Perineural Epinephrine for Brachial Plexus Block Increases the Incidence of Hypotension during Dexmedetomidine Infusion: A Single-Center, Randomized, Controlled Trial.

BACKGROUND

Sedation using dexmedetomidine is frequently associated with hypotension. In contrast, epinephrine, a commonly used adjunctive agent in regional anesthesia, is a potent vasopressor. We hypothesized that perineural epinephrine used in brachial plexus blockade may reduce hypotension during dexmedetomidine infusion.

METHODS

Patients scheduled for upper extremity surgery were randomly allocated into a control and an epinephrine group. All patients received brachial plexus blockade, consisting of 25 mL of a 1:1 mixture of 1% lidocaine and 0.75% ropivacaine, with patients in the epinephrine group also receiving 125 μg epinephrine. Intraoperative sedation was induced using dexmedetomidine at a loading dose of 1 µg/kg and maintenance dose of 0.4 µg/kg/hr. The primary outcome was the incidence of intraoperative hypotension or hypotension in the post-anesthesia care unit (PACU).

RESULTS

One hundred and thirty patients were included (65 per group). The incidence of hypotension was significantly higher in the epinephrine than in the control group (80.6% vs. 56.9%, = 0.009). The duration of hypotension and the maximal change in blood pressure were also greater in the epinephrine group.

CONCLUSIONS

Perineural epinephrine for brachial plexus blockade does not reduce hypotension due to dexmedetomidine infusion and may actually augment the occurrence of hypotensive events.