The Effectiveness of Low-Dose Ketamine versus Dexamethasone as Prophylactic Interventions for Post-Spinal Anesthesia Shivering in Patients Undergoing Elective Surgery : A Prospective, Randomized, Placebo-Controlled Trial

Abstract

Objective : To evaluate the effectiveness of low-dose ketamine (0.25 mg/kg) compared with dexamethasone (4 mg) for the prevention of post-spinal anesthesia shivering.

Methods : This randomized, placebo-controlled trial was conducted in 135 patients classified as ASA physical status I–II, aged 18–65 years, undergoing elective surgery under spinal anesthesia. Patients were randomly allocated into three groups: the control group receiving normal saline solution as placebo, the K group receiving ketamine 0.25 mg/kg, and the D group receiving dexamethasone 4 mg, all administered intravenously. The incidence and severity of shivering were assessed, along with secondary outcomes including hemodynamic responses, level of sedation, and postoperative nausea and vomiting during the intraoperative period and in the post-anesthesia care unit (PACU).

Result : The incidence of shivering was 20% in the K group and 24.44% in the D group, both significantly lower than in the control group. Ketamine and dexamethasone reduced the risk of shivering by 69%, with comparable prophylactic effectiveness between the two agents (RR = 1.06, 95% CI 0.47–2.43, P = 0.884). Mild sedation was observed in the K group. There were no significant differences among the three groups regarding hemodynamic changes or the incidence of postoperative nausea and vomiting.

Conclusion : Low-dose ketamine (0.25 mg/kg) and dexamethasone (4 mg) demonstrate comparable effectiveness in preventing post-spinal anesthesia shivering, significantly reducing its incidence compared with placebo, with no serious adverse effects.