Magnesium sulfate infusion prevents shivering during transurethral prostatectomy with spinal anesthesia: a randomized, double-blinded, controlled study

Study ObjectiveTo determine whether magnesium sulfate (MgSO4) infusion during surgery reduces shivering during spinal anesthesia.DesignDouble-blinded placebo-controlled, randomized trial.SettingOperation room of a university hospital.Patients60 patients, aged 40 to 70 years, scheduled for elective transurethral resection of the prostate (TURP) during spinal anesthesia.InterventionsSubarachnoid anesthesia consisting of hyperbaric bupivacaine three mL 0.5% was injected using a 25-G Quincke spinal needle. Patients received either saline (Group C, n = 30) or MgSO4 (Group Mg, n = 30). Group Mg received an intravenous (IV) bolus of MgSO4 80 mg/kg via syringe pump over a 30-minute period, followed by a two g/hr infusion during the intraoperative period. Group C received an equal volume of saline.MeasurementsMotor blockade was evaluated by Bromage motor scale. Sensory block level was assessed by pinprick test. Shivering was assessed after the completion of subarachnoid drug injection. Side effects were recorded.Main ResultsHypothermia was observed in all patients (100%) in Group Mg and in 24 patients (80%) in Group C (P = 0.024). The decrease in core temperature in Group Mg was significantly greater (P < 0.005). Shivering was observed in two patients (6.7%) in Group Mg and 20 patients (66.7%) in Group C (P = 0.0001).ConclusionsMgSO4 infusion in the perioperative period significantly reduced shivering during TURP with spinal anesthesia. MgSO4 infusion prevents shivering in patients receiving spinal anesthesia but increases the risk of hypothermia.