We compared the prophylactic anti-emetic efficacy of ramosetron, a newly developed 5-HT3 antagonist, granisetron and ondansetron in patients at high-risk for postoperative nausea and vomiting after laparoscpic abdominal surgery.

This study was conducted to determine the efficacy of three 5-HT3 receptor antagonists in the prevention of PONV for laparoscopic surgery in patients receiving PCA IV.

Occurrences of nausea and vomiting, the severity of nausea (VAS), rescue antiemetic drug use, and amount of PCEA infusion and rescue pethidine were monitored after the end of surgery during four time periods: 0-2 h; 2-6 h; 6-24 h; and 24-48 h. Nausea was defined as the subjectively unpleasant sensation associated with awareness of the urge to vomit; vomiting included retching (defined as the laboured spastic, rhythmic contraction of the respiratory muscles without the expulsion of the gastric contents) and vomiting (defined as the forceful expulsion of gastric contents from the mouth) [11]. A complete response was defined as no PONV and no need for rescue anti-emetic drug. If two or more episodes of PONV occurred during the study period, a rescue anti-emetic (metoclopramide 10 mg) was given IV. The primary outcome was the incidence of nausea during the study period.

Inclusion Criteria:

• female gender, non-smoking and use of postoperative opioids undergoing laparocopic abdominal surgery

Exclusion criteria included laparoscopic abdominal surgey, allergy to one of the study drugs, opioid dependence, history of gastro-intestinal disease or Parkinson's disease, history of previous PONV and motion sickness, contra-indication for epidural block (previous back surgery, bleeding diathesis or neurological dysfunction), anti-emetic medication within 24 h before surgery, inability to use the PCEA device or comprehend the visual analogue scales (VAS) for pain and nausea assessment, or unwillingness to be enrolled in the study.

The sample size was determined based on the ability to detect a difference in the primary outcome variable, the incidence of nausea. With 30 patients in each group there was 80% power at an a of 0.05 to detect a 30% difference in the number of patients with nausea up to 24 h after surgery.