Anesthesiology
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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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Comparative Study
Continuous, noninvasive, and localized microvascular tissue oximetry using visible light spectroscopy.
The authors evaluated the ability of visible light spectroscopy (VLS) oximetry to detect hypoxemia and ischemia in human and animal subjects. Unlike near-infrared spectroscopy or pulse oximetry (SpO2), VLS tissue oximetry uses shallow-penetrating visible light to measure microvascular hemoglobin oxygen saturation (StO2) in small, thin tissue volumes. ⋯ VLS oximetry provides a continuous, noninvasive, and localized measurement of the StO2, sensitive to hypoxemia, regional, and global ischemia. The reproducible and narrow StO2 normal range for oral/enteric mucosa supports use of this site as an accessible and reliable reference point for the VLS monitoring of systemic flow.
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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.
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Comparative Study
Correlation between the distribution of contrast medium and the extent of blockade during epidural anesthesia.
If the epidural spread of contrast medium can be well correlated with the spread of local anesthetics, epidurography can predict the dermatomal distribution of the anesthetic block. The authors evaluated the relation between radiographic and analgesic spread. ⋯ Epidurography is useful to indicate epidural catheter position and can help to predict the exact dermatomal distribution of analgesic block.
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Comparative Study
Measurement of cardiac output with indocyanine green transcutaneous fluorescence dilution technique.
Cardiac output is an essential parameter for the hemodynamic assessment of patients with cardiovascular disease. The authors tested in an animal model the feasibility of measuring cardiac output by transcutaneous fluorescence monitoring of an intravenous bolus injection of indocyanine green. ⋯ The proposed technique yielded accurate estimates of the cardiac output in experimental animals. This study should provide an initial framework for clinical testing of this new minimally invasive method for measuring cardiac output.