Comparison of Different Doses of Magnesium Sulfate in Prevention of Postoperative Shivering in Patients Undergoing Spinal Anesthesia

Shivering is an oscillating and involuntary activity of the muscles which increases the metabolic hyperthermia and is considered as a complication in neuraxial anesthesia. Shivering also increases the cardiopulmonary activity and oxygen consumption of the tissue. In this research project, different doses of magnesium sulfate in prevention of postoperative shivering in patients undergoing spinal anesthesia were investigated. In this double-blind randomized study, 99 patients with ASA classes 1 or 2 aged between 20 -80 years old who were under spinal anesthesia were selected. The patients were divided into 3 groups of 33 each with simple sampling method. During the operation and upon completion of surgery, the patients were controlled regarding the observable shivering for one hour by the researcher. The data were analyzed using SPSS software version 22. To ensure of the normal distribution of the data, the normality test of Kolmogorov Smirnov was used. The p-value was considered significant at < 0.05 level. The results showed that there was no significant difference between groups A and B regarding the frequency and intensity of occurrence of shivering (p = 0.374). Also, no significant difference was observed between group A and group C considering the frequency and intensity of occurrence of shivering (p = 0.631). Further, the frequency and intensity of occurrence of shivering between group B and group C was not significantly different (P=0.676). The results indicated that a low dose of magnesium sulfate 20% (30mg/kg) is effective in the prevention of postoperative shivering in patients undergoing spinal anesthesia to the same degree that higher doses are.