Efficiency of Magnesium Sulphate as a Sole Muscle Relaxant for General Anaesthesia with Vecuronium Bromide for Tracheal Intubation: A Prospective Interventional Study

Introduction: Neuromuscular blocking drugs are the standard for tracheal intubation; however, misuse can cause allergies, intraoperative awareness and prolonged blockage. As a result, intubation without these drugs is being explored, with magnesium sulphate as an alternative. Aim: To assess the effect of magnesium sulphate on intubating conditions after the induction of anaesthesia without a neuromuscular blocking drug. Materials and Methods: This was a prospective interventional study at the Department of Anaesthesiology, Armed Forces Medical College and Hospital in Pune, Maharashtra, India from June 2012 to June 2014 involving 200 patients, divided into two groups of 100 each: Group M and Group V. The study included both male and female patients with an American Society of Anaesthesiologists (ASA) physical status of I or II, Mallampati Class I or II, aged between 18 and 50 years. All patients were scheduled for elective surgery under General Anaesthesia (GA) with endotracheal intubation. In Group M, patients received a 40 mg/kg magnesium infusion over five minutes, followed by a 2.5 mg/kg injection of propofol intravenously. Laryngoscopy was performed after two minutes and then a 0.5 mg/kg intravenous injection of atracurium was administered one minute after intubation. In Group V, patients were given 100 mL Normal Saline (NS) over five minutes, followed by induction with 2.5 mg/kg propofol intravenously and a 0.1 mg/kg intravenous injection of vecuronium, with laryngoscopy performed after three minutes. Intubation conditions were evaluated using the Copenhagen Consensus Conference and Mean Arterial Pressure (MAP) and pulse rates were also recorded during the study. Demographic data were compared using t-tests and Chi-square tests. Results: The mean ages for these groups were 39.78±8.42 years for Group V and 38.91±7.63 years for Group M. In terms of clinically acceptable intubation conditions, Group V had 100 patients (100%), while Group M had 78 patients (78%) (p>0.05). In the Copenhagen scoring system for intubating conditions, Group V (94 patients) scored significantly better than Group M (21 patients). Pulse rate and MAP were comparable until laryngoscopy, but were significantly higher in Group M after T5 (p<0.05). The duration of intubation was shorter in Group V, averaging 18.73±2.26 seconds, compared to 22.71±4.70 seconds in Group M (p<0.01). Conclusion: The administration of magnesium sulphate before the induction of anaesthesia significantly lowers intubating conditions without requiring neuromuscular blocking agents. Magnesium sulphate serves as an alternative to a non depolarising muscle relaxant to avoid the side-effects caused by muscle relaxants, but it is inferior to a non depolarising muscle relaxant.