Manipulation of tissue forces in treating the adult respiratory distress syndrome.

In 16 anesthetized dogs, low-pressure pulmonary edema was induced by the intravenous infusion of oleic acid (0.02 mL/kg). One group of four animals served as controls. In the remaining 12 animals, the pulmonary capillary wedge pressure (Pcwp) was lowered in an effort to decrease the accumulation of extravascular lung water (EVLW). In eight dogs, the EVLW value decreased as measured by the thermal green dye, double-indicator method. The low Pcwp was maintained until the EVLW reached a minimum. In four dogs, reduction of the Pcwp did not decrease the accumulation of EVLW but did reduce the rate of accumulation. In animals in which the EVLW reached a minimum, restoration of Pcwp to baseline values did not increase edema, while the control animals continued to deteriorate. Presumably, changes in tissue and lymphatic dynamics compensated for the increased capillary permeability.