Journal of clinical monitoring
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Interest in two-wavelength classic, that is, nonpulse, oximetry began early in the 20th century. Noninvasive in vivo measurements of oxygen saturation showed promise, but the methods were beset by several problems. The pulse oximetry technique, by focusing on the pulsatile arterial component, neatly circumvented many of the problems of the classic nonpulse arterial approach. ⋯ Many clinicians have recognized how valuable the assessment of the patient's oxygenation in real time can be. This appreciation has propelled the use of pulse oximeters into many clinical fields, as well as nonclinical fields such as sports training and aviation. Understanding how and what pulse oximetry measures, how pulse oximetry data compare with data derived from laboratory analysis, and how the pulse oximeter responds to dyshemoglobins, dyes, and other interfering conditions must be understood for the correct application and interpretation of this revolutionary monitor.
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Three patients are described in whom vascular complications occurred after placement of central venous catheters. Inappropriate catheter length and site of cannulation, catheter movement, and unsuitable catheter material can lead to complications. Guidelines for cannulation of central veins are defined, and recommendations for chest roentgenography, which could result in early recognition of catheter misplacement, are provided.
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This article describes several research directions exploring the application of artificial intelligence techniques in anesthesia and intensive care. Artificial intelligence can be loosely defined as the discipline of designing computer systems that exhibit "intelligent" behavior. ⋯ A discussion of the central research themes that arise in medical artificial intelligence, many of which are common to different projects and to different medical settings, is followed by a description of specific research projects that apply artificial intelligence techniques in anesthesiology, ventilatory management, and cardiovascular management. Finally, further comments are made on the current state of the field.
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Facial and hand muscles are used frequently for monitoring neuromuscular blockade. Therefore, we compared changes in electrically evoked muscle potential magnitude in upper facial and hypothenar muscles after fixed doses of neuromuscular blockers (succinylcholine, 750 micrograms/kg; pancuronium, 70 micrograms/kg; vecuronium, 50 micrograms/kg; and atracurium, 300 micrograms/kg). Face-hand comparisons were made in both anesthetized (nitrous oxide/narcotic, n = 51) and comatose (closed-head injuries, n = 5) patients. ⋯ The neuromuscular blockade in both the hand (49 +/- 54%) and the upper facial area (68 +/- 28%, P greater than 0.05) of comatose patients was smaller and more variable than that seen during anesthesia. These results illustrate the value of quantitative monitoring of neuromuscular function, especially during highly variable and unpredictable drug-induced blockade in the comatose state. We conclude that during narcotic-based anesthesia the upper facial and hand muscles are differentially sensitive to commonly used neuromuscular blockers.