Anesthesia and analgesia
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Anesthesia and analgesia · Oct 2000
The efficacy and safety of EMLA cream for awake fiberoptic endotracheal intubation.
EMLA Cream (EC; Astra, Westborough, MA) has been widely used as a local anesthetic. Limited safety information is available with respect to the application of EC to the oral mucous membranes. The purpose of this pilot study was to evaluate the efficacy and safety of EC when applied to oral mucosa for fiberoptic intubation. ⋯ The measured peak plasma concentration of lidocaine or prilocaine did not reach toxic levels in any patient. Methemoglobin levels did not exceed normal values (1.5%) in any patient, and there was no relationship between methemoglobin levels and patient weight, amount of EC used, measured peak plasma concentration, or times to measured peak concentrations of prilocaine or lidocaine. We conclude that EC provided satisfactory topical anesthesia allowing for successful oral fiberoptic intubation in all patients and should be considered a safe alternative for anesthetizing the airway of patients requiring awake oral fiberoptic intubation.
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Anesthesia and analgesia · Oct 2000
Comparative StudyA magnetic resonance imaging study of modifications to the infraclavicular brachial plexus block.
A previously described infraclavicular brachial plexus block may be modified by using a more lateral needle insertion point, while the patient abducts the arm 45 degrees or 90 degrees. In performing the modified block on patients abducting 45 degrees, we often had problems finding the cords of the brachial plexus. Therefore, we designed an anatomic study to describe the ability of the recommended needle direction to consistently reach the cords. ⋯ Comparing the two arm positions, target precision and risk of contacting the pleura were more favorable with the greater arm abduction. We conclude that when the arm is abducted to 90 degrees, a 65 degrees -needle angle to the skin appears optimal for contacting the cords, still with a minimal risk of penetrating the pleura. However, this needs to be confirmed by a clinical study.
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Anesthesia and analgesia · Oct 2000
Comparative StudyA pilot study of left tracheal pulse oximetry.
We tested the hypothesis that left tracheal pulse oximetry (SpO(2)) is more accurate than finger SpO(2) when compared with oxygen saturation from arterial blood samples (SaO(2)) in anesthetized patients with normal thoracic anatomy. We also tested the hypothesis that tracheal oximetry readings are primarily derived from the tracheal mucosa. We studied 20 hemodynamically stable, well oxygenated, anesthetized patients with normal anatomy (ASA physical status I-III, 18-80 yr old). ⋯ We conclude that left tracheal SpO(2) is feasible and provides similar readings to arterial blood samples and more accurate readings than finger oximetry in hemodynamically stable, well oxygenated, anesthetized patients with normal thoracic anatomy. Tracheal oximetry readings are not primarily derived from the tracheal mucosa. The technique merits further evaluation.
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Anesthesia and analgesia · Oct 2000
The nonimmobilizer 1,2-dichlorohexafluorocyclobutane does not affect thermoregulation in the rat.
Inhaled and other anesthetics profoundly affect the central nervous system, causing amnesia, immobility in the face of noxious stimulation, and depression of thermoregulation. Nonimmobilizers, inhaled compounds whose lipophilicity suggests that they should be anesthetics, do not produce immobility, but they do cause amnesia. Their effects on thermoregulation were the subject of the present study. ⋯ The specific outcome was increased metabolism, as reflected in increased output of carbon dioxide. Isoflurane decreased the temperature threshold for such increases and the maximum response intensity, doing so in a concentration-dependent manner, whereas 2N had a minimal or no effect at any concentration up to 0.9 minimum alveolar concentration (estimated from its lipophilicity). Thus, 2N may be a useful tool for studies of the mechanisms mediating the thermoregulatory depression produced by anesthetics: 2N should not affect such a mechanism.
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Anesthesia and analgesia · Oct 2000
Comment Letter Comparative StudyNo need for claims: facts rule performance of jet ventilation.