Abstract

ABSTRACT Background: Magnesium sulphate is used during anaesthesia for its antihypertensive/ antiarrhythmic properties and attenuating the response to endotrachial intubation and as an anticonvulsant for women with eclampsia. At the motor nerve terminal, MgSO4 inhibits acetylcholine release. Thus, it enhances the effect of neuromuscular blocking agents. Aims & Objectives: To determine the effect of magnesium sulphate pre-treatment on the onset, duration and recovery of non- depolarizing muscle relaxant and to quantify the haemodynamic effects of administration of MgSO4 on the arterial blood pressure.
Materials and Methods: One year old prospective, randomized, double blinded, controlled clinical study was conducted on randomly selected 45 patients of either sex, aged between 18-55 years, of grade I or II of American Society of Anaesthesiologists, undergoing elective surgery at a Medical College of eastern Uttar Pradesh. Patients were divided into three groups according to the doses of MgSO4 used for pre-treatment. Statistical evaluation was done by using student’s ‘t’ test for paired data.
Results: The Mean Arterial Blood Pressure response to laryngoscopy, tracheal intubation, was almost abolished in Group A (p<0.05) followed by Group B (p<0.05) and maximum pressure response occurred in Group C where MgSO4 was not used (p<0.05). The speed of onset of neuromuscular block was accelerated by pre-treatment with MgSO4 before non-depolarizing muscle relaxants. The mean onset time was 144.3 ± 12.08 seconds (p<0.001) in Group A, 192.66 ± 19.81 second (p<0.001) in Group B and 286.33 ± 34.20 seconds in Group C. The clinical duration was prolonged in MgSO4 group as compared with control group. Mean value was 52.4 ± 8.97 minutes (p<0.001), 44.86 ± 6.59 minutes (p<0.01), and 34.2±8.05 minutes respectively in Group A, B and C. Pre-treatment with MgSO4 before non-depolarizing muscle relaxant, accelerated speed of onset of neuromuscular block, necessary for intubation of trachea. MgSO , in the presence of non-depolarizing muscle relaxant, intensified and prolonged the neuromuscular blockade and 4 recovery. Conclusion: Monitoring of neuromuscular function and reduction in dose of vecuronium are required when using these two drugs in combination.