Oxygenation response to a recruitment maneuver during supine and prone positions in an oleic acid-induced lung injury model

Prone position and recruitment maneuvers (RM) are proposed as adjuncts to mechanical ventilation to open up the lung and keep it open. We studied the oxygenation response to a RM (composed of a 30-s sustained inflation at 60 cm H2O airway pressure) performed in prone and supine positions in dogs after oleic acid-induced lung injury using an inspired O-2 fraction of 0.60. In one group (n = 6) first supine then prone positions were examined after a RM at 8 cm H2O and 15 cm H2O of positive end-expiratory pressure (PEEP). In the second group (n = 6) the sequence of positions was reversed. Prone positioning after supine position always improved oxygenation, whereas the decrement in Pa-O2 was relatively small when dogs were returned to the supine position. Oxygenation improved in both groups after a RM, and the improvement was sustained (after 15 min) in the prone position at 8 cm H2O of PEEP, but 15 cm H2O of PEEP was required in supine position. Our results suggest that a RM improves oxygenation more effectively with a decreased PEEP requirement for the preservation of the oxygenation response in prone compared with supine position.