Risk factors for mechanical ventilation and ECMO in COVID-19 patients admitted to the ICU: A multicenter retrospective observational study

BACKGROUND: The primary purpose of this study was to investigate risk factors associated with the need for mechanical ventilation (MV) and extracorporeal membrane oxygenation (ECMO) in COVID-19 patients admitted to the intensive care unit (ICU). METHODS: We retrospectively enrolled 66 consecutive COVID-19 patients admitted to the ICUs of three Japanese institutions from February 2020 to January 2021. We performed logistic regression analyses to identify risk factors associated with subsequent MV and ECMO requirements. Further, multivariate analyses were performed following adjustment for Acute Physiology and Chronic Health Evaluation (APACHE) II scores. RESULTS: At ICU admission, the risk factors for subsequent MV identified were: higher age (Odds Ratio (OR) 1.04, 95% Confidence Interval (CI) 1.00–1.08, P = 0.03), higher values of APACHE II score (OR 1.20, 95% CI 1.08–1.33, P < 0.001), Sequential Organ Failure Assessment score (OR 1.53, 95% CI 1.18–1.97, P < 0.001), lactate dehydrogenase (LDH) (OR 1.01, 95% CI 1.00–1.02, p<0.001) and C-reactive protein (OR 1.09, 95% CI 1.00–1.19, P = 0.04), and lower values of lymphocytes (OR 1.00, 95% CI 1.00–1.00, P = 0.02) and antithrombin (OR 0.95, 95% CI 0.91–0.95, P < 0.01). Patients who subsequently required ECMO showed lower values of estimated glomerular filtration rate (OR 0.98, 95% CI 0.96–1.00, P = 0.04) and antithrombin (OR 0.94, 95% CI 0.88–1.00, P = 0.03) at ICU admission. Multivariate analysis showed that higher body mass index (OR 1.19, 95% CI 1.00–1.40, P = 0.04) and higher levels of LDH (OR 1.01, 95% CI 1.01–1.02, P < 0.01) were independent risk factors for the need for MV. Lower level of antithrombin (OR 0.94, 95% CI 0.88–1.00, P = 0.03) was a risk factor for the need for ECMO. CONCLUSION: We showed that low antithrombin level at ICU admission might be a risk factor for subsequent ECMO requirements, in addition to other previously reported factors.