Regional anesthesia
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Regional anesthesia · Sep 1995
Randomized Controlled Trial Clinical TrialEpinephrine prolongs duration of subcutaneous infiltration of local anesthesia in a dose-related manner. Correlation with magnitude of vasoconstriction.
Epinephrine is frequently combined with local anesthesia to prolong analgesia. Determination of the minimal concentration and the dose of epinephrine that produces prolongation of analgesia is important in the face of epinephrine's potential for systemic and local toxicity. The authors undertook this study to determine a dose-response curve of epinephrine on duration of analgesia of both 1% lidocaine and 0.25% bupivacaine after local infiltration. In order to determine whether epinephrine-induced vasoconstriction affected duration of analgesia, the authors correlated duration of analgesia with magnitude of local vasoconstriction as measured with laser Doppler flowmetry. ⋯ Epinephrine prolongs duration of analgesia after local infiltration in a dose-related manner. Addition of epinephrine in concentrations of 1:50,000 or 1:200,000 increases duration of analgesia after local infiltration by approximately 200%. Addition of doses as dilute as 1:3,200,000 still increases duration of analgesia by approximately 100%. Duration of analgesia appears to correlate with magnitude of epinephrine-induced vasoconstriction using laser Doppler flowmetry. Based on study data, the use of epinephrine in concentrations from 1:200,000 to 1:3,200,000 is recommended for prolongation of analgesia after local infiltration.
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Regional anesthesia · Sep 1995
Randomized Controlled Trial Clinical TrialAlkalinization of local anesthetics. Which block, which local anesthetic?
A number of clinical studies have been performed in an attempt to establish the effects of alkalinization on potency of local anesthetics. Conflicting results were obtained probably because different studies used different methods as well as different definitions of the effects. To determine the efficacy of alkalinization using different local anesthetic solutions and different regional blocks, 180 patients were studied in a randomized, double-blind fashion. The local anesthetic solutions studied were bupivacaine, mepivacaine, and lidocaine; the regional blocks studied were epidural block, axillary brachial plexus block, and femoral and sciatic nerve block. ⋯ Alkalinization produced the best results with lidocaine and bupivacaine for epidural block, with lidocaine for brachial plexus block, and with mepivacaine for sciatic and femoral nerve blocks.