The role of postoperative ketamine infusion in ERAS protocols following elective open abdominal surgeries, a systematic review and meta-analysis.

Abstract

<h4>Introduction</h4>Enhanced Recovery After Surgery (ERAS) protocols are multimodal, evidence-based pathways designed to accelerate postoperative recovery and reduce complications. A key component of ERAS is optimizing pain management to minimize opioid reliance. Ketamine, an NMDA receptor antagonist, has demonstrated potential as a multimodal analgesic for reducing opioid consumption and postoperative pain; however, its specific role and efficacy within comprehensive ERAS protocols remain under-evaluated, with variations in dosing and patient response. The current literature lacks a clear consensus on the efficacy of postoperative ketamine infusion for critical ERAS outcomes, including pain control, opioid consumption, postoperative nausea and vomiting (PONV), and length of hospital stay. This meta-analysis evaluates the impact of postoperative ketamine infusion on pain, opioid use, and recovery outcomes within ERAS protocols for elective open abdominal surgeries.<h4>Methods</h4>A systematic review and meta-analysis were conducted by screening PubMed, Scopus, and EMBASE up to June 2024. Randomized controlled trials involving adult patients undergoing elective open abdominal surgery were included if they compared postoperative ketamine infusion with standard care or placebo within an ERAS setting. The primary outcomes were postoperative pain intensity, measured using the Visual Analog Scale (VAS), and opioid consumption, converted to morphine equivalents. The risk of bias was assessed using the Cochrane Risk of Bias 2 tool, and evidence quality was graded using the GRADE approach. A random-effects model was applied to account for heterogeneity across studies.<h4>Results</h4>Fourteen RCTs involving 1067 patients met inclusion criteria. Ketamine significantly reduced postoperative pain scores (standardized mean difference - 0.53, 95% CI [-0.84, -0.22], p < 0.05) and opioid consumption within the first 24 h post-surgery (standardized mean difference - 0.44, 95% CI [-0.75, -0.13], p < 0.05) compared to control treatments. However, effects on PONV and other adverse events were not statistically significant (Log OR -0.19, 95% CI [-0.81, 0.43], p = 0.55), with considerable heterogeneity across studies (I² = 72.69%).<h4>Conclusion</h4>Postoperative ketamine infusion within ERAS protocols appears effective in reducing both pain and opioid consumption without significantly impacting PONV or adverse effects. These findings suggest ketamine may be a valuable adjunct in ERAS for elective open abdominal surgeries, though variability in results indicates that optimal dosing and administration strategies require further investigation to maximize patient recovery benefits and minimize side effects.