LIMITED INTENTIONAL NORMOVOLEMIC HEMODILUTION - ST-SEGMENT CHANGES AND USE OF HOMOLOGOUS BLOOD PRODUCTS IN PATIENTS WITH LEFT MAIN CORONARY-ARTERY STENOSIS

Objective: To assess and compare the effects of limited intentional no rmovolemic hemodilution (LINH) on ST-segment changes and to evaluate t he need for homologous blood products. Design: Prospective, randomized study. Setting: University hospital. Participants: Seventy-one patien ts with left main stenosis scheduled for semi-urgent coronary artery b ypass grafting. Interventions: Patients in group A (n = 39) underwent LINH during the prebypass period until a hematocrit of 34% was obtaine d. Simultaneously, succinyl-linked gelatin was infused. In group B (n = 32), no hemodilution was performed. Mean arterial pressure and centr al venous pressure were kept as constant as possible. During the postb ypass period, autologous blood was retransfused. The need for homologo us blood products was noted intraoperatively and postoperatively. Meas urements and Main Results: ST-segment analysis of lead II and chest le ad was continuously performed in all patients. An ST-segment change wa s defined as a decrease from baseline of 1.0 mm (-0.1 mV). The appeara nce and degree of ST-segment depression were comparable in both groups (group A: 7 patients -0.1 mV, 7 patient -0.2 mV: group B: 5 patients -0.1 mV: 3 patients -0.2 mV). In group A, ST-segment depression occurr ed during and after the blood exchange. However, the mean duration of the ST-segment depression (group A: 33 +/- 18 minutes; group B: 20 +/- 20 minutes) was comparable between groups. In group A, a mean of 750 mL +/- 245 mL of blood was obtained. Total blood loss was significantl y higher in group B (p < 0.052); 25 patients in group A (64%) and 12 p atients in group B (38%) did not require homologous blood products (p < 0.03). Intraoperatively, only the need for packed red cells was grea ter in group B (p < 0.04). Postoperatively, the use of homologous bloo d products is higher than intraoperatively (p < 0.02). Conclusions: LI NH performed in patients with left main stenosis, scheduled for semi-u rgent coronary bypass, is not associated with increases in frequency, degree, or duration of ST-segment changes. This procedure allowed a re duction in the number of patients who received homologous blood produc ts. Copyright (C) 1997 by W.B. Saunders Company.