The Australia and New Zealand Extracorporeal Membrane Oxygenation (ANZ ECMO) Influenza Investigators*. JAMA. 2009;302(17). Early Release Article, posted October 12, 2009 JAMA
Figure. ECMO and hemofiltration in the ICU of PYNEH being used concurrently for the treatment of a human swine influenza patient. Deoxygenated blood is taken out of the patient through a large catheter and part of it is circulated to the hemofiltration machine. Overall nursing manpower is minimized as the ECMO is running itself by the centrifugation pump while replacement fluid for hemofiltration is produced online. (Photo courtesy of Pamela Youde Nethersole Eastern Hospital, Hong Kong, China)
Context The novel influenza A(H1N1) pandemic affected Australia and New Zealand during the 2009 southern hemisphere winter. It caused an epidemic of critical illness and some patients developed severe acute respiratory distress syndrome (ARDS) and were treated with extracorporeal membrane oxygenation (ECMO).
Objectives To describe the characteristics of all patients with 2009 influenza A(H1N1)–associated ARDS treated with ECMO and to report incidence, resource utilization, and patient outcomes.
Design, Setting, and Patients An observational study of all patients (n = 68) with 2009 influenza A(H1N1)–associated ARDS treated with ECMO in 15 intensive care units (ICUs) in Australia and New Zealand between June 1 and August 31, 2009.
Main Outcome Measures Incidence, clinical features, degree of pulmonary dysfunction, technical characteristics, duration of ECMO, complications, and survival.
Results Sixty-eight patients with severe influenza-associated ARDS were treated with ECMO, of whom 61 had either confirmed 2009 influenza A(H1N1) (n = 53) or influenza A not subtyped (n = 8), representing an incidence rate of 2.6 ECMO cases per million population. An additional 133 patients with influenza A received mechanical ventilation but no ECMO in the same ICUs. The 68 patients who received ECMO had a median (interquartile range [IQR]) age of 34.4 (26.6-43.1) years and 34 patients (50%) were men. Before ECMO, patients had severe respiratory failure despite advanced mechanical ventilatory support with a median (IQR) PaO2/fraction of inspired oxygen (FIO2) ratio of 56 (48-63), positive end-expiratory pressure of 18 (15-20) cm H2O, and an acute lung injury score of 3.8 (3.5-4.0). The median (IQR) duration of ECMO support was 10 (7-15) days. At the time of reporting, 48 of the 68 patients (71%; 95% confidence interval [CI], 60%-82%) had survived to ICU discharge, of whom 32 had survived to hospital discharge and 16 remained as hospital inpatients. Fourteen patients (21%; 95% CI, 11%-30%) had died and 6 remained in the ICU, 2 of whom were still receiving ECMO.
Conclusions During June to August 2009 in Australia and New Zealand, the ICUs at regional referral centers provided mechanical ventilation for many patients with 2009 influenza A(H1N1)–associated respiratory failure, one third of whom received ECMO. These young adults with severe hypoxemia had a 21% mortality rate at the end of the study period.
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