Double-blind, randomized comparison of ondansetron and intraoperative propofol to prevent postoperative nausea and vomiting.

BACKGROUND

Breast surgery is associated with a high incidence of postoperative nausea and vomiting. Propofol and prophylactic administration of ondansetron are associated with a lower incidence of postoperative nausea and vomiting. To date no comparison of these two drugs has been reported. A randomized study was done to compare the efficacy of ondansetron and intraoperative propofol given in various regimens.

METHODS

Study participants included 89 women classified as American Society of Anesthesiologists physical status 1 or 2 who were scheduled for major breast surgery. Patients were randomly assigned to one of four groups. Group O received 4 mg ondansetron in 10 ml 0.9% saline and groups PI, PIP, and PP received 10 ml 0.9% saline before anesthesia induction. Group O received thiopental, isoflurane, nitrous oxide-oxygen, and fentanyl for anesthesia. Group PI received propofol, isoflurane, nitrous oxide-oxygen, and fentanyl. Group PIP received propofol, isoflurane, nitrous oxide-oxygen, and fentanyl. Thirty minutes before expected skin closure, isoflurane was discontinued and 50 to 150 micrograms.kg-1.min-1 propofol was given intravenously to maintain anesthesia. Group PP received propofol for induction and maintenance of anesthesia, nitrous oxide-oxygen, and fentanyl. Postoperative pain relief was provided with morphine administered by a patient-controlled analgesia pump. The incidence of nausea and vomiting, requests for rescue antiemetic and sedation, pain scores, and hemodynamic data were recorded for 24 h.

RESULTS

Within 6 h of surgery, groups O and PP had a lower incidence of nausea compared with groups PI and PIP (P < 0.05). Fewer patients in group PP (19%) vomited during the 24-h period compared with groups O (48%), PI (64%), and PIP (52%) (P < 0.05). The incidence of antiemetic use was also less in group PP (P < 0.05). Patients in group PP had lower sedation scores at 30 min and at 1 h (P < 0.05). There were no differences among the groups in pain scores, blood pressure, heart rate, respiratory rate, and incidence of pruritus.

CONCLUSIONS

Propofol administered to induce and maintain anesthesia is more effective than ondansetron (with thiopental-isoflurane anesthesia) in preventing postoperative vomiting and is associated with fewer requests for rescue antiemetic and sedation in the early phase of recovery. It is equally effective in preventing postoperative nausea as ondansetron in the first 6 h after operation. Propofol used only as an induction agent or for induction and at the end of surgery were not as protective against postoperative nausea and vomiting.