Anesthesiology
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The visual analog scale is widely used in research studies, but its connection with clinical experience outside the research setting and the best way to administer the VAS forms are not well established. This study defines changes in dosing of intravenous patient-controlled analgesia as a clinically relevant outcome and compares it with VAS measures of postoperative pain. ⋯ When pain is an outcome measure in research studies, grouping final VAS scores into a small number of categories provides greater clinical relevance for comparisons than using the full spectrum of measured values or changes in value. Seeing an earlier VAS form has no apparent influence on later values.
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Clinical Trial
The transfer half-life of morphine-6-glucuronide from plasma to effect site assessed by pupil size measurement in healthy volunteers.
Clinical and experimental data suggested a long delay between the plasma concentration versus time course of morphine-6-glucuronide and the time course of its central opioid effects. This study was aimed at the quantification of the transfer half-life (t(1/2,ke0)) of this delay. ⋯ The reported numerical value of the t(1/2,ke0) of M6G in humans obtained after direct administration of M6G is a step toward a complete modeling approach to the prediction of the clinical effects of morphine. The study raises questions about the high interindividual variability of the transfer half-life between plasma and effect site (ke0) values and the apparent low potency of M6G.
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Clinical Trial
Internal jugular vein occlusion test for rapid diagnosis of misplaced subclavian vein catheter into the internal jugular vein.
During subclavian vein catheterization, the most common misplacement of the catheter is cephalad, into the ipsilateral internal jugular vein (IJV). This can be detected by chest radiography. However, after any repositioning of the catheter, subsequent chest radiography is required. In an effort to simplify the detection of a misplaced subclavian vein catheter, the authors assessed a previously published detection method. ⋯ The IJV occlusion test successfully detects the misplacement of subclavian vein catheter into the IJV. However, it does not detect any other misplacement. The test may allow avoidance of repeated exposure to x-rays after catheter insertion and repositioning.
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Ocular perfusion pressure is commonly defined as mean arterial pressure minus intraocular pressure (IOP). Changes in mean arterial pressure or IOP can affect ocular perfusion pressure. IOP has not been studied in this context in the prone anesthetized patient. ⋯ Prone positioning increases IOP during anesthesia. Ocular perfusion pressure could therefore decrease, despite maintenance of normotension.