Evaluating the Prophylactic Effect of Magnesium Sulfate and Combination of Midazolam and Ketamine for Prevention of Shivering during Regional Anaesthesia

Shivering after spinal anaesthesia is an unpleasant feeling that causes discomfort for patient and interferes with monitoring systems. The goal of this study was comparing the prophylactic use of magnesium sulfate infusion and midazolam plus ketamine for prevention of shivering in spinal anaesthesia.
In this double-blinded study, 90 patients with status 1 or 2 of American Society of Anesthesiologists (ASA) classification, undergoing orthopedic surgery under spinal anaesthesia (with 15 mg of bupivacaine), were included. All the patients were randomly allocated to one of three equal groups: 1) Group MK received 0.25 mg ketamine 37.5 μg/kg midazolam. 2) Group Mg received intravenous (IV) bolus dose of 80 mg/kg MgSO4 over 30 minute period followed by infusion of 2 g/hour. Group S received saline without any prophylactic drug. Shivering score was recorded at 10-minutes intervals. Peripheral and core body temperature were recorded at 10-minutes intervals.
Findings: Shivering frequency and intensity were significantly higher in group S compared to groups MK (P = 0.001) and Mg (P 0.999).
There was no difference between the use of ketamine plus midazolam and magnesium sulfate in preventing shivering during spinal anaesthesia.