Background and objectives: Although epinephrine commonly is added to local anesthetics for regional anesthesia, rarely it may cause undesirable hemodynamic side effects. This study compared the hemodynamic and blockade effects of 25 and 200 microg epinephrine during axillary brachial plexus blockade with lidocaine 1.5%.
Methods: Sixty American Society of Anesthesiologist classification I or II patients were divided randomly into 3 groups. Patients in group 1 received 5 mL of saline containing 25 microg epinephrine and then 35 mL of 1.5% lidocaine; patients in group 2 received 5 mL of saline alone and then 200 microg of epinephrine mixed with 35 mL of 1.5% lidocaine; patients in group 3 received 5 mL of saline alone and then 35 mL of 1.5% lidocaine. Hemodynamic data were measured for 1 to 10 minutes at 1-minute intervals after axillary injection. The duration time of motor and sensory block was recorded.
Results: Complete anesthesia was achieved in 85% of patients in groups 1 and 3 and 90% in group 2. Motor block duration was significantly longer in group 2 than in groups 1 and 3 (P <.05). There were no significant differences in analgesia between groups 1 and 2. Analgesia duration was significantly longer in groups 1 and 2 than in group 3 (P <.05). Heart rate from the 3rd to 6th minute was higher in group 2 than in groups 1 and 3 (P <.05). Systolic arterial pressure from the 3rd to 5th minute and diastolic arterial pressure from 2nd to 6th minute were higher in group 2 than in groups 1 and 3 (P <.05).
Conclusions: Low-dose epinephrine offers more stable hemodynamics and similar blockade, and thus may be beneficial for patients undergoing forearm and hand surgery who are at risk for tachycardia and/or hypertension.