ONDANSETRON VS PLACEBO

Abstract

S344 Nausea has been reported to occur in 65% of patients after infratentorial craniotomy [1]. Antiemetic sedation makes treatment of this complication difficult. We selected ondansetron, an antiemetic with minimal sedative side-effects, for evaluation as prophylaxis against acute nausea and yomiting (PONV) after infratentorial craniotomy. In addition, patients were followed for prolonged intervals to define the natural history of this adverse event. METHODS: With IRB approval 32 adults requiring infratentorial craniotomy were administered midazolam, thiopental, fentanyl, muscle relaxant and isoflurane/N (2) O/O2 anesthesia. Patients were randomly assigned to ondansetron 8mg iv or placebo given at skin closure. Incidence of nausea, emesis, and rescue antiemetic use were recorded at 0, 1/2, 1, 4, 8, 12, 24 and 48 hr. The study was performed in a double-blind fashion. Data were analyzed by chi-square, Mann-Whitney U; p<0.05(*) was considered significant. RESULTS: Groups were similar in age, weight, duration of procedure and postoperative codeine dose. A greater % of females was present in the ondansetron group. Within 1 hr post op 65% in ondansetron group and 80% in placebo had experienced nausea. By 4 hrs, 41% of ondansetron group received rescue antiemetic vs 60% of placebo. Approximately 50% of patients in both groups were still nauseated and 30% vomiting at 48 hours post op. 85% had experienced nausea at some time over 48h. At both 24 hr and 48 hrs, the incidence of PONV was similar for males and females. (Table 1 and Figure 1)Table 1Figure 1DISCUSSION: This analysis shows: 1. nausea was significantly less in the ondansetron group within the expected duration of action of a single dose of the drug (i.e., 1 hr post-anesthesia) although gender distribution may account in part for this observation; 2. protracted nausea occurs commonly after infratentorial craniotomy; 3. gender does not influence PONV occurring late after infratentorial craniotomy.