Postoperative nausea and vomiting ( PONV ) is one of the common complications after general anesthesia while genetic factors may play an important role in Postoperative nausea and vomiting. In this study, the investigators investigated the relationship between gene polymorphism ( such as single nucleotide polymorphism ) of the gene HTR3A ( 5-hydroxytryptamine receptor 3A ), HTR3B ( 5-hydroxytryptamine receptor 3B ), HTR3C ( 5-hydroxytryptamine receptor 3C ) and TACR1 ( tachykinin receptor 1 ) etc. with nausea and vomiting after general anesthesia. Simultaneously, the investigators explored the influencing factors of nausea and vomiting.

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.

Inclusion Criteria:

• Undergoing breast surgery with general anesthesia
• American Society of Anesthesiologists Physical Status Classifications 1-2
• No history of smoking
• body mass index (BMI) <35 kg/m2

Exclusion Criteria:

• Declined to participate
• Had used antiemetics, steroids, H2 antagonists, anticholinergics, antihistamines, butyrophenones, phenothiazines, metoclopramide or opioids within 24 hours
• Gastroesophageal reflux, gastrointestinal obstruction or ulcer, vestibular or hearing dysfunction
• Liver impairment, renal impairment, psychiatric disorder, chronic pain
• Pregnant and lactating patients
• Requiring postoperative patient-controlled analgesia
• Requiring prophylactic use of antiemetics
• Allergic to drugs related in the study
• Receiving chemotherapy within one week before surgery

Han population who were admitted to department of breast surgery, Fujian Medical University Union Hospital.