Primary outcome: Observe the incidence of PONV in the PACU. Secondary outcome: Observe the incidence of PONV within 24 hours after surgery; General data such as age, weight, body mass index, ASA classification, and Apfel score were collected; Record the operation time, recovery time and dosage of remimazolam and alfentanil. Postoperative nausea is when the patient only has a feeling of nausea but no contractile movements of the diaphragm or abdominal muscles. Postoperative vomiting occurs when the patient experiences contraction of the diaphragm or abdominal muscles with or without vomiting of stomach contents, or when both nausea and vomiting are present.[1 (link)] Appel designed a PONV risk score[9 (link)] based on 4 major risk factors for adult PONV: female, nonsmoking, history of PONV and/ or motion sickness, and postoperative use of opioids. The risk of PONV was 10 %, 20 %, 40 %, 60 % and 80 % for each factor scored 0, 1, 2, 3, and 4, respectively.