The Preventive Role of Low-Dose Intravenous Ketamine on Postoperative Shivering in Children: A Placebo Randomized Controlled Trial

BACKGROUND: Postoperative shivering is a major problem in children undergoing general anesthesia. OBJECTIVES: The aim of the present study was to investigate the role of low-dose intravenous ketamine for prevention of shivering after induction of general anesthesia in children who had undergone tonsillectomy. PATIENTS AND METHODS: This was a randomized, double-blinded, placebo-controlled trial including 80 children, of American society of anesthesiologists (ASA) physical status I or II, scheduled for tonsillectomy under general anesthesia who were randomly assigned to an intravenous ketamine (0.5 mg/kg, n = 40; group K) group or matched dose placebo (n = 40; group N) group. Surgical and demographic data, unexpected side effects, and the occurrence of shivering for each child were assessed by a blinded observer at the following time points: T0, in the recovery room; T10, at 10 minutes; T20, at 20 minutes; T30, and at 30 minutes. RESULTS: With regards to the demographic and surgical data, no significant differences between the two study groups were observed (P ≥ 0.05). Shivering intensity in children who had received ketamine was significantly lower than children who had not received ketamine, at T0, T10, T20, and T30 after arrival (P < 0.05). There were no significant differences in hallucination, nausea, vomiting, hemodynamic dysfunction, blurred vision, and seizure in the K group compared with the N group (P ≥ 0.05). CONCLUSIONS: Administration of intravenous ketamine at a dosage of 0.5 mg/kg immediately after anesthesia induction had a preventive effect on shivering intensity without hemodynamic alterations in children undergoing general anesthesia for tonsillectomy.