Effect of oral clonidine premedication on anesthetic requirement, hormonal response, hemodynamics, and recovery in coronary artery bypass graft surgery patients

Study Objective: To examine how premedication with clonidine affects opioid use, hemodynamic effects, hormonal responses, and recovery effects. Design: Double-blind, placebo-controlled study. Setting: Operating room and surgical intensive care unit of a university medical center. Patients: 54 patients undergoing elective coronary artery bypass graft (CABG) surgery. Interventions: Patients received approximately 5 mu g/kg of oral clonidine or a placebo together with 40 mu g/kg lorazepam 90 minutes pries to titrated sufentanil induction of anesthesia. Thirty minutes prior to cardiopulmonary bypass, a second dose of either approximately 5 mu g/kg clonidine or placebo runs given as a slurry via a nasogastric tube. Measurements and Main Results: Opioid use, hemodynamic effects, hormonal responses, and recovery effects were recorded. Values for ten hemodynamic variables were compiled on the evening prior to surgery, prior to Induction, and during seven additional events and compared. Catecholamines and beta-endorphins were measured prior to induction, after intubation, and after sternotomy. The amount of sufentanil used for induction, maintenance, and total opioid were compared. The times to awakening and response to verbal commands were compared. The two groups exhibited similar patient demographics, cardiopulmonary bypass time, and duration of surgery. Patients receiving clonidine required significantly (p < 0.04) less sufentanil for indiction (clonidine: 2.19 +/- 0.95 mu g/kg vs. placebo: 2.93 +/- 1.07 mu g/kg) and total amount of sufentanil (clonidine: 9.1 +/- 3.9 mu g/kg vs. placebo. 11.7 +/- 4.6 mu g/kg). Patients receiving clonidine required significantly (p < 0.01) less isoflurane (9.7 +/- 6.8 MAC min vs. 19.7 +/- 9 MAC min) to maintain heart rate (HR) and mean arterial pressure (MAP) to within 15% of baseline without significant differences in other vasoactive drugs. Catecholamine concentrations were significantly (p < 0.02) lower in patients receiving clonidine without any difference in beta-endorphin concentrations. Patients receiving clonidine had significantly (p < 0.02) lower HR, systolic arterial pressure, MAP, and systemic vascular resistance prior to induction than patients receiving placebo without differences in other hemodynamic variables. Conclusion: Clonidine decreases opioid use and lowers hormonal response while maintaining stable hemodynamics in patients undergoing CABG with sufentanil anesthesia.