The 'primeless pump': a novel technique for intraoperative blood conservation

Purpose: Hemodilution during cardiopulmonary bypass may lead to anemia requ iring intraoperative transfusions. Prime removal from the cardiopulmonary b ypass circuit was used to limit dilution and intraoperative transfusions. M ethods: The technique of prime removal consists of arterial and then venous side evacuation of crystalloid prior to cardiopulmonary bypass. The effect iveness of this technique, to maintain a higher hematocrit and reduce intra operative transfusions, was studied prospectively in two consecutive groups of patients undergoing coronary revascularization (controls versus primele ss). Results: Intraoperative hematocrits were significantly higher (P < 0.0 001) and transfusions lower (4%) in the primeless versus the control group (19%) (P = 0.003). Prime removal is of particular benefit in anemic (hemato crit less than or equal to 35%) and/or small patients (body surface area le ss than or equal to 2 m(2)). Conclusion: The technique of prime removal is simple, safe and cost-effective, reducing intraoperative transfusions, espe cially in small and/or anemic patients. It could be part of blood conservat ion strategies in most adult cardiac operations. (C) 1999 The International Society for Cardiovascular Surgery. Published by Elsevier Science Ltd. All rights reserved.