Comparison of Two Doses of Dexmedetomidine for Supraclavicular Brachial Plexus Block: A Randomized Controlled Trial

Dexmedetomidine is commonly used as an additive in supraclavicular brachial plexus block (SBPB). Due to its adverse effects such as bradycardia and hypotension, finding the appropriate dose of dexmedetomidine is the question.

We aimed to compare two commonly used doses of dexmedetomidine (1 μg/kg and 2 μg/kg) added to levobupivacaine in ultrasound-guided SBPB in terms of its effect on duration of analgesia, hemodynamics, and associated adverse effects.

This randomized, double-blinded prospective study was conducted over a period of 1.5 years in our tertiary care hospital.

Clearance from the Institutional Ethical Committee and Clinical Trial Registry of India was taken. Ninety patients' physical status American Society of Anesthesiologists Classes I and II undergoing upper limb surgeries under SBPB were included in this study. Patients in Group I received 1 μg/kg dexmedetomidine, whereas patients in Group II received 2 μg/kg dexmedetomidine added to 20 cc levobupivacaine. The primary outcome measure was the duration of analgesia after administering the block. Secondary outcomes included effect on hemodynamics, duration of blockade, and adverse effects.

Statistical analysis was carried out using Stata Version 10. Unpaired t-test and Chi-square test were used.

The duration of analgesia and sensory and motor blockade were similar in both the groups. The heart rate (HR) and mean arterial pressure were statistically lower in Group II. The incidence of bradycardia and hypotension was more in Group II.

Increasing the dose of dexmedetomidine does not prolong the duration of analgesia, but it is associated with lower HR and blood pressure. Incidence of hypotension and bradycardia is also more. Hence, a lower dose of 1 μg/kg dexmedetomidine added to 0.5% levobupivacaine is a good balance between safety and efficacy.