This placebo-controlled, randomized, double-blind trial was designed to evaluate the efficacy of three prophylactic antiemetic regimens on postoperative nausea and vomiting (PONV) during patient-controlled analgesia (PCA) with morphine. We studied 286 elective surgical patients for 36 h postoperatively. Group 1 was saline control. In Groups 2 and 3, metoclopramide or droperidol was administered as an intravenous (IV) bolus and then added to morphine in the PCA device. In Group 4, tropisetron, a long-acting investigational 5-hydroxytryptamine subtype 3 (5-HT3) antagonist was given as a single IV dose. We assessed the frequency and severity of PONV, as well as the need for rescue, frequency of side effects, and overall patient satisfaction. Severity of PONV was measured with a symptom-severity score (STS) which was based on both intensity and duration. The average total doses of antiemetics were metoclopramide 53.8 ± 2.2 mg, droperidol 5.99 ± 0.3 mg, and tropisetron 6.1 ± 0.2 mg. Control patients had a 54% incidence of PONV. Droperidol reduced both the incidence (P < 0.001) and severity (P < 0.01) of PONV for the entire 36 h. Tropisetron reduced incidence and severity (P < 0.05), but the effect of the single bolus dose lasted only 18 h. Metoclopramide had a marginally significant effect under these conditions. Only droperidol decreased the need for rescue medication (P < 0.01), although rescue with tropisetron was highly effective. Side effects and patient satisfaction were comparable among the groups, but patients receiving droperidol were sleepier (P < 0.05) than control patients and recalled somewhat more anxiety (P = 0.03). When used together with morphine PCA, droperidol is a highly effective antiemetic for 36 h. Tropisetron is also effective, but more than one dose is required.
Address correspondence and reprint requests to Markus A. Kaufmann, MD, Department of Anesthesia, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114.
© 1994 International Anesthesia Research Society