Anesthesiology
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Randomized Controlled Trial Comparative Study Clinical Trial
Phase Ia and Ib study of amitriptyline for ulnar nerve block in humans: side effects and efficacy.
The antidepressant amitriptyline is used as an adjuvant in the treatment of chronic pain conditions. Among its many actions, this drug also blocks ion channels, such as Na channels. Preliminary animal studies suggested that amitripty-line would be a longer-lasting local anesthetic than bupivacaine, with potentially fewer side effects. Therefore, the authors investigated the adverse effects and effectiveness of this drug when given for ulnar nerve blockade in human volunteers. ⋯ Because of the lack of evidence that amitripty-line provides better nerve blockade than current local anesthetics and the potential for neurotoxicity, its use for peripheral nerve blockade in humans seems limited.
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Randomized Controlled Trial Comparative Study Clinical Trial
Pharmacodynamic interaction between propofol and remifentanil regarding hypnosis, tolerance of laryngoscopy, bispectral index, and electroencephalographic approximate entropy.
The purpose of this investigation was to describe the pharmacodynamic interaction between propofol and remifentanil for probability of no response to shaking and shouting, probability of no response to laryngoscopy, Bispectral Index (BIS), and electroencephalographic approximate entropy (AE). ⋯ Remifentanil alone is ineffective at ablating response to stimuli but demonstrates potent synergy with propofol. BIS and AE values corresponding to 95% probability of ablating response are influenced by the combination of propofol and remifentanil to achieve this endpoint, with higher propofol concentrations producing lower values for BIS and AE.
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Randomized Controlled Trial Comparative Study Clinical Trial
A response surface analysis of propofol-remifentanil pharmacodynamic interaction in volunteers.
Characterizing drug interactions using a response surface allows for the determination of the interaction over a complete range of clinically relevant concentrations. Gathering the data necessary to create this surface is difficult to do in a clinical setting and requires the use of volunteer experiments with surrogate noxious stimuli to adequately control the process for data collection. The pharmacodynamic synergy of opioids and hypnotics was investigated using a volunteer study paradigm. ⋯ The response surface models reveal the tremendous synergy between remifentanil and propofol. The surface morphologic features give some indication of the relative contribution of sedation and analgesia to blunting subject response. Further, the results of this investigation validate the volunteer study paradigm and use of surrogate effect measures for its clinical relevance.
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Randomized Controlled Trial Comparative Study Clinical Trial
Electrical nerve localization: effects of cutaneous electrode placement and duration of the stimulus on motor response.
Recommendations regarding the technical aspects of nerve stimulator-assisted nerve localization are conflicting. The objectives of this study were to determine whether the placement of the cutaneous electrode affects nerve stimulation and to determine the duration and intensity of an electrical stimulus that allows nerve stimulation with minimal discomfort. ⋯ Site of placement of the cutaneous electrode is not important when constant current nerve stimulators are used during nerve localization in regional anesthesia. There is an inverse relation between the current required to obtain a visible motor response and current duration. Selecting a current duration between 0.05 and 1.0 ms to specifically stimulate sensory or motor components of a mixed nerve does not seem to be important in clinical practice.
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Clinical Trial Controlled Clinical Trial
Determination of the pharmacodynamic interaction of propofol and remifentanil during esophagogastroduodenoscopy in children.
Propofol is commonly used to anesthetize children undergoing esophagogastroduodenoscopy. Opioids are often used in combination with propofol to provide total intravenous anesthesia. Because both propofol and remifentanil are associated with rapid onset and offset, the combination of these two drugs may be particularly useful for procedures of short duration, including esophagogastroduodenoscopy. The authors previously demonstrated that the median effective concentration (C50) of propofol during esophagogastroduodenoscopy in children is 3.55 microg/ml. The purpose of this study was to describe the pharmacodynamic interaction of remifentanil and propofol when used in combination for esophagogastroduodenoscopy in pediatric patients. ⋯ A remifentanil infusion of 25 ng.kg(-1).min(-1) reduces the concentration of propofol required for adequate anesthesia for esophagogastroduodenoscopy from 3.7 to 2.8 microg/ml. Increasing the remifentanil infusion yields minimal additional decrease in propofol concentration and may increase the risk of side effects.