and ALI, different studies that have advanced the understanding of the epidemiology and outcomes of these entities, and several diagnostic issues that are important for both clinicians and researchers.

In the last 7 years, 14 randomized controlled trials in patients with acute respiratory distress syndrome (ARDS) have shown that: Mechanical ventilation with a tidal volume of 6 mL/kg of predicted body weight is better than mechanical ventilation with a tidal volume of 12 mL/kg of predicted body weight. Prone positioning improves oxygenation but poses safety concerns. A high level of positive end-expiratory pressure does not improve survival. High-frequency oscillatory ventilation is in theory the ideal "lung-protective" method, but its benefits have not been proven. No drug therapy has been shown to improve survival in patients with ARDS. Exogenous surfactant may improve oxygenation but has no significant effect on the death rate or length of use of mechanical ventilation. Low-dose inhaled nitric oxide has no substantial impact on the duration of ventilatory support or on the death rate. Partial liquid ventilation may be beneficial in young patients with acute lung injury or ARDS, although further study is needed to confirm this.

The increased understanding of the pathophysiology of ALI that has been achieved over the last decade has led to several new pharmacologic approaches for the prevention and management of ALI and ARDS. Based on in vitro information and animal model data, many of these strategies seem quite compelling. Nevertheless, to date, no specific pharmacologic approach for the prevention or treatment of ARDS has been conclusively validated in clinical trials. Active basic and clinical research continues, and it is hoped that these investigations will lead to new therapies that can be applied by the clinician to improve clinical outcomes for patients who have ALI and ARDS.

Study Objective: To identify outcome predictors and prognostic factors in long-term survivors (> 30 days post-transplant) of single-lung and double-lung transplants on readmission to the medical ICU (MICU)., Design: Retrospective study., Setting: MICU of the Cleveland Clinic Foundation, a lung transplantation center., Patients: As of August 2000, 210 lung transplantations have been performed at our institution. The records of 33 lung transplant recipients who required readmission to the MICU after the initial 30-day post-transplant period over a 4-year period from August 16, 1996 to August 15, 2000 were reviewed., Results: Thirty-three patients had a total of 46 MICU readmissions. Twenty-seven MICU admissions (59%) were due to respiratory deterioration with mechanical ventilation (10 deaths), and 16 MICU admissions (35%) were due to the systemic inflammatory response syndrome (SIRS; 8 deaths). The MICU mortality rate was 37% per admission in our group of patients. A preadmission diagnosis of bronchiolitis obliterans syndrome was observed in 7 of 14 nonsurvivors (50%) and in 5 of 25 patients (20%) surviving to hospital discharge., Conclusions: Respiratory failure and SIRS are the predominant causes of MICU readmissions and are frequent causes of death. APACHE (acute physiology and chronic health evaluation) III scores, nonpulmonary organ system dysfunction, initial serum albumin level, and duration of mechanical ventilation are important prognostic factors.

Study Objectives: To assess the incidence of the ARDS in a well-defined adult population., Design: Kaiser Permanente of northeast Ohio, a health maintenance organization, uses the Cleveland Clinic Foundation as its only tertiary care center. In an ongoing prospective assessment in the Cleveland Clinic ICUs, we identified adult Kaiser Permanente patients with ARDS between 1996 and 1999. ARDS was defined according to the 1994 American-European Consensus Conference criteria. The denominator in the incidence calculation was the adult members of Kaiser Permanente of each year of the study period, and the numerator was the new adult ARDS patients in this particular year. The cause of ARDS, the mortality, and the cause of death were retrospectively identified, as well as other characteristics of the study population., Results: ARDS was diagnosed in 66 patients during the 3-year study period. The incidence per 100,000 population was 11.4 in 1996, 19.8 in 1997, and 14.4 in 1998; the overall incidence was 15.3/100,000/yr. The mean PaO(2)/fraction of inspired oxygen (+/- SD) was 110.8 +/- 37.8, the mean APACHE II was 23.4 +/- 6.9, and the mean ICU stay was 12.0 +/- 9.5 days. The most common cause of ARDS was direct lung injury (75.8%), and the most common cause of death was septic shock (53.8%)., Conclusion: The incidence of ARDS in an adult population in northeast Ohio was 15.3/100,000/yr, a number that is slightly higher but comparable to recent estimates reported by other researchers.

In a recent major study, patients with acute respiratory distress syndrome or acute lung injury were randomly assigned to have their respirators set to deliver tidal volumes of either 6 mL/kg or a more-traditional 12 mL/kg. Mortality in the low-tidal-volume group was 31.0%, compared with 39.8% in the traditional-tidal-volume group, a 22% difference (P = .007).