Normothermia vs hypothermia in cardiopulmonary bypass cardiac surgery – a retrospective clinical study

M. Crîsnic¹,  P. Deutsch¹, Daniela Crîsnic², Anca Micu³

¹ Clinica Anestezie Terapie Intensivă, Institutul de Boli Cardiovasculare Timişoara
² Disciplina Fiziologie, Universitatea de Medicină şi Farmacie „Victor Babeş” Timişoara
³ Clinica Anestezie Terapie Intensivă, Spitalul Clinic Judeţean de Urgenţă Timişoara

Abstract

Background and objectives: There have been many studies to compare both the advantages and disadvantages of hypothermia and normothermia in cardiac surgery. We retrospectively compared the effects of hypothermia and normothermia on perioperative outcome in patients undergoing elective cardiac surgery at the Unit of Cardiovascular Surgery of the Institute of Cardiovascular Diseases Timisoara.
Methods: 100 pacients divided in 2 groups were studied respectively: the last 50 patients undergoing hypothermic cardiopulmonary bypass surgery (group H) and the first 50 patients undergoing normothermic cardiopulmonary bypass surgery (group N). Intra- and postoperatively the following parameters were evaluated: the cardiopulmonary bypass time, the crossclamping time, the surgical hemostasis time, miocardial protection and hemodinamic stability (requirement for electrical defibrillation and inotrope drugs, use of intraaortic balloon pump, the serum level of cardiac enzymes,  the incidence of arrhythmia and metabolic acidosis), postoperative bleeding, duration of stay in Intensive Care Unit (ICU) and the incidence of renal failure.
Results:The cardiopulmonary bypass time and the crossclamping time were longer in group H compared with group N, but the differences were not statistically significant. Although the postoperative mediastinal bleeding was significantly greater in group H compared to group N, there were no differences in the need for postoperative surgical reexploration (p = 0.2). We found differences statistically significant between the 2 groups regarding the requirement for electrical defibrillation after the removal of the aortic crossclamp (greater in group H, p < 0.001), the requirement for inotrope drugs after the cardiopulmonary bypass (greater in group H, p < 0.05), and duration of mechanical ventilation and of the stay in ICU (longer in group H, p < 0.01, respectively p < 0.01). On the other hand, the differences regarding the incidences of postoperative arrhythmias, elevation of seric level of cardiac enzymes, metabolic acidosis and postoperative renal failure were not statistically significant (p = 0.07; p = 0.27; p = 0.8; respectively p > 0.05).
Conclusion: The normothermic cardiopulmonary bypass surgery as compared with the hypothermic one was associated with a lower requirement for blood products and inotrope drugs and a shorter duration of the mechanical ventilation and the time spent in the ICU.

Keywords: hypothermia, normothermia, cardiopulmonary bypass, cardiac surgery

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