Chest
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The effects of changes in arterial carbon dioxide tension (PaCO2) on the oxygenation of tissues in 34 patients undergoing surgery for aortocoronary bypass were studied while temperature, systemic blood flow, and the delivery of oxygen to the peripheral tissues remained constant. Mixed venous and superior vena caval oxygen tensions (PvO2 and PsvcO2, respectively) and oxyhemoglobin saturations and the in vivo partial pressure of oxygen at which 50 percent of the hemoglobin is saturated (P50) increased with PaCO2, while peripheral vascular resistance, in vitro P50, the level of 2,3-diphosphoglyceric acid in the red blood cells, and the level of lactate in the blood remained constant. ⋯ This indicated that the total-body consumption of oxygen diminished with increases in PaCO2 but that some regional redistribution of oxygen consumption occurred between the superior and inferior vena caval vascular beds. Since the level of lactate in the blood remained constant and since signs of metabolism acidosis did not develop, the reduced oxygen consumption due to increases in PaCO2 did not result in detectable increases in anaerobic metabolism.
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Case Reports
Psoriasis, sacroiliitis, and aortitis: an echocardiographic mimic of aortic root dissection.
A patient with psoriasis, HLA-B27-positive sacroiliitis, and aortitis presented with clinical features suggesting acute aortic dissecting aneurysm. Although M-mode and two dimensional echocardiography supported the diagnosis, dissection was excluded by angiography and by direct observation at surgery. Asymmetric thickening of the right coronary cusp secondary to psoriatic aortitis was found to be etiologic of both the regurgitation and the false-positive echo for dissection. It is emphasized that in the setting of any fibrocalcific or inflammatory disease of the aorta, the echo diagnosis of dissection is fraught with hazard.
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In ten patients with bilateral vocal cord paralysis, we demonstrated variable extrathoracic airway obstruction. The ratio of forced expiratory flow at 50 percent vital capacity to forced inspiratory flow at the same lung volume (VE50/VI50) was 1.65 +/- 0.77 (mean +/- 1 SD). ⋯ Nine of the ten patients required tracheostomy for symptoms of dyspnea. Follow-up flow volume loops were obtained to document the effects of surgical intervention and tracheostomy.
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Comparative Study
Racial and sexual differences in the standard electrocardiogram of black vs white adolescents.
Standard 12-lead electrocardiograms were recorded in 114 healthy adolescents to substantiate possible influences of race and sex on the "juvenile pattern" (increased precordial voltages of QRS complex, precordial T wave inversions, and ST-segment elevations considered pathologic in adults) in this age group. Black male subjects had the highest precordial QRS amplitudes and the highest incidence of biphasic or negative precordial T waves and ST-segment deviations. In white male subjects, these findings were less pronounced but were more evident than in black or white female subjects. Results indicate the following: (1) race-specific and sex-specific normal electrocardiographic standards should be developed in adolescents; (2) criteria for left ventricular hypertrophy are race-specific and sex-specific and should be tested against independent anatomic or physiologic information in adolescents with left ventricular overload; and (3) the "juvenile pattern" may be viewed as a predictable continuum of age-related changes starting in childhood and progressing through adolescence on to later life.
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Case Reports
Tuberculous aneurysms of the descending thoracic aorta: report of a case with fatal rupture.
Tuberculous aortic aneurysm is a rare disease entity. The majority of affected patients succumb to perforation and exsanguination. ⋯ Post-mortem examination revealed that the mechanism of aneurysm formation was by direct caseous involvement of the descending thoracic aorta from a juxtaposed left upper lobe parenchymal tuberculous process. Our findings also favor the concept that miliary dissemination (in the presence of tuberculous aortic aneurysm) is the result rather than the cause of the tuberculous aortic process.