Influence of hematocrit and pump prime on cerebral oxygen saturation in on-pump coronary revascularization

Abstract

Background: The couplings between cerebral oxygenation (rSO2), on-pump hematocrit and circuit prime are explored in this study. Methods: Thirty-eight consecutive patients undergoing coronary revascularization with cardiopulmonary bypass (CPB) were matched on preoperative hematocrit < 40% and >40% ( n=16). Similarly, six blood prime patients were matched with six crystalloid prime patients. Hematocrit and rSO2 levels were then compared on CPB. Results: The pre-operative hematocrit >40% group retained higher levels on pump run ( p < 0.01) and significantly higher rSO2 prior to CPB (64.8±9.6 versus 73.2±7.3), and on and off CPB (61.1±8.8 versus 67.4±6.4). Blood priming increased absolute rSO2 (2.3± 6.3 versus − 10.9±5.9) and% rSO2 (4.7±11.8 versus −14.2±7.4%) in the low hematocrit group. Conclusion: Blood primes are instrumental in high-risk and low preoperative hematocrit patients in preventing cerebral oxygen desaturation during initiation and maintenance of CPB.