Comparative Efficacy of Nebulised Magnesium Sulphate and Lignocaine in Attenuating the Haemodynamic Response to Laryngoscopy and Intubation: A Randomised Controlled Study

Introduction: The haemodynamic alterations occurring during laryngoscopy and intubation presents a significant challenge for Anaesthesiologists. It causes a transient but marked rise in Heart Rate (HR) and blood pressure which is highly undesirable. Aim: To analyse the comparative role of nebulised magnesium sulphate and nebulised lignocaine in managing the pressor response triggered by laryngoscopy and endotracheal intubation under anaesthesia. Materials and Methods: The present randomised controlled was carried out in the Department of Anaesthesia and critical care at PGIMS, Rohtak,India from September 2023 to August 2024 .The study included 80 patients scheduled for elective surgery requiring general anaesthesia. Group M (n=40) received nebulisation with 5 mL of a solution containing 1 mL of 50% (500 mg) magnesium sulphate diluted in 4 mL of saline. Group L (n=40) was nebulised with 5 mL of a 2% lignocaine hydrochloride solution. Baseline haemodynamic parameters (V0 ) were recorded, and subsequent parameters were measured after nebulisation (V1 ), prior to laryngoscopy (V2 ), and at intervals following endotracheal intubation: one minute (V3 ), three minutes (V4 ), and 5 minutes (V5 ). Data was expressed as frequency(n) or mean with standard deviation and appropriate statistical tests were applied for intragroup and intergroup comparison. Results were considered significant if the p-value was less than 0.05. Results: The demographic and clinical profiles of patients (age, sex, Body Mass Index (BMI), American Society of Anaesthesiologists (ASA) and Mallampatti Grading (MPG) were statistically similar across both groups. Baseline measurements for haemodynamic parameters were comparable between the groups. Group M had higher SBP values just before laryngoscopy (p=0.004) while Group L demonstrated significantly higher mean Systolic Blood Pressure (SBP) values than Group M at multiple time points: 1st minute (p=0.003), 3rd minute (p=0.001), and 5th minute (p=0.001) after laryngoscopy and endotracheal intubation. Similarly, Group L exhibited higher mean Diastolic Blood Pressure (DBP) values at comparable time intervals (p=0.03, p=0.001, p=0.001 and p=0.003). A more pronounced rise in mean MAP was observed in Group L compared to Group M at 1st min (p=0.001) and 3rd min post-intubation (p=0.001). Group L also had higher HR values than Group M after nebulisation (p=0.03), before laryngoscopy (p=0.04), and at 1st minute (p=0.006) and 3rd minute (p=0.001) postintubation. Conclusion: The present study revealed that Group L exhibited significantly greater haemodynamic responses to laryngoscopy and endotracheal intubation than Group M at multiple time points in patient receiving general anaesthesia when compared with nebulised lignocaine. So The authors concluded that nebulised magnesium sulphate provided more persistent and effective attenuation for the pressor response.