Abstract ID: A24

Abstract Title: HOW LOW (mA) CAN YOU GO TO SAFELY AND EFFECTIVELY PERFORM PERIPHERAL NERVE BLOCKS IN ANESTHETIZED PATIENTS?

Poster Type: Poster


ABSTRACT BODY

Introduction: Regional anesthesia is a useful tool in the management of postoperative pain. Successful peripheral nerve blocks can eliminate the need for intravenous opioids and overnight hospitalization. Most peripheral nerve blocks in children can only be performed under general anesthesia. However, the risk of nerve injury has limited a widespread use of this technique. The purpose of this study was to determine the safety and efficacy of nerve blocks using a nerve stimulator technique with higher than usual current settings.

Materials and Methods: We reviewed the intra- and post-operative charts of 110 patients who had peripheral nerve blocks under general anesthesia between November 2002 and November 2003. A combination of local anesthetic (bupivacaine or ropivacaine) and clonidine was used. The following data were analyzed: age, sex, type of nerve block, intensity of the current (mA) used during peripheral nerve block, consumption of intravenous and oral opioids in the first 24 hours after surgery, incidence of failed blocks, and nerve injuries. We defined: 1) failed blocks as those where we found an incomplete sensory block on physical examination in the immediate postoperative period, 2) nerve injury as the presence of numbness and/or paresthesia which extended beyond a 24 hour period. None of the patients received intravenous pain medications intra-operatively.

Results: There were 97 (88%) peripheral nerve blocks that were completely successful. Of the 13 (12%) insufficient blocks: 1) 3 (2.7%) were complete failures, all femoral nerve blocks, 2) 10 (9.1%) (7 femoral, 2 axillary, 1 sciatic) were blocks that did not completely block the surgical site and required intravenous pain medication supplementation post-operatively. Six of the failed femoral nerve blocks were due to omission of the lateral femoral cutaneous nerve. There was only one (0.9%) complication that was prolonged numbness of the great toe after a sciatic nerve block that resolved on day 5. The median mA for all of the blocks was 0.56 with the mA range of 0.4-0.8. No correlation was found between mA used and nerve block failure.

Discussion: Peripheral nerve blocks can be done safely in anesthetized children. Even with use of relatively high current (0.55-0.60 mA), adequate blocks can be obtained. Peripheral nerve blocks may be effective techniques in providing not only adequate but potentially, total analgesia in the immediate post-operative period.

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ATTACHED FILES

A24_TABLE 1.doc





Reg Anesth Pain Med 2004; 29(2):A24