RESUMEN
Postoperative nausea and vomiting [PONV] is a common distressing experience in patients following laparoscopic cholecystectomy. This study was aimed at comparing the better timing of Ondansetron administration in prevention of PONV in female patients underwent elective laparoscopic cholecystectomy done under general anesthesia. Fifty ASA physical status one and two female patients, aged 19 to 45 years, were enrolled in this prospective study to receive 4mg four Ondansetron preoperatively [Group A], or 4 mg four Ondansetron postoperatively [Group B], 25 patients each. A standardized general anesthetic technique was employed. Any episode of PONV was assessed at 8 hours postoperative period, every 2 hours, starting at time zone 0 [at post-anesthesia recovery unit], and ending at time zone 3 [hour 8 postoperatively]. Complete response is defined as no PONV during 8 hours postoperative period. Incomplete response is defined as developing of postoperative nausea only during 8 hours postoperative period. Failure of prevention is defined as developing of PONV during 8 hours postoperative period. Complete response occurred in 60 and 64% in Groups A and B respectively. Incomplete response occurred in 12 and 4% in Groups A and B respectively. Failure of prevention occurred in 28 and 32% in Groups A and B respectively. There is no significant clinical difference between preoperative or postoperative Ondansetron administration of the same dosage in both groups in prevention of postoperative nausea and vomiting.