Anesthesiology
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Application of radiofrequency currents to the dorsal root ganglia, in the treatment of various pain syndromes, has been clinically practiced for more than 30 yr. The clinical efficacy and the safety of this technique, however, remain poorly understood. The authors reviewed the literature on this modality of pain relief to determine its clinical efficacy, safety, and mechanisms of action. ⋯ Five randomized controlled trials evaluated their clinical use; these trials were relatively short-termed and small in size, and their results were variable. The mechanism of action of these techniques was unclear. Larger controlled clinical trials evaluating the long-term effects of these techniques and basic science research to determine their precise mode of action are needed.
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Clinical Trial
Using permutation entropy to measure the electroencephalographic effects of sevoflurane.
Approximate entropy (AE) has been proposed as a measure of anesthetic drug effect in electroencephalographic data. Recently, a new method called permutation entropy (PE) based on symbolic dynamics was also proposed to measure the complexity in an electroencephalographic series. In this study, the AE and PE were applied to electroencephalographic recordings for revealing the effect of sevoflurane on brain activity. The dose-response relation of PE during sevoflurane anesthesia was compared with that of AE. ⋯ The results show that PE can estimate the sevoflurane drug effect more effectively than AE. This method could be applied to design a new electroencephalographic monitoring system to estimate sevoflurane anesthetic drug effect.
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Previous studies have shown that genetic variability at position 118 of the human mu-opioid receptor gene altered patients' response to intravenous morphine. The purpose of this study was to investigate whether this polymorphism contributes to the variability in response to morphine for postcesarean analgesia. ⋯ Genetic variation at position 118 of the mu-opioid receptor is associated with interindividual differences in pain scores, self-administered intravenous morphine, and the incidence of nausea postoperatively.
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Malignant hyperthermia (MH) is a hypermetabolic condition caused by a genetic disposition leading to increased Ca release from the sarcoplasmic reticulum after exposure to triggering agents. In the authors' ongoing evaluation of patients undergoing MH testing in Austria, they detected a family with a new variant of the ryanodine receptor 1. Guidelines suggest that genetic tests are possible only for individuals from families in which the mutations are known. The aim of this study was to provide functional data that establish a potential link between this new variant and susceptibility to MH, and thus enable application in genetic tests. ⋯ These data document a role of the new W3985R variant in MH susceptibility.
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Biography Historical Article
John H. Eisenach, M.D., recipient of the 2008 Presidential Scholar Award.