Timing of Transversus Abdominis Plane Block and Postoperative Pain Management

Background: Transversus abdominis plane (TAP) blocks using liposomal bupivacaine can reduce postoperative pain and opioid consumption after surgery. The impact of timing of administration of such blocks has not been determined. Materials and Methods: A retrospective cohort study of all adult patients that underwent colorectal procedures between January 2013 and October 2015 and received TAP blocks with liposomal bupivacaine at our institution was conducted. The primary outcomes were postoperative pain scores and opioid consumption. Secondary outcomes included postoperative use of non-opioid analgesics as well as total hospital cost of admission and postoperative hospital length of stay. Results: A total of 287 patients were identified and included in the analysis. A total of 71 patients received blocks prior to induction of general anesthesia (pre-ind), 85 patients received blocks after induction of general anesthesia but prior to surgical incision (post-ind) and 131 patients received blocks after completion of surgery (post-op). No significant differences were observed in the postoperative pain scores (either in the first 4 hours or for the entire duration of hospital stay) or opioid consumption between the pre-ind and the post-ind groups. More ketorolac was used in the post-op group compared to the pre-ind group (or=3.36, 95% CI (1.08, 10.43); p=0.03). Conclusion: Our findings suggest that there seems to be no difference if tap blocks with liposomal bupivacaine are performed before or after induction of anesthesia. Patient preference as well as operating room efficiency should be considered when deciding on the timing of these blocks.