The effect of acute normovolemic hemodilution on homologous blood requirements and total estimated red blood cell volume lost

Background: Acute normovolemic hemodilution combined with retransfusion is one of the various techniques proposed to avoid homologous blood transfusion in cardiac surgery. The purpose of the present paper is to study the effect of the volume of autologous blood collected pre-cardiopulmonary bypass (CPB) on homologous blood requirements and total estimated red blood cell (RBC) volume lost in coronary artery bypass grafting (CABG) surgery. Methods: Following induction of anesthesia, sequestration of one (5-8 ml/kg; Group I, n=14) or two units (12-15 ml/kg; Group II, n=14) of fresh autologous blood was performed under electrocardiographic and hemodynamic control. Group III (n=14) was designated as the control group. Autologous blood was reinfused at the conclusion of CPB. Results: The use of homologous blood in the study groups was significantly less than in the control group. High-volume phlebotomy did not make a significant difference in the requirement of the homologous blood, while causing a mild increase in the total estimated RBC volume lost. No significant differences could be demonstrated in preoperative, post-CPB and discharge hematocrit levels and postoperative blood drainage between the groups. Conclusion: Acute intraoperative hemodilution with high- and low-volume phlebotomy reduced the homologous blood requirements similarly regardless of the amount of phlebotomy. (C) Acta Anaesthesiologica Scandinavica 41 (1997).