This issue of the Korean Journal of Anesthesiology includes a study conducted by Yoo et al. [3] that compares the incidence of PONV after general anesthesia between remimazolam and sevoflurane. Forty patients undergoing laparoscopic cholecystectomy or hemicolectomy were randomized to receive either total intravenous anesthesia (TIVA) with remimazolam/remifentanil or balanced anesthesia with sevoflurane/remifentanil. Patients anesthetized with remimazolam showed a significantly lower incidence of PONV and a reduced rescue antiemetic requirement within the first 24 h postoperatively. The reduction in PONV was most notable in the immediate postoperative period. According to the Quality of Recovery-15 questionnaire results, patients who received remimazolam scored higher on PONV but had significantly lower scores on “a feeling of general well-being” than those who received sevoflurane. The authors attributed this to worse pain in the post-anesthesia care unit and a higher rescue analgesic requirement during the first 24 h postoperatively in patients who received remimazolam anesthesia.

Midazolam, a relatively short-acting benzodiazepine, is a common anxiolytic agent used in the perioperative period. The antiemetic properties of midazolam, possibly mediated by decreased dopaminergic activity and 5-hydroxytryptamine release, were first reported in the 1990s [4,5]. Multiple studies have demonstrated that intravenous midazolam, administered as premedication, at the induction of anesthesia, or prior to the end of surgery, reduces PONV [6,7]. Midazolam has also been shown to effectively treat acute refractory emesis after chemotherapy [8]. Additionally, the efficacy of midazolam for the treatment of PONV has be shown to be comparable to that of ondansetron [9]. Despite accumulating evidence, midazolam is currently not recommended solely for the prophylaxis or treatment of PONV because of its potent sedative effect. Additionally, propofol, which possesses antiemetic properties and more favorable pharmacokinetic characteristics, has become popular as a hypnotic agent for monitored anesthesia care or general anesthesia.

Remimazolam is a novel ultra-short-acting benzodiazepine. Owing to its rapid metabolism by nonspecific esterases, it has a fast onset and offset, a short context-sensitive half-life even after prolonged infusion, and highly predictable and titratable effects [10]. Remimazolam has been shown to be at least non-inferior to propofol for the induction and maintenance of general anesthesia, with notable hemodynamic stability [11,12]. Because volatile anesthetics are an established risk factor for PONV, TIVA with propofol has been promoted to reduce PONV. However, propofol can predispose patients to profound hypotension, particularly vulnerable populations. Thus, some clinicians prefer induction with midazolam and balanced anesthesia with volatile anesthetics for patients with compromised cardiovascular function.

Unfortunately, current evidence is insufficient to conclude whether remimazolam or propofol is more effective for PONV prophylaxis. However, remimazolam does not appear to increase the incidence or severity of PONV compared with propofol [13]. Therefore, remimazolam has the potential to be a superior alternative to propofol TIVA or balanced anesthesia with volatile agents, especially for patients at a high risk of both cardiovascular instability and PONV.