Anesthesiology
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Randomized Controlled Trial Comparative Study Clinical Trial
Absence of bronchodilation during desflurane anesthesia: a comparison to sevoflurane and thiopental.
Bronchospasm is a potential complication in anyone undergoing general anesthesia. Because volatile anesthetics relax bronchial smooth muscle, the effects of two newer volatile anesthetics, desflurane and sevoflurane, on respiratory resistance were evaluated. The authors hypothesized that desflurane would have greater bronchodilating effects because of its ability to increase sympathetic nervous system activity. ⋯ Sevoflurane causes moderate bronchodilation that is not observed with desflurane or sodium thiopental. The bronchoconstriction produced by desflurane was primarily noted in patients who currently smoked. (Key words: Bronchospasm; respiratory resistance; volatile anesthetics.)
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Randomized Controlled Trial Clinical Trial
Acute opioid tolerance: intraoperative remifentanil increases postoperative pain and morphine requirement.
Rapid development of acute opioid tolerance is well established in animals and is more likely to occur with large doses of short-acting drugs. The authors therefore tested the hypothesis that intraoperative remifentanil administration results in acute opioid tolerance that is manifested by increased postoperative pain and opioid requirement. ⋯ Relatively large-dose intraoperative remifentanil increased postoperative pain and morphine consumption. These data suggest that remifentanil causes acute opioid tolerance and hyperalgesia.
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Randomized Controlled Trial Clinical Trial
Epidural infusion of ropivacaine for postoperative analgesia after major orthopedic surgery: pharmacokinetic evaluation.
Changing plasma protein concentrations may affect the protein binding and pharmacokinetics of drugs in the postoperative phase. Therefore, the authors evaluated the pharmacokinetics of ropivacaine, administered by 72-h epidural infusion to provide postoperative analgesia. ⋯ Postoperative increases in plasma alpha1-acid glycoprotein concentrations enhance the protein binding of ropivacaine and pipecoloxylidide, causing divergence of total and unbound plasma concentrations.
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Randomized Controlled Trial Clinical Trial
Competence of the internal jugular vein valve is damaged by cannulation and catheterization of the internal jugular vein.
Experimental results suggest that the competence of the internal jugular vein (IJV) valve may be damaged when the IJV is cannulated for insertion of a central venous catheter. It has further been hypothesized that the risk of causing incompetence of the proximally located valve might be reduced by using a more distal site for venous cannulation. The present study evaluated these hypotheses in surgical patients. ⋯ Cannulation and catheterization of the IJV may cause persistent incompetence of the IJV valve. Choosing a more distal site for venous cannulation may slightly lower the risk of causing valvular incompetence but does not reliably avoid it.
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This study determined the responses to increasing plasma concentrations of dexmedetomidine in humans. ⋯ Increasing concentrations of dexmedetomidine in humans resulted in progressive increases in sedation and analgesia, decreases in heart rate, cardiac output, and memory. A biphasic (low, then high) dose-response relation for mean arterial pressure, pulmonary arterial pressure, and vascular resistances, and an attenuation of the cold pressor response also were observed.