Critically ill patients with 2009 H1N1 infection in an Indian ICU

The 2009 pandemic influenza A (H1N1) has taken its toll across most parts of India. We aimed to study its epidemiology, clinical characteristics and outcomes from an Indian multidisciplinary intensive care unit (ICU).

All patients admitted to our ICU with a flu-like illness and who tested positive for the 2009 H1N1 by reverse -transcriptase polymerase- chain -reaction assay during a 3 month period were prospectively studied.

Thirty one patients were admitted to the ICU during the study period. Patients were in the younger age group with a median age of 35 years (IQR: 28.2-42.8). Obesity was the commonest risk factor. Twenty six patients (83.9%) required ventilator support; the median duration of ventilator support was 10 days (IQR: 4-22). Severe hypoxemia was the predominant feature in all patients. Circulatory failure requiring vasopressors occurred in 18 (58.1%) patients and acute kidney injury in 6 (3.2%) patients. Twenty six patients were alive at the end of 28 days; subsequently all except one were discharged. The median duration of hospital stay was 15 (IQR: 8-22.5) days. Increasing APACHE II scores were associated with an increased risk of death (Hazard Ratio: 1.1; CI: 1.08 -1.2; P = 0.04). Mean tidal volumes in non-survivors were significantly lower; this was related to poor lung compliance in this group.

2009 H1N1 infection caused severe disease in relatively young patients without significant co-morbidities, characterized by severe hypoxemia and the requirement for prolonged mechanical ventilation. Extra-pulmonary organ failure included circulatory and renal failure.