Effects of opioid-free anaesthesia compared with balanced general anaesthesia on nausea and vomiting after video-assisted thoracoscopic surgery: a single-centre randomised controlled trial

Objectives Opioid-free anaesthesia (OFA) has emerged as a promising approach for mitigating the adverse effects associated with opioids. The objective of this study was to evaluate the impact of OFA on postoperative nausea and vomiting (PONV) following video-assisted thoracic surgery. Design Single-centre randomised controlled trial. Setting Tertiary hospital in Shanghai, China. Participants Patients undergoing video-assisted thoracic surgery were recruited from September 2021 to June 2022. Intervention Patients were randomly allocated to OFA or traditional general anaesthesia with a 1:1 allocation ratio. Primary and secondary outcome measures The primary outcome measure was the incidence of PONV within 48 hours post-surgery, and the secondary outcomes included PONV severity, postoperative pain, haemodynamic changes during anaesthesia, and length of stay (LOS) in the recovery ward and hospital. Results A total of 86 and 88 patients were included in the OFA and control groups, respectively. Two patients were excluded because of severe adverse events including extreme bradycardia and epilepsy- like convulsion. The incidence and severity of PONV did not significantly differ between the two groups (29 patients (33.0%) in the control group and 22 patients (25.6%) in the OFA group; relative risk 0.78, 95% CI 0.49 to 1.23; p=0.285). Notably, the OFA approach used was associated with an increase in heart rate (89 +/- 17 vs 77 +/- 15 beats/min, t- test: p<0.001; U test: p<0.001) and diastolic blood pressure (87 +/- 17 vs 80 +/- 13 mm Hg, t- test: p=0.003; U test: p=0.004) after trachea intubation. Conversely, the control group exhibited more median hypotensive events per patient (mean 0.5 +/- 0.8 vs 1.0 +/- 2.0, t- test: p=0.02; median 0 (0-4) vs 0 (0-15), U test: p=0.02) during surgery. Postoperative pain scores, and LOS in the recovery ward and hospital did not significantly differ between the two groups.Conclusions Our study findings suggest that the implementation of OFA does not effectively reduce the incidence of PONV following thoracic surgery when compared with traditional total intravenous anaesthesia.