Effects of oleic acid lung injury and positive end-expiratory pressure on central hemodynamics and regional blood flow.

The objective of our study was to investigate the influence on central and regional circulation of the application of positive end-expiratory pressure (PEEP=P) in a canine model of low hydrostatic pulmonary edema. Eight mongrel dogs with oleic acid-induced pulmonary edema were artificially ventilated with and without PEEP. Regional blood flow was determined using radioactive microspheres directly injected into the left ventricle. Regional blood flow to the brain was maintained under all experimental conditions, while the blood flow to the gastric fundal mucosa and to the pancreas significantly decreased following PEEP, oleic acid injection (OA) and with PEEP and oleic acid combination (P+OA). The renal blood flow decreased only during the P+OA phase. We conclude that the observed decrease in blood flow to the gastrointestinal mucosa and renal circulation in this acute low hydrostatic pressure pulmonary edema may correlate with the increased incidence of gastrointestinal and renal complications that accompany critically ill patients.