Patients undergoing bariatric surgery are at high risk of postoperative nausea and vomiting. The use of opioid-free anesthesia (OFA) has been described to reduce the risk of PONV but, to date, few studies have shown the superiority of OFA than general anesthesia with opioids in bariatric surgery. The present study aims to investigate the potential usefulness of the OFA in reducing the post-operative nausea and vomiting in bariatric surgery.

Over a 2-year period, from May 2019 to November 2021, all patients who underwent bariatric surgery at our institution were retrospectively assessed for eligibility on a prospectively maintained database. Patients were divided in two groups according to the type of anesthesia they underwent, either an OFA or a classic anesthesia. As primary endpoint we considered the length of hospital stay. Data was collected on a dedicated electronic dataset and analyzed.

Over the study period, 344 consecutive patients undergoing bariatric surgery at our institution were included in the study. Of them, 265 (77.0%) were female, mean age was 46.2 ± 11.2 years and 238 (69.2%) patients had at least one comorbidity. In our study population, 209 (60.8%) patients received OFA and 135 (39.2%) received a classic anesthesia. Demographic and clinical characteristics of the two study population groups resulted similar. Operative time (107 ± 41 min vs. 111 ± 45 min, p=0.466), anesthesia and setting time (85 ± 19 min vs. 81 ± 22 min, p=0.087) and recovery room time (117 ± 71 min vs. 108 ± 89 min, p=0.305) were similar. Postoperatively, we observed no significant difference in opioid use the day of surgery or at postoperative day 1, 2 and, while significantly less doses of antiemetics were administered in the OFA group at postoperative day 1 (0.4 ± 0.7 doses vs. 0.7 ± 1.0 doses, p=0.006) and 2 (0.1 ± 0.4 doses vs. 0. ± 0.6 doses, p=0.022). No difference in postoperative complications was noted. In the OFA group the length of stay was significantly shorter than in classic anesthesia group (2.8 ± 0.9 days vs. 3.5 ± 2.0 days, p<0.001).

Despite limitations, our study showed that OFA seems to reduce PONV and the length of hospital stay. Such encouraging results were also confirmed in the propensity score-matched analysis. Beyond the potential clinical benefit, OFA might also have an impact in reducing hospital costs.