Introduction: Impaired thermoregulation after spinal anesthesia ultimate shivering. This shivering increases tissue oxygen consumption, minute ventilation and cardiac work. Select an appropriate medication to reduce shivering with minimal maternal and neonatal side effects in cesarean section is important. The present study was done to investigate the effects of low-dose infusion of magnesium sulfate to reduce shivering during spinal anesthesia in cesarean section.
Methods: This interventional prospective clinical trial was conducted on 80 pregnant women with ASA class 1 who underwent cesarean section with spinal anesthesia in 2012. Patients were divided into 2 groups. Case group received 30 mg/kg magnesium sulfate in 50 cc normal saline and control group received 50cc normal saline over 30 minutes as placebo. Vital signs, shivering and tympanic temperature were measured before and after spinal anesthesia every 15 minutes for 90 minutes. Data were analyzed using SPSS software (version 11.5) and t-test, non-parametric Mann-Whitney, Chi-square and Mann-Whitney tests. P value less than 0.05 was considered significant.
Results: Age, weight, vital signs before surgery (MAP, HR, SpO₂) and duration of surgery were similar between two groups. Incidence of hypotension, bradycardia, nausea, vomiting and use of drugs for treatment of complication were not different between two groups. Shivering rates at minutes 15, 30 and 45 was not significant between two groups but shivering rates at minutes 60, 75 and 90 were higher in control group than magnesium group and the differences were statistically significant (p=0.004, p=0.049, p=0.022, respectively). Two groups were significantly different in terms of body temperature after spinal anesthesia (p<0.001).
A significant difference was proved between groups in body temperature during surgery.
Conclusion: The use of intravenous magnesium during spinal anesthesia can maintain body temperature higher and reduce shivering during or after surgery without increasing in adverse effect.