FiO2 predicts outcome in infants with respiratory syncytial virus-induced acute respiratory distress syndrome

Abstract

Objective: Respiratory syncytial virus (RSV) infection can progress to acute respiratory distress syndrome (ARDS) in infants. ARDS is a life-threatening condition that is characterized by severe hypoxemia, defined as PaO2/FiO2 ratio <300 mmHg. This ratio is used in many trials as the sole oxygenation criterion for ARDS. Recently, however, it has been shown in adults with ARDS that FiO2, independently of the PaO2/FiO2 ratio predicts mortality. Because epidemiology and outcome of ARDS differ strongly between children and adults, we determined if FiO2 on admission (baseline FiO2) independently predicted the duration of mechanical ventilation (MV) and length of stay (LOS) in the pediatric intensive care unit (PICU) in infants with RSV-induced ARDS. Design: Retrospective observational study. Setting: A 14-bed pediatric intensive care unit. Patients: One hundred twenty-nine mechanically ventilated infants with RSV-induced ARDS. Interventions: None. Measurements and main results: Independent predictors for outcome, including baseline FiO2 and PEEP, were analyzed using the cox regression model. Endpoints were duration of MV and LOS in the PICU. A higher baseline FiO2 was independently associated with a longer duration of MV (HR 0.12, CI 0.02–0.87, P = 0.036) and increased LOS in the PICU (HR 0.09, CI 0.01–0.57, P = 0.023). Neither baseline PEEP nor PaO2/FiO2 ratio correlated with outcome. Conclusions: FiO2 level independently predicted outcome in infants with RSV-induced ARDS, whereas both PEEP and the PaO2/FiO2 ratio did not. This suggests that FiO2 should be taken into account in defining disease severity in infants with RSV-induced ARDS. Pediatr Pulmonol. 2014; 49:1138–1144. © 2013 Wiley Periodicals, Inc.