OBJECTIVE: to analyze the short-term effects of prone positioning on the oxygenation of mechanically-ventilated children suffering from severe hypoxemia. MATERIALS AND METHODS: a prospective, nonrandomized trial (each patient as his/her own control) was conducted between July 1998 and July 1999. Mechanically-ventilated children with peak inspiratory pressure greater than or equal to 30 cm H2O, FiO2 greater than or equal to 0.5, and PaO2/FiO2 ratio less than or equal to 200 were included in the study. Each patient was kept in the prone position for two hours, returning to the supine position after this period. Oxygenation was assessed by means of PaO2/FiO2 in the supine position (one hour before prone positioning), one hour after prone positioning, and one hour after returning to the supine position. Patients who presented an increase of at least 20 in PaO2/FiO2 were considered responsive. The results were compared by Student t-test, Friedman test, chi-square test, Fisher's exact test, and confidence interval (CI). RESULTS: eighteen children (10 males), whose mean age was 11.5 ±11.5 months, with initial PaO2/FiO2 of 96.06 ± 41.78, participated in the study. After one hour in the prone position, 27.7% of the patients (5/18) improved their PaO2/FiO2 ratio (P=0.045). Six of these patients presented reduced lung compliance (four of them had acute respiratory distress syndrome); and twelve patients showed increased airway resistance (six of them presented bronchiolitis). No significant difference was observed between these two groups (reduced lung compliance x increased airway resistance) in terms of age, sex, duration of ventilation prior to change in position, peak inspiratory pressure, FiO2, severity of hypoxemia, and outcome. CONCLUSION: prone positioning during mechanical ventilation of children with severe hypoxemia may improve the PaO2/FiO2 ratio in the first hour.
pronation; oxygenation; acute respiratory distress syndrome; pediatric intensive care unit; children, artificial respiration
