DEXMEDETOMIDINE IN CARDIAC SURGERY: JUDGE, JURY AND EXECUTIONER A FREQUENCY OF BRADYARRHYTHMIAS AND ATRIOVENTRICULAR BLOCKS IN CARDIAC SURGERY

Abstract

Introduction Dexmedetomidine is an alpha 2 agonist drug with several theoretical benefits supported in the literature for cardiac surgery including a decrease of mortality (1, 2); however, many anesthesiologists restrict its use due to side effects such as disturbances of the cardiac conduction system. Therefore, it is important to describe the rhythm alterations associated with the use of dexmedetomidine in the postoperative period of cardiac surgery, and its impact in the postoperative course of this patient population. The following study pretend to describe the frequency of appearance of Atrial Ventricular Blocks related to the intraoperative use of dexmedetomidine in patients undergoing cardiovascular surgery. Methods After IRB approval of a cross sectional descriptive study. All patients undergoing cardiac surgery under general anesthesia with dexmedetomidine 0.5mcg/kg/h since the beginning of the case between 2015 and 2019 at the center were included. Most data were taken from the anesthesia and intensive care unit medical records. Standard demographic variables were collected, frequency measures were established for relevant events such as bradyarrhythmias, and their frequency was described according to severity and need for intraoperative and postoperative intervention. Results 148 patients who underwent simple or combined surgical procedures were included in the study; the prevalence of atrioventricular blocks was 6%, according to it severity, first degree blocks were reported in 2.7%, second degree blocks were reported in 0.6% and complete blocks were reported in 2,7%. Bradyarrhythmias associated with the use of dexmedetomidine varies between 24.2% - 28.2% (period) depending on the time of diagnosis. According to its severity, sinus bradycardia varies between 20.1% - 24.32%, and nodal rhythm 0.6% - 1.2%. 25.6% of the patients required transient postoperative pacemakers, 1.2% of the patients required a permanent pacemaker. The most frequent tachyarrhythmia was atrial fibrillation in 14.8%. An overall mortality of 2% was reported. Discussion The use of dexmedetomidine predisposes to an increase in the presentation of sinus bradycardia in the immediate postoperative period of cardiovascular surgery compared to that reported in the literature, without increasing the prevalence of atrioventricular blocks. There is a greater tendency to use an epicardial pacemaker during the intraoperative period, which for the most part was not necessary in the immediate postoperative period. There is a decreasing trend in the presentation of atrial fibrillation as described in previous studies. There is no increase in the mortality of these patients compared to local and international reports. Prospective studies are required to verify the exploratory findings of this study and judge its benefits against the development of bradyarrhythmias in this patient population.