Influence of Perfusate Characteristics on Pulmonary Vascular Response to Endotoxin

¹ From the Department of Physiology, The Medical School, University of Minnesota, Minneapolis, Minnesota

The isolated ventilated dog lung was perfused with heparinized gelatin, dextran and plasma. The typical response to endotoxin of the isolated lung perfused with heparinized whole blood does not occur when gelatin or dextran are substituted as the perfusate. When plasma free from formed elements is used, the pulmonary vascular response to endotoxin is either minimal or does not occur. Lungs perfused with dextran, gelatin and plasma were shown to be reactive by their characteristic response to test drugs and by their subsequent response to endotoxin during perfusion with heparinized fresh whole blood. It is believed that endotoxin does not have a direct effect on lung tissue but that some components of whole blood are required for the pulmonary vascular response. These studies have not, however, excluded tissue factors nor have they conclusively shown whether plasma, formed elements or both, are involved in the pulmonary vascular response to endotoxin.