A shift in lung macrophage composition is associated with COVID-19 severity and recovery.

Although it has been more than 2 years since the start of the coronavirus disease 2019 (COVID-19) pandemic, COVID-19 continues to be a worldwide health crisis. Despite the development of preventive vaccines, therapies to treat COVID-19 and other inflammatory diseases remain a major unmet need in medicine. Our study sought to identify drivers of disease severity and mortality to develop tailored immunotherapy strategies to halt disease progression. We assembled the Mount Sinai COVID-19 Biobank, which was composed of almost 600 hospitalized patients followed longitudinally through the peak of the pandemic in 2020. Moderate disease and survival were associated with a stronger antigen presentation and effector T cell signature. In contrast, severe disease and death were associated with an altered antigen presentation signature, increased numbers of inflammatory immature myeloid cells, and extrafollicular activated B cells that have been previously associated with autoantibody formation. In severely ill patients with COVID-19, lung tissue-resident alveolar macrophages not only were drastically depleted but also had an altered antigen presentation signature, which coincided with an influx of inflammatory monocytes and monocyte-derived macrophages. In addition, we found that the size of the alveolar macrophage pool correlated with patient outcome and that alveolar macrophage numbers and functionality were restored to homeostasis in patients who recovered from COVID-19. These data suggest that local and systemic myeloid cell dysregulation are drivers of COVID-19 severity and modulation of alveolar macrophage numbers and activity in the lung may be a viable therapeutic strategy for the treatment of critical inflammatory lung diseases.

Wellness and Coping of Physicians Who Worked in ICUs During the Pandemic: A Multicenter Cross-Sectional North American Survey.

OBJECTIVES: Few surveys have focused on physician moral distress, burnout, and professional fulfilment. We assessed physician wellness and coping during the COVID-19 pandemic. DESIGN: Cross-sectional survey using four validated instruments. SETTING: Sixty-two sites in Canada and the United States. SUBJECTS: Attending physicians (adult, pediatric; intensivist, nonintensivist) who worked in North American ICUs. INTERVENTION: None. MEASUREMENTS AND MAIN RESULTS: We analysed 431 questionnaires (43.3% response rate) from 25 states and eight provinces. Respondents were predominantly male (229 [55.6%]) and in practice for 11.8 ± 9.8 years. Compared with prepandemic, respondents reported significant intrapandemic increases in days worked/mo, ICU bed occupancy, and self-reported moral distress (240 [56.9%]) and burnout (259 [63.8%]). Of the 10 top-ranked items that incited moral distress, most pertained to regulatory/organizational ( n = 6) or local/institutional ( n = 2) issues or both ( n = 2). Average moral distress (95.6 ± 66.9), professional fulfilment (6.5 ± 2.1), and burnout scores (3.6 ± 2.0) were moderate with 227 physicians (54.6%) meeting burnout criteria. A significant dose-response existed between COVID-19 patient volume and moral distress scores. Physicians who worked more days/mo and more scheduled in-house nightshifts, especially combined with more unscheduled in-house nightshifts, experienced significantly more moral distress. One in five physicians used at least one maladaptive coping strategy. We identified four coping profiles (active/social, avoidant, mixed/ambivalent, infrequent) that were associated with significant differences across all wellness measures. CONCLUSIONS: Despite moderate intrapandemic moral distress and burnout, physicians experienced moderate professional fulfilment. However, one in five physicians used at least one maladaptive coping strategy. We highlight potentially modifiable factors at individual, institutional, and regulatory levels to enhance physician wellness.

Impact of ICU strain on outcomes.

PURPOSE OF REVIEW: Acute surge events result in health capacity strain, which can result in deviations from normal care, activation of contingencies and decisions related to resource allocation. This review discusses the impact of health capacity strain on patient centered outcomes. RECENT FINDINGS: This manuscript discusses the lack of validated metrics for ICU strain capacity and a need for understanding the complex interrelationships of strain with patient outcomes. Recent work through the coronavirus disease 2019 pandemic has shown that acute surge events are associated with significant increase in hospital mortality. Though causal data on the differential impact of surge actions and resource availability on patient outcomes remains limited the overall signal consistently highlights the link between ICU strain and critical care outcomes in both normal and surge conditions. SUMMARY: An understanding of ICU strain is fundamental to the appropriate clinical care for critically ill patients. Accounting for stain on outcomes in critically ill patients allows for minimization of variation in care and an ability of a given healthcare system to provide equitable, and quality care even in surge scenarios.

Identifying Strategies to Boost COVID-19 Vaccine Acceptance in the United States

This study presents the results of an evaluation of the root causes of COVID-19 vaccine hesitancy to inform strategies to boost vaccine acceptance among vaccine-hesitant populations in the United States. The authors conducted a literature review of the causes of vaccine hesitancy and vaccine acceptance;focus groups with patients, pre-hospital first responders, and hospital-based health care providers;a social media platform sentiment analysis to review attitudes regarding the COVID-19 vaccine;and a roundtable discussion with experts on vaccine hesitancy. Drawing on this mixed-methods analysis, the authors recommend strategies to help boost COVID-19 vaccine acceptance in the United States, grouping them according to three overall goals: boosting confidence in the safety and effectiveness of the COVID-19 vaccines, combating complacency about the pandemic, and increasing the convenience of getting vaccinated. The authors emphasize that combating misinformation about the COVID-19 vaccine is key to achieving these goals. These recommendations can inform the development of a toolkit of strategies to reach herd immunity and end the pandemic.

Predictors of Respiratory Support Use in Emergency Department Patients With COVID-19-Related Respiratory Failure.

BACKGROUND: Given the known downstream implications of choice of respiratory support on patient outcomes, all factors influencing these decisions, even those not limited to the patient, warrant close consideration. We examined the effect of emergency department (ED)-specific system factors, such as work load and census, on the use of noninvasive versus invasive respiratory support. METHODS: We conducted a multi-center retrospective cohort study of all adult subjects with severe COVID-19 requiring an ICU admission from 5 EDs within a single urban health care system. Subject demographics, severity of illness, and the type of respiratory support used were obtained. Using continuous measures of ED census, boarding, and active management, we estimated ED work load for each subjects' ED stay. The subjects were categorized by type(s) of respiratory support used: low-flow oxygen, noninvasive respiratory support (eg, noninvasive ventilation [NIV] and/or high-flow nasal cannula [HFNC]), invasive mechanical ventilation, or invasive mechanical ventilation after trial of NIV/HFNC. We used multivariable logistic regression to examine system factors associated with the type of respiratory support used in the ED. RESULTS: A total of 634 subjects were included. Of these, 431 (70.0%) were managed on low-flow oxygen alone, 108 (17.0%) on NIV/HFNC, 54 (8.5%) on invasive mechanical ventilation directly, and 41 (6.5%) on NIV/HFNC prior to invasive mechanical ventilation in the ED. Higher severity of illness and underlying lung disease increased the odds of requiring invasive mechanical ventilation compared to low-flow oxygen (odds ratio 1.05 [95% CI 1.03-1.07] and odds ratio 3.47 [95% CI 1.37-8.78], respectively). Older age decreased odds of being on invasive mechanical ventilation compared to low-flow oxygen (odds ratio 0.96 [95% CI 0.94-0.99]). As ED work load increased, the odds for subjects to be managed initially with NIV/HFNC prior to invasive mechanical ventilation increased 6-8-fold. CONCLUSIONS: High ED work load was associated with higher odds on HFNC/NIV prior to invasive mechanical ventilation.

Anti-Granulocyte-Macrophage Colony-Stimulating Factor Monoclonal Antibody Gimsilumab for COVID-19 Pneumonia: A Randomized, Double-Blind, Placebo-controlled Trial.

Rationale: GM-CSF (granulocyte-macrophage colony-stimulating factor) has emerged as a promising target against the hyperactive host immune response associated with coronavirus disease (COVID-19). Objectives: We sought to investigate the efficacy and safety of gimsilumab, an anti-GM-CSF monoclonal antibody, for the treatment of hospitalized patients with elevated inflammatory markers and hypoxemia secondary to COVID-19. Methods: We conducted a 24-week randomized, double-blind, placebo-controlled trial, BREATHE (Better Respiratory Education and Treatment Help Empower), at 21 locations in the United States. Patients were randomized 1:1 to receive two doses of intravenous gimsilumab or placebo 1 week apart. The primary endpoint was all-cause mortality rate at Day 43. Key secondary outcomes were ventilator-free survival rate, ventilator-free days, and time to hospital discharge. Enrollment was halted early for futility based on an interim analysis. Measurements and Main Results: Of the planned 270 patients, 225 were randomized and dosed; 44.9% of patients were Hispanic or Latino. The gimsilumab and placebo groups experienced an all-cause mortality rate at Day 43 of 28.3% and 23.2%, respectively (adjusted difference = 5% vs. placebo; 95% confidence interval [-6 to 17]; P = 0.377). Overall mortality rates at 24 weeks were similar across the treatment arms. The key secondary endpoints demonstrated no significant differences between groups. Despite the high background use of corticosteroids and anticoagulants, adverse events were generally balanced between treatment groups. Conclusions: Gimsilumab did not improve mortality or other key clinical outcomes in patients with COVID-19 pneumonia and evidence of systemic inflammation. The utility of anti-GM-CSF therapy for COVID-19 remains unclear. Clinical trial registered with www.clinicaltrials.gov (NCT04351243).

Characteristics and Outcomes of US Patients Hospitalized With COVID-19.

BACKGROUND: Understanding COVID-19 epidemiology is crucial to clinical care and to clinical trial design and interpretation. OBJECTIVE: To describe characteristics, treatment, and outcomes among patients hospitalized with COVID-19 early in the pandemic. METHODS: A retrospective cohort study of consecutive adult patients with laboratory-confirmed, symptomatic SARS-CoV-2 infection admitted to 57 US hospitals from March 1 to April 1, 2020. RESULTS: Of 1480 inpatients with COVID-19, median (IQR) age was 62.0 (49.4-72.9) years, 649 (43.9%) were female, and 822 of 1338 (61.4%) were non-White or Hispanic/Latino. Intensive care unit admission occurred in 575 patients (38.9%), mostly within 4 days of hospital presentation. Respiratory failure affected 583 patients (39.4%), including 284 (19.2%) within 24 hours of hospital presentation and 413 (27.9%) who received invasive mechanical ventilation. Median (IQR) hospital stay was 8 (5-15) days overall and 15 (9-24) days among intensive care unit patients. Hospital mortality was 17.7% (n = 262). Risk factors for hospital death identified by penalized multivariable regression included older age; male sex; comorbidity burden; symptoms-to-admission interval; hypotension; hypoxemia; and higher white blood cell count, creatinine level, respiratory rate, and heart rate. Of 1218 survivors, 221 (18.1%) required new respiratory support at discharge and 259 of 1153 (22.5%) admitted from home required new health care services. CONCLUSIONS: In a geographically diverse early-pandemic COVID-19 cohort with complete hospital folllow-up, hospital mortality was associated with older age, comorbidity burden, and male sex. Intensive care unit admissions occurred early and were associated with protracted hospital stays. Survivors often required new health care services or respiratory support at discharge.

Oxyhemoglobin concentrations do not support hemoglobinopathy in COVID-19.

Based on computerized modeling studies, it has been postulated that the severe hypoxemia in COVID-19 may result from impaired oxygen carrying capacity on hemoglobin. Standard pulse oximetry may not detect hypoxemia resulting from hemoglobinopathy, therefore hemoglobin co-oximetry is needed to evaluate this divergence. In a clinical data analysis of a multicenter cohort of hospitalized patients with COVID-19, we found a minimal effect, less than 1%, on the correlation between oxyhemoglobin concentration and predicted oxygen saturation in the presence of COVID-19 infection. This effect is unlikely to explain the clinically significant hypoxia in COVID-19 patients.

Prone Positioning and Survival in Mechanically Ventilated Patients With Coronavirus Disease 2019-Related Respiratory Failure.

OBJECTIVES: Therapies for patients with respiratory failure from coronavirus disease 2019 are urgently needed. Early implementation of prone positioning ventilation improves survival in patients with acute respiratory distress syndrome, but studies examining the effect of proning on survival in patients with coronavirus disease 2019 are lacking. Our objective was to estimate the effect of early proning initiation on survival in patients with coronavirus disease 2019-associated respiratory failure. DESIGN: Data were derived from the Study of the Treatment and Outcomes in Critically Ill Patients with coronavirus disease 2019, a multicenter cohort study of critically ill adults with coronavirus disease 2019 admitted to 68 U.S. hospitals. Using these data, we emulated a target trial of prone positioning ventilation by categorizing mechanically ventilated hypoxemic (ratio of Pao2 over the corresponding Fio2 ≤ 200 mm Hg) patients as having been initiated on proning or not within 2 days of ICU admission. We fit an inverse probability-weighted Cox model to estimate the mortality hazard ratio for early proning versus no early proning. Patients were followed until death, hospital discharge, or end of follow-up. SETTING: ICUs at 68 U.S. sites. PATIENTS: Critically ill adults with laboratory-confirmed coronavirus disease 2019 receiving invasive mechanical ventilation with ratio of Pao2 over the corresponding Fio2 less than or equal to 200 mm Hg. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Among 2,338 eligible patients, 702 (30.0%) were proned within the first 2 days of ICU admission. After inverse probability weighting, baseline and severity of illness characteristics were well-balanced between groups. A total of 1,017 (43.5%) of the 2,338 patients were discharged alive, 1,101 (47.1%) died, and 220 (9.4%) were still hospitalized at last follow-up. Patients proned within the first 2 days of ICU admission had a lower adjusted risk of death compared with nonproned patients (hazard ratio, 0.84; 95% CI, 0.73-0.97). CONCLUSIONS: In-hospital mortality was lower in mechanically ventilated hypoxemic patients with coronavirus disease 2019 treated with early proning compared with patients whose treatment did not include early proning.

The Influence of the COVID-19 Pandemic on ICU Organization, Care Processes, and Frontline Clinician Experiences: A Qualitative Study.

BACKGROUND: The COVID-19 pandemic resulted in unprecedented adjustments to ICU organization and care processes globally. RESEARCH QUESTIONS: Did hospital emergency responses to the COVID-19 pandemic differ depending on hospital setting? Which strategies worked well to mitigate strain as perceived by intensivists? STUDY DESIGN AND METHODS: Between August and November 2020, we carried out semistructured interviews of intensivists from tertiary and community hospitals across six regions in the United States that experienced early or large surges of COVID-19 patients, or both. We identified themes of hospital emergency responses using the four S framework of acute surge planning: space, staff, stuff, system. RESULTS: Thirty-three intensivists from seven tertiary and six community hospitals participated. Clinicians across both settings believed that canceling elective surgeries was helpful to increase ICU capabilities and that hospitals should establish clearly defined thresholds at which surgeries are limited during future surge events. ICU staff was the most limited resource; staff shortages were improved by the use of tiered staffing models, just-in-time training for non-ICU clinicians, designated treatment teams, and deployment of trainees. Personal protective equipment (PPE) shortages and reuse were widespread, causing substantial distress among clinicians; hands-on PPE training was helpful to reduce clinicians' anxiety. Transparency and involvement of frontline clinicians as stakeholders were important components of effective emergency responses and helped to maintain trust among staff. INTERPRETATION: We identified several strategies potentially to mitigate strain as perceived by intensivists working in both tertiary and community hospital settings. Our study also demonstrated the importance of trust and transparency between frontline staff and hospital leadership as key components of effective emergency responses during public health crises.

Variation in Initial U.S. Hospital Responses to the Coronavirus Disease 2019 Pandemic.

OBJECTIVES: The coronavirus disease 2019 pandemic has strained many healthcare systems. In response, U.S. hospitals altered their care delivery systems, but there are few data regarding specific structural changes. Understanding these changes is important to guide interpretation of outcomes and inform pandemic preparedness. We sought to characterize emergency responses across hospitals in the United States over time and in the context of local case rates early in the coronavirus disease 2019 pandemic. DESIGN: We surveyed hospitals from a national acute care trials group regarding operational and structural changes made in response to the coronavirus disease 2019 pandemic from January to August 2020. We collected prepandemic characteristics and changes to hospital system, space, staffing, and equipment during the pandemic. We compared the timing of these changes with county-level coronavirus disease 2019 case rates. SETTING AND PARTICIPANTS: U.S. hospitals participating in the Prevention and Early Treatment of Acute Lung Injury Network Coronavirus Disease 2019 Observational study. Site investigators at each hospital collected local data. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Forty-five sites participated (94% response rate). System-level changes (incident command activation and elective procedure cancellation) occurred at nearly all sites, preceding rises in local case rates. The peak inpatient census during the pandemic was greater than the prior hospital bed capacity in 57% of sites with notable regional variation. Nearly half (49%) expanded ward capacity, and 63% expanded ICU capacity, with nearly all bed expansion achieved through repurposing of clinical spaces. Two-thirds of sites adapted staffing to care for patients with coronavirus disease 2019, with 48% implementing tiered staffing models, 49% adding temporary physicians, nurses, or respiratory therapists, and 30% changing the ratios of physicians or nurses to patients. CONCLUSIONS: The coronavirus disease 2019 pandemic prompted widespread system-level changes, but front-line clinical care varied widely according to specific hospital needs and infrastructure. Linking operational changes to care delivery processes is a necessary step to understand the impact of the coronavirus disease 2019 pandemic on patient outcomes.

Hyperglycemia Is Associated With Increased Mortality in Critically Ill Patients With COVID-19

Objective: To explore the relationship between diabetes mellitus (DM), hyperglycemia, and adverse outcomes in critically ill patients with coronavirus disease 2019 (COVID-19).

Hyperglycemia is Associated With Increased Mortality in Critically Ill Patients With COVID-19.

OBJECTIVE: To explore the relationship between hyperglycemia in the presence and absence of diabetes mellitus (DM) and adverse outcomes in critically ill patients with coronavirus disease 2019 (COVID-19). METHODS: The study included 133 patients with COVID-19 admitted to an intensive care unit (ICU) at an urban academic quaternary-care center between March 10 and April 8, 2020. Patients were categorized based on the presence or absence of DM and early-onset hyperglycemia (EHG), defined as a blood glucose >180 mg/dL during the first 2 days after ICU admission. The primary outcome was 14-day all-cause in-hospital mortality; also examined were 60-day all-cause in-hospital mortality and the levels of C-reactive protein, interleukin 6, procalcitonin, and lactate. RESULTS: Compared to non-DM patients without EHG, non-DM patients with EHG exhibited higher adjusted hazard ratios (HRs) for mortality at 14 days (HR 7.51, CI 1.70-33.24) and 60 days (HR 6.97, CI 1.86-26.13). Non-DM patients with EHG also featured higher levels of median C-reactive protein (306.3 mg/L, P = .036), procalcitonin (1.26 ng/mL, P = .028), and lactate (2.2 mmol/L, P = .023). CONCLUSION: Among critically ill COVID-19 patients, those without DM with EHG were at greatest risk of 14-day and 60-day in-hospital mortality. Our study was limited by its retrospective design and relatively small cohort. However, our results suggest the combination of elevated glucose and lactate may identify a specific cohort of individuals at high risk for mortality from COVID-19. Glucose testing and control are important in individuals with COVID-19, even those without preexisting diabetes.

The Intersection of Work and Home Challenges Faced by Physician Mothers During the Coronavirus Disease 2019 Pandemic: A Mixed-Methods Analysis.

Objectives: The coronavirus disease 2019 (COVID-19) pandemic has presented extreme challenges for health care workers. This study sought to characterize challenges faced by physician mothers, compare differences in challenges by home and work characteristics, and elicit specific needs and potential solutions. Methods: We conducted a mixed-methods online survey of the Physician Moms Group (PMG) and PMG COVID19 Subgroup on Facebook from April 18th to 29th, 2020. We collected structured data on personal and professional characteristics and qualitative data on home and work concerns. We analyzed qualitative data thematically and used bivariate analyses to evaluate variation in themes by frontline status and children's ages. Results: We included 1,806 participants in analysis and identified 10 key themes. The most frequently identified need/solution was for Community and Government Support (n = 545, 47.1%). When comparing frontline and nonfrontline physicians, those on the frontline more frequently raised concerns about Personal Health and Safety (67.8% vs. 48.4%, p < 0.001), Organizational Communication and Relationships (31.8% vs. 23.8%, p < 0.001), and Family Health and Safety (27.2 vs. 16.6, p < 0.001), while nonfrontline physicians more frequently addressed Patient Care and Safety (56.4% vs. 48.2%, p < 0.001) and Financial/Job Security (33.8% vs. 46.9%, p < 0.001). Participants with an elementary school-aged child more frequently raised concerns about Parenting/Homeschooling (44.0% vs. 31.1%, p < 0.001) and Work/Life Balance (28.4 vs. 13.7, p < 0.001), and participants with a preschool-aged child more frequently addressed Access to Childcare (24.0 vs. 7.7, p < 0.001) and Spouse/Partner Relationships (15.8 vs. 9.5, p < 0.001), when compared to those without children in these age groups. Conclusions: The physician workforce is not homogenous. Health care and government leaders need to understand these diverse challenges in order to meet physicians' professional and family needs during the pandemic.

Cardiovascular Disease and Severe Hypoxemia Are Associated With Higher Rates of Noninvasive Respiratory Support Failure in Coronavirus Disease 2019 Pneumonia.

Acute hypoxemic respiratory failure is the major complication of coronavirus disease 2019, yet optimal respiratory support strategies are uncertain. We aimed to describe outcomes with high-flow oxygen delivered through nasal cannula and noninvasive positive pressure ventilation in coronavirus disease 2019 acute hypoxemic respiratory failure and identify individual factors associated with noninvasive respiratory support failure. DESIGN: Retrospective cohort study to describe rates of high-flow oxygen delivered through nasal cannula and/or noninvasive positive pressure ventilation success (live discharge without endotracheal intubation). Fine-Gray subdistribution hazard models were used to identify patient characteristics associated with high-flow oxygen delivered through nasal cannula and/or noninvasive positive pressure ventilation failure (endotracheal intubation and/or in-hospital mortality). SETTING: One large academic health system, including five hospitals (one quaternary referral center, a tertiary hospital, and three community hospitals), in New York City. PATIENTS: All hospitalized adults 18-100 years old with coronavirus disease 2019 admitted between March 1, 2020, and April 28, 2020. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: A total of 331 and 747 patients received high-flow oxygen delivered through nasal cannula and noninvasive positive pressure ventilation as the highest level of noninvasive respiratory support, respectively; 154 (46.5%) in the high-flow oxygen delivered through nasal cannula cohort and 167 (22.4%) in the noninvasive positive pressure ventilation cohort were successfully discharged without requiring endotracheal intubation. In adjusted models, significantly increased risk of high-flow oxygen delivered through nasal cannula and noninvasive positive pressure ventilation failure was seen among patients with cardiovascular disease (subdistribution hazard ratio, 1.82; 95% CI, 1.17-2.83 and subdistribution hazard ratio, 1.40; 95% CI, 1.06-1.84, respectively). Conversely, a higher peripheral blood oxygen saturation to Fio2 ratio at high-flow oxygen delivered through nasal cannula and noninvasive positive pressure ventilation initiation was associated with reduced risk of failure (subdistribution hazard ratio, 0.32; 95% CI, 0.19-0.54, and subdistribution hazard ratio 0.34; 95% CI, 0.21-0.55, respectively). CONCLUSIONS: A significant proportion of patients receiving noninvasive respiratory modalities for coronavirus disease 2019 acute hypoxemic respiratory failure achieved successful hospital discharge without requiring endotracheal intubation, with lower success rates among those with comorbid cardiovascular disease or more severe hypoxemia. The role of high-flow oxygen delivered through nasal cannula and noninvasive positive pressure ventilation in coronavirus disease 2019-related acute hypoxemic respiratory failure warrants further consideration.

Extracorporeal membrane oxygenation in patients with severe respiratory failure from COVID-19.

PURPOSE: Limited data are available on venovenous extracorporeal membrane oxygenation (ECMO) in patients with severe hypoxemic respiratory failure from coronavirus disease 2019 (COVID-19). METHODS: We examined the clinical features and outcomes of 190 patients treated with ECMO within 14 days of ICU admission, using data from a multicenter cohort study of 5122 critically ill adults with COVID-19 admitted to 68 hospitals across the United States. To estimate the effect of ECMO on mortality, we emulated a target trial of ECMO receipt versus no ECMO receipt within 7 days of ICU admission among mechanically ventilated patients with severe hypoxemia (PaO2/FiO2 < 100). Patients were followed until hospital discharge, death, or a minimum of 60 days. We adjusted for confounding using a multivariable Cox model. RESULTS: Among the 190 patients treated with ECMO, the median age was 49 years (IQR 41-58), 137 (72.1%) were men, and the median PaO2/FiO2 prior to ECMO initiation was 72 (IQR 61-90). At 60 days, 63 patients (33.2%) had died, 94 (49.5%) were discharged, and 33 (17.4%) remained hospitalized. Among the 1297 patients eligible for the target trial emulation, 45 of the 130 (34.6%) who received ECMO died, and 553 of the 1167 (47.4%) who did not receive ECMO died. In the primary analysis, patients who received ECMO had lower mortality than those who did not (HR 0.55; 95% CI 0.41-0.74). Results were similar in a secondary analysis limited to patients with PaO2/FiO2 < 80 (HR 0.55; 95% CI 0.40-0.77). CONCLUSION: In select patients with severe respiratory failure from COVID-19, ECMO may reduce mortality.