Clinical effectiveness of transversus abdominis plane (TAP) block in abdominal surgery: a systematic review and meta-analysis.

AIM Reduced opioid use in the immediate postoperative period is associated with decreased complications. This study aimed to determine the effect of transversus abdominis plane (TAP) block on morphine requirements 24 h after abdominal surgery. Secondary outcomes included the effect of TAP block on morphine use 48 h after surgery, incidence of postoperative nausea and vomiting (PONV) and impact on reported pain scores (visual analogue scale). METHOD A systematic review of the literature was conducted for randomised controlled trials (RCTs) evaluating the effects of TAP block in adults undergoing abdominal surgery. For continuous data, weighted mean differences (WMD) were formulated; for dichotomous data, odds ratios (OR) were calculated. Results were produced with a random effects model with 95% confidence intervals (CI). RESULTS Nine studies, including published and unpublished data, containing a total of 413 patients were included. Of these 205 received a TAP block and 208 a placebo. Cumulative morphine utilization was statistically significantly reduced at 24 h. [WMD=23.71mg (38.66-8.76); P=0.002] and 48h [WMD=38.08mg (18.97-57.19); P<0.0001] in patients who received a TAP block and the incidence of PONV was significantly reduced [OR=0.41(0.22-0.74); P=0.003]. There was a nonsignificant reduction in the visual analogue scales of postoperative pain [WMD=0.73cm (1.84-0.38), P=0.2]. There were no reported adverse events following TAP block. CONCLUSION Transversus abdominis plane block is safe, reduces postoperative morphine requirements, nausea and vomiting and possibly the severity of pain after abdominal surgery. It should be considered as part of a multimodal approach to anaesthesia and enhanced recovery in patients undergoing abdominal surgery.