Optimum dose of ketamine for prevention of postanesthetic shivering; a randomized double-blind placebo-controlled clinical trial.Acta Anaesthesiol Belg. 2011; 62(1):33-6.AA
Our objective was to investigate the efficacy and the optimum dosage of ketamine for post anesthetic shivering prevention. One-hundred and twenty patients (ASA I-II) scheduled for elective orthopedic surgery were randomly allocated to receive ketamine in 3 groups ; groups A (0.125 mg/Kg), groups B (0.25 mg/Kg) and C (0.5 mg/Kg) along with those receiving 0.9% normal saline as the placebo group. Tympanic temperature was measured immediately after induction of anesthesia, 30 min after induction, before administration of the study drug and by the end of the surgery. The four groups did not differ significantly in their hemodynamic parameters and tympanic temperature. The frequency of shivering was significantly less in groups B (0.25 mg/Kg) and C (0.5 mg/Kg) than in groups A (0.125 mg/Kg) and D (placebo). In addition recovery, extubation time and hallucination was observed to be less in group B compared to group A. Prophylactic 0.25 and 0.5 mg/kg ketamine was found to be effective in preventing postanesthetic shivering with a better response observed with 0.25 mg/kg dosage.