Abstract
BACKGROUND: Postoperative nausea and vomiting (PONV) are common complications after surgery. Opioid use is a significant risk factor. We utilised a crossover design to test this hypothesis in the same individuals that opioid-free anaesthesia (OFA) compared with opioid-inclusive anaesthesia reduces PONV. METHODS: This randomised double-blind crossover trial included adult patients undergoing two surgical procedures for lower extremity wounds under general anaesthesia. Each patient received both OFA (i.v. lidocaine, esketamine, dexmedetomidine and propofol) and opioid-inclusive anaesthesia (sufentanil and propofol); which came first was determined by randomisation. The primary outcome was the incidence of PONV during the first 48 h postoperatively. Secondary outcomes were the severity of PONV, use of rescue antiemetics, postoperative pain, need for rescue analgesia, adverse events, time to extubation, and length of recovery room stay. RESULTS: Sixty-six patients completed this study (mean age 53 years, 36% female). The median washout period was 9 days. Compared with opioid-inclusive anaesthesia, OFA reduced the incidence of PONV 0-48 h postoperatively (5% vs. 23%, odds ratio [OR] = 0.13, 95% CI: 0.03-0.55, p = 0.006), which remained significant in the prespecified adjusted analysis (OR = 0.06, 95% CI: 0.01-0.32, p = 0.001). OFA also led to a reduced severity of PONV, a lower rate of hypotension, and a longer time to extubation. Postoperative pain and other outcomes were similar between the two anaesthetic techniques. CONCLUSION: This crossover trial demonstrates that OFA reduced PONV following lower extremity wound surgery, providing compelling evidence for the administration of OFA to enhance perioperative care. REGISTRATION: ChiCTR2200061511 (https://www.chictr.org.cn).