Despite the severity of disease and the intensity of treatment, most patients in Australia and New Zealand who experienced respiratory failure as a result of 2009 influenza A(H1N1) and were treated with extracorporeal membrane oxygenation (ECMO) survived the disease, according to a new study.
The influenza A(H1N1) pandemic affected Australia and New Zealand during the 2009 southern hemisphere winter, causing an epidemic of critical illness. Some patients developed severe acute respiratory distress syndrome (ARDS) and were treated with ECMO.
ARDS is a lung condition that leads to respiratory failure due to the rapid accumulation of fluid in the lungs. ECMO is a type of life support that circulates blood through a system that adds oxygen. It was used for the patients in this study because they developed very low blood oxygen levels that developed rapidly despite standard ventilator (or respirator) settings. ECMO is generally used for a limited time because of the risks of bleeding, clotting, infection, and organ failure.
The researchers looked at incidence, clinical features, the degree of lung dysfunction, technical characteristics, the duration of ECMO, complications and survival.
The study found that 68 patients with severe influenza-associated ARDS were treated with ECMO, including 53 with confirmed 2009 influenza A(H1N1). An additional 133 patients with influenza A received mechanical ventilation, but not ECMO, in the same ICUs. The 68 patients who received ECMO had a median age of 34.4 years and half were men.
“Affected patients were often young adults, pregnant or postpartum, obese, had severe respiratory failure before ECMO, and received prolonged mechanical ventilation and ECMO support,” the study’s authors noted.
The median duration of ECMO support was ten days. At the time of reporting, 54 of the 68 patients had survived and 14 (21 per cent) had died. Six patients remained in ICU, including two who were still receiving ECMO. Sixteen patients were still hospitalised, but out of ICU, and 32 had been discharged from the hospital.
“Despite their illness severity and the prolonged use of life support, most of these patients survived,” the authors concluded.