Extracorporeal Membrane Oxygenation For Patients With Severe Respiratory Failure Induced By Avian Influenza A(H7N9) Viral Infection:Outcomes And Predictors Of Mortality

BackgroundA novel avian-origin influenza A(H7N9)virus infection had emerged in mainland China since March,2013,posing a pandemic threat to human beings.Until 7 December,2017,a total of 1566 laboratory-confirmed cases of human infection with avian influenza A(H7N9)viruses,including at least 613deaths,have been reported to WHO.Extracorporeal membrane oxygenation(ECMO)is a feasible therapeutic option that can provide basic life support and reduces or eliminates the risk of ventilation-related lung damage in patients.ECMO treatment for H7N9-caused ARDS patients have been reported in several cases.However,there were limited studies about patients who are at high risk of death for ECMO therapy in patients with severe respiratory failure due to H7N9 virus infection.AimTo identify risk factors for mortality in patients who received ECMO for ARDS due to H7N9 virus infection.MethodAll statistical analyses were performed using the Statistical Package for Social Science(spss,Inc.,Chicago,USA)version 23.0.A stepwise COX regression model was used for multivariate analysis.Statistically non-significant variables(P>0.05)were removed from the multivariate analysis.Odds ratios(ORs)with 95%confidence intervals(95%Cls)were presented for the stepwise COX regression analysis.ResultA total of 38 patients,aged 56.41 ± 12.99 years,were analysed;63.1%of patients were male with 52.6%mortality.Univariate analysis showed that risk factors included the duration of mechanical ventilation,secondary bloodstream infection,cardiac arrest,PO2 level,absolute lymphocyte count,hemoglobin level,platelet level,CRP level,and PCT level.According to multivariate analysis,it was found that the duration of mechanical ventilation(OR 0.945,95%CI 0.913-0.977,P=0.001),hemoglobin level(OR 0.959,95%CI 0.922-0.999,P=0.043),absolute lymphocyte count(OR 2.916,95%CI 1.080-4.464,P=0.030),CRP level(OR 1.008,95%CI 1.000-1.015,P=0.044)and secondary bloodstream infection(OR 7.069,95%CI 1.677-29.791,P=0.008)were independent risk factors for avian influenza A H7N9 patients during ECMO therapy.The positive rate of blood culture and the mortality of patients admitted in the past two epidemics were significantly lower than the previous three epidemics.ConclusionThe duration of mechanical ventilation,hemoglobin level,absolute lymphocyte count,CRP level and secondary bloodstream infection were independent risk factors for avian influenza A H7N9 patients during ECMO therapy.These findings will add to understanding of this disease,appropriate clinical care to reduce complications and fatality.