Regional anesthesia and pain medicine
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Reg Anesth Pain Med · Sep 2001
Randomized Controlled Trial Clinical TrialEffect of impulse duration on patients' perception of electrical stimulation and block effectiveness during axillary block in unsedated ambulatory patients.
Chronaxie of the motor-neurons (A-alpha) is shorter than that of the sensory A-delta and C neurons. Therefore, a short current impulse should elicit a painless muscle twitch. This randomized, double-blind study of patients having ambulatory axillary block by multiple neurostimulations compared patients' perception of electrical stimulation, latency, and quality of analgesia and the incidence of adverse effects. ⋯ This study did not confirm our hypothesis that short-current impulses (0.1 ms) make neurostimulation of peripheral nerves painless, by selectively depolarizing motor-neurons. Longer impulses (0.3 ms) shorten block performance time, probably by easier location of the nerves, but the clinical relevance of this finding is doubtful.
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Reg Anesth Pain Med · Sep 2001
Randomized Controlled Trial Clinical TrialAnalgesic effects of low-dose ropivacaine for interscalene brachial plexus block for outpatient shoulder surgery-a dose-finding study.
Interscalene brachial plexus block (ISB) with low-dose bupivacaine provides effective postoperative shoulder analgesia in outpatients. The analgesic effect of low-dose ropivacaine for ISB is unknown. ⋯ Interscalene brachial plexus block with low-dose ropivacaine, 10 mL of 0.25% and 0.5%, provides effective long-lasting shoulder analgesia in a majority of patients after arthroscopic surgery.
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Reg Anesth Pain Med · Sep 2001
Randomized Controlled Trial Clinical TrialThe effects of single and fractionated doses of mepivacaine on the extent of thoracic epidural block.
The effects of single and fractionated doses of local anesthetic on the extent of thoracic epidural blockade has not yet been determined. This single blinded and randomized study was designed to examine the effects of the initial dose and timing of the additional dose of local anesthetic on the sensory block level of the thoracic epidural anesthesia. ⋯ We concluded that the timing of the second administration of mepivacaine was one of the factors for the spread of the drug into thoracic epidural space. The more extensive sensory block level occurred by shorter time interval of the second drug administration.
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Reg Anesth Pain Med · Sep 2001
Randomized Controlled Trial Clinical TrialIntrathecal labor analgesia with bupivacaine and sufentanil: the effect of adding 2.25 microg epinephrine.
Epinephrine, 25 microg and 200 microg, has been found to prolong the duration of intrathecal labor analgesia when added to an opioid. In our hospital we use the standard epidural mixture, prepared by the pharmacist, containing epinephrine 1:800,000; i.e., 1.25 microg/mL for both spinal and epidural labor analgesia. We wanted to evaluate whether such a low dose, depending on its effect on duration or quality of analgesia, should be maintained or deleted in future mixtures. ⋯ It was concluded that epinephrine in a dose as low as 2.25 microg significantly prolonged the duration of intrathecal analgesia of bupivacaine-sufentanil by 15 minutes. No other differences were noticed. Diluting the commercially available bupivacaine 0.5% with epinephrine 1:200,000 may avoid the need of freshly prepared epinephrine solutions.
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Reg Anesth Pain Med · Sep 2001
Randomized Controlled Trial Clinical TrialSuccess rate of unilateral spinal anesthesia is dependent on injection flow.
The dependence of unilateral spinal anesthesia on injection flow is controversial. We hypothesized that it is possible to achieve strictly unilateral sympathetic block (as assessed by temperature measurements of the limbs) and unilateral sensory and motor block, respectively, during spinal anesthesia by a slow and steady injection of a hyperbaric local anesthetic solution. ⋯ For hyperbaric spinal anesthesia, the injection flow is an important factor in achieving unilateral sympathetic block. A slow injection proves useful to restrict spinal anesthesia to the side of surgery.