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

Abstract

Study Objective To determine whether magnesium sulfate (MgSO 4) infusion during surgery reduces shivering during spinal anesthesia. Design Double-blinded placebo-controlled, randomized trial. Setting Operation room of a university hospital. Patients 60 patients, aged 40 to 70 years, scheduled for elective transurethral resection of the prostate (TURP) during spinal anesthesia. Interventions Subarachnoid 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 MgSO 4 (Group Mg, n = 30). Group Mg received an intravenous (IV) bolus of MgSO 4 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. Measurements Motor 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 Results Hypothermia 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). Conclusions MgSO 4 infusion in the perioperative period significantly reduced shivering during TURP with spinal anesthesia. MgSO 4 infusion prevents shivering in patients receiving spinal anesthesia but increases the risk of hypothermia.