Regional anesthesia and pain medicine
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Reg Anesth Pain Med · Nov 2014
Randomized Controlled TrialThe Effect of Gowning on Labor Epidural Catheter Colonization Rate: A Randomized Controlled Trial.
The need to gown for labor epidural catheter insertion is controversial. The American Society of Regional Anesthesia and Pain Medicine has identified a lack of randomized controlled trials investigating this issue. The purpose of this study was to examine the effect of gowning on colonization rates following epidural catheter insertion for labor analgesia. ⋯ The use of gowns in the current study did not affect catheter colonization rate. Overall, there was a relatively high incidence of catheter-tip colonization in both groups, which underscores the need for strict aseptic technique.
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Dose-finding studies enable the successful conduct of peripheral nerve blocks by ensuring the administration of appropriate doses of local anesthetic. However, the optimal dose-finding methodology remains ambiguous. In this research methodology article, we set out to review the basic aspects pertaining to dose-response curves (graded vs quantal), the pharmacodynamic indices required by dose-finding studies, the properties of different dose-finding methods (sigmoidal dose-response curve analysis, Dixon-Mood method, Biased Coin Design, and Bayesian analysis), as well as strategies and recommendations for future research.
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Reg Anesth Pain Med · Nov 2014
Evaluation of Epidural and Peripheral Nerve Catheter Heating During Magnetic Resonance Imaging.
Many epidural and peripheral nerve catheters contain conducting wire that could heat during magnetic resonance imaging (MRI), requiring removal for scanning. ⋯ Most but not all catheters can be left in place during 1.5-T MRI scans. Heating of less than 3°C during MRI for most catheters is not expected to be injurious. While heating was lower at 1.5 T versus 3 T, performance differences between products underscore the need for safety testing before performing MRI.
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Reg Anesth Pain Med · Nov 2014
Interscalene Brachial Plexus Blocks Under General Anesthesia in Children: Is This Safe Practice?: A Report From the Pediatric Regional Anesthesia Network (PRAN).
A practice advisory on regional anesthesia in children in 2008, published in this journal, supported the placement of regional blocks in children under general anesthesia (GA). Interscalene brachial plexus (IS) blocks were specifically excluded, based on case reports (level 3 evidence) of injury, which occurred predominantly in heavily sedated or anesthetized adult patients. Apart from case reports, there is a paucity of data that explore the safety of IS blocks placed in patients under GA, and the level of evidence available on which to base recommendations is limited. ⋯ Analyzing interscalene blocks in children placed under GA, we identified no serious adverse events. The upper limit of the confidence interval for these events is similar to that in awake or sedated adults receiving IS blocks. Based on these prospectively collected data, placement of IS blocks under GA in children is no less safe than placement in awake adults, calling into question the American Society of Regional Anesthesia and Pain Medicine advisory proscribing GA during IS block in pediatric patients.
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Reg Anesth Pain Med · Nov 2014
Mechanisms Underlying Midazolam-Induced Peripheral Nerve Block and Neurotoxicity.
The benzodiazepine midazolam has been reported to facilitate the actions of spinally administrated local anesthetics. Interestingly, despite the lack of convincing evidence for the presence of γ-aminobutyric acid type A (GABAA) receptors along peripheral nerve axons, midazolam also has been shown to have analgesic efficacy when applied alone to peripheral nerves.These observations suggest midazolam-induced nerve block is due to another site of action. Furthermore, because of evidence indicating that midazolam has equal potency at the benzodiazepine site on the GABAA receptor and the 18-kd translocator protein (TSPO), it is possible that at least the nerve-blocking actions of midazolam are mediated by this alternative site of action. ⋯ Our results indicate that processes underlying midazolam-induced nerve block and neurotoxicity are separable, and suggest that selective activation of TSPO may facilitate modality-selective nerve block while minimizing the potential for neurotoxicity.