Efficacy of combining midazolam vs dexamethasone with ondansetron for prevention of Postoperative Nausea and Vomiting among women undergoing emetogenic surgeries - A randomised control trial

Postoperative nausea and vomiting (PONV) occurs in 20–30% of surgeries in the general population and in up to 70% of high risk patients within the first 24 hours after surgery.

Routinely, the simplified risk score by Apfel et al is used to predict the risk of PONV in adult patients. The strongest predictive factors for PONV are female sex, non-smoking status, history of PONV or motion sickness and postoperative use of opioids.Surgical procedures such as cholecystectomy, gynaecological surgery, breast surgeries, middle ear surgeries and laparoscopic approach are associated with a higher incidence of PONV when compared with general surgery as a reference group and such surgeries are now considered as independent risk factor for PONV.In this study we are considering 2 risk factors – Female gender and Surgical risk factor ie. type of surgery.

Combination therapy for PONV prophylaxis is preferable to using a single drug alone6,4. Apfel et al. demonstrated that the effects of antiemetics acting on different receptors are additive. Therefore adults at moderate and high risk for PONV should receive combination therapy with drugs from different classes.

In this study we aim to compare the efficacy of midazolam when combined with ondansetron, against the most widely used combination of dexamethasone and ondansetron.