A CLINICAL-STUDY ON THE EFFECTS OF PULSATILE CARDIOPULMONARY BYPASS ON THE BLOOD ENDOTOXIN LEVELS

Levels of endogenous endotoxins have been reported to increase after c ardiopulmonary bypass. Endotoxin levels have also been implicated in m ultiple organ failure and may contribute to the immunocompromised stat e seen after bypass. We evaluated the effects of pulsatile cardiopulmo nary bypass circulation on endogenous endotoxin levels. The study popu lation consisted of 15 consecutive adult patients who underwent cardia c operations with cardiopulmonary bypass. Pulsatile flow was used duri ng aortic crossclamping in eight patients (group I) and nonpulsatile f low was used in the remaining seven patients (group II). Changes in bl ood endotoxin levels were monitored during aortic crossclamping, after release of the clamp, and after weaning from bypass. The blood endoto xin level at each stage was expressed as a percentage of the level at the beginning of bypass. Group I patients a significantly lower blood endotoxin percentage than group II (from 20 to 120 minutes after the i nitiation of aortic crossclamping). In group I, the blood endotoxin pe rcentage was nearly constant during aortic crossclamping. After releas e of aortic crossclamping, group I also had a lower blood endotoxin pe rcentage than group II. Endogenous endotoxin levels appear to increase in the presence of intestinal congestion and ischemia. Improvement in intestinal circulation by pulsatile cardiopulmonary bypass may preven t increases in endogenous endotoxin levels by reducing these factors.