Anesthesiology
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Randomized Controlled Trial Clinical Trial
Relative analgesic potencies of levobupivacaine and ropivacaine for epidural analgesia in labor.
The minimum local analgesic concentration has been defined as the median effective local analgesic concentration (EC50) in a 20-ml volume for epidural analgesia in the first stage of labor. The aim of this study was to assess the relative analgesic potencies of epidural levobupivacaine and ropivacaine by determination of their respective minimum local analgesic concentrations. ⋯ This study demonstrated that levobupivacaine and ropivacaine are of similar potency for epidural analgesia in the first stage of labor.
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The effects of epidural needle design, angle, and bevel orientation on cerebrospinal fluid leak after puncture have not been reported. The impact of these factors on leak rate was examined using a dural sac model. Dural trauma was examined using scanning electron microscopy. ⋯ Cerebrospinal fluid leak after puncture was influenced most by epidural needle gauge. Leak rate was significantly less for the 20-gauge Tuohy needle.
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Cervical and high thoracic epidural anesthesia and analgesia have gained increasing importance in the treatment of painful conditions and as components of anesthetics for cardiac and breast surgery. In contrast to the hanging-drop technique, the loss-of-resistance technique is thought to rely on the penetration of the ligamentum flavum. However, the exact morphology of the ligamentum flavum at different vertebral levels remains controversial. Therefore, the aim of this study was to investigate the incidence and morphology of cervical and high thoracic ligamentum flavum mid-line gaps in embalmed cadavers. ⋯ In conclusion, the present study shows that gaps in the ligamenta flava are frequent at cervical and high thoracic levels but become rare at the T3/T4 level and below, such that one cannot always rely on the ligamentum flavum as a perceptible barrier to epidural needle placement at these levels.
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Nerve growth factor (NGF) is central to processes involved in an inflammatory hyperalgesia. Administration of exogenous NGF induces a hyperalgesia that is dependent on local neutrophil influx. The effects of administration of the cannabinoid anandamide and the cannabimimetic palmitoylethanolamide on an NGF-induced hyperalgesia and neutrophil accumulation were examined in this study. ⋯ NGF induced a thermal hyperalgesia that was attenuated by anandamide and palmitoylethanolamide. Only palmitoylethanolamide reduced neutrophil influx. Thus, cannabinoids show a neuronal CB1 receptor-mediated antihyperalgesic action and a separate inhibition of a proinflammatory neuroimmune process. Such a mechanism suggests a therapeutic site of analgesic action separable from central side effects.