Opioid-free total intravenous anaesthesia reduces postoperative nausea and vomiting in bariatric surgery beyond triple prophylaxis

Background. Patients undergoing bariatric surgery are at high risk of postoperative nausea and vomiting (PONV). Despite triple PONV prophylaxis, up to 42.7% of patients require antiemetic rescue medication (AERM). Methods. This prospective, randomized study was conducted from November 2011 to October 2012. In the Classic group (n=59), patients underwent general anaesthesia with volatile anaesthetics and opioids. In the Total i.v. anaesthesia (TIVA) group (n=60), patients underwent opioid-free TIVA with propofol, ketamine, and dexmedetomidine. The severity of PONV was assessed using a Likert scale (none, mild, moderate, and severe). Results. Patients in both groups had similar clinical characteristics, surgical procedure, and PONV risk scores and required similar amounts of postoperative opioid. In the Classic group, 22 patients (37.3%) reported PONV compared with 12 patients (20.0%) in the TIVA group [P=0.04; risk 1.27 (1.01-1.61)]. The absolute risk reduction was 17.3% (number-needed-to-treat=6). The severity of nausea was statistically different in both groups (P=0.02). The severity of PONV was significantly worse in the Classic group. There was no difference either in the number of patients requiring AERM in the postoperative period or in the number of AERM doses required. Conclusions. This prospective randomized study demonstrates that opioid-free TIVA is associated with a large reduction in relative risk of PONV compared with balanced anaesthesia.