The Hemodynamic Responses to Hypothermic and Normothermic Cardiopulmonary Bypass


Abstract: This prospective randomized clinical study was designed to assess and compare the effects of normothermic and hypothermic nonpulsative cardiopulmonary bypass in patients with mitral valve replacement. Forty patients undergoing elective mitral valve replacement were randomly divided into two groups according to the temperature of perfusion. Group N (15 patients) underwent normothermic cardiopulmonary perfusion and Group H (25 patients) underwent hypothermic cardiopulmonary perfusion. These groups were compared using clinical and electrocardiographic criteria and cardiovascular evaluation parameters. Quantitative data were analyzed using the paired Student t test. While there was a significant increment in heart rate in Group N in relation to preoperative values, there was no change in heart rate in Group H. Increasing values in systemic vascular resistance (SVR) parameters were detected in both groups. Oxygen consumption (VO_2) values decreased in Group N in relation to Group H. There was no significant change in alveolar-arterial O_2 difference (DO_2) values between these two groups. These results indicate that the temperature of cardiopulmonary perfusion had no effect on the immediate postoperative values but did cause an increase in heart rate in the normothermic group.

Keywords: normothermia, cardiopulmonary bypass

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