Efficacy of ultrasound-guided continuous transverses abdominis plane block when used for postoperative analgesia in patients undergoing total hysterectomy

Abstract

Objective To evaluate the efficacy of ultrasound-guided continuous transverses abdominis plane (TAP) block when used for postoperative analgesia in the patients undergoing total hysterectomy. Methods Forty American Society of Anesthesiologists physical status Ⅰ or Ⅱpatients, aged 38-64 yr, weighing 50-80 kg, undergoing elective total hysterectomy with general anesthesia, were divided into 2 groups using a random number table: continuous TAP block group (CTAP group, n=21) and patient-controlled intravenous analgesia (PCIA) group (n=19). In group CTAP, bilateral TAP block was performed with 0.2% ropivacaine 20 ml under ultrasound guidance before operation, and 0.2% ropivacaine 5 ml/h was infused into bilateral TAPs after extubation.In group PCIA, the patients received PCIA with sufentanil 1 μg/ml after extubation, and the PCIA pump was set up to deliver a 2 ml bolus dose, a 15 min lockout interval and background infusion at a rate of 2 ml/h.Analgesia lasted until 72 h after operation in both groups.When visual analog scale>4, morphine 5 mg was intramuscularly injected as rescue analgesic.The recovery time of postoperative intestinal function, length of hospital stay, patient′s satisfaction with analgesia, requirement for rescue analgesia, TAP block-related adverse reactions and development of postoperative nausea and vomiting were recorded.In group CTAP, blood samples were collected from the peripheral vein immediately after the end of operation and at 2, 6, 12, 24, 48 and 72 h after operation for determination of concentrations of ropivacaine in plasma and free ropivacaine in plasma using high-performance liquid chromatography. Results Compared with group PCIA, the requirement for rescue analgesia and incidence of nausea and vomiting were significantly decreased, the recovery time of postoperative intestinal function was shortened, the score for patient′s satisfaction with analgesia was increased (P 0.05). No TAP block-related adverse reactions were found in group CTAP.In group CTAP, the concentration of ropivacaine in plasma began to increase at 2 h after operation and peaked at 48 h after operation, the concentration of free ropivacaine in plasma began to increase at 2 h after operation and peaked at 24 h after operation (P<0.05). Conclusion Ultrasound-guided continuous TAP block produces good analgesic efficacy when used for the patients undergoing total hysterectomy. Key words: Nerve block; Transverses abdominis plane; Ultrasonography; Analgesia