Comparison of Two Different Doses of Prophylactic Intravenous Magnesium Sulphate for the Prevention of Shivering in Patients Undergoing Procedures Under Spinal Anesthesia

TL;DR

This study compares two doses of magnesium sulfate to prevent shivering during spinal anesthesia, finding both equally effective with no major side effects.

Contribution

The study demonstrates that a lower dose of magnesium sulfate is as effective as a higher dose in preventing shivering during spinal anesthesia.

Findings

Both 25 mg/kg and 50 mg/kg magnesium sulfate doses effectively prevented shivering in patients undergoing spinal anesthesia.

No significant differences in hemodynamic parameters or shivering incidence were observed between the two doses.

The lower dose (25 mg/kg) is recommended for routine use due to equivalent efficacy and safety.

Abstract

Introduction: Shivering is a common and distressing complication of spinal anesthesia associated with increased metabolic demand, hemodynamic fluctuations, and impaired monitoring. Magnesium sulfate (MgSO4), an N-methyl-D-aspartate (NMDA) receptor antagonist, has been investigated for its thermoregulatory benefits. This study compared two prophylactic intravenous (IV) doses of magnesium sulfate (25 mg/kg vs 50 mg/kg) for the prevention of shivering in patients undergoing surgeries under spinal anesthesia.

Materials and methods: A prospective observational study was conducted at a tertiary care center over one year among 88 adult patients undergoing elective procedures under spinal anesthesia. Participants were allocated into two groups: Group A (50 mg/kg IV magnesium sulfate bolus) and Group B (25 mg/kg IV magnesium sulfate bolus). Hemodynamic parameters, temperature, and shivering grades were monitored intraoperatively and postoperatively. Shivering was graded on a 0-4 scale. Data were analyzed using IBM SPSS Statistics version 20 (IBM Corp., Armonk, USA); p < 0.05 was considered statistically significant.

Results: Demographic characteristics were comparable between groups. No significant differences were observed in heart rate, systolic/diastolic blood pressure, peripheral oxygen saturation (SpO2), or temperature at any time point (p > 0.05). Overall, 93.2% of patients did not develop shivering: 42/44 (95.5%) in Group A and 40/44 (90.9%) in Group B, with no statistically significant difference in shivering incidence or grade (p > 0.97). Shivering onset was clinically delayed in Group A, though without statistical significance.

Conclusion: Both 25 mg/kg and 50 mg/kg prophylactic IV magnesium sulfate effectively prevented shivering after spinal anesthesia without significant hemodynamic instability. The lower dose (25 mg/kg) demonstrated equivalent efficacy and safety, supporting its use as a preferable dose for routine prophylaxis.