Anesthesiology
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Randomized Controlled Trial
Mechanism-based pharmacokinetic-pharmacodynamic modeling of the antinociceptive effect of buprenorphine in healthy volunteers.
The objective of this investigation was to characterize the pharmacokinetic-pharmacodynamic relation of buprenorphine's antinociceptive effect in healthy volunteers. ⋯ This is consistent with observations in rats, suggesting that the rate-limiting step in the onset and offset of the antinociceptive effect is biophase distribution rather than slow receptor association-dissociation. In the dose range studied, no saturation of receptor occupancy occurred explaining the lack of a ceiling effect for antinociception.
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Randomized Controlled Trial
Short thyromental distance: a predictor of difficult intubation or an indicator for small blade selection?
Short thyromental distance (TMD; < 5 cm) has been correlated with difficult direct laryngoscopic intubation in adult patients. The authors hypothesized that a smaller Macintosh curved blade (No. 2 MCB) would improve the predicted difficult laryngoscopy in short-TMD patients over that with a standard Macintosh curved blade (No. 3 MCB). ⋯ The predicted difficult laryngoscopy and intubation with the use of the adult No. 3 MCB in standard adult patients with a TMD < or = 5 cm is significantly easier with use of the smaller No. 2 MCB.
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Randomized Controlled Trial
Differences between midazolam and propofol sedation on upper airway collapsibility using dynamic negative airway pressure.
Upper airway obstruction (UAO) during sedation can often cause clinically significant adverse events. Direct comparison of different drugs' propensities for UAO may improve selection of appropriate sedating agents. The authors used the application of negative airway pressure to determine the pressure that causes UAO in healthy subjects sedated with midazolam or propofol infusions. ⋯ At the mild to moderate level of sedation studied, midazolam and propofol sedation resulted in the same propensity for UAO. In this homogeneous group of healthy subjects, there was a considerable range of negative pressures required to cause UAO. The specific factors responsible for the maintenance of the upper airway during sedation remain to be elucidated.
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Neuropathic pain and radicular low back pain both have a major impact on human health worldwide. Microarray gene analysis on central nervous system tissues holds great promise for discovering novel targets for persistent pain modulation. ⋯ These two models of persistent pain produce similar allodynic outcomes but produce differential gene expression. These results suggest that diverging mechanisms lead to a common behavioral outcome in these pain models. Furthermore, these distinct pathophysiologic mechanisms in neuropathic versus radicular pain may implicate unique drug therapies for these types of chronic pain syndromes.