Inert gas exchange during pneumoperitoneum at incremental values of positive end-expiratory pressure

Laparoscopy is a surgical technique for a growing variety of abdominal oper ations. In patients undergoing this procedure, arterial blood oxygenation a nd hemodynamics are frequently depressed. This study evaluated the Effect o f different levels of positive end-expiratory pressure (PEEP) during intrap eritoneal CO2 insufflation on the lung's ventilation-perfusion distribution in a porcine model. We studied 13 anesthetized pigs with an intraperitonea l pressure of 15 cm H2O applied at either incremental values of PEEP (5-20 em H2O, increments of 5 cm H2O) or a constant PEEP of 5 cm H2O. The effects of CO2 pneumoperitoneum on inert gas exchange and hemodynamics were examin ed with the multiple inert gas elimination technique. During pneumoperitone um, gas exchange was most augmented by 15 and 20 cm H2O of PEEP. Although t he differences in hemodynamics between the individual settings were insigni ficant, 10 cm H2O of PEEP provided the smallest impairment of hemodynamics. We conclude that PEEP of 15 H2O during pneumoperitoneum resulted in a mode st hemodynamic depression but significant gas exchange augmentation in our experiment. Implications: Anesthetized pigs, with a pneumoperitoneum of 15 cm H2O, were treated either with incremental values of positive end-expirat ory pressure (5-20 cm H2O, increments of 5 cm H2O) or with a constant posit ive end-expiratory pressure of 5 cm H2O. Fifteen and 20 cm H2O resulted in significantly improved pulmonary gas exchange compared with 5 cm H2O.