Anesthesiology
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Randomized Controlled Trial Clinical Trial
Thermoregulatory thresholds for vasoconstriction in patients anesthetized with various 1-minimum alveolar concentration combinations of xenon, nitrous oxide, and isoflurane.
Nitrous oxide limits intraoperative hypothermia because the vasoconstriction threshold with nitrous oxide is higher than with equi-minimum alveolar concentrations of sevoflurane or isoflurane, presumably because of its stimulating actions on the sympathetic nervous system. Xenon, in contrast, does not cause sympathetic activation. Therefore, the authors tested the hypothesis that the vasoconstriction threshold during xenon-isoflurane anesthesia is less than during nitrous oxide-isoflurane anesthesia or isoflurane alone. ⋯ Xenon inhibits thermoregulatory control more than isoflurane, whereas nitrous oxide is the least effective in this respect.
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Randomized Controlled Trial Clinical Trial
Ritonavir's role in reducing fentanyl clearance and prolonging its half-life.
The human immunodeficiency virus protease inhibitor ritonavir is a potent inhibitor of the cytochrome P450 3A4 enzyme, and ritonavir's concomitant administration with the substrates of this enzyme may lead to dangerous drug interactions. ⋯ Ritonavir can inhibit the metabolism of fentanyl significantly, so caution should be exercised if fentanyl is given to patients receiving ritonavir medication.
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Inhaled nitric oxide is often used in patients with adult respiratory distress syndrome. However, nitric oxide also may be significantly toxic, especially if administered concurrently with hyperoxia. The authors evaluated the isolated effect of nitric oxide and the combined effects of nitric oxide and hyperoxia on lung injury in rats after acid aspiration. ⋯ These results show that inhaled nitric oxide at 80 ppm for a short duration (5 h) increases the severity of the inflammatory microvascular lung injury after acid aspiration. The pulmonary damage is exacerbated further in the presence of high oxygen concentrations. Although lower concentrations of nitric oxide did not increase the extent of lung injury, longer exposure times need to be assessed.
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Intrathecally administered adenosine receptor agonists have antinociceptive effects in animals, suggesting that intrathecal adenosine might provide analgesia in humans. The authors performed preclinical neurotoxicity studies to define the safety of intrathecally administered adenosine in rats and dogs. ⋯ The current study in rats and dogs failed to provide behavioral or histologic evidence of neurotoxicity from intrathecal administration of adenosine. This provides evidence for the presumption of safety of adenosine in this dose range, and supports phase I safety trials of acute intrathecal adenosine administration in humans.
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Randomized Controlled Trial Comparative Study Clinical Trial
Preoxygenation: comparison of maximal breathing and tidal volume breathing techniques.
Preoxygenation with tidal volume breathing for 3-5 min is recommended by Hamilton and Eastwood. This report compares tidal volume preoxygenation technique with deep breathing techniques for 30-60 s. ⋯ Rapid preoxygenation with the eight deep breaths within 60 s can be used as an alternative to the traditional 3-min technique.