Effects of extreme haemodilution on the immediate post-operative course of coronary artery bypass patients

The immediate post-operative course was investigated in 70 patients who had undergone coronary artery bypass grafting under normovolaemic moderate and subsequent extreme haemodilution, and in 70 control patients who underwent a similar operation with a haemic prime in the heart-lung machine. Altogether 8 patients (5.7%), 4 from the haemodilution group and 4 from the controls required re-exploration for excessive post-operative bleeding and were examined as their own group. There were no marked differences in bleeding through chest tubes or in blood haemoglobin concentration between patients who had undergone intra-operative haemodilution and controls. Post-operatively both patient groups required approximately analogous amounts of infused blood, colloids and crystalloids. Central venous pressure was consistently lower in haemodiluted patients. Opening of peripheral circulation as indicated by a rise in skin temperature occurred significantly faster in haemodiluted patients than in controls. Before and after weaning from the respirator, arterial blood oxygen tension was slightly lower in patients who had undergone intra-operative haemodilution. Serum creatinine levels were lower and blood platelet counts significantly higher in haemodiluted patients than in controls. Rates of peri-operative myocardial infarctions showed no essential difference between the groups.