British journal of anaesthesia
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Central venous catheter (CVC) placement under ECG guidance in the left thoracocervical area can lead to catheter misplacement. The aim of this study was to identify the cause and quantify the magnitude of this error. ⋯ CVC placement under ECG guidance is a reliable method to site the line tip at the optimal position. However, when using a left-sided thoracocervical access point, the Seldinger wire-conducted ECG delivered a constant error. This could be adjusted for by advancing the CVC 20 mm in addition to the wire-based measurement of the insertion depth at the left IJ vein and 10 mm at the left SC vein.
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Post-dural puncture headache (PDPH) might be related to cerebrospinal fluid hypotension. Studies in brain-injured patients have shown a good relationship between optic nerve sheath diameter (ONSD) measured by ocular sonography and invasively measured intracranial pressure (ICP). The aim of this study was to evaluate changes in ONSD after lumbar epidural blood patch (EBP). ⋯ In this preliminary report, EBP was followed by ONSD enlargement in subjects with successful EBP, but not in the subject with EBP failure. Since ONSD is a surrogate marker of ICP, this suggests that a sustained increase in ICP is associated with successful EBP.
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Topical capsaicin formulations are used for pain management. Safety and modest efficacy of low-concentration capsaicin formulations, which require repeated daily self-administration, are supported by meta-analyses of numerous studies. A high-concentration capsaicin 8% patch (Qutenza™) was recently approved in the EU and USA. ⋯ Defunctionalization is due to a number of effects that include temporary loss of membrane potential, inability to transport neurotrophic factors leading to altered phenotype, and reversible retraction of epidermal and dermal nerve fibre terminals. Peripheral neuropathic hypersensitivity is mediated by diverse mechanisms, including altered expression of the capsaicin receptor TRPV1 or other key ion channels in affected or intact adjacent peripheral nociceptive nerve fibres, aberrant re-innervation, and collateral sprouting, all of which are defunctionalized by topical capsaicin. Evidence suggests that the utility of topical capsaicin may extend beyond painful peripheral neuropathies.