Anesthesiology
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Randomized Controlled Trial Clinical Trial
Tryptase levels are not increased during vancomycin-induced anaphylactoid reactions.
Anaphylaxis, mediated by immunoglobulin E, may be clinically indistinguishable but is mechanistically different than chemically mediated anaphylactoid reactions induced by drugs such as morphine, curare, and vancomycin. A test to distinguish anaphylactic from anaphylactoid reactions would clarify therapeutic and medicolegal issues. Tryptase levels identify anaphylactic reactions but have not been evaluated in vivo during anaphylactoid reactions. A prospective, randomized, double-blinded, placebo-controlled trial of antihistamine chemoprophylaxis for rapid vancomycin infusion was performed, and plasma tryptase was measured using a new immunoassay. Histamine release was established by measurement of plasma histamine and the ability of prophylactic H1 and H2 antagonists to prevent common histamine-associated side effects. Tryptase levels were compared with histamine levels and clinical symptoms. ⋯ Plasma tryptase levels were not significantly elevated in confirmed anaphylactoid reactions, so they can be used to distinguish chemical from immunologic reactions.
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Randomized Controlled Trial Comparative Study Clinical Trial
Epidural bupivacaine-morphine analgesia versus patient-controlled analgesia following abdominal aortic surgery: analgesic, respiratory, and myocardial effects.
The efficacy and effects of epidural analgesia compared with patient-controlled analgesia (PCA) have not been reported in patients undergoing major vascular surgery. We compared the effects of epidural bupivacaine-morphine with those of intravenous PCA morphine after elective infrarenal aortic surgery. ⋯ Epidural morphine-bupivacaine is associated with reduced early postoperative intravenous opioid requirements, more rapid tracheal extubation, and superior analgesia after abdominal aortic surgery, with comparable respiratory effects.
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Randomized Controlled Trial Clinical Trial
Reversal of the sedative and sympatholytic effects of dexmedetomidine with a specific alpha2-adrenoceptor antagonist atipamezole: a pharmacodynamic and kinetic study in healthy volunteers.
Specific and selective alpha2-adrenergic drugs are widely exploited in veterinary anesthesiology. Because alpha2-agonists are also being introduced to human practice, the authors studied reversal of a clinically relevant dexmedetomidine dose with atipamezole, an alpha2-antagonist, in healthy persons. ⋯ The sedative and sympatholytic effects of intramuscular dexmedetomidine were dose dependently antagonized by intravenous atipamezole. The applied infusion rate (75 microg x kg(-1) x min(-1)) for the highest atipamezole dose was, however, too fast, as evident by transient sympathoactivation. Similar elimination half-lives of these two drugs are a clear advantage considering the possible clinical applications.
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Randomized Controlled Trial Clinical Trial
Bispectral EEG index during nitrous oxide administration.
Nitrous oxide (N2O) is a commonly used sedative for painful diagnostic procedures and dental work. The authors sought to characterize the effects of N2O on quantitative electroencephalographic (EEG) variables including the bispectral index (BIS), a quantitative parameter developed to correlate with the level of sedation induced by a variety of agents. ⋯ Although the spectral content of the EEG changed during N2O administration, reflecting some pharmacologic effect, the subjects remained cooperative and responsive throughout, and therefore N2O can only be considered a weak sedative at the tested concentrations. Despite changes in the lower and higher frequency ranges of EEG activity, the BIS did not change, which is consistent with its design objective as a specific measure of hypnosis.
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Diphenhydramine is used as an antipruritic and antiemetic in patients receiving opioids. Whether it might exacerbate opioid-induced ventilatory depression has not been determined. ⋯ Diphenhydramine counteracts the alfentanil-induced decrease in the slope of the ventilatory response to carbon dioxide. However, at PETCO2 = 46 mmHg, it does not significantly alter the alfentanil-induced shift in the carbon dioxide response curve. In addition, diphenhydramine does not exacerbate the opioid-induced depression of the hypoxic ventilatory response during moderate hypercarbia.