Extracorporeal Membrane Oxygenation for 2009 Influenza A(H1N1) Acute Respiratory Distress Syndrome.
BACKGROUND
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).


OBJECTIVE
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.


METHODS
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.


METHODS
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) Pao(2)/fraction of inspired oxygen (Fio(2)) ratio of 56 (48-63), positive end-expiratory pressure of 18 (15-20) cm H(2)O, 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 ECMO-treated patients were often young adults with severe hypoxemia and had a 21% mortality rate at the end of the study period.
FRACP, FJFICM, Intensive Care Unit, Alfred Hospital, Commercial Road, Melbourne, Victoria 3004, Australia. a.davies@alfred.org.au
Davies
Andrew
A
Jones
Daryl
D
Bailey
Michael
M
Beca
John
J
Bellomo
Rinaldo
R
Blackwell
Nikki
N
Forrest
Paul
P
Gattas
David
D
Granger
Emily
E
Herkes
Robert
R
Jackson
Andrew
A
McGuinness
Shay
S
Nair
Priya
P
Pellegrino
Vincent
V
Pettilä
Ville
V
Plunkett
Brian
B
Pye
Roger
R
Torzillo
Paul
P
Webb
Steve
S
Wilson
Michael
M
Ziegenfuss
Marc
M
D000328:Adult; D001315:Australia; D015897:Comorbidity; D015199:Extracorporeal Membrane Oxygenation; D005260:Female; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype; D007251:Influenza, Human / Q000150:complications / Q000401:mortality / Q000628:therapy; D007362:Intensive Care Units; D007902:Length of Stay; D008297:Male; D009520:New Zealand; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000401:mortality / Q000628:therapy; D012121:Respiration, Artificial; D012128:Respiratory Distress Syndrome / Q000209:etiology* / Q000401:mortality / Q000628:therapy*; D016019:Survival Analysis