Aim: We describe futures of ICU admission, demographic characteristics, treatment and outcome for critically ill patients with laboratory-confirmed and suspected infection with the H1N1 virus admitted to the three different critical care departments in Turkey.

Methods: Retrospective study of critically ill patients with 2009 influenza A(H1N1) at ICU. Demographic data, symptoms, comorbid conditions, and clinical outcomes were collected using a case report form.

Results: Critical illness occurred in 61 patients admitted to an ICU with confirmed (n=45) or probable and suspected 2009 influenza A(H1N1). Patients were young (mean, 41.5 years), were female (54%). Fifty-six patients, required mechanical ventilation (14 invasive, 27 noninvasive, 15 both) during the course of ICU. On admission, mean APACHE II score was 18.7±6.3 and median PaO(2)/FIO(2) was 127.9±70.4. 31 patients (50.8%) was die. There were no significant differences in baseline PaO(2)/FIO(2 )and ventilation strategies between survivors and nonsurvivors. Patients who survived were more likely to have NIMV use at the time of admission to the ICU.

Conclusion: Critical illness from 2009 influenza A(H1N1) in ICU predominantly affects young patients with little major comorbidity and had a high case-fatality rate. NIMV could be used in 2009 influenza A (H1N1) infection-related hypoxemic respiratory failure.