Impact of timing of midazolam administration on incidence of postoperative nausea and vomiting in patients undergoing laparoscopic gynecological surgery: A randomized, double-blinded, controlled study

Background
A frequently used anxiolytic, midazolam, has recently been recognized for its antiemetic activity during the perioperative period. This study sought to investigate the best time to provide midazolam in order to decrease the frequency of postoperative nausea and vomiting (PONV) without increasing the risk of sedation.
Methods
A total of 120 women aged 20–60 years who underwent laparoscopic gynecological surgeries were distributed randomly to three groups: group M1 (n = 40) received intravenous 2 mg midazolam 15 min prior anesthesia induction, group M2 (n = 40) received intravenous 2 mg midazolam approximately 30 min prior surgery conclusion, and group C (n = 40) received intravenous normal saline. The frequency of PONV and the rescue antiemetics needs were measured as the primary outcomes during the first 24 hr postoperatively. The secondary outcomes were the severity of nausea, timing of initial emetic attack, time of PACU discharge, patient sedation, and pain scores.
Results
The frequencies of vomiting and rescue antiemetic use were lower in midazolam groups than controls during early (0–2) and late (0–24) time periods after surgery (P < 0.05), with insignificant difference between M1 and M2 groups. The timing of the first emetic episode was significantly longer in M2 than in C groups (458.3 vs 128.8 minutes) (P < 0.01). Insignificant differences with regard to frequency and severity of nausea, time of PACU discharge, and sedation score were detected among the three groups.
Conclusion
Midazolam was effective in reducing PONV, whether it was given prior induction of anesthesia or prior end of surgery, without influencing recovery duration or sedation level of the patients.