Regional anesthesia and pain medicine
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Reg Anesth Pain Med · Jul 2009
Review Case ReportsRetained intrathecal catheter fragment after spinal drain insertion.
The placement of lumbar spinal drains is being done with increasing frequency to facilitate high-risk surgical procedures. One risk associated with these procedures is catheter shearing, resulting in a retained foreign body in the intrathecal space. Unlike retained epidural fragments, there are no guidelines on the management of this complication. The purpose of this article was to synthesize the literature on this subject to come up with guidelines for preventing and managing this complication. ⋯ A retained intrathecal catheter can be managed conservatively in certain contexts. Periodic follow-up visits, with or without repeat imaging, are recommended in these circumstances.
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Reg Anesth Pain Med · Jul 2009
Randomized Controlled Trial Comparative StudyA randomized, observer-blinded determination of the median effective volume of local anesthetic required to anesthetize the sciatic nerve in the popliteal fossa for stimulating and nonstimulating perineural catheters.
Stimulating perineural catheters are developed to overcome technical problems of nonstimulating catheters, but their efficacy remains controversial. However, no volume-response study has compared success rates between stimulating and nonstimulating catheters. This study of stimulating versus nonstimulating catheters compares the minimal effective volume required to successfully block the sciatic nerve in 50% of patients scheduled for unilateral hallux valgus repair. ⋯ Stimulating popliteal catheters dramatically decrease the volume required to block the sciatic nerve in 50% of patients, compared with nonstimulating catheters.
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Reg Anesth Pain Med · Jul 2009
Randomized Controlled Trial Comparative StudyUltrasound machine comparison: an evaluation of ergonomic design, data management, ease of use, and image quality.
The use of ultrasound technology for vascular access and regional anesthesia is gaining widespread acceptance among anesthesia providers. As a result, many group practices and medical institutions are considering purchasing ultrasound equipment. Currently, comparative information regarding the ergonomic design, physical and adjustable features, data management, ease of use, cost, and image quality of various ultrasound machines is not available. The primary goal of this investigation was to develop an objective process of evaluating ultrasound equipment before purchase. The process of evaluation used in the current investigation may be used when comparing a variety of medical technologies. ⋯ Anesthesia providers considering an ultrasound equipment purchase should objectively evaluate machine models that have features most important to their own clinical practice. Ergonomic design, physical and adjustable features, data management, ease of use, image quality, and cost are important features to consider when evaluating an ultrasound machine.
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Reg Anesth Pain Med · Jul 2009
Calcium chloride prolongs the effects of lidocaine and bupivacaine in rat sciatic nerve.
Elevated extracellular calcium ion has been shown to shift the voltage dependence of Na+- and K+-ion channels rightward, making the nerve less excitable. We hypothesized that calcium chloride (CaCl2) when used as an adjuvant prolongs and intensifies the block by local anesthetics (LAs). We investigated the effects of LAs combined with calcium in rat sciatic nerve blockade and in cultured rat GH3 cells expressing Na+ channels. Furthermore, we tested for histologic changes due to CaCl2. ⋯ The mechanism of prolonged nerve block of CaCl2 coadministered with LAs seems to be a raised threshold for nerve excitation. Major histopathologic changes at higher concentrations of CaCl2 are evident, and therefore, clinical application as an adjuvant to LAs seems unlikely.
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Reg Anesth Pain Med · Jul 2009
Measurement of shift of the cauda equina in the subarachnoid space by changing position.
To perform spinal anesthesia, patients are usually placed in the lateral decubitus position with the knees drawn up to the stomach, the legs fully flexed, and the neck flexed to curve the back outward. Because the nerve roots of the cauda equina have considerable mobility in the subarachnoid space, the position of the cauda equina in the lateral decubitus position may be different from that in the supine position. However, the anatomic position of the cauda equina in the lateral decubitus position with fully flexed legs has not been carefully studied. In the present study, we geometrically measured the movement of the cauda equina in the subarachnoid space by changing positions, using magnetic resonance imaging (MRI). ⋯ The present study using MRI showed dynamical movement of the spinal cord and cauda equina due to changing position. The most obvious movements by changing from supine to lateral decubitus position and fully flexed legs were observed at the L2/3 and L1/2 levels, respectively.