Intraoral Nitroglycerine Spray versus Intraoral Lignocaine Spray to Suppress the Haemodynamic Response to Endotracheal Intubation in Patients Undergoing Elective Surgeries under General Anaesthesia: A Randomised Clinical Trial

Introduction: General Anaesthesia (GA) is the keystone in the management of complicated and specialised surgeries, enabling the safe and effective performance of procedures that would otherwise be intolerable or unsuccessful for patients. Airway manipulation during GA, especially laryngoscopy and endotracheal intubation, leads to acute haemodynamic changes that may pose risks in susceptible individuals. Aim: To compare the effect of intraoral Nitroglycerine (NTG) spray versus the intraoral lignocaine spray before laryngoscopy and endotracheal intubation. Materials and Methods: A single-centre, double-blinded, randomised clinical trial was conducted in the Department of Anaesthesia, Sree Balaji Medical College/BIHER, Chennai, Tamil Nadu, India over 18 months from January 2021 to June 2023. Total of 60, American Society of Anaesthesiologists (ASA) grade I and II patients undergoing elective surgery under GA were randomised into two groups: group A received an intraoral spray of nitroglycerin 400 mcg, and group B received an intraoral spray of 10% lignocaine 20 mg. Haemodynamic parameters were recorded at multiple time points during induction, intubation and at various time intervals post-intubation. Data were analysed using Statistical Package for Social Sciences (SPSS) software version 23.0 via independent two-tailed t-test and One-way Analysis of Variance (ANOVA) for parametric data and via Chi-square test for non parametric data. A p-value < 0.05 was considered statistically significant. Results: Among total of 60 participants, 33 (55%) belonged to the age group 20-29 years, and 37 (61.67%) were males. The data showed significant attenuation of Blood Pressure (BP) and Heart Rate (HR) changes during laryngoscopy, intubation and post-intubation in both groups (Mean HR: 85.42 vs 77.22 bpm) {Mean Systolic Blood Pressure (SBP): 124.1 vs 128.53 mmHg} {(Mean Diastolic Blood Pressure (DBP): 78.16 vs 81.27 mmHg} and {Mean Arterial Pressure (MAP): 93.47 vs 97.04 mmHg}, with comparative analysis suggesting that NTG exhibited superior control over blood pressure and the results were statistically significant (p-value <0.05). Conclusion: Both intraoral lignocaine and nitroglycerin sprays effectively attenuate intubation-induced haemodynamic responses, with nitroglycerin providing superior blood pressure control during laryngoscopy and intubation. Nitroglycerin spray may be preferred for patients requiring enhanced haemodynamic stability, especially those with hypertension or coronary artery disease, pending further large-scale studies.