Intraperitoneal local anesthetics for postoperative pain management following intra-abdominal surgery: a systematic review and meta-analysis.

importanceAlthough intraperitoneal local anesthetics are commonly used following intra-abdominal surgical procedures, the level of evidence supporting their use for postoperative pain management remains uncertain.

objectiveTo evaluate the effect of intraperitoneal local anesthetics on postoperative pain following intra-abdominal surgery. DATA SOURCES: Medline (PubMed), Embase (Embase.com), CENTRAL, Web of science and ClinicalTrials.gov databases were searched from their inception to July 15th, 2022. TRIAL SELECTION: Randomized controlled trials comparing IPLA to placebo, usual care or other analgesic regimens among patients of any age undergoing any type of surgery. DATA EXTRACTION AND SYNTHESIS: Trial selection, data extraction, risk of bias assessment and the certainty of evidence were conducted in duplicate independently. Meta-analyses were performed using random effect models. MAIN OUTCOMES AND MEASURES: The co-primary outcomes were abdominal pain intensity at 6, 12, 24, 48, and 72 h after surgery. Secondary outcomes included postoperative nausea and vomiting, opioid use, recovery of gastrointestinal transit, length of hospital stay, postoperative chronic pain, persistent postoperative opioid use, quality of recovery and adverse events.

resultsA total of 150 trials (n = 11,821 participants were included in our systematic review (97% of trials among adults). Intraperitoneal local anesthetics reduced postoperative pain intensity at 6 h (-0.86 point [95%CI -1.02 to -0.70]), 12 h (-0.74 point [95%CI -0.93 to -0.55]), 24 h (-0.65 point [95%CI -0.82 to -0.48]), and 48 h (-0.51 point [95%CI -0.70 to -0.31]), but not at 72 h (-0.38 point [95%CI -1.04 to 0.27]), with very low to low certainty of evidence. Modelled risk difference for achieving the clinically important effect and subgroup analyses among participants with moderate or high pain showed potential clinically significant effect from IPLA. Opioid use at 24 h (-10.4 mg of oral morphine equivalent [95% CI -13.1 to -7.6]), postoperative nausea and vomiting (RR 0.79 [95% CI -0.71 to 0.88]), and time to gastrointestinal transit recovery (-3.80 h [95% CI -7.54 to -0.07]) were also reduced. We found no association for other outcomes. CONCLUSION AND RELEVANCE: Intraperitoneal local anesthetics may be associated with a small analgesic effect following intra-abdominal surgery. Considering the low to very low level of evidence supporting these findings, along with the limited data on adverse effects and long-term outcomes, their adoption as a standard of care intervention cannot be recommended at this stage. REGISTRATION NUMBER: CRD42018115062.