Inability to predict outcome of acute respiratory distress syndrome in children when using high frequency oscillation

OBJECTIVE: To (a) describe the experience with high-frequency oscillation (HFO) in children with acute respiratory distress syndrome (ARDS) unresponsive to conventional ventilation; (b) compare observed survival to that predicted by pediatric mortality scores and (c) determine if oxygenation index changes during HFO can predict survival. DESIGN: Retrospective, observational study. SETTING: A university hospital pediatric intensive care unit. PATIENTS: Nineteen children with ARDS (PaO(2)/FIO(2)<200) unresponsive to conventional ventilation treated with HFO from January 1995 to September 1996. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: The following were recorded: demographic, arterial blood gas and ventilator variables at the time points 0, 6, 12 and 24 h after the start of HFO; PRISM in the first 24 h of admission and pediatric respiratory failure and multiple organ system failure scores on the day of starting HFO. The mortality rate was 26% (5/19). The survival was better than predicted by the Pediatric Respiratory Failure score (p<0.01). None of the scores differentiated survivors from non-survivors (p>0.25). There was no significant change in oxygenation index over the first 24 h (p>0.18). Of patients with an initial oxygenation index higher than 20 who did not have at least a 20% reduction in oxygenation index by the time 6 h, 6/9 (67%) survived (sensitivity 75%, specificity 57%). CONCLUSIONS: Survival in pediatric ARDS patients treated with HFO could not be predicted using several outcome scores or the oxygenation index (in the first 24 h). Survival was significantly better than predicted by the Pediatric Respiratory Failure score. A prospective randomized controlled trial of HFO in ARDS is warranted.