General anaesthesia is necessary for many surgical operations, including otorhinolaryngological (ENT) surgeries, which require direct laryngoscopy and endotracheal intubation. Mechanical stimulation of the larynx, pharynx, epiglottis, and trachea is associated with high sympathetic activity, which is a side effect of these operations [1]. Temporary tachycardia, hypertension, and elevated myocardial oxygen demand are typical symptoms of this sympathoadrenal reaction. Patients with cardiovascular disease, hypertension, cerebrovascular diseases, and other concomitant conditions are at increased risk for serious consequences, despite the fact that healthy persons typically tolerate these haemodynamic alterations well [2, 3].

Laryngoscopy and intubation trigger the sympathetic nervous system to release catecholamines, which in turn activate the cardiovascular response. A number of variables, such as the length and intensity of the laryngoscopy, the level of anaesthesia, the structure of the airway, and patient-specific traits, determine the extent to which this reaction occurs. For those who are vulnerable, sudden spikes in blood pressure and heart rate might cause cardiac ischaemia, arrhythmias, heart failure, or a rise in intracranial pressure. Consequently, one of the primary goals of anaesthetics is to reduce the haemodynamic reaction [4-6].

To lessen the pressor reaction that comes with airway manipulation, researchers have looked into a number of pharmaceutical drugs. Some examples of these medications are alpha-2 adrenergic agonists, beta-blockers, opioids, vasodilators, calcium channel blockers, and local anaesthetics. An optimal medication that successfully reduces the haemodynamic response without generating major side effects is still being searched after, even though there are numerous therapeutic choices available [7, 8].

When administering laryngoscopy or intubation, lidocaine, a common local anaesthetic, dampens sensory stimulation and inhibits airway reflexes. Topical anaesthesia of the upper airway mucosa is achieved by nebulised lidocaine, which reduces reflex sympathetic activation. As a premedication for several airway management treatments, it has proven to be effective, is easy to administer, and does not cause any harm [9].

With its sedative, analgesic, anxiolytic, and sympatholytic effects, dexmedetomidine is a very selective α2-adrenergic receptor agonist. It lowers the reactions of the heart and blood pressure to stressful stimuli by lowering central sympathetic outflow and attenuating catecholamine release. As a non-invasive method of delivery that offers good systemic absorption with a favourable safety profile, nebulised dexmedetomidine has lately attracted attention. Dexmedetomidine has multiple potential uses, including lowering the haemodynamic response to laryngoscopy, which could lead to less anaesthesia needed and better comfort during the operation [10, 11].

When it comes to managing cardiovascular responses during airway manipulation, multiple studies have shown that lidocaine and dexmedetomidine are both effective. Nevertheless, there is a lack of information about the effectiveness of nebulised lidocaine compared to nebulised dexmedetomidine in patients having ear, nose, and throat procedures. It is clinically vital to identify an effective and safe premedication technique for this surgical population because airway instrumentation is frequently seen [12, 13].

The purpose of this study was to evaluate the effectiveness of two nebulised medications in reducing the haemodynamic response to direct laryngoscopy and endotracheal intubation during endotracheal intubation and general anaesthesia in patients having ear, nose, and throat procedures. This study set out to compare the two methods of reducing the stress reaction to airway manipulation by looking at changes in HR, BP, and perioperative haemodynamic stability.

This prospective comparative study was conducted in the Department of Anesthesiology, NRI Medical College & General Hospital, Guntur, Andhra Pradesh, between July 2023 and June 2024. A total of 40 patients scheduled for elective ENT surgeries under general anesthesia requiring direct laryngoscopy and endotracheal intubation were included in the study after obtaining written informed consent. All patients underwent detailed pre-anesthetic evaluation, including medical history, physical examination, airway assessment, and routine laboratory investigations. The study medication was administered via nebulization approximately 30 minutes before induction of anesthesia. Methods: Prior to nebulisation, baseline heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), and oxygen saturation (SpO₂) were measured. Throughout the intraoperative phase, standard monitoring techniques such as capnography, pulse oximetry, non-invasive blood pressure monitoring, and electrocardiography were employed. Attenuation of the haemodynamic response to laryngoscopy and intubation was the main outcome measure. Perioperative side effects such hypotension, bradycardia, excessive sedation, oxygen desaturation, nausea, vomiting, and the need for additional anaesthetic agents were among the secondary outcome measures. Inclusion Criteria: • Patients aged 18–60 years. • Patients of either gender undergoing elective ENT surgeries under general anesthesia. • American Society of Anesthesiologists (ASA) physical status I and II. • Patients requiring endotracheal intubation following direct laryngoscopy. • Patients willing to participate and provide written informed consent. Exclusion Criteria: • Patients with anticipated difficult airway. • ASA physical status III or IV. • Severe hepatic, renal, or respiratory dysfunction. • Pregnant or lactating women. • Patients with active upper respiratory tract infection. • Patients unwilling to participate in the study. Statistical Analysis: The data that had been entered into Microsoft Excel was analysed using SPSS version 26.0. Frequencies and percentages were used to represent categorical data, whilst mean ± standard deviation (SD) was used to express continuous variables. The two groups' continuous variables were compared using the Student's t-test. Haemodynamic parameter changes over time were assessed using repeated measures analysis of variance (ANOVA). Adverse events and categorical factors were compared using the Chi-square test or Fisher's exact test. Statistical significance was defined as a p-value of less than 0.05.significant.

A total of 40 patients undergoing elective ENT surgeries under general anesthesia were enrolled in the study. Patients were randomly divided into Group L (Nebulized Lidocaine, n=20) and Group D (Nebulized Dexmedetomidine, n=20). Both groups were comparable regarding demographic characteristics and baseline hemodynamic parameters.

Table 1: Demographic Characteristics of Study Participants

Table 1 demonstrates that both groups were comparable with respect to age, gender distribution, body weight, and ASA physical status.

Table 2: Comparison of Heart Rate (beats/min) at Different Time Intervals

Table 2 shows that patients receiving nebulized dexmedetomidine exhibited significantly lower heart rate responses following laryngoscopy and intubation compared to those receiving nebulized lidocaine.

Table 3: Comparison of Systolic Blood Pressure (mmHg)

Table 3 demonstrates significantly better control of systolic blood pressure in the dexmedetomidine group following airway manipulation.

Table 4: Comparison of Mean Arterial Pressure (MAP) (mmHg)

Table 4 indicates that nebulized dexmedetomidine maintained significantly lower MAP values following intubation compared with nebulized lidocaine.

Table 5: Adverse Events

Table 5 shows that adverse effects were infrequent and comparable between the two groups. All events were mild and managed conservatively.

Significant sympathetic stimulation is linked to direct laryngoscopy and endotracheal intubation, which causes brief elevations in blood pressure and heart rate. Even though these reactions are typically transient, people with cardiovascular and cerebrovascular conditions may be at significant risk. As a result, numerous pharmacological treatments have been studied to lessen these haemodynamic alterations. The effectiveness of preoperative nebulised lidocaine and nebulised dexmedetomidine in lowering the cardiovascular reaction to direct laryngoscopy and intubation in patients undergoing ENT procedures under general anaesthesia was compared in this study [14, 15].

The current study's results showed that nebulised lidocaine and nebulised dexmedetomidine both worked well to reduce the haemodynamic reaction brought on by airway manipulation. However, at all assessed intervals after intubation, patients receiving nebulised dexmedetomidine showed noticeably improved control of heart rate, systolic blood pressure, and mean arterial pressure. These results imply that topical lidocaine-induced airway anaesthesia is not as effective in suppressing the sympathoadrenal response as dexmedetomidine [16-18].

Additionally, a greater percentage of patients in the dexmedetomidine group maintained overall haemodynamic stability, according to the current study. After intubation, fewer patients had clinically significant

elevations in blood pressure and heart rate. This discovery is especially significant for patients undergoing ENT surgery, as seamless anaesthesia induction and maintenance promote ideal surgical circumstances and lower perioperative risk [19-21].

Nebulisation is a practical and non-invasive method of administering drugs that avoids the discomfort of intravenous administration while offering efficient mucosal absorption. Nebulised dexmedetomidine has shown promising results, indicating that it could be a useful alternative premedication method for reducing the stress reaction to airway instrumentation [22, 23].

There are some limitations to the current investigation. The investigation was carried out at a single tertiary care facility, and the sample size was very modest. Anaesthetic usage and long-term surgical results were not thoroughly assessed. More information about the ideal dosage and wider applicability of nebulised dexmedetomidine in other surgical groups may come from larger multicenter studies [23, 24].

The current investigation showed that the haemodynamic response to direct laryngoscopy and endotracheal intubation could be effectively reduced by both nebulised lidocaine and nebulised dexmedetomidine. Nebulised dexmedetomidine, on the other hand, considerably improved perioperative haemodynamic stability by attenuating increases in heart rate, systolic blood pressure, and mean arterial pressure. There were few side effects and no major complications from the intervention, which was well tolerated. Therefore, in patients undergoing ENT procedures under general anaesthesia, preoperative nebulised dexmedetomidine may be regarded as a safe and effective substitute for nebulised lidocaine in reducing the sympathoadrenal response related to airway manipulation.

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