Seasonal variation in severe influenza requiring extracorporeal membrane oxygenation: A binational, observational study

Abstract

Introduction: The 2009 H1N1 influenza pandemic saw unprecedented numbers of patients with severe respiratory failure requiring extracorporeal membrane oxygenation (ECMO). However seasonal variation in the influenza phenotype is common, and little is known how this might impact outcomes in patients on ECMO. Objectives/Aims: The aim of this study was to compare the phenotypes and outcomes of patients with severe influenza requiring ECMO in 2017 to 2009. Methods: This binational, multicenter, observational study was conducted in seven Australian and New Zealand adult and paediatric centers who had confirmed influenza patients on ECMO in 2017. Data were collected on the clinical syndrome and patient outcomes, and were compared to a previous database of the 2009 H1N1 outbreak. Results: In 2017, 29 patients were commenced on ECMO as compared to 68 in 2009. The H3N2 strain was more common in 2017 compared to 2009 (14.2 vs 0%), and a venoarterial ECMO mode was used more commonly (14 vs 4%). Patients in 2017 were older (47 vs 30 years), had higher plasma lactate levels (5.8 vs 2.4 mmol/L) and had higher creatinine levels (144 vs 83 umol/L) on initiation of ECMO, however they were less hypoxic (PaO2:FiO2 ratio 76 vs 51 mmHg) (p<0.05 for all). Proning was less common in 2017 than in 2009 (19.7 vs 7.1%). The duration of ECMO in 2017 was similar (10 vs 12 days), however mechanical ventilation duration was shorter (14 vs 26 days). Hospital mortality was higher in 2017 compared to 2009 (34.5 vs 22.1%). Conclusion: Significant seasonal variation exists between different strains of Influenza virus, phenotypes and outcomes. These factors should be considered when weighing the potential benefit of ECMO.L6342803432021-03-02 <br />