Regional anesthesia and pain medicine
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Reg Anesth Pain Med · Jan 2013
Systematic ultrasound identification of the dorsal scapular and long thoracic nerves during interscalene block.
The use of ultrasound for in-plane interscalene block shifts needle insertion to a more posterior approach through the middle scalene muscle, when compared with classic nerve stimulator techniques. Branches from the brachial plexus, including the dorsal scapular and long thoracic nerves, are often anatomically located within the middle scalene muscle. The aim of this study was to use ultrasound to identify and characterize the frequency and position of the dorsal scapular and long thoracic nerves located in the middle scalene muscle. ⋯ This descriptive study revealed that the dorsal scapular and long thoracic nerves routinely could be identified with ultrasound.
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Reg Anesth Pain Med · Jan 2013
The κ-opioid receptor agonist U-50488 blocks Ca2+ channels in a voltage- and G protein-independent manner in sensory neurons.
κ-Opioid receptor (κ-OR) activation is known to play a role in analgesia and central sedation. The purpose of the present study was to examine the effect of the κ-OR agonist, U-50488 (an arylacetamide), on Ca channel currents and the signaling proteins involved in acutely isolated rat dorsal root ganglion (DRG) neurons expressing the putative promoter region of the tetrodotoxin-resistant Na channel (NaV 1.8) that is known to be involved in pain transmission. ⋯ These results suggest that the antinociceptive actions mediated by U-50488 are likely due to both a direct block of Ca channels in sensory neurons as well as G protein modulation of Ca currents via κ-OR-expressing neurons.
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Reg Anesth Pain Med · Jan 2013
Minimum effective volume of lidocaine for double-injection ultrasound-guided axillary block.
The aim of this study was to determine the minimum effective volume of lidocaine 1.5% with epinephrine 5 μg/mL in 90% of patients (MEV90) for double-injection ultrasound-guided axillary block (AXB). ⋯ For double-injection ultrasound-guided AXB, the MEV90 of lidocaine 1.5% with epinephrine 5 μg/mL is 5.5 and 23.5 mL for the musculocutaneous nerve and perivascular injection, respectively. Further dose-finding studies are required for other concentrations of lidocaine, other local anesthetic agents, and other techniques for ultrasound-guided AXB.