Ultrasound-guided transversus abdominis plane block versus dexmedetomidine infusion in open ovarian cystectomy: Analgesic efficacy and effect on stress response

Abstract

Background Ultrasound (US)-guided transversus abdominis plane (TAP) block has been proven to be an effective method of providing postoperative analgesia in laparotomy. Dexmedetomidine has sedative, analgesic, sympatholytic, and amnestic properties. In the present study, we evaluated the analgesic efficacy and the attenuation of stress surgical response of US-guided TAP block in comparison with dexmedetomidine infusion in patients undergoing open ovarian cystectomy in a randomized, double-blinded clinical study. Patients and methods A total of 60 patients were randomly assigned into two groups (30 in each) to be administered, before skin incision, either a combination of general anesthesia with a US-guided TAP block (TAP group), or an intraoperative intravenous infusion of dexmedetomidine (DEX group). In the DEX group, loading dose of 1 μg/kg of dexmedetomidine was infused over 10 min, followed by infusion of 0.2-0.6 μg/kg/h. Measurements included hemodynamics, stress hormones, pain score, time of first analgesia, and amount of pethidine during the first 24 h postoperative. Results In the DEX group, there was a significant decrease in heart rate (HR) at 45, 60, and 90 min after surgical incision in comparison with preoperative HR. In the TAP group, there was a significant decrease in HR at 60 and 90 min after surgical incision in comparison with preoperative HR. In the DEX group, there was a significant decrease in mean arterial pressure at 30, 45, 60, and 90 min after surgical incision in comparison with preoperative mean arterial pressure. The DEX group had shown a statistically significant increase with regard to change in the blood level of stress hormones 12 and 24 h postoperative in comparison with the preoperative values. There was a highly significant increase in postoperative pethidine supplementation in the DEX group than in the TAP group. There was a significant difference with regard to time of the first postoperative request of analgesia in the DEX group than in the TAP group. Conclusion In open ovarian cystectomy, US-guided TAP block was comparable to dexmedetomidine infusion with regard to intraoperative hemodynamic stability and opioid requirement without change in stress response hormones. However, TAP block provided superior analgesia when compared with dexmedetomidine infusion up to 24 h postoperatively.