Biomedical subjects
G C Prechter
Publications and source records attributed to G C Prechter.
Nonabandonment: medical ethics.
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The ventilatory recruitment threshold for carbon dioxide.
We report our initial experience with a technique with which the chemoresponsiveness of the respiratory controller can be characterized in terms of an inspiratory on-switch threshold to CO2. After suppression of phasic respiratory muscle activity by mechanical ventilation, a CO2 recruitment threshold (PCO2RT) was defined as the lowest alveolar CO2 tension at which CO2 supplementation to inspired gas caused a reappearance of inspiratory efforts. Because PCO2RT can be determined in the absence of a mechanical load on the ventilatory pump, respiratory system mechanics and inspiratory muscle function should not influence the measurement itself. Thus, this technique may be helpful to study ventilatory requirements and load responses in critically ill patients with respiratory failure. We have shown that inspiratory muscle recruitment can be equally well-inferred from changes in the airway pressure and flow tracings during mechanical ventilation, from the pattern of chest wall displacement, and from the integrated diaphragm electromyogram. Within a subject, PCO2RT is a reproducible measurement that is not influenced by ventilator settings and end-expiratory lung volume, provided that phasic respiratory muscle has been suppressed prior to CO2 supplementation. Details of the methodology, the likely determinants of PCO2RT, and the clinical utility of this technique are discussed.
Bronchoscopy in the diagnosis of pulmonary histoplasmosis.
Although histoplasmosis is the most common fungal infection of the lungs in the United States, there are no reports evaluating the efficacy of fiberoptic bronchoscopy in the diagnosis of this disease. We reviewed all cases of histoplasmosis diagnosed at our institution from 1972 to 1987. Of 469 patients, 71 underwent fiberoptic bronchoscopy and had culture/histologic proof of histoplasmosis established by fiberoptic bronchoscopy or other means. A diagnosis of pulmonary histoplasmosis could be made without thoracotomy in only 27. Among those not requiring thoracotomy, diagnosis of pulmonary histoplasmosis was confirmed by fiberoptic bronchoscopy and cultures of sputum, gastric washings, blood, bone marrow, and urine. In this subgroup, fiberoptic bronchoscopy was the only positive diagnostic method in eight of 27 patients. We conclude that fiberoptic bronchoscopy is a useful adjunct to other noninvasive measures yielding diagnostic material in most cases, except for solitary pulmonary nodule where it is rarely helpful.
Postinfluenza toxic shock syndrome.
Postinfluenza toxic shock syndrome is a recently described entity that results from a respiratory tract infection with toxin-producing Staphylococcus aureus following an episode of influenza or influenzalike illness. This report describes a 19-year-old man who developed an influenza B respiratory infection complicated by staphylococcal pneumonia and toxic shock syndrome. The patient improved rapidly with specific antibiotic therapy, emphasizing the importance of considering this otherwise highly lethal syndrome in any individual who becomes critically ill after an initial influenzalike illness.
X-ray-negative dysphagia: is endoscopy necessary?
We reviewed our experience with patients with symptoms of dysphagia to determine whether endoscopy increased the chance of finding esophageal carcinoma when barium studies of the esophagus were normal. Endoscopy reports from 1974 to 1982 identified 195 patients with x-ray-negative dysphagia. In no patient was esophageal carcinoma found endoscopically. When patients with hiatal hernia (22) or endoscopic Grade I or II esophagitis (52) were excluded, only eight patients were found to have an endoscopic abnormality not demonstrated previously by x-ray. In addition, 56 cases of esophageal carcinoma seen at our institution over the same period all showed abnormal barium esophagrams at the time of presentation. We conclude that endoscopy to exclude esophageal carcinoma in patients with dysphagia is not as necessary as claimed, at least when adequate barium studies of the esophagus are normal.