Anesthesiology
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Randomized Controlled Trial Clinical Trial
Oral clonidine premedication does not alter the efficacy of simulated intravenous test dose containing low dose epinephrine in awake volunteers.
Clonidine premedication modifies the hemodynamic responses to sympathomimetics. The present study was designed to test whether clonidine altered the response to a small intravenous dose of epinephrine, such as that which might be used in an epidural test dose. ⋯ Oral clonidine does not alter the efficacy of epinephrine-containing test doses used for detecting intravascular injection.
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Randomized Controlled Trial Clinical Trial
Dose-range effects of clonidine added to lidocaine for brachial plexus block.
Although addition of clonidine to local anesthetics can prolong pain relief after peripheral nerve block, a dose-range effect has not been determined. ⋯ This study suggests that a small dose of clonidine enhances the quality of the peripheral blocks from lidocaine and limits the classical alpha2-agonist side effects to sedation.
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Increased carboxyhemoglobin concentrations in patients receiving inhalation anesthetics (desflurane, enflurane, and isoflurane) have been reported. Recent in vitro studies suggest that dry carbon dioxide absorbents may allow the production of carbon monoxide. ⋯ An oxygen flow rate of 10 l/min for 24 h in a conventional anesthesia circuit can dry carbon dioxide absorbents sufficiently to produce extremely high levels of carbon monoxide with high carboxyhemoglobin concentrations in desflurane-anesthetized pigs. When the reservoir bag is in place on the anesthesia machine or when a lower oxygen flow rate (5 l/min) is used, carbon dioxide absorbent drying still occurs, but 24-48-h exposure time is insufficient to allow for carbon monoxide production with desflurane.
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A knowledge of the distribution of different fluids given by intravenous infusion is basic to the understanding of the effects of fluid therapy. Therefore, a mathematical model was tested to analyze the volume kinetics of three types of fluids. ⋯ The distribution of intravenous fluids can be analyzed by a kinetic model adapted for fluid spaces, but slightly different results are obtained, depending on the marker used to indicate dilution of the primary fluid space. Analysis and simulation of plasma volume expansion by this model is a tool that can help the anesthetist to better plan fluid therapy.
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It has been suggested that the combination of analgesic drugs may have additive or synergistic effects. In clinical practice, this might allow better analgesia and reduction of side effects. ⋯ This study found a synergy between intravenous morphine and diclofenac that is consistent with and helps explain the clinical value of this type of combination in the treatment of acute pain in humans.