Analgesic, Sedative and Hemodynamic Effects of Dexmedetomidine Following Major Abdominal Surgeries: A Randomized, Double- Blinded Comparative Study with Morphine

Abstract

This was a randomized double-blinded study; in which 60 ASAI-II adult patients scheduled for major abdominal surgeries (colostomy, radical cystectomy, major gynecological surgery, and abdominal vascular surgery) were received standard general anesthesia. Twenty minutes before the anticipated end of surgery, patients were randomized into two equal groups: dexmedetomidine group (group D) and morphine group (group M). Group D received dexmedetomidine IV infusion 4μg/kg/h for 15 minutes (1μg/Kg) followed by 0.4μg/kg/h for 3h. Group M received morphine sulfate IV (0.07mg/kg). All patients were given a morphine patient controlled analgesia (PCA) pump in the post anesthesia care unit (PACU), delivering IV morphine 2mg with a lockout time of 5 minutes if pain score assessed through visual analog scale (VAS) was more than 5 at any given 5-min assessment. During the PACU recovery period, morphine consumption; pain and sedation scores; hemodynamic variables (heart rate, mean arterial blood pressure, oxygen saturation and respiratory rate); and postoperative nausea, retching and vomiting (PONV) were recorded every 30 min for 3h (study period) by a member of staff blinded to the treatment. The study demonstrated that the use of dexmedetomidine led to significant decrease in the total amount of morphine consumed throughout the entire PACU recovery period (P 0.05); significant decrease in mean arterial pressure (P 0.05); without any significant changes in oxygen saturation (P<0.05) or respiratory rate (P<0.05). In conclusion, dexmedetomidine exhibited both analgesic and sedative properties. The associated cardiovascular protective pharmacological profile and the lack of respiratory depression made it potentially extremely interesting for postoperative analgesia after major abdominal surgeries.