Pediatric Pulmonology 49:1138–1144 (2014)
FiO2 Predicts Outcome in Infants With Respiratory Syncytial Virus-Induced Acute Respiratory Distress Syndrome Kiry M. Schene, MSc,1* Elske van den Berg, MD,1 Roelie M. Wo¨sten-van Asperen, MD, PhD,1 Rick R. van Rijn, MD, PhD,2 Albert P. Bos, MD, PhD,1 and Job B.M. van Woensel, MD, PhD1 Summary. 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 94% with a PEEP 5 cmH2O, FiO2 0.4, tidal volume 8 ml/kg with a normal respiratory rate in a trial of spontaneous ventilation for minimal 30 min with pressure support set at 10 cmH2O or less. After extubation patients are kept in the PICU for a minimum of 24 h before they are discharged to the referring hospital. Pediatric Pulmonology
Schene et al.
The pediatric index of mortality (PIM) score was used as a measurement of disease severity.16,17 In our unit the level of FiO2 is adjusted based on the target value of a transcutaneous measured oxygen saturation of 95–97%. The ventilator settings are altered based on arterial blood gas analyses at the discretion of the attending pediatric intensivist. The primary choice of ventilator mode in this patient cohort was time-cycled, pressure-controlled aiming at a tidal volume of 7 ml/kg. During the entire study period, standard management of the children with RSV-induced ARDS did not change substantially. All children received standardized adequate analgesia and sedation, using midazolam and morphine. No additional investigations other than those clinically indicated in the management of ARDS were performed. Statistical Analysis
Microsoft Access was used to calculate incidence rates. All other statistical analyses were performed using SPSS 17.0 software (SPPS, Chicago, IL). Patient characteristics are reported as percentage or median with interquartile range (median; IQR). The results of the univariate and multivariate cox regression analysis are reported as hazard ratio (HRs) with corresponding 95% confidence interval (CIs) and P value (HR (95% CI), P-value). A multivariate cox proportional hazard model was used to evaluate the independent effect of baseline FiO2 and
PEEP on outcome, because both outcomes (i.e., LOS in the PICU and duration of MV) are time-related events and not normally distributed. Since the hazard was defined as successful weaning from MVor discharge from the PICU, a HR