Effect of pulmonary artery occlusion and reperfusion on extravascular fluid accumulation

Abstract

The effect of pulmonary hypoperfusion on extravascular water accumulation in anesthetized dogs was determined by occluding the left pulmonary artery for 3 h and then reperfusing it for 2h. The lung was reperfused either at normal left atrial pressure .**GRAPHIC**. or during increased .**GRAPHIC**. induced by a left atrial balloon. In each case the extravascular water content-to-bloodless dry weight ratio (W/D) of the left lung was compared with that of the right lung. The W/D of the left lung of 3.26 .+-. 0.49 ml/g was not significantly different from the value of 2.87 .+-. 0.37 for the right lung after the reperfusion at normal .**GRAPHIC**. The W/D of the left lung of 5.10 .+-. 0.38 ml/g was greater (P < 0.05) than the value of 4.42 .+-. 0.34 for the right lung after reperfusion at .**GRAPHIC**. of 25 torr. This difference could not be prevented by pretreatment with heparin, suggesting that the increase in lung water content was not due to activation of intravascular coagulation secondary to stasis occurring during the occlusion. Because the left lung was more edematous than the right one, even though both lungs were subjected to the same increase in .**GRAPHIC**. a period of pulmonary hypoperfusion evidently causes an increase in the interstitial protein concentration.