The effect of preoperative ondansetron on the incidence of postoperative nausea and vomiting in patients undergoing outpatient dentoalveolar surgery and general anesthesia

Purpose: The purpose of this investigation was to evaluate the efficacy of ondansetron in controlling postoperative nausea and vomiting (PONV) when us ed prophylactically in patients undergoing routine dentoalveolar surgery pe rformed under general anesthesia. Patient and Methods: This was a prospective, double-blind, randomized, plac ebo-controlled evaluation. Fifty adult ASA I or II patients, requiring rout ine dentoalveolar surgery performed under general anesthesia, without a pri or history of PONV, were randomly assigned to the experimental or control g roups. Ondansetron (2.0 mL = 4.0 mg) or normal saline (2.0 mL) were adminis tered intravenously before surgery. Age, gender, type of surgery, duration of surgery, anesthetic dosages, and PONV were evaluated. PONV was evaluated at time 0 (end of anesthesia) and at 30 and 60 minutes postoperatively. Na usea was evaluated using a visual analog scale (1, not nauseous; 5, about t o vomit). Vomiting was assessed as ayes or no response. At 20 to 28 hours p ostoperatively, PONV was evaluated via a telephone call as ayes or no respo nse, along with the number of episodes of nausea, vomiting, or both. Means and standard deviations were calculated for age, surgery, and anesthetics, and differences were assessed using an independent samples t-test. Differen ces for gender between the control and experimental groups were tested by a nonparametric chi-squared test. Differences between groups for nausea and vomiting were tested with a continuity correction chi-squared test. Differe nces were considered significant for a P <.05. Results: No significant differences (P<.05) were found between the PONV gro ups for gender, duration of procedure, or anesthetic dosages. Statistically significant differences were noted in age and the type of surgical procedu res performed. No statistically significant differences (P <.05) were noted between groups for nausea or vomiting. Conclusion: Based on the results of this study, PONV occurred in approximat ely 20% of patients (20% for nausea, 8% for vomiting). With the types of an esthetic agents and techniques used in this investigation, there were no si gnificant differences between ondansetron and placebo for prophylaxis again st PONV.