This randomized control trial, which was carried out at Sindh Institute of Urology and Transplantation (SIUT), used a non-probability consecutive sampling technique for six months from January 1, 2025, to June 30, 2025.

A prospective, randomized, blinded, placebo-controlled clinical trial was conducted in the Sindh Institute of Urology and Transplantation (SIUT) Department of Anesthesiology. Before their involvement in the study, all individuals provided written informed consent.

In order to account for potential dropouts, 35 participants were recruited in each group (the dexmedetomidine group and the control group), for a total of 70 participants.

The method of non-probability consecutive sampling was utilized to select the eligible participants until the necessary sample size was obtained.

Randomization was done using computer-generated sequences, while allocation concealment was done using opaque, sealed envelopes. The sample was split into a 1:1 control group and a dexmedetomidine group at random.

Dexmedetomidine: 0.5 μg/kg of dexmedetomidine was prepared in 20 mL of 0.9% saline to infuse in the dexmedetomidine group.

Placebo: 20 mL of 0.9% saline was used to infuse in the control group.

The study infusion was assigned and administered within ten minutes of the anesthetic induction, following baseline monitoring and intravenous cannulation. Non-invasive blood pressure, pulse oximetry, three-lead ECG, end-tidal CO₂ (EtCO₂), and capnography were all part of routine monitoring. Anesthesia was induced with lignocaine. After three minutes of mask ventilation, the experienced anesthesiologists carried out direct laryngoscopy and tracheal intubation, and the laryngoscopy time was measured. Anesthesia was supported by isoflurane in a mixture of air and oxygen, and mechanical ventilation was supported to keep EtCO₂ at 35 to 40 mmHg. Bradycardia (less than 50 beats per minute) was corrected using atropine 0.5 mg intravenously, and hypotension was corrected with ephedrine 5 mg intravenously.

Inclusion Criteria:

• Ages from 18 to 65 years.
• Patients with a known case of controlled hypertension.
• ASA II
• Elective surgical procedure under general anaesthesia.
• Mallampati grades 1 and 2.
• Patients consenting to participate in this study

Exclusion Criteria:

• Patients with an anticipated difficult intubation.
• Those requiring more than 15 seconds or more than one attempt or use of a bougie during laryngoscopy.
• A patient who has not taken an antihypertensive drug early morning on the day of surgery.
• Patients with a history of allergy to drugs being used.
• Patients with uncontrolled hypertension (BP > 140/90 mmHg).
• History of bradycardia (resting heart rate < 60 bpm).
• Patients on beta blockers if resting heart rate < 60 bpm.
• History of valvular heart disease, uncontrolled diabetes, liver, or kidney disease.
• Pregnancy.

Full anonymous raw data, results and statistical analysis

The sample was split into a 1:1 control group and a dexmedetomidine group at random. The dexmedetomidine group was infused with 0.5 μg/kg of dexmedetomidine in 20 mL of 0.9% saline. Whereas the control group was infused with 20 mL of 0.9% saline only. The preparation of the study infusions was carried out by an independent anaesthesiologist who was not engaged in the care or data collection of the patients. The participants, as well as the outcome assessors, were blinded regarding grouping.

The study infusion was assigned and administered within ten minutes of the anaesthetic induction, following baseline monitoring and intravenous cannulation. Non-invasive blood pressure, pulse oximetry, three-lead ECG, end-tidal CO₂ (EtCO₂), and capnography were all part of routine monitoring.