A Comparative Study on the Effect of Low-Dose Ketamine Versus Dexamethasone Versus Placebo on Intraoperative Nausea and Vomiting During Cesarean Section under Spinal Anesthesia

Background and Objectives: Intraoperative Nausea and Vomiting (IONV) can be distressing for patients, obstetricians, and anesthetists, and it may increase the risk of visceral injury during surgery due to involuntary uncontrolled abdominal movements. This study aimed to compare the antiemetic efficacy of low-dose Ketamine versus Dexamethasone in reducing the incidence of IONV during Cesarean Section (C/S) under spinal anesthesia.

Materials and Methods: The study included 135 full-term parturient women, aged between 18 and 40 years, who were candidates for cesarean section under spinal anesthesia in the operating room. The participants were randomly allocated to three groups using a randomized blocking method. Group I (n = 45) received 8 mg Dexamethasone with a total syringe volume of 5 ml, while group II (n = 45) received 20 mg Ketamine with a total syringe volume of 5 ml, and control group III (n = 45) received 5 ml normal saline. An anesthetist, blinded to the drug administered to the patient, recorded the number of nausea, retching, and vomiting episodes during the intraoperative period. Intraoperative hypotension and bradycardia were also recorded. The patients were asked to report any symptoms of nausea, vomiting, and shivering that occurred at intervals. Vomiting was managed by administering Metoclopramide 10 mg slowly intravenously. A standardized surgical technique was used in all cesarean sections. Statistical analysis was performed using the Statistical Package for the Social Sciences version 21 program (SPSS21).

Results: The study included 135 parturient women divided into three groups, with 45 members in each group (the first group received Dexamethasone, the second and third groups received Ketamine and Placebo, respectively). The average age was 30.35 ± 5.94 years in the Dexamethasone group, 29.97 ± 6.18 years in the Ketamine group, and 29.6 ± 6.03 years in the control group (P = 0.840). The study found a statistically insignificant increase in the rate of successful prevention of IONV (P = 0.062) and shivering (P = 0.550) using preoperative Ketamine and Dexamethasone. However, there was a statistically significant decrease in the rate of IONV in the Ketamine group compared to the Dexamethasone group (P=0.023). The studied groups were comparable in terms of mean arterial blood pressure (Table 7) and heart rate (Table 9), and there was no statistically significant difference between the groups during the study period. Additionally, there was no statistically significant difference in hypotensive episodes (P = 0.885), the total amount of Ephedrine administered (average amount in those who experienced hypotension and received Ephedrine) (P = 0.623), and bradycardia (P = 0.146) between the studied groups during the intraoperative period. However, there was a statistically significant decrease in the incidence of bradycardia in the Ketamine group compared to the Dexamethasone group(P=0.049).

Conclusion: This study demonstrates that there was no statistically significant difference between the groups receiving Dexamethasone and low-dose Ketamine compared to the control group regarding the decrease in the rate of nausea and vomiting(P=0.062), hypotension (P=0.885), and shivering (P=0.550) during the operation period.