Anesthesiology
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A newly developed microemulsion propofol consisted of 10% purified poloxamer 188 and 0.7% polyethylene glycol 660 hydroxystearate. The authors studied the physicochemical properties, aqueous free propofol concentration, and plasma bradykinin generation. Pharmacokinetics and pharmacodynamics were also evaluated in rats. ⋯ Microemulsion propofol produced a high concentration of free propofol in the aqueous phase. For the applied dose range, microemulsion propofol showed nonlinear pharmacokinetics.
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Application of radiofrequency currents to the dorsal root ganglia, in the treatment of various pain syndromes, has been clinically practiced for more than 30 yr. The clinical efficacy and the safety of this technique, however, remain poorly understood. The authors reviewed the literature on this modality of pain relief to determine its clinical efficacy, safety, and mechanisms of action. ⋯ Five randomized controlled trials evaluated their clinical use; these trials were relatively short-termed and small in size, and their results were variable. The mechanism of action of these techniques was unclear. Larger controlled clinical trials evaluating the long-term effects of these techniques and basic science research to determine their precise mode of action are needed.
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Randomized Controlled Trial Clinical Trial
Motor and somatosensory evoked potentials are well maintained in patients given dexmedetomidine during spine surgery.
Many commonly used anesthetic agents produce a dose-dependent amplitude reduction and latency prolongation of evoked responses, which may impair diagnosis of intraoperative spinal cord injury. Dexmedetomidine is increasingly used as an adjunct for general anesthesia. Therefore, the authors tested the hypothesis that dexmedetomidine does not have a clinically important effect on somatosensory and transcranial motor evoked responses. ⋯ Use of dexmedetomidine as an anesthetic adjunct at target plasma concentrations up to 0.6 ng/ml does not change somatosensory or motor evoked potential responses during complex spine surgery by any clinically significant amount.
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Randomized Controlled Trial
Antiinflammatory effect of peripheral nerve blocks after knee surgery: clinical and biologic evaluation.
Nerve blocks provide analgesia after surgery. The authors tested whether nerve blocks have antiinflammatory effects. ⋯ Nerve blocks inhibited clinical inflammation after total knee arthroplasty, with no change in tissue and plasma cytokine concentrations.
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Intraneural injection during peripheral nerve blockade can cause neurologic injury. Current approaches to prevent or detect intraneural injection lack reliability and consistency, or only signal intraneural injection upon the event. A change in electrical impedance (EI) could be indicative of intraneural needle placement before injection. ⋯ With further study, EI could prove to be a quantifiable warning signal to alert clinicians to intraneural needle placement, preventing local anesthetic injection and subsequent nerve injury.