Comparison of efficacy of intranasal nebulized and intravenous routes of dexmedetomidine for blunting hemodynamic response to laryngoscopy and tracheal intubation in elective intracranial surgeries. A prospective randomized single-blind clinical study.

Laryngoscopy and tracheal intubation are common procedures that often elicit significant hemodynamic responses, including hypertension, tachycardia, arrhythmias, and an increase in intracranial pressure. This observation is supported by the finding that hemodynamic responses to tracheal intubation are associated with an increase in plasma catecholamine concentrations. Although the mechanisms underlying these responses are not completely understood, they have been attributed to a reflex sympathetic discharge caused by stimulation of the upper respiratory tract, mainly the supraglottic region, by the laryngoscope blade, along with the tracheal tube placement and cuff inflation.These effects must be reduced as much as possible, especially in high-risk patients, such as those with coronary artery disease, asthma, elevated intracranial pressure, or a cerebral aneurysm. To avoid such changes in intracranial pressure and hemodynamic parameters, various drugs are used for the attenuation of the laryngoscopic response; one such drug is Dexmedetomidine. It has also been found to be effective in attenuating the increase in ICP associated with laparoscopic surgeries. Dexmedetomidine, a highly selective alpha-2 receptor agonist, has sedative, amnestic, and analgesic-sparing effects without causing respiratory depression. It also possesses a sympatholytic effect, which can reduce the stress response to laryngoscopy and intubation. Intravenous administration is the most common and extensively studied route for Dexmedetomidine. However, intravenous administration may cause bradycardia and hypotension. Therefore, it is essential to investigate alternative routes of administration. Nebulized dexmedetomidine may be an alternative to intravenous administration because drug deposition following nebulization occurs over the nasal, buccal, as well as respiratory mucosa, resulting in better systemic absorption. Dexmedetomidine is rather rapidly and efficiently absorbed after intranasal administration; therefore, it has been used as a premedication for intravenous deep sedation in pediatric dental treatment. Intranasal administration is more convenient because it is innocuous, odorless, and requires no intravenous infusion. Furthermore, intranasal administration of a substance allows it to cross the blood-brain barrier and reach the central nervous system directly. Because of the increased vascularity of the nasal mucosa, medications can gain rapid access to the venous blood of the systemic circulation, thereby bypassing first-pass metabolism in the liver. Randomized controlled trials comparing the efficacy and side effects of all three administration routes—intranasal, nebulized, and intravenous dexmedetomidine—in attenuating the hemodynamic response to laryngoscopy and tracheal intubation specifically during elective intracranial surgeries are currently unavailable. This study was therefore designed to address this critical gap, aiming to optimize anesthetic techniques, improve perioperative outcomes, and enhance patient safety during airway manipulation in neurosurgical contexts.