Efficacy of intravenous acetaminophen as adjunct analgesia in patients undergoing cardiovascular surgery: a systematic review and meta-analysis.

Background: Although intravenous (IV) acetaminophen (AAP) may help reduce severe postoperative pain and opioid use after cardiovascular surgery, its effectiveness must be further validated. Therefore, the authors aimed to evaluate the analgesic efficacy of perioperative IV AAP in patients undergoing cardiovascular surgery by conducting this meta-analysis.

Methods: A comprehensive literature search was conducted of PubMed, Embase, CENTRAL, CINAHL, Scopus, and Web of Science databases for studies published up to March 21, 2024. Six randomized controlled trials comparing IV AAP with a placebo in cardiovascular surgery were included. The mean difference (MD) was calculated to estimate pooled effect sizes. The primary outcome was opioid consumption, measured in morphine equivalent dose, and the secondary outcome was postoperative pain score.

Results: Postoperative opioid consumption was significantly reduced with IV AAP than it was with a placebo (MD: -21.68, 95% confidence interval [CI]: -38.41 to -4.95, P = 0.011). Significant reductions in postoperative pain scores were observed at 6 hours (MD: -0.76, 95% CI: -1.43 to -0.10, P = 0.025) and 24 hours (MD: -0.63, 95% CI: -1.02 to -0.25, P = 0.001) after surgery. However, these reductions did not meet clinically meaningful thresholds. No significant differences were observed at 12, 18, and 48 hours postoperatively.

Conclusions: IV AAP was more effective than a placebo for postoperative adjunct analgesia in patients who underwent cardiovascular surgery.