Materials and methods:
Demographic data and risk factors responsible for PONV, including the history of PONV and motion sickness, were collected preoperatively by interviewing participants the day before anesthesia.
All study subjects received a standardized anesthesia regimen. General anesthesia was induced by midazolam 0.04 mg/kg, propofol 1.5 mg/kg, sufentanil 0.4 μg/kg, and cisatracurium 0.2 mg/kg (to facilitate tracheal intubation) given intravenously.Participants' lungs were ventilated with 50% oxygen in air.
During general anesthesia, concentration of sevoflurane maintained 1.0% to 3.0% at the discretion of anesthetist who was not involved in the study. General anesthesia also uses propofol 1 mg kg-1 h-1 and sufentanil 0.1 μg kg-1 h-1 by continuous intravenous infusion. An Entropy index monitor was used to maintain the appropriate anesthesia depth by 40-60. Participants received a repeated bolus of sufentanil 0.1 μg/kg or cisatracurium intravenously on demand.
After surgery the investigators recorded the data such as Anesthesia duration, doses of sufentanil and propofol and so on.
At the end of surgery and after returning to the ward, flurbiprofen axetil 50 mg injection i.v. was administered as an analgesic therapy, respectively. Cholinesterase inhibitor-based neuromuscular reversal drugs and vitamine B6 were not administered after surgery. Bucinnazine hydrochloride 100 mg intramuscular injection (i.m.) as a rescue medication was administered to any participant whose visual analogue scale/score (VAS) was \> 3.
Ondansetron was given intravenously to the participants if necessary or requested . Unaware of the genotypes of the subjects, the investigators collected the participants' data including nausea, vomiting and pain.
