Application of extracorporeal membrane oxygenation in patients with severe acute respiratory distress syndrome induced by avian influenza A (H7N9) viral pneumonia: national data from the Chinese multicentre collaboration

Background: Evidence concerning the efficacy and safety of extracorporeal membrane oxygenation (ECMO) in patients with influenza A (H7N9) has been was limited to case reports. Our study is aimed to investigate the current application, efficacy and safety of ECMO in for severe H7N9 pneumonia-associated acute respiratory distress syndrome (ARDS) in the Chinese population. Methods: A multicentre retrospective cohort study was conducted at 20 hospitals that admitted patients with avian influenza A (H7N9) viral pneumonia patients' admission from 9 provinces in China between October 1, 2016, and March 1, 2017. Data from the National Health and Family Planning Commission of China, including general conditions, outcomes and ECMO management, were analysed. Then, successfully weaned and unsuccessfully weaned groups were compared. Results: A total of 35 patients, aged 57 +/- 1 years, were analysed; 65.7% of patients were male with 63% mortality. All patients underwent invasive positive pressure ventilation (IPPV), and rescue ventilation strategies were implemented for 23 cases (65.7%) with an average IPPV duration of 5 +/- 1 d, PaO2/FiO(2) of 78 +/- 23 mmHg, tidal volume (VT) of 439 +/- 61 ml and plateau pressure (P-plat) of 29 +/- 8 cmH(2)O pre-ECMO. After 48 h on ECMO, PaO2 improved from 56 +/- 21 mmHg to 90 +/- 24 mmHg and PaCO2 declined from 52 +/- 24 mmHg to 38 +/- 24 mmHg. Haemorrhage, ventilator-associated pneumonia (VAP) and barotrauma occurred in 45.7%, 60% and 8.6% of patients, respectively. Compared with successfully weaned patients (n = 14), the 21 unsuccessfully weaned patients had a longer duration of IPPV pre-ECMO (6 +/- 4 d vs. 2 +/- 1 d, P < 0.01) as well as a higher P-plat (25 +/- 5 cmH(2)O vs. 21 +/- 3 cmH(2)O, P < 0.05) and VT (343 +/- 96 ml vs. 246 +/- 93 ml, P < 0.05) after 48 h on ECMO support. Furthermore, the unsuccessfully weaned group had a higher mortality (100% vs. 7.1%, P < 0.01) with more haemorrhage (77.3% vs. 28.6%, P < 0.01). Conclusions: ECMO is effective at improving oxygenation and ventilation of patients with avian influenza A (H7N9) induced severe ARDS. Early initiation of ECMO with appropriate IPPV settings and anticoagulation strategies are necessary to reduce complications.