SELECTIVE POSITIVE END-EXPIRATORY PRESSURE AND RIGHT-VENTRICULAR FUNCTION IN DOGS

Differential ventilation with selective positive end-expiratory pressu re (PEEP) has been shown to reduce cardiac output less than general PE EP. In previous studies we have demonstrated that during selective PEE P left ventricular preload is better maintained than during general PE EP. The present study was designed to determine whether the different haemodynamic responses to selective and general PEEP also might be due to different effects on RV preload. The study was performed on nine a cutely instrumented dogs, in which extraventricular pressure was measu red by pericardial balloon transducers. Measures of RV preload were ob tained by the use of ultrasonic segment length transducers as well as end-diastolic transmural pressure (RVEDP(TM)). The study showed reduct ions in RVEDP(TM) during general and selective right (R) PEEP, accompa nied by moderate reductions in RV inflow tract segment lengths. These changes were most marked with general PEEP. Selective LPEEP did not ch ange RV preload significantly Therefore, better maintained cardiac out put with selective PEEP than with general PEEP is partly due to less i mpairment of right ventricular filling.