Tehran University Medical Journal

Background: Axillary block is used for inducing anesthesia in outpatient hand and forearm surgeries. Few researches have studied hemodynamic and blockade effects of low doses of Epinephrine. The aim of the present study was to compare the duration of analgesia and hemodynamic changes following the injection of high/low epinephrine doses in such surgeries.

Methods: The present randomized clinical trial study was conducted on healthy individuals (ASA I-II) who were candidates for hand and forearm surgeries. The patients were randomly divided into three groups. The first two groups were allocated to receive lidocaine with low (0.6µg/cc) and high (5µg/cc) doses of epinephrine whereas lidocaine plus normal saline was injected in the third group. The hemodynamic changes (Mean arterial blood pressure and heart rate) and the occurance of any side-effects along with the duration of analgesia and motor block were recorded.

Results: From among the total of 75 patients, 15 cases were excluded due to incomplete blockade or failure needing general anesthesia. The duration of analgesia and the motor block were longer in the high dose epinephrine group, the difference, however, was not statistically significant. Heart rate changes within the groups was significant in the 4^th-7^th and 10^th minutes. Mean arterial blood pressure changes was only significant in the 4^th minute, within the groups.

Conclusions: Administering low doses of epinephrine plus lidocaine as a local anesthetic not only provides acceptable analgesia compared to higher doses of the medication, but also is associated with fewer side effects.