Anesthesia and analgesia
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Anesthesia and analgesia · Feb 2012
Comparative StudyR(+)-, Rac-, and S(-)-bupivacaine stereostructure-specifically interact with membrane lipids at cardiotoxically relevant concentrations.
It remains questionable whether local anesthetics can interact with membrane lipids at clinically relevant concentrations to show the difference between enantiomers. We compared the effects of bupivacaine stereoisomers on biomimetic membranes containing cardiolipin and cholesterol. ⋯ Such differences became greater with decreasing drug concentrations, possibly explaining the inconsistent cardiotoxic potencies of bupivacaine stereoisomers reported previously. The interactivity with biomembranes may in part contribute to the mode of toxic action of local anesthetics.
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Anesthesia and analgesia · Feb 2012
Determination of minimum alveolar concentration for isoflurane and sevoflurane in a rodent model of human metabolic syndrome.
Morbid obesity affects the pharmacokinetics and pharmacodynamics of anesthetics, which may result in inappropriate dosing. We hypothesized that obesity significantly alters the minimum alveolar concentration (MAC) for isoflurane and sevoflurane. To test this hypothesis, we used a rodent model of human metabolic syndrome developed through artificial selection for inherent low aerobic capacity runners (LCR) and high aerobic capacity runners (HCR). The LCR rats are obese, display phenotypes homologous to those characteristic of human metabolic syndrome, and exhibit low running endurance. In contrast, HCR rats have high running endurance and are characterized by improved cardiovascular performance and overall health. ⋯ Obesity and associated comorbidities do not affect anesthetic requirements as measured by MAC in a rodent model of metabolic syndrome. By contrast, high aerobic capacity is associated with a higher MAC for isoflurane and may be a risk factor for subtherapeutic dosing.
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Anesthesia and analgesia · Feb 2012
Editorial Historical ArticleRegional analgesia for postoperative pain: then & now.