Extracorporeal Membrane Oxygenation for COVID-19-associated Severe Acute Respiratory Distress Syndrome in Chile: A Nationwide Incidence and Cohort Study

Abstract

Rationale: The role of and needs for extracorporeal membrane oxygenation (ECMO) at a population level during the coronavirus disease (COVID-19) pandemic have not been completely established. Objectives: To identify the cumulative incidence of ECMO use in the first pandemic wave and to describe the Nationwide Chilean cohort of ECMO-supported patients with COVID-19. Methods: We conducted a population-based study from March 3 to August 31, 2020, using linked data from national agencies. The cumulative incidence of ECMO use and mortality risk of ECMO-supported patients were calculated and age standardized. In addition, a retrospective cohort analysis was performed. Outcomes were 90-day mortality after ECMO initiation, ECMO-associated complications, and hospital length of stay. Cox regression models were used to explore risk factors for mortality in a time-to-event analysis. Measurements and Main Results: Ninety-four patients with COVID-19 were supported with ECMO (0.42 per population of 100,000, 14.89 per 100,000 positive cases, and 1.2% of intubated patients with COVID-19); 85 were included in the cohort analysis, and the median age was 48 (interquartile range [IQR], 41-55) years, 83.5% were men, and 42.4% had obesity. The median number of pre-ECMO intubation days was 4 (IQR, 2-7), the median Pa_O2/Fi_O2 ratio was 86.8 (IQR, 64-99) mm Hg, 91.8% of patients were prone positioned, and 14 patients had refractory respiratory acidosis. Main complications were infections (70.6%), bleeding (38.8%), and thromboembolism (22.4%); 52 patients were discharged home, and 33 died. The hospital length of stay was a median of 50 (IQR, 24-69) days. Lower respiratory system compliance and higher driving pressure before ECMO initiation were associated with increased mortality. A duration of pre-ECMO intubation ≥10 days was not associated with mortality. Conclusions: Documenting nationwide ECMO needs may help in planning ECMO provision for future COVID-19 pandemic waves. The 90-day mortality of the Chilean cohort of ECMO-supported patients with COVID-19 (38.8%) is comparable to that of previous reports.

Keywords: COVID-19; extracorporeal membrane oxygenation; pandemic; severe acute respiratory distress syndrome.

Figure 1.

Age-specific cumulative incidence of extracorporeal membrane oxygenation (ECMO) use per population of 100,000 and 90-day mortality for (A) patients receiving ECMO support and (B) daily patients on ECMO during the first wave of the coronavirus disease (COVID-19) pandemic in Chile. The incidence (black dots), cumulative incidence of ECMO use (solid line), mortality risk (black crosses), and age-specific 90-day mortality risk (dashed line) for patients receiving ECMO support are shown.

Figure 2.

Complications during ECMO support. ECMO = extracorporeal membrane oxygenation; HAI = healthcare-associated infections; VAP = ventilator-associated pneumonia.

Figure 3.

Survival according to days on mechanical ventilation before ECMO initiation. ECMO = extracorporeal membrane oxygenation.