Comparison of Adrenaline vs. Phenylephrine as Adjuvants to Ropivacaine in Supraclavicular Brachial Plexus Block: A Randomized Clinical Study

Abstract Background: Supraclavicular brachial plexus block (SBPB) is a common anaesthetic technique for upper limb surgeries, offering advantages over general anaesthesia. Ropivacaine is a long-acting local anaesthetic, but its analgesic duration may be insufficient, necessitating adjuvants like adrenaline and phenylephrine. Objective: To compare the efficacy and safety of adrenaline and phenylephrine as adjuvants to ropivacaine in SBPB for upper limb surgeries. Methods: A prospective, randomized, double-blind clinical trial was conducted at GMC, Kathua, and ASCOMS, Jammu, over 01 years (January 2024 - December 2024). Eighty-six adult patients (ASA I and II) scheduled for elective upper limb surgeries were randomly assigned to receive either 30 mL of 0.5% ropivacaine with 5 μg/mL adrenaline (Group A) or 30 mL of 0.5% ropivacaine with 5 μg/mL phenylephrine (Group P). Data on block characteristics, hemodynamic parameters, and adverse events were collected and analysed. Results: The demographic profiles of both groups were comparable. The duration of analgesia was longer in Group A compared to Group P. Onset times for sensory (12.6 ± 2.8 min vs. 14.3 ± 3.1 min) and motor blocks (15.8 ± 3.1 min vs. 17.2 ± 2.9 min) were faster in Group A, with no significant differences (p ≈ 0.281 and p ≈ 0.701, respectively). Group A also showed longer durations of sensory and motor blocks compared to Group P. Hemodynamic parameters indicated a higher heart rate in Group A (75.2 ± 12.4 bpm) compared to Group P (71.6 ± 10.8 bpm, p ≈ 0.021), while Group P exhibited higher systolic, diastolic, and mean arterial pressures. Adverse effects were comparable between groups. Conclusion: The addition of adrenaline to ropivacaine in SBPB resulted in a longer duration of analgesia and faster onset of sensory and motor blocks compared to phenylephrine. Hemodynamic effects were more pronounced in the phenylephrine group. Both adjuvants were found to be relatively safe.