Journal of anesthesia
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Journal of anesthesia · Jun 2015
Cannulation needle-induced anterior wall tenting of internal jugular vein causing posterior wall penetration.
Unintentional posterior venous wall penetration during internal jugular vein (IJV) cannulation may cause critical arterial injuries in spite of ultrasound guidance. We aimed to evaluate whether small venous diameter and anterior venous wall tenting by a needle would be associated with posterior venous wall penetration, and to seek factors related to the venous wall tenting. We conducted a retrospective review in patients who underwent IJV cannulation. ⋯ The longer anterior venous tenting would be expected with reducing needle angle (p = 0.004) or increasing anterior venous wall thickness (p = 0.006). In conclusion, small IJV and anterior venous wall tenting lead to posterior venous wall penetration. Anterior venous wall tenting is longer with reducing needle angle, or increasing the anterior venous wall thickness.
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Journal of anesthesia · Jun 2015
µ-Opioid receptor activation by tramadol and O-desmethyltramadol (M1).
Tramadol has been used as an analgesic for several decades. µ-Opioid receptors (µORs) are the major receptors that mediate the analgesic effects of opioids. Although µORs have been thought to be one of the sites of action of tramadol, there has been no report that directly proves whether tramadol is an agonist of μOR or not. In this study, we examined the effects of tramadol and its main active metabolite O-desmethyltramadol (M1), on the function of µORs using Xenopus oocytes expressing cloned human µORs. ⋯ Tramadol and M1 also evoked Cl(-) currents in the oocytes expressing µOR-G(qi5); however, relatively higher concentrations (compared to DMAGO) were necessary to induce such currents. Tramadol and M1 had a direct effect on µORs expressed in Xenopus oocytes. Although the monoamine uptake system and several types of ligand-gated ion channels are thought to be one of the targets for tramadol, tramadol-induced antinociception may be mediated at least in part, by the direct activation of µORs.