Opioid-sparing Anesthesia in Cardiac Surgery: A Meta-analysis

Abstract

This systematic review and meta-analysis evaluated the impact of opioid-sparing versus opioid-based anesthesia in adult patients undergoing cardiac surgery. A comprehensive literature search was conducted across major databases from 2015 to 2025. Eligible studies included randomized controlled trials and observational cohorts reporting at least one of the following outcomes: opioid consumption (in morphine milligram equivalents [MME]), intensive care unit (ICU) length of stay, mechanical ventilation duration, pain scores, and mortality. A total of 27 studies (8 randomized controlled trials and 19 observational studies), including 58,998 patients, were analyzed. Opioid-sparing protocols, involving multimodal analgesia and regional anesthesia, were significantly associated with reduced intraoperative and postoperative opioid consumption. The pooled mean difference in opioid consumption was -2.48 MME (95% confidence interval [CI]: -2.60 to -2.35, p < 0.001). Opioid-sparing strategies were also associated with shorter ICU length of stay (odds ratio [OR]: 1.32, 95% CI: 1.14-1.51), reduced duration of mechanical ventilation (OR: 1.46, 95% CI: 1.24-1.72), and lower postoperative pain scores at 12 hours (OR: 1.18, 95% CI: 1.07-1.30). No significant difference was observed in postoperative mortality (OR: 0.20; 95% CI: 0.04-1.14). Narrative outcomes such as persistent opioid use, postoperative nausea, early mobilization, and patient satisfaction generally favored opioid-sparing anesthesia, although reporting was inconsistent. Adverse events related to nonopioid adjuncts were inconsistently reported. The overall risk of bias was low to moderate, and heterogeneity was moderate across most outcomes. These findings support opioid-sparing strategies in selected cardiac surgery patients as part of multimodal, enhanced recovery protocols, but highlight the need for standardized definitions and prospective trials with rigorous safety reporting.

Keywords: ICU length of stay; cardiac surgery; mechanical ventilation; multimodal analgesia; opioid-sparing anesthesia; persistent opioid use.