Articles: nerve-block.
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Randomized Controlled Trial Comparative Study Clinical Trial
Differential onset of median nerve block: randomized, double-blind comparison of mepivacaine and bupivacaine in healthy volunteers.
We have compared the delay in onset of 1% mepivacaine and 0.33% bupivacaine in different nerve fibre types in 10 volunteers undergoing median nerve blocks, in a randomized, double-blind, crossover study. Hot, cold, pinprick and light touch sensations, compound motor action potentials (CMAP), sensory nerve action potentials (SNAP) and skin temperature were recorded at 2-min intervals. Hot, cold, pinprick, light touch sensations, SNAP and CMAP were significantly inhibited, and skin temperature was significantly increased after administration of both agents. ⋯ Bupivacaine and mepivacaine inhibited SNAP and CMAP with a similar time delay to steady-state. Bupivacaine produced steady-state inhibition of hot and cold sensations significantly later than mepivacaine; nevertheless, the sequence that sensory modalities failed, with few exceptions, and the extent of anaesthesia at 40 min were similar for both agents. Our technique provides a novel, multi-modal method of comparing local anaesthetics and related agents over time.
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Randomized Controlled Trial Clinical Trial
Evaluation of the effects of the addition of morphine sulfate to a standard Bier block solution in peripheral arm surgery.
The purpose of this study was to analyze postoperative pain differences in patients undergoing peripheral arm surgery. Differences between patients' perceived pain who received 2 mg of morphine sulfate added to the standard Bier block solution and the standard Bier block solution without morphine were studied. A quasi-experimental nonequivalent control group design was utilized. ⋯ A larger sample may have yielded different results. Many issues remain undecided regarding the potential role of opioids in various regional anesthetic techniques. Further studies are warranted to investigate the peripheral effects of opioids and to understand the mechanisms of action of opioid analgesics at peripheral sites.
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Anesthesia and analgesia · Oct 1998
Infraclavicular brachial plexus block: parasagittal anatomy important to the coracoid technique.
Infraclavicular brachial plexus block is a technique well suited to prolonged continuous catheter use. We used a coracoid approach to this block to create an easily understood technique. We reviewed the magnetic resonance images of the brachial plexus from 20 male and 20 female patients. Using scout films, the parasagittal section 2 cm medial to the coracoid process was identified. Along this oblique section, we located a point approximately 2 cm caudad to the coracoid process on the skin of the anterior chest wall. From this point, we determined simulated needle direction to contact the neurovascular bundle and measured depth. At the skin entry site, the direct posterior insertion of a needle will make contact with the cords of the brachial plexus where they surround the second part of the axillary artery in all images. The mean (range) distance (depth along the needle shaft) from the skin to the anterior wall of the axillary artery was 4.24 +/- 1.49 cm (2.25-7.75 cm) in men and 4.01 +/- 1.29 cm (2.25-6.5 cm) in women. Hopefully, this study will facilitate the use of this block. ⋯ We sought a consistent, palpable landmark for facilitation of the infraclavicular brachial plexus block. We used magnetic resonance images of the brachial plexus to determine the depth and needle orientation needed to contact the brachial plexus. Hopefully, this study will facilitate the use of this block.
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Recent advances in the application of regional anesthesia to the care of patients undergoing shoulder surgery are discussed. New techniques for the management of postoperative pain are highlighted, with an emphasis on interscalene patient-controlled analgesia and suprascapular block. ⋯ Intraoperative hypotension and bradycardia caused by activation of the Bezold-Jarisch reflex is considered. The ongoing debate regarding the use of paresthesia versus nerve-stimulator techniques is examined.
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Randomized Controlled Trial Comparative Study Clinical Trial
Prospective, randomized comparison of deep or superficial cervical plexus block for carotid endarterectomy surgery.
Carotid endarterectomy may be performed under cervical plexus block with local anesthetic supplementation by the surgeon as necessary during surgery. It is unclear, however, whether deep or superficial cervical plexus block offers the best operating conditions or patient satisfaction. Therefore, the authors compared the two in patients undergoing carotid endarterectomy. ⋯ Carotid endarterectomy may be performed satisfactorily during superficial or deep cervical plexus block placement with no differences in terms of supplemental local anesthetic requirements, although this is influenced by whether paresthesia is elicited during placement of the deep block. Therefore, the clinician's decision to use one block rather than another need not be based on any assumed superiority of one block based on intraoperative conditions or patient satisfaction.