Dependency of respiratory system mechanics on positive end-expiratory pressure and recruitment maneuvers in lung healthy pediatric patients - a randomized crossover study.

BACKGROUND: The lungs of pediatric patients are subjected to tidal derecruitment during mechanical ventilation and in contrast to adult patients this unfavorable condition cannot be resolved with small positive end-expiratory pressure increases. This raises the question if higher end-expiratory pressure increases or recruitment maneuvers may resolve tidal derecruitment in pediatric patients. AIMS: We hypothesized that higher positive end-expiratory pressure resolves tidal derecruitment in pediatric patients and that recruitment maneuvers between the pressure changes support the improvement of respiratory system mechanics. METHODS: The effects of end-expiratory pressure changes from 3 to 7 cm H2 O and vice versa without and with intermediate recruitment maneuvers on respiratory system mechanics and regional ventilation were investigated in 57 mechanically ventilated pediatric patients. The intratidal respiratory system compliance was determined from volume and pressure data before and after PEEP changes and categorized to indicate tidal derecruitment. RESULTS: Tidal derecruitment occurred comparably frequently at positive end-expiratory pressure 3 cmH2 O without (13 out of 14 cases) and with recruitment maneuver (14 out of 14 cases) and at positive end-expiratory pressure 7 cmH2 O without (13 out of 14 cases) and with recruitment maneuver (13 out of 15 cases). CONCLUSIONS: We conclude that contrary to our hypothesis, positive end-expiratory pressure up to 7 cm H2 O is not sufficient to resolve tidal derecruitment and that recruitment maneuvers may be dispensable in mechanically ventilated pediatric patients.