Bolus administration versus continuous infusion of intravenous magnesium sulfate in prevention of shivering following cesarean section under spinal anesthesia: a single-blind randomized clinical trial study

Shivering following spinal anesthesia is caused by a disturbance in body temperature regulation that increases tissue oxygen consumption and cardiopulmonary activity. So far, various methods have been used to reduce and treat it. Magnesium sulfate is a common drug used in pregnant women that also has anti-shivering properties. This study was performed with aim to compare the effectiveness of intravenous magnesium sulfate with bolus infusion in the prevention of shivering after cesarean section.

This interventional clinical trial study was performed in 2017 on 300 pregnant women with term pregnancy, singleton pregnancy, and ASA class I clinical anesthesia in the United States who underwent elective cesarean section at Ayatollah Rouhani Hospital in Babol. The subjects were divided into 3 groups who immediately after spinal anesthesia received 30-minute infusion of magnesium sulfate, bolus injection of magnesium sulfate and normal saline, respectively. P< 0.05 was considered statistically significant.

Overall, shivering in 30, 60, 75 and 90 minutes were significantly lower in the magnesium sulfate infusion group than the bolus and control injection groups, (p=0.018) for the infusion group and (p=0.038) for the bolus group.

The prevalence of shivering significantly reduced by injection of magnesium sulfate. Compared to the method of administration of magnesium sulfate, administration of the drug by infusion within 30 minutes to reduce the incidence of shivering was significantly superior to the bolus administration of the drug and is recommended in patients with a previous history of intraoperative shivering.