Incidence of nausea and vomiting in outpatients undergoing general anesthesia in relation to selection of intraoperative opioid

Study Objective: To measure the incidence of nausea and vomiting in outpatients in relation to selection of, or withholding of, intraoperative opioid. Design: Prospective, randomized, double-blind control trial. Setting: University general hospital. Patients: 200 unpremeditated ASA status I and II patients, 8 to 80 years old, undergoing general anesthesia for ambulatory surgery. Intervention: Patients were randomized to four groups, three of which received equipotent doses of different opioids intravenously (IV) during indication of anesthesia. Group 1 received nalbuphine 0.25 mg/kg, Group 2, alfentail 20 ug/kg; Group 3, fentanyl 2 ug.kg; and Group 4, normal saline. Measurements and Main Results: We evaluated (1) incidence and severity of nausen and vomiting in the postanesthesia care unit (PACU) and over the next 24 hours; (2) time to PACU discharge; (3) need for antiemetic therapy; and (4) need for analgesic rescue in the PACU. The incidences of nausea and vomiting were similar in all groups, as were time to discharge, antiemetic, and nonsteroidal antiinflamatory drug requirements. The highest indicidences of nausea and vomiting occurred at 6 hours in all groups (23% and 9.5%, respectively). Group I required lower rescue doses of morphine in the PACU but this result may have been an artifact due to employing the mixed agonist-antagonist opioid, nalbuphine, in this group. Conclusions: Opioid administration at the doses employed during induction of anesthesia does not promote postoperative nausea or vomiting, nor increase length of stay in the PACU.