Dexmedetomidine added to levobupivacaine prolongs axillary brachial plexus block.

Background And Objectives: We evaluated the effect of adding dexmedetomidine to levobupivacaine for axillary brachial plexus blockade. The primary endpoints were the onset and duration of sensory and motor block and duration of analgesia.

Methods: Sixty patients scheduled for elective forearm and hand surgery were divided into 2 equal groups in a randomized, double-blind fashion. The 4 main nerves in the axilla (musculocutaneus, radial, median, ulnar) were identified using neural stimulation. Patients were assigned randomly to 1 of the 2 groups. In group L (n = 30), 40 mL (200 mg) of 0.5% levobupivacaine + 1 mL saline and in group LD (n = 30), 40 mL (200 mg) of 0.5% levobupivacaine + 1 mL dexmedetomidine were given. Motor and sensory block onset times, block durations, and duration of analgesia were recorded.

Results: Demographic data and surgical characteristics were similar in both groups. Sensory and motor block onset times were shorter in group LD than in group L (P < 0.05). Sensory and motor blockade durations were longer in group LD than in group L (P < 0.01). Duration of analgesia was longer in group LD than in group L (P < 0.05). Systolic arterial blood pressure levels in group LD at 10, 15, 30, 45, 60, 90, and 120 minutes were significantly lower than those in group L (P < 0.05). Diastolic arterial blood pressure levels in group LD at 60, 90, and 120 minutes were significantly lower than those in group L (P < 0.05). Heart rate levels in group LD, except basal measurements, were significantly lower than those in group L (P < 0.05). In group LD bradycardia was observed in 7 patients, although there was no bradycardia in group L (P < 0.05).

Conclusions: Dexmedetomidine added to levobupivacaine for axillary brachial plexus block shortens the onset time and prolongs the duration of the block and the duration of postoperative analgesia. However, dexmedetomidine also may lead to bradycardia.