Preincision Initiation of Dexmedetomidine Maximally Reduces the Risk of Junctional Ectopic Tachycardia in Children Undergoing Ventricular Septal Defect Repairs

Objective: To evaluate whether initiation of dexmedetomidine (DEX) infusion before surgical incision and cardiopulmonary bypass (CPB) versus initiation after CPB had an impact on the incidence of junctional ectopic tachycardia (JET). Design: Retrospective cohort study. Setting: Single tertiary-care cardiac center. Participants: Children undergoing cardiopulmonary bypass for repair of congenital heart disease involving ventricular septal defects between January 2010 and February 2013. Interventions: None. Measurements and Main Results: One hundred thirty-four patients undergoing ventricular septal defect closure were included in the final analysis. Of the 99 patients (74%) exposed to DEX, intraoperative initiation was performed in 73 (pre-CPB, n = 39 patients [29%]; intraoperative post-CPB initiation. n = 34 patients [25%]), and postoperative initiation was performed on arrival to the intensive care unit (ICU) in 26 patients (19%). In 71 of the 73 patients, infusions that were initiated intraoperatively were continued in the postoperative period for up to the first 12 hours. Postoperative JET was observed in 22 of the 134 patients (15%). Of the 99 patients exposed to DEX in the perioperative period, JET was observed in 8 patients (11%). Of the 35 patients not exposed to any DEX, JET was observed in 12 patients (34%). Analysis was performed using DEX exposure and timing as predictor variables. Multivariable analysis modeled with DEX exposure as a predictor variable showed that when initiated preincision and continued through the postoperative period, DEX was associated with significant reduction in postoperative JET (odds ratio [OR] 0.09, 95% confidence interval [CI] 0.02-0.37, p = 0.002). Exposure to DEX in the postoperative period alone did not result in suppression of JET (OR 0.5, 95% CI 0.11-2.17, p = 0.366). When modeled by using timing of DEX initiation as the predictive variable, preincision initiation of DEX infusion resulted in significantly greater suppression of JET (OR 0.04, 95% CI 0.002-0.28, p = 0.006) compared with initiation intraoperatively after CPB (OR 0.16, 95% Cl 0.03-0.71, p = 0.024) or on arrival to the ICU (OR 0.504, CI 0.105-2.171, p = 0.365). Use of DEX exclusively in the postoperative period did not demonstrate any significant benefit in reducing JET (OR 0.506, 95% CI 0.106-2.17, p = 0.366). Conclusions: Preincision initiation of DEX and its continued use during the immediate postoperative period are significantly associated with reduced risk of JET after congenital heart surgeries involving repair of ventricular septal defect. (C) 2017 Elsevier Inc. All rights reserved.