All but one of the included trials reported adequate allocation concealment (defined as sealed envelopes or central telephone randomization). Since there were no deaths in this trial we could not assess the effect of inadequate allocation concealment on mortality. Pooling the five remaining trials did not change the direction of the effect and did not significantly Meta-analysis of trials of surfactant in children with acute respiratory failure: Mortality Meta-analysis of trials of surfactant in children with acute respiratory failure: Mortality. ALI, acute lung injury; ARDS, acute respiratory distress syndrome; 95% CI, 95% confidence interval; RR, relative risk; RSV, respiratory syncytial virus.