EXPERIMENTAL PULMONARY-EDEMA - EFFECT OF UNILATERAL PEEP ON THE ACCUMULATION OF LUNG WATER

Abstract

The effect of PEEP [positive end expiratory pressure] in retarding the development of pulmonary edema produced by elevation of left atrial (LA) pressure to 25 cm water was studied in dogs. Using 2 synchronized volume respirators connected to a double lumen endotracheal tube, 10 or 25 cm H2O PEEP was applied to 1 lung while the contralateral lung was ventilated with an equal tidal volume without PEEP. LA pressure was elevated by inflating a Foley catheter balloon in the LA until the desired LA pressure was reached. After 3 h of pulmonary edema with ventilation of 1 lung, with PEEP lung water was quantitated by wet-to-dry wt. There were no differences in wet to dry wt of PEEP and nonPEEP lungs at either 10 or 25 cm H2O level. Additional blood flow studies showed that 25 cm H2O of PEEP reduced blood flow to the PEEP lung by 25% and to the nonPEEP lung by 7%. PEEP probably will not mechanically retard the accumulation of lung water due to increased pulmonary capillary hydrostatic pressure.