[Addition of fentanyl to mepivacaine in axillary brachial plexus block. Effects on the anesthetic and postoperative analgesic quality].

The possible potentiating effect of phentanyl on mepivacaine in brachial plexus blockade was evaluated, both for operative anesthesia and postoperative analgesia. Sixty ASA I patients, scheduled for upper limb surgery, were selected and distributed in 3 groups: 1) Mepivacaine 1% 40 ml (control group); 2) Mepivacaine 1% 40 ml + phentanyl 100 micrograms; 3) Mepivacaine 1% 40 ml + subcutaneous phentanyl 100 micrograms. The latency time and the quality of anesthesia were evaluated. The duration of analgesia was evaluated on the basis of the time from the administration of the first analgesic. There were no significant differences between the 3 groups in the latency times of the development of blockade nor in the quality of surgical anesthesia. Also, there were no significant differences in the duration of postoperative analgesia (307, 316 and 326 minutes, respectively, in each group). It was concluded that the addition of phentanyl 100 micrograms to the local anesthetic in the axillary blockade of the brachial plexus does not change the anesthetic characteristics nor the time of postoperative analgesia.