Intravenous Low Dose Ketamine for Post-Spinal Shivering Prophylaxis in Cesarean Section

Dear Editor, In the latest issue of Journal of Obstetric Anesthesia and Critical Care, a letter to editor has been published by authors Magoon et al.[1] highlighting few points of concern related to our published article entitled “Efficacy of Intravenous Low-Dose Ketamine for Prevention of Post-Spinal Anesthesia Shivering in Cesarean Section: A Double-Blind, Randomized Controlled Study.” To begin with, query was raised regarding the role of ASA grading in calculating the sample size for our study, we would like to clarify that we calculated the sample size on the basis of previous study by Rabi’u et al.[2] in which both ASA I (92.68%) and ASA II patients undergoing vesicovaginal fistula repair were included. In most of the non-obstetric studies on incidence of post spinal shivering both ASA I and II patients have been included and none of them reported any difference in incidence of shivering among Grade I and II.[3,4] Moreover, our patients were considered grade II because of pregnancy else they were free of any comorbidity. Hence, we do not find any reason to believe that variation in distribution of ASA grading between reference article[2] and our study would have had any impact on our study results. Further, the prospective observational study by Jeevan et al.[5] highlights that preoperative patient anxiety is an independent risk factor for post-spinal shivering in CS. The study was published in February 2024 and emphasizes a very important independent variable in considering for future trials. Our study was conducted prior to the above study (January 2022 to June 2022) and hence, we could not include the above observations. Also in our reference articles,[2–4] none of the study considered preoperative anxiety as a predictor of post spinal shivering and hence also it was missed in our study. Lastly, in our manuscript we have mentioned that nausea-vomiting were treated accordingly and was not elaborated due to word limit restrictions. We administered injection ondansetron 4 mg for treatment of intraoperative nausea and vomiting. Nausea and vomiting were observed in six patients in group S and five patients in group K (P = 0.745). Hence, administration of ondansetron, if affected the results, would have similar effect in both the groups as the incidence of nausea-vomiting was nearly equal. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.