The Effect of Intravenous Magnesium Sulphate Treatment on the Spinal Anaesthesia Produced by Bupivacaine in Pre-eclamptic Patients

Objective: In our study, the effect of intravenous magnesium sulphate in normal and pre-eclamptic patients on spinal anaesthesia produced by bupivacaine was investigated. Methods: Sixty-four pregnant (32 normal and 32 pre-eclamptic) were accepted in this study. Pregnants were divided into four groups as patients given intravenous magnesium sulphate and as control. Spinal anaesthesia was induced with 12.5 mg 0.5% hyperbaric bupivacaine. Intraoperative and postoperative haemodynamic variables, sensorial block periods, onset times of sensorial and motor block, maximum sensorial block levels, the time to reach maximum block level, Bromage scores, consumptions of intraoperative analgesic and ephedrine, the quality of anaesthesia, the duration of spinal anaesthesia and magnesium levels in blood and cerebrospinal fluid were measured and recorded. Results: The level of magnesium in blood and cerebrospinal fluid was significantly higher in the group given magnesium in pre-eclamptic patients (p<0.01). Onset of sensory block times were significantly longer in intravenous magnesium group than in groups 1, 2 and 3 (p<0.05). Onset of motor block times were significantly longer and the duration of anaesthesia was shorter in groups given magnesium (p<0.05). Although the quality of anaesthesia was similar, supplemental analgesic consumption was significantly higher in pre-eclamptic pregnants given magnesium sulphate than in pre-eclamptic pregnants who were not given magnesium sulphate (p<0.05). Conclusion: Intravenous magnesium sulphate treatment during the spinal anaesthesia produced by bupivacaine extended the onset of sensory and motor block times, shortened the duration of spinal anaesthesia and therefore led to early analgesic requirement.