Comparative study on the clinical profile of different doses of dexmedetomidine with levobupivacaine in supraclavicular brachial plexus block

Many studies have been conducted using dexmedetomidine as adjuvant to local anaesthetics in peripheral nerve blocks, but few studies compare the effect of different doses of dexmedetomidine. We aimed at comparing the clinical profile of different doses of dexmedetomidine as adjuvant to levobupivacaine in supraclavicular brachial plexus block and finding out the dose which provides maximum improvement in block parameters with minimum undesirable effects.

This double blinded comparative study was conducted in 120 patients belonging to American Society of Anaesthesiologist Physical Status (ASA PS) I or II, undergoing elective upper limb orthopaedic procedures. The subjects were randomly allocated into four groups of 30 each. Supraclavicular brachial plexus blocks were performed in each group. While group LS received plain levobupivacaine, group LD30, LD60 and LD100 received 30 microgram(mcg), 60mcg and 100mcg dexmedetomidine along with levobupivacaine. The primary outcomes studied were block parameters and the secondary outcomes were hemodynamic profile, oxygen saturation and sedation scores. Statistical analysis was done using ANOVA test, chi-square test and Scheffe's multiple comparison tests.

The demographic profile and hemodynamic variables were comparable in all four groups. Increasing doses of dexmedetomidine showed statistically significant improvement in block parameters and increase in sedation score, while significant decrease was found in heart rate and blood pressure.

A dose of 60mcg of dexmedetomidine showed clinically significant improvement in block characteristics with minimum undesirable effects like bradycardia, sedation and prolonged motor blockade.