Critically ill children with pandemic influenza (H1N1) in pediatric intensive care units in Turkey

Abstract

Objectives: To outline the epidemiologic features, clinical presentation, clinical courses, and outcomes in critically ill children with pandemic influenza in pediatric intensive care units.

Design: Retrospective, observational, multicenter study.

Setting: Thirteen tertiary pediatric intensive care units in Turkey.

Patients: Eighty-three children with confirmed infection attributable to pandemic influenza detected by reverse-transcriptase polymerase chain reaction assay between November 1 and December 31, 2009 who were admitted to critical care units.

Interventions: None.

Measurements and main results: During a 2-month period, 532 children were hospitalized with pandemic influenza and 83 (15.6%) needed critical care. For the 83 patients requiring critical care, the median age was 42 (range, 2-204) months, with 24 (28.9%) and 48 (57.8%) of patients younger than 2 and 5 yrs, respectively. Twenty (24.1%) patients had no underlying illness, but 63 (75.9%) children had an underlying chronic illness. Indications for admission to the pediatric intensive care unit were respiratory failure in 66 (79.5%), neurologic deterioration in six (7.2%), and gastrointestinal symptoms in five (6.0%) patients. Acute lung injury was diagnosed in 23 (27.7%), acute respiratory distress syndrome was diagnosed in 34 (41%), and 51 (61.4%) patients were mechanically ventilated. Oseltamivir was used in 80 (96%) patients. The mortality rate for children with pandemic influenza 2009 was 30.1% compared to an overall mortality rate of 13.7% (p = .0016) among pediatric intensive care unit patients without pandemic influenza during the study period. Also, the mortality rate was 31.7% in patients with comorbidities and 25.0% in previously healthy children (p = .567). The cause of death was primary pandemic influenza infection in 16 (64%), nosocomial infection in four (16%), and primary disease progression in five (20%) patients. The odds ratio for respiratory failure was 14.7 (95% confidence interval, 1.85-111.11), and odds ratio for mechanical ventilation was 27.7 (95% confidence interval, 0.003-200).

Conclusions: Severe disease and high mortality rates were seen in children with pandemic influenza. Death attributable to pandemic influenza occurred in all age groups of children with or without underlying illness. Multiple organ dysfunction syndrome is associated with increased mortality, and death is frequently secondary to severe lung infection caused by pandemic influenza.