Analgesic efficacy of bilateral continuous transversus abdominis plane blocks using an oblique subcostal approach in patients undergoing laparotomy for gynaecological cancer: a prospective, randomized, triple-blind, placebo-controlled study

Abstract

Background: The analgesic efficacy of continuous transversus abdominis plane (TAP) blocks in comparison with that of single-injection TAP blocks is not clear. This randomized, triple-blind, placebo-controlled trial investigated the benefits of adding continuous TAP blocks to single-injection TAP blocks after a laparotomy. Methods: Eighty consecutive patients undergoing midline laparotomy for gynaecological cancer were randomized and received bilateral TAP infusions with either ropivacaine 0.1% (n=40, Rop group) or normal saline (n=40, NS group) at 10 ml h−1 per side for 50 h after surgery. After surgery, bilateral oblique subcostal TAP blocks were performed using ropivacaine 0.1%, 50 ml per side, and then catheters were threaded into the bilateral TAPs. Subsequently, continuous TAP infusions and patient-controlled i.v. morphine administration were initiated. The primary outcome was cumulative morphine consumption by 24 h after TAP catheter placement. Secondary outcomes included pain scores, postoperative nausea and vomiting severity, and time to first ambulation and flatus. Results: The cumulative morphine consumption (median [interquartile range]) 24 h after TAP catheter placement was lower in the Rop group (0.25 [0.11–0.48] mg kg−1) than in the NS group (0.44 [0.24–0.73] mg kg−1; 95% confidence interval difference in medians, −0.30 to − 0.03; P=0.01). No statistically significant differences were observed in the secondary outcomes, except for reduced pain scores in the Rop group obtained during coughing 1 and 24 h after TAP catheter placement. Conclusions: Addition of continuous TAP blocks to single-injection TAP blocks reduces pain and morphine consumption after a laparotomy for gynaecological cancer. Clinical trial registration: UMIN Clinical Trials Registry identification number UMIN000013449 (http://www.umin.ac.jp/ctr/index.htm).