Positive end-expiratory pressure modulates perfluorochemical evaporation from the lungs

To study the effects of positive end-expiratory pressure (PEEP) level on perfluorochemical (PFC) elimination profiles (EL), 6 ml/kg of perflubron were instilled into healthy anesthetized rabbits. The ventilation strategy was to maintain constant minute ventilation (300 ml/kg/min) and mean airway pressure (7-8 cm H2O) while randomly changing the PEEP levels from 5 to 0, 1, 3, and 10 cm H2O, each for a period of 15 min. The PFC content in the expired gas was measured and the EL was calculated. There was a significant reduction in the EL when decreasing the PEEP levels from 5 to 0 cm H2O, but no differences were seen when the PEEP was increased from 5 to 10 cm H2O. The results indicate that PEEP levels influence PFC elimination profiles; therefore, the measurement of the EL and PEEP levels should be considered when optimizing supplemental PFCs during partial liquid ventilation. Copyright © 2003 S. Karger AG, Basel.