Articles: general-anesthesia.
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The relative accuracy of Thermoscan PRO-1 (Thermoscan, USA), an infrared ear thermometer, in an unadjusted mode was examined in 21 patients under general anesthesia, using the esophageal and tympanic membrane temperatures as the reference values. The correlation coefficient between the temperature measured by Thermoscan PRO-1 and the esophageal temperature, and that between the temperature measured by Thermoscan PRO-1 and the tympanic membrane temperature, were 0.953 and 0.942, respectively (P < 0.01). The "limits of agreement" between the temperature measured by Thermoscan PRO-1 and esophageal temperature, and between the temperature measured by Thermoscan PRO-1 and tympanic membrane temperature, were -0.5-0.4 degrees C and -0.5-0.5 degrees C, respectively. We conclude that Thermoscan PRO-1 is sufficiently reliable for monitoring body temperature during surgery.
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Anaesth Intensive Care · Aug 1994
ReviewControl of carbon dioxide levels during neuroanaesthesia: current practice and an appraisal of our reliance upon capnography.
With the widespread availability of capnography, many anaesthetists have swung away from formally verifying hypocapnia by intraoperative arterial blood gas analysis and, instead, have come to rely upon capnography as an acceptable and constant predictor of arterial CO2 tension (PaCO2) during neurosurgery. However, the nature of the arterial-end-tidal CO2 gradient is complex, and is frequently unexpectedly large, or even negative. The importance of close intraoperative CO2 control during neurosurgery--more specifically, routine hyperventilation, and our reliance upon capnography to guide intraoperative management--is reappraised. There is a growing appreciation of the adverse effects of hyperventilation and hypocarbia, especially upon abnormal or ischaemic brain, and it is clear that capnography alone cannot be used to confidently predict the true PaCO2 during neuroanaesthesia.
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Review Comparative Study
Anesthesia for microlaryngeal surgery: the case for subglottic jet ventilation.
Although the techniques for surgery on the endolarynx using suspension and the operating microscope have been fully developed, the safest, and least obtrusive anesthetic technique has yet to be manifested, as evidenced by more than 200 references to anesthesia for microlaryngoscopy in the world literature. This study reviews the physiology, physics, and problems of each anesthetic technique. In light of this review, animal and human studies are reported demonstrating the utility and safety of subglottic ventilation when provided with proper monitoring using an automatic ventilator. ⋯ There was no difference in the flammability of Silastic, rubber or PVC when struck by these lasers in this study. For these reasons, subglottic ventilation using a fluoroplastic, monitored, self-centering, subglottic, jet ventilation tube driven by an automatic ventilator with a shutdown feature, in the event of excessive pressure buildup, is proposed for anesthetizing healthy patients undergoing suspension microlaryngoscopy, and who have no airway obstructing lesion. A large tube with inflatable cuff is indicated when a supraglottic lesion may obstruct the airway.
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Anesthesia and analgesia · Aug 1994
Changes in heart rate variability under propofol anesthesia: a possible explanation for propofol-induced bradycardia.
We propose to study the bradycardia associated with propofol anesthesia. Ten women undergoing laparoscopy for benign disease were studied using ambulatory electrocardiogram monitoring. Anesthesia was induced with an intravenous bolus of propofol and maintained with an infusion. ⋯ We conclude that high-frequency variability reflects parasympathetic tone. Propofol anesthesia reduces parasympathetic tone to a lesser degree than sympathetic tone. This autonomic milieu predisposes the patient to developing bradycardia in response to parasympathetic stimuli.