Eleven Years of Venovenous Extracorporeal Membrane Oxygenation for Acute Respiratory Distress Syndrome: From H1N1 to SARS-CoV-2. Experience and Perspectives of a National Referral Center

OBJECTIVE: Despite growing expertise and wide application of venovenous extracorporeal membrane oxygenation (VV ECMO) treatment for acute respiratory distress syndrome (ARDS) of different origin and during pandemics (H1N1 Influenza A virus and SARS-CoV-2), large reports are few and pertain mostly to multicenter registries, and randomized trials are difficult to perform. The aim of this study was to report outcomes, trends, and innovations of VV ECMO treatment over the last 11 years. DESIGN, SETTING, AND PARTICIPANTS: Observational study on 142 patients treated at the IRCCS San Raffaele Hospital in Milan from June 2009 (year of the H1N1 pandemic) to May 2020 (SARS-CoV-2 pandemic). INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The main causes of ARDS were H1N1 pneumonia in 36% of patients, bacterial pneumonia in 17%, and SARS-CoV-2 in 9%. Seventy-two percent of patients were centralized from remote hospitals, of whom 33% had implanted VV ECMO before transport. The most common cannulation strategy was the dual-lumen catheter cannulation system (55%), and anticoagulation was performed with bivalirudin in most patients (79%). Refractory hypoxia was treated with intravenous beta-blockers (64%), nitric oxide (20%), and pronation (8%). Almost one-third of patients (32%) were extubated while on ECMO. Forty-nine percent of patients were discharged from the intensive care unit, and hospital discharge was 46%; survival was lower in patients requiring VV ECMO for more than three weeks compared with shorter support duration (23% v 56%, p = 0.007). Anticoagulation with bivalirudin was associated with higher survival, compared with heparin (55% v 31%, p = 0.03), and lower thrombocytopenia incidence (69% v 35%, p = 0.003). CONCLUSION: VV ECMO is the pivotal rescue treatment for refractory ARDS—timely treatment and optimal care are needed to optimize therapy, as duration of support is associated with outcome. Anticoagulation with bivalirudin may improve outcome.