Chest
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The Epworth Sleepiness Scale (ESS) is a simple questionnaire measuring the general level of daytime sleepiness, called here the average sleep propensity. This is a measure of the probability of falling asleep in a variety of situations. The conceptual basis of the ESS involves a four-process model of sleep and wakefulness. ⋯ ESS scores significantly distinguished patients with primary snoring from those with obstructive sleep apnea syndrome (OSAS), and ESS scores increased with the severity of OSAS. Multiple regression analysis showed that ESS scores were more closely related to the frequency of apneas than to the degree of hypoxemia in OSAS. ESS scores give a useful measure of average sleep propensity, comparable to the results of all-day tests such as the multiple sleep latency test.
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Case Reports
Diagnosis of circumferential dissection of the ascending aorta by transesophageal echocardiography.
A 28-year-old woman with Marfan's syndrome presented with chest pain; transesophageal echocardiography showed circumferential dissection of the ascending aorta. Both aortic angiography with digital subtraction and computed tomography scanning with contrast were negative for dissection. Circumferential dissection of the ascending aorta was confirmed by surgery at which time replacement of the aorta and aortic valve were performed. Transesophageal echocardiography may become the most practical and reliable procedure for the diagnosis of aortic dissection.
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Tube thoracostomy is a standard therapy for a number of pulmonary disorders. The procedure is associated with a certain incidence of morbidity related to the technique of insertion, the patient population selected, and the length of time the tube remains in place. ⋯ A case of a delayed pulmonary perforation developing several days after placement of a chest tube is described with a discussion of the clinical and radiographic findings associated with this complication. A possible pathophysiologic mechanism by which this complication may have occurred is proposed.
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Comparative Study
Skeletal muscle metabolism in the chronic fatigue syndrome. In vivo assessment by 31P nuclear magnetic resonance spectroscopy.
Previous study of patients with chronic fatigue syndrome (CFS) has demonstrated a markedly reduced dynamic exercise capacity, not limited by cardiac performance and in the absence of clinical neuromuscular dysfunction, suggesting the possibility of a subclinical defect of skeletal muscle. ⋯ Patients with CFS and normal control subjects have similar skeletal muscle metabolic patterns during dynamic exercise and reach similar clinical and metabolic end points. However, CFS patients reach exhaustion much more rapidly than normal subjects, at which point they also have relatively reduced intracellular concentrations of ATP. These data suggest a defect of oxidative metabolism with a resultant acceleration of glycolysis in the working skeletal muscles of CFS patients. This metabolic defect may contribute to the reduced physical endurance of CFS patients. Its etiology is unknown. Whether CFS patients' overwhelming tiredness at rest has a similar metabolic pathophysiology or etiology also remains unknown.
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Supranormal mixed venous oxygen saturation (mixed venous hyperoxia), although reported, has never been characterized in humans resuscitated from cardiac arrest (postarrest cardiogenic shock). By contrast, cardiogenic shock without cardiopulmonary arrest (primary cardiogenic shock) is accompanied by mixed venous hypoxia under similar conditions of low oxygen delivery (DO2). The appearance of mixed venous hyperoxia indicates an excessive supply relative to demand in perfused tissue or cellular impairment of oxygen utilization, ie, low systemic oxygen consumption (VO2). Failure to improve VO2 has been associated with a poor outcome in other shock states. ⋯ These findings indicate an impairment of systemic oxygen utilization in postarrest cardiogenic shock patients. In spite of a lower DO2 than survivors, the OER in nonsurvivors remained lower than expected. Venous hyperoxia is a clinical manifestation of this derangement. Epinephrine dose may have a causal relationship. The inability to attain a VO2 of greater than 90 ml/min.m2 after the first 6 h of aggressive therapy was associated with a 100 percent mortality in 24 h.