Regional anesthesia and pain medicine
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Reg Anesth Pain Med · Sep 2000
Alkalinization and precipitation characteristics of 0.2% ropivacaine.
Alkalinization of local anesthetics has been used to increase the speed of onset of nerve blocks. However, alkalinization of local anesthetic solutions may cause precipitation, thereby decreasing bioavailability and anesthetic activity. Alkalinization of ropivacaine has not been described. This laboratory study assessed the alkalinization and precipitation characteristics of ropivacaine. ⋯ A laboratory evaluation that establishes the alkalinization characteristics of ropivacaine is a prerequisite for designing a clinical study of alkalinized ropivacaine. In our experiment, low doses of bicarbonate produced significant increases in the proportion of nonionized ropivacaine with only modest precipitation. There would be a low likelihood of substantial drug precipitation if the mixture was administered within 5 to 10 minutes after alkalinization. These results indicate that alkalinized ropivacaine should not be used for infusions and that ropivacaine should not be alkalinized until just before use.
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Reg Anesth Pain Med · Sep 2000
Randomized Controlled Trial Clinical TrialEfficacy of oral mexiletine for neuropathic pain with allodynia: a double-blind, placebo-controlled, crossover study.
Mexiletine is an oral sodium channel antagonist that has been reported to be effective in a variety of neuropathic pain syndromes. However, recent reports question the efficacy of oral mexiletine in neuropathic pain. The objectives of this study were to examine the effect of oral mexiletine on pain, neurosensation, allodynia, and quality of life. ⋯ At doses of up to 900 mg/d, mexiletine has minimal effects on pain and allodynia of neuropathic pain. However, side effects may preclude higher doses.
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Reg Anesth Pain Med · Sep 2000
Effect of clonidine on upper extremity tourniquet pain in healthy volunteers.
Tourniquet pain is often a limiting factor during intravenous regional anesthesia (IVRA). The purpose of this study was to evaluate the efficacy of 1 microg/kg of clonidine added to IVRA-lidocaine in decreasing the onset of severe tourniquet pain. ⋯ This study shows that the addition of 1 microg/kg of clonidine to 40 mL of 0.5% IVRA-L delays the onset time of tourniquet pain in healthy, unsedated volunteers.
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Reg Anesth Pain Med · Jul 2000
Clinical Trial Controlled Clinical TrialRespiratory gas exchange and hemodynamics during lumbar epidural anesthesia: effects of lidocaine with and without epinephrine.
Epinephrine modifies the hemodynamic response to epidural local anesthetic; effects on respiratory gas exchange are not known. We hypothesized that epidural epinephrine would increase oxygen consumption and carbon dioxide production. ⋯ The addition of epinephrine, 5 microg x mL(-1), to the epidural injection of 2% lidocaine is associated with changes not only in hemodynamics, but also in respiratory gas exchange.