Regional anesthesia and pain medicine
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Reg Anesth Pain Med · Sep 2003
Clinical TrialRelationship between evoked motor response and sensory paresthesia in interscalene brachial plexus block.
This study sought to define the relationship between a paresthesia and a motor response (MR) to electrical nerve stimulation using a peripheral nerve stimulator (PNS) during interscalene block. We sought to determine if at a low amperage (< or =1.0 mA) a MR would precede a paresthesia. ⋯ MR preceded paresthesia in every patient. The most likely explanation for this observation is that MR can be achieved at a small distance from the nerve, whereas elicitation of mechanical paresthesia requires either nerve contact or more intimate location of the needle's tip relative to the nerve. Another possible explanation is that motor fibers are located in a more superficial position and are therefore encountered first. Motor and sensory responses are separate and discrete phenomena.
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Ambulatory perineural local anesthetic infusion is a relatively new method for providing postoperative analgesia, and many aspects of this technique remain in the domain of conjecture and speculation. This retrospective chart review and survey was undertaken to investigate patients' opinions on various aspects of their ambulatory perineural infusion experience. ⋯ This investigation suggests that perineural local anesthetic infusion is generally well tolerated by ambulatory patients.
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Reg Anesth Pain Med · Sep 2003
Altered perceptions after upper and lower extremity blocks: an initial investigation.
Nerve blocks frequently produce unusual altered perceptions in the extremities. We examined perceptual changes experienced after peripheral blocks. ⋯ The results of this study confirm and quantify the perceptions experienced by patients undergoing upper and lower extremity blocks. These perceptions are prevalent. This knowledge is helpful in providing patients with accurate preoperative preparation. Further investigation is warranted to determine the neurologic etiology of these observations.
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Reg Anesth Pain Med · Sep 2003
Clinical TrialEarly experience with continuous cervical paravertebral block using a stimulating catheter.
This study reports our early experience with continuous cervical paravertebral block (CCPVB) using a stimulating catheter for the management of acute pain after shoulder surgery. ⋯ An average of 2 (range 1-7) attempts were needed to advance the catheter while still stimulating the nerve. Average postoperative pain ranged from 0.27 +/- 1.04 cm to 0.78 +/- 1.56 cm (mean +/- SD) on a visual analog scale (VAS) (0-10 cm) for the first 48 hours and 3.8 +/- 2.1 cm and 3.5 +/- 2.4 cm at 60 hours and 14 days, respectively. Patient satisfaction on a VAS of 0 to 5 was 4.19 +/- 1.1, 4.28 +/- 1.01, and 4.69 +/- 1.05 at times 0, 6 hours, and 14 days, respectively. Motor function returned to normal in the fingers within 24 hours and in the shoulder within 60 hours. Complications included Horner's syndrome (40%), dyspnea (8%), superficial skin infection (5%), posterior neck pain (22%), subclavian artery puncture (1%), contralateral epidural spread (4%), and 8% of the patients complained of an unpleasant "dead feeling" of the arm. Ninety-one percent of patients would request CCPVB again for future shoulder surgery. There was no evidence of nerve damage.
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Reg Anesth Pain Med · Sep 2003
Case ReportsUltrasound-guided popliteal block demonstrates an atypical motor response to nerve stimulation in 2 patients with diabetes mellitus.
Nerve stimulation is a useful technique to identify peripheral nerves before blockade. We report 2 cases of the failure of nerve stimulation to accurately localize the sciatic nerve in patients with diabetes mellitus undergoing outpatient foot procedures. We also introduce a novel approach to performing a popliteal fossa block using ultrasound guidance. ⋯ Ultrasound facilitated the accurate localization of the sciatic nerve in 2 patients with diabetes mellitus. Neither patient had a paresthesia or muscle twitch below 2.4 mA. There is theoretical concern that patients with underlying neuropathy, such as patients with diabetes mellitus, may have an altered response to either motor or sensory stimulation.