Subarachnoid clonidine and trauma response in cardiac surgery with cardiopulmonary bypass

Background and objectives: The intense trauma response triggered by cardiopulmonary bypass can lead to increased morbidity and mortality. The present study evaluated whether clonidine, a drug of the class of 0-2 agonists, administered by spinal route, without association with local anesthetics or opioids, reduces this response in cardiac surgery with cardiopulmonary bypass. Method: A total of 27 patients between 18 and 75 years old, divided by non-blinded fashion into a control group (15) and a clonidine group (12), were studied. All patients underwent identical technique of general anesthesia. Then, only the clonidine group received 1 lig kg(-1) clonidine by spinal route. Levels of blood glucose, lactate and cortisol were measured at three consecutive times: Ti, at the time of installation of invasive arterial pressure; 12, 10 min after the first dose for cardioplegia; and T3, at the time of skin suture; and troponin I values at Ti and T3. The variation of results between T2-T1, 13-T2, and T3-T1 was also evaluated. Results: There was a statistically significant difference only with respect to the variation in blood glucose in the clonidine group: T3-T2, p=0.027 and T3-T1, p =0.047. Conclusions: Spinal clonidine at a dose of 1 mu g kg(-1) did not decrease blood measurements of troponin, cortisol, or lactate. Blood glucose suffered a more moderate variation during the procedure in the clonidine group. This fact, already reported in the literature, requires further investigation to be clarified. (C) 2014 Sociedade Brasileira de Anestesiologia. Published by Elsevier Editora Ltda. All rights reserved.