Effects of Intranasal and Intravenous Dexmedetomidine on Hemodynamic Responses to Tracheal Intubation and Skull Pin Holder Fixation: A Double-Blinded, Randomized Controlled Trial.

Background Laryngoscopy and tracheal intubation (L&I) and the fixation of skull-pin head-holders are associated with various sympathetic stimuli leading to hemodynamic changes. These changes may lead to myocardial ischemia, brain edema, an increase in intracranial pressure, or intracranial hemorrhage. Many drugs have been used in different combinations to attenuate the sympathetic responses to L&I and skull-pin insertion. The aim of this study was to compare the efficacy of intranasal (IN) dexmedetomidine with intravenous (IV) dexmedetomidine (IV) in attenuating the hemodynamic responses to L&I and the fixation of skull-pin holders in patients undergoing craniotomy. Material and methods This randomized-controlled, double-blind study was conducted on 120 patients with American Society of Anesthesiology (ASA) physical status I and II, aged 18 to 70 years, undergoing elective craniotomy and requiring skull-pin insertion. Patients were randomly divided into two equal groups. Group DIV: IV dexmedetomidine 0.50 µg/kg given over 40 minutes before induction. Group DIN: Undiluted dexmedetomidine 1µg/kg given as IN drops 40 minutes before induction. Heart rate (HR), mean arterial pressure (MAP), systolic (SBP), and diastolic blood pressure (DBP) were noted at baseline and at predetermined intervals after L&I and skull-pin fixation. Sedation scores were assessed preoperatively at baseline and at 10, 20, 30, and 40 minutes after study drug administration. Data were analyzed using IBM SPSS Statistics for Windows, version 25.0. Results Both IN and IV dexmedetomidine successfully attenuated the stress responses to L&I and skull-pin fixation without significant hypertension or tachycardia. All hemodynamic parameters (MAP, SBP, DBP, HR) were maintained within normal limits (±20% of baseline) before and during L&I and after skull-pin fixation in both groups. However, the preoperative Ramsay sedation scale score was significantly higher in the IV than in the IN group at 10, 20, and 30 minutes of drug administration (p<0.05). The incidence of hypoxia and bradycardia was also higher in the IV than in the IN group. Nausea, vomiting, or respiratory depression were not observed in any patient. Conclusion Both IN and IV dexmedetomidine are effective in blunting the hemodynamic responses to L&I and skull-pin fixation. However, IN dexmedetomidine is a better alternative to IV dexmedetomidine as it causes less sedation and fewer side effects.