Evaluation of optimal positive end-expiratory pressure in mechanically ventilated pediatric patients
Current recommendations for mechanically ventilating pediatric patients with acute lung injury include the use of positive end-expiratory pressure (PEEP) to improve arterial oxygenation, recruit and maintain lung volume, and enhance CO2 elimination. Optimal PEEP is the PEEP level that achieves the highest benefit to adverse effect ratio. No prior study has presented an effective single noninvasive parameter for titration of optimal PEEP. Our objective was to determine whether the combination of noninvasive respiratory mechanics and echocardiography could help guide meaningful PEEP therapy in pediatric patients with acute lung injury. We hypothesized that for each patient a single PEEP could be determined noninvasively that would optimize oxygenation, respiratory mechanics, and cardiac output. Methods: Intubated patients admitted to the PICU with acute lung injury as defined by a PaO 2/FiO2 ratio between 100-300 torr were eligible. Patients had a functional arterial line, less than 20% endotracheal tube air leak, and stable hemodynamics. Prior to the study, the ventilator mode and settings were determined by the clinical care team, and were left unchanged during the study. The CO2SMOPlus Respiratory Mechanics monitor (Novametrix, Wallingford CT) was connected to the patient at the endotracheal tube before the start of data collection. Three PEEP values (4, 8, 12 cmH2O) were applied in random order to each patient. There was a 30-minute equilibration period after each PEEP adjustment. An echocardiogram was performed for cardiac output estimation. Thirteen physiologic variables were recorded for evaluation of PEEP effects. For each variable, the PEEP level producing optimal clinical results for that variable was identified as "best" PEEP. All "best" PEEP values were compared using ANOVA. Each variable was tested for PEEP effect by repeated measures ANOVA. Results: 32 patients aged 10 days to 16 years were evaluated. We found that no single PEEP level could optimize all variables for any given patient. Conclusion: We may conclude that in this group of patients there is no single noninvasive parameter by which to set optimal PEEP therapy.
Hipp, BL; Gaskin, P; Gentile, MA; Cheifetz, IM; Meliones, J
Volume / Issue
International Standard Serial Number (ISSN)