Use of Dexmedetomidine as an Adjunct to Pain Control Following OPCAB: A Randomized, Double-Blind Study

Abstract

Use of Dexmedetomidine as an Adjunct to Pain Control Following OPCAB: A Randomized, Double-Blind Study Jeffrey L. Horswell MD, Michael J. Mack MD, Donna A Bachand RN PhD, Luis Michelsen MD, Tina Worley RN BSN CCRC Objectives: The purpose of this study was to determine whether use of dexmedetomidine leads to improved clinical outcomes in immediately extubated, post-operative off-pump coronary artery bypass (OPCAB) patients. Patients and Methods: 24 patients scheduled for elective OPCAB consented to participate in the study. Patients who were previously selected for epidural analgesia or who had elevated serum creatinine levels were excluded. Fifteen minutes prior to extubation, patients were prospectively randomized in a double-blind fashion into one of two groups: Group 1 (n=12) received an 18 hour infusion of dexmedetomidine 0.2 to 0.7 μg/kg/hr. Group 2 (n=12) received an 18 hour infusion of normal saline. All patients received a standard anesthetic consisting of propofol, sufentanil, vecuronim, and desflurane. Post-operative pain was managed with ketorolac and morphine. Total morphine use was recorded. Hemodynamic monitoring, incentive spirometry volumes, visual analog scale pain ratings, activity, and anxiety levels were recorded every 2 hours for 18 hours post-operatively. Results are reported as mean ± standard deviation. Student’s t-test was used to test the difference in means between the two groups. Paired t-tests were used to evaluate changes across time intervals. Results: Mean narcotic use was 2.1 times greater in the placebo group (23.5 ± 20.7 mg) compared to the treatment group (11.4 ± 6.3 mg; p=.03). Time to achieving adequate pain control (VAS rating <35) was more rapid in the treatment group (6 hours vs. 8 hours). Although morphine doses were available on demand to all patients, those in the treatment group reported less pain at all time points. Patients in the treatment group were out of bed earlier (564 ± 361 vs. 292 ± 89 minutes; p=.03). There were no significant changes in heart rate, blood pressure, pulmonary artery pressure, central venous pressure, cardiac output, or systemic oxygen saturation in either group. When hemodynamic data were analyzed by subject, no significant changes could be detected. Conclusion: Dexmedetomidine provides effective post-operative pain control without untoward hemodynamic changes in immediately extubated OPCAB patients. Superior pain control can be achieved with minimal doses of narcotics. Objectives Determine whether use of dexmedetomidine leads to improved clinical outcomes in immediately extubated, post-operative off-pump coronary artery bypass (OPCAB) patients Patients and Methods • 24 patients were prospectively randomized in a double-blind fashion and scheduled for elective/urgent OPCAB. • All caregivers were blinded to treatment arm. • Patients who were previously selected for epidural analgesia or who had elevated serum creatinine levels were excluded. • Fifteen minutes prior to extubation, patients were randomly selected for one of two groups: • Group 1 (n=12) received an 18 hour infusion of dexmedetomidine 0.2 to 0.7 μg/kg/hr • Group 2 (n=12) received an 18 hour infusion of normal saline. • All patients received a standard anesthetic. Induction Maintenance Sufentanil 15-20 μg Sufentanil 10-15 μg/hr Propofol 50-100 mg Desflurane titrated to a BIS of 50-60 Vecuronium 0.1 mg/kg Vecuronium titrated to 1/4 twitch • All patients were extubated in the operating room. • For post-operative pain management, patients received ketorolac 30 mg followed by 15 mg IV every 6 hours for 6 doses. 15 minutes prior to extubation, the study infusion was begun at a dosage of 0.5 μg/kg/hr. • The study drug was adjusted within the range of 0.2 to 0.7 μg/kg/hr to achieve a visual analog scale (VAS) value < 40 on a 100 mm scale. Breakthrough pain was treated with morphine 2 mg every 5 minutes until the VAS was < 40. • Clinical monitoring recorded every 2 hours for 18 hours post-operatively • Hemodynamic values • Incentive spirometry volumes • Visual analog scale pain ratings • Activity and anxiety levels. • Results are reported as mean ± standard deviation. Student’s t-test was used to test the difference in means between the two groups. Paired t-tests were used to evaluate changes across time intervals. Results • Mean narcotic use was 2.1 times greater in the placebo group (23.5 ± 20.7 mg) compared to the treatment group (11.4 ± 6.3 mg; p=0.03) Graph 1 No difference in preoperative risk factors by treatment group