A comparative study on effect of low dose Ketamine versus Dexamethasone on intraoperative nausea and vomiting during cesarean section under spinal anesthesia

Intraoperative nausea and vomiting causes anxiety for the patient , gynecologist and anesthesiologist, and can increase the risk of visceral injury during surgery due to unintentional abdominal movements. The purpose of this study was to compare the efficacy of low-dose Ketamine and dexamethasone in controlling nausea and vomiting in patients undergoing cesarean section with spinal anesthesia.

A total of 135 patients underwent cesarean section by spinal anesthesia in the operating room. All patients were 18-40 years old and ASAI-II. Patients were randomly divided into three groups using blocking method as Ketamine intake group (including 45 subjects diluted 20mg ketamine diluted in normal saline 5ml total volume), dexamethasone group (including 45 patients diluted 8mg dexamethasone normal saline 5ml total volume) and control group (including 45 patients who received 5 ml of saline) and the incidence of nausea and vomiting were recorded during anesthesia, nausea by an anesthesia technician under the supervision of an anesthetic resident who was unaware of the patient`s group. Finally, all data were analyzed by statistical analysis (spss21) program.

In this study, 135 patients were divided into three groups of 45 (dexamethasone, ketamine and placebo). In this study, low dose of dexamethasone and ketamine before cesarean section did not significantly reduce the incidence of nausea and vomiting (P=0.02) and shivering (P=0.550). However, the intensity of nausea and vomiting was significantly decreased in the low dose ketamine group compared to the dexamethasone group. There was no significant change in the blood pressure and heart rate of the patients, and blood pressure falctuations were consistent at different times. Also, there was no significant difference in the incidence of hypotension (P=0.885), Ephedrine intake for hypertension (P=0.623), and the incidence of bradycardia (P=0.146) in the study groups. On the other hand, it was observed that the incidence of bradycardia was significantly lower in the ketamine recipients than in the dexamethasone group.

This study showed significant reduction in nausea and vomiting in the Ketamine group compared to Dexamethasone and no significant difference between two groups regarding the hypotension and shivering. It also showed that there was no statistically significant difference between groups receiving Dexamethasone and low dose Ketamine compared to control group during the operation period regarding the decrease in rate of nausea and vomiting, hypotension and shivering.