Comparing Clinical Features and Outcomes in Mechanically Ventilated Patients with COVID-19 and the Acute Respiratory Distress Syndrome.

Sjoding, Michael W; Admon, Andrew J; Saha, Anjan K; Kay, Stephen G; Brown, Christopher A; Co, Ivan; Claar, Dru; McSparron, Jakob I; Dickson, Robert P

RATIONALE Patients with severe coronavirus disease 2019 (COVID-19) meet clinical criteria for the acute respiratory distress syndrome (ARDS), yet early reports suggested they differ physiologically and clinically from patients with non-COVID-19 ARDS, prompting treatment recommendations that deviate from standard evidence-based practices for ARDS. OBJECTIVES To compare respiratory physiology, clinical outcomes, and extrapulmonary clinical features of severe COVID-19 with non-COVID ARDS. METHODS We performed a retrospective cohort study, comparing 130 consecutive mechanically ventilated patients with severe COVID-19 with 382 consecutive mechanically ventilated patients with non-COVID-19 ARDS. Initial respiratory physiology and 28-day outcomes were compared. Extrapulmonary manifestations (inflammation, extrapulmonary organ injury, and coagulation) were compared in an exploratory analysis. RESULTS Comparison of patients with COVID-19 and non-COVID-19 ARDS suggested small differences in respiratory compliance, ventilatory efficiency, and oxygenation. 28-day mortality was 30% in COVID-19 patients and 38% in non-COVID ARDS. In adjusted analysis, point estimates of differences in time-to-breathing-unassisted at 28 days (adjusted SHR 0.98 [95% CI 0.77-1.26]) and 28-day mortality (risk ratio = 1.01 [95% CI 0.72-1.42]) were small for COVID-19 vs. non-COVID ARDS, although the confidence intervals for these estimates include moderate differences. Patients with COVID-19 had lower neutrophil counts but did not differ in lymphocyte count or other measures of systemic inflammation. CONCLUSIONS In this single center cohort, we found no evidence for large differences between COVID-19 and non-COVID ARDS. Many key clinical features of severe COVID-19 were similar to those of non-COVID-19 ARDS, including respiratory physiology and clinical outcomes, although our sample size precludes definitive conclusions. Further studies are needed to define COVID-19-specific pathophysiology before deviation from evidence-based treatment practices can be recommended.