Comparison of Combination of Low Dose Intravenous Dexmedetomidine and Lidocaine Infusion with Intravenous Lidocaine Infusion to Attenuate Haemodynamic Response to Laryngoscopy and Endotracheal Intubation in Adult Patients Undergoing General Anaesthesia

Laryngoscopy and endotracheal intubation often trigger a transient activation of the sympathoadrenal system, which can be harmful—and occasionally life-threatening—in high-risk patients. This randomized study included 70 patients, aged 18 to 60 years, classified as ASA physical status I or II, who were scheduled for elective surgery under general anesthesia. Participants were divided into two equal groups at random: Group 1 received combined low-dose lignocaine and dexmedetomidine, while Group 2 received only standard-dose lignocaine.

In Group 1, preservative-free lignocaine (1 mg/kg) was infused over 3 minutes before induction, after 0.5 mcg/kg of intravenous dexmedetomidine (diluted in 0.9% normal saline) was administered over 10 minutes. Group 2 received 1.5 mg/kg of preservative-free intravenous lignocaine over 3 minutes, along with a 10-minute infusion of 0.9% normal saline as placebo. Hemodynamic parameters monitoring, which included heart rate (HR), systolic (SBP), diastolic (DBP), and mean arterial pressure (MAP) were recorded during several perioperative intervals: upon arrival to the theatre, 2 and 5 minutes after receiving the drug, just before and after induction, and at 1, 3, 5, and 10 minutes post intubation. Results indicated that Group 1 sustained heart rate and blood pressure values below baseline during the entire 10-minute post intubation period. It is concluded that a low dose combination of dexmedetomidine 0.5 mcg/kg and lignocaine 1 mg/kg provided greater attenuation of the pressor response to laryngoscopy and intubation, without significant hemodynamic alterations, when compared to lignocaine 1.5 mg/kg alone during general anaesthesia.