High mortality in patients with influenza A pH1N1 2009 admitted to a pediatric intensive care unit: a predictive model of mortality.

OBJECTIVE: To describe the clinical characteristics and outcome of patients admitted to pediatric intensive care with influenza A (pH1N1) 2009 in Argentina.

DESIGN: Retrospective observational study.

SETTING: Thirteen pediatric intensive care units in Argentina.

SUBJECTS: One hundred and forty-two patients with confirmed or suspected influenza A (H1N1).

INTERVENTIONS: None.

MEASUREMENTS AND MAIN RESULTS: We included 142 critically ill patients. The median age was 19 months (range, 2-110 months) with 39% of the patients <24 months of age. Ninety-nine patients (70%) had an underlying disease. Influenza A (pH1N1) 2009 infection was confirmed in 90 patients and the remaining 52 had a positive direct immunofluorescence assay for influenza A. The median length of stay in the pediatric intensive care unit was 12 days (range, 2-52 days). One hundred eighteen patients (83%) received invasive mechanical ventilation and 19 patients were treated with noninvasive ventilation; however, seven of the patients receiving noninvasive ventilation later needed mechanical ventilation. Sixty-eight patients died (47%) with the most frequent cause refractory hypoxemia. Multivariate logistic regression analysis showed that age <24 months (odds ratio, 2.87; 2.35-3.93), asthma (odds ratio, 1.34; 1.20-2.91), and respiratory coinfection with respiratory syncytial virus (odds ratio, 2.92; 1.20-4.10) were associated with higher mortality. As expected, mechanical ventilation and treatment with inotropes were also associated with increased mortality.

CONCLUSIONS: The mortality of children admitted to the pediatric intensive care unit with 2009 pH1N1 influenza was high (47%) in our population. Age <24 months, asthma, respiratory coinfection, need of mechanical ventilation, and treatment with inotropes were predictors of poorer outcome.