Articles: nerve-block.
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Comparative Study
Prolonged duration local anesthesia from tetrodotoxin-enhanced local anesthetic microspheres.
There is interest in developing prolonged duration local anesthesics. Here we examine whether tetrodotoxin (TTX) can be used to prolong the block from bupivacaine microspheres with and without dexamethasone. Rats received sciatic nerve blocks with 75 mg of microspheres containing 0.05% (w/w) TTX, 50% (w/w) bupivacaine and/or 0.05% (w/w) dexamethasone. 0.1% (w/w) TTX microspheres were also tested. ⋯ In summary, coencapsulation of TTX in controlled release devices containing bupivacaine and dexamethasone resulted in very prolonged nerve blocks. As formulated here, this preparation had a narrow margin of safety. While the myotoxicity appears consistent with the well-known reversible myotoxicity associated with local anesthetics, its long-term significance remains to be established.
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Reg Anesth Pain Med · Jul 2003
Case ReportsApplying ultrasound imaging to interscalene brachial plexus block.
Previous studies have examined ultrasound-assisted brachial plexus blocks, but few have applied this imaging technology to the interscalene region. We report a case of interscalene brachial plexus block using ultrasound guidance to show the clinical usefulness of this technology. ⋯ Advanced ultrasound technology is useful for nerve localization and can generate brachial plexus images of high resolution in the interscalene groove, guide block needle placement and advancement in real time to targeted nerves, and assess adequacy of local anesthetic spread at the time of injection. Ultrasound imaging guidance can potentially improve success during interscalene brachial plexus block.
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Comparative Study
Variability in determination of point of needle insertion in peripheral nerve blocks: a comparison of experienced and inexperienced anaesthetists.
Accurate identification of surface landmarks is essential for the successful performance of peripheral nerve blocks. The variability between experienced and inexperienced practitioners in identifying anatomical landmarks has not been studied previously. Anaesthetists were asked to identify the point of needle insertion for posterior lumbar plexus and sciatic nerve blocks on a volunteer using a standard textbook description. ⋯ The sciatic nerve block X, Y co-ordinates were 77 [62-99], 70 [49-89] and 68 [29-116], 62 [26-93] in the experienced and inexperienced groups, respectively. The variance for the point of needle insertion was significantly greater in the inexperienced group (p <0.01) for both the lumbar plexus and sciatic nerve blocks. We conclude that with increasing experience, there is decreased variability in determining the point of needle insertion using anatomical landmarks.
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The vertical infraclavicular blockade of the brachial plexus (VIP) according to Kilka et al.is a technique which has gained more importance over the past years. This method distinguishes itself from other periclavicular techniques by a very low risk of pneumothorax (0.2%), which seems to be increased with asthenic patients. ⋯ As a consequence, we assume that if the distance between the leading points jugulum and ventral process of acromion is smaller than 20 cm, the puncture point for a vertical infraclavicular blockade of the brachial plexus should be lateralized as described above; additionally, the "finger-point" should be determined in order to verify the puncture point and to finally give an idea of the direction, in case of a possible need for correcting the puncture point.