Introduction
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. Many trials use this ratio as an inclusion criterion. Recently, however, it has been shown in adults with ARDS that FiO2, independently predicts mortality, suggesting that the PaO2/FiO2 ratio alone might be insufficient to identify patients for clinical trials. In this study we determined if FiO2 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.
Methods
A retrospective study was conducted between 1999-2011. Infants with an RSV infection who were admitted to the PICU for MV were screened for ARDS up to 48 hours after admission. Independent predictors for outcome were analyzed using the cox regression model. Endpoints were duration of MV and LOS in the PICU.
Results
In total 129 infants were included in the study. In a multivariate analysis a higher initial FiO2 was independently associated with a longer duration of MV (HR 0.06, CI 0.01-0.48, p = 0.008) and increased LOS in the PICU (HR 0.07, CI 0.01-0.58, p = 0.014). In the univariate analysis PaO2/FiO2 ratio did not correlate with outcome.
Conclusion
Initial FiO2 level independently predicted outcome in children with RSV-induced ARDS, whereas the PaO2/FiO2 did not. Therefore FiO2 should be taken into account in clinical trials in infants with RSV-induced ARDS.