ALTERED REACTIVITY TO ACETYLCHOLINE IN THE PULMONARY CIRCULATION AFTER CARDIOPULMONARY BYPASS IS PART OF REPERFUSION INJURY

Study Objective: To investigate whether a time sequence of acetylcholi ne (AGH) reactivity indicative of endothelial reperfusion injury could be demonstrated in the pulmonary circulation in patients after cardio pulmonary bypass (CPB). Design. Prospective study. Setting: Operating theater and intensive care unit of a university hospital. Patients: 10 ASA physical status III and IV patients with ischemic or valvular hea rt disease. Interventions: Pulmonary vascular resistance index (PVRI) was measured before and during an infusion ACH. This procedure was don e after induction of anesthesia but before surgery, immediately after weaning from bypass, and at 1 to 1.5 and 4 hours after CPR. Measuremen ts and Main Results: ACH caused a decrease in PVRI before (p <0.01) an d directly after CPB (p <0.05) but not at 1 to 1.5 or 4 hours after by pass. Conclusions: The maintained reactivity to ACH directly after CPB , followed by no reaction at 1 to 1.5 and 4 hours, was in agreement wi th experimental findings and indicates endothelial reperfusion injury caused by the period with no blood flow through the pulmonary artery d uring CPB and subsequent reperfusion. (C) 1998 by Elsevier Science Inc .