Intrathecal Dexmedetomidine as an Adjuvant to Low Dose Hyperbaric 0.5% Bupivacaine on Haemodynamic Parameters in Patients Undergoing Transurethral Resection of Prostate.

Objective: To determine the role of dexmedetomidine in potentiating the local anaesthetic efficacy of a low dose of bupivacaine when used as an adjuvant.

Study design: A prospective, double-blind, randomised study. Place and Duration of the Study: Department of Anaesthesia, Sindh Institute of Urology and Transplantation, Karachi, Pakistan, from July 2021 to February 2022.

Methodology: One hundred and eight patients of ASA physical class I-III undergoing transurethral resection of the prostate (TURP) under sub-arachnoid block (SAB) were enroled and distributed into two equal groups. Group BUPIPURE (BP) was given 7.5 mg of pure 0.5% hyperbaric bupivacain whereas group BUPIDEX (BD) was given 6 mg of 0.5% hyperbaric bupivacain with 3 μg dexmedetomidine intrathecally. The effects in Both groups were compared using chi-square and unpaired t-tests. A significance level of p <0.05 was used to evaluate the statistical significance.

Results: Both groups demonstrated a steady decrease in mean heart rate (mean HR 98.9-62.7 per minute as compared to 79.1-59.4 per minute in groups BP and BD, respectively), however, no patient reached to HR <50/min. Group BP had a higher HR variability than group BD. The two groups' median peak sensory levels were similar. However, a statistically significant difference was revealed in the time taken for 2-segment regression (87.5 ± 11.3 min vs. 115.5 ± 6.2 min p <0.001 in BP and BD), as well as the time to reach T10 sensory level (13.56 ± 2.5 min vs. 10.9 ± 3.0 min p <0.001).

Conclusion: In patients having TURP, intrathecal dexmedetomidine combined with low-dose bupivacaine results in a quicker start, extended sensory and motor block, and a decreased need for rescue analgesics.

Key words: Adjuvants, Dexmedetomidine, Spinal anaesthesia, Transurethral Resection of Prostate.