Comparison between Nebulised and Intravenous Form of Magnesium Sulphate for Attenuation of Haemodynamic Response during Endotracheal Intubation in Hypertensive Patients undergoing General Anaesthesia: A Randomised Controlled Study

Introduction: Endotracheal intubation induces a significant sympathetic pressor response, particularly in hypertensive patients, leading to Heart Rate (HR) and Blood Pressure (BP) elevations. Magnesium Sulphate (MgSO4 ), administered Intravenous (i.v.) or via nebulisation, attenuates this response through calcium channel antagonism and catecholamine suppression. Aim: To evaluate the effects of nebulised and intravenous MgSO4 on attenuation of haemodynamic responses during endotracheal intubation in hypertensive patients undergoing general anaesthesia. Materials and Methods: This single-blinded randomised controlled study of 100 hypertensive adults undergoing elective surgery under general anaesthesia were randomised into two groups. Group A received i.v. MgSO4 (30 mg/kg) and group B received nebulised MgSO4 (40 mg/kg in 5 mL saline), 15 minutes before induction. Primary outcomes included Heart Rate (HR), Systolic Blood Pressure (SBP), Diastolic Blood Pressure (DBP), and Mean Arterial Pressure (MAP), measured at baseline, postintervention, postinduction, postintubation, and at 2, 5, and 10 minutes thereafter. The secondary outcome was time to first maintenance dose of muscle relaxant, assessed by Trainof-Four (TOF) monitoring. Data were analysed using unpaired Student’s t-test and Fisher’s exact test and p-values <0.05 were considered statistically significant. Results: Demographic data, including age, height, weight, Body Mass Index (BMI), gender, and baseline characteristics were comparable between groups. Haemodynamic parameters remained statistically similar at all time points. A transient, non significant elevation in HR was observed postintubation in the nebulisation group (87.88±11.17) compared with the i.v. group (84.28±12.53). DBP showed a trend toward elevation at 5 minutes postintubation (75.88±7.30) than the i.v. group (70.98±6.39), while baseline SBP was slightly higher in the i.v. group (127.72±8.31 vs. 124.42±7.39). The MAP remained comparable throughout. The nebulisation group demonstrated a longer interval before neuromuscular redosing (49.1±8.7 vs 44.8±8.6), suggesting a trend toward prolonged blockade. Conclusion: Both nebulised and i.v. MgSO4 effectively maintained haemodynamic stability during induction, intubation and postintubation in hypertensive patients. Nebulised MgSO4 , being non invasive, better tolerated, and potentially safer, offers an attractive alternative for smoother haemodynamic control, making it a promising adjunct in the anaesthetic management of hypertensive patients.