Biomedical subjects
Publications and source records attributed to J B Bass.
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The physiologic effects, efficacy, and serum lidocaine concentrations were determined in 10 normal volunteers who inhaled nebulized lidocaine from a compressed gas-powered jet nebulizer. Physiologic variables and serial venous serum lidocaine concentrations were measured during and after lidocaine inhalation. All 10 subjects experienced loss of the gag reflex, which returned to normal at 32 +/- 5.9 min (mean +/- 1 SD), with a range of 20 to 40 min. There were no significant changes in systolic or diastolic blood pressures or heart rates. There were no significant changes from baseline in any of the measured spirometric variables (FVC, FEV1, peak expiratory flow rate, peak inspiratory flow rate). The peak mean serum lidocaine concentration measured at 20 min after beginning lidocaine inhalation was 0.52 microgram/ml, and the highest single value measured was 1.05 micrograms/ml. We conclude that inhalation of lidocaine from a compressed gas-powered jet nebulizer can produce safe and effective oropharyngeal anesthesia with minimal drug absorption.
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A previous report from our institution showed that the use of a two-step tuberculin testing program in new employees reduced the apparent rate of conversion in annual skin testing by eliminating the effect of the booster phenomenon. However, the converter rate subsequently remained too high. We propose that the use of 10 mm of induration as the cutting point gave a high rate of false conversion in our area of high prevalence of sensitivity to nontuberculous mycobacteria. A change to 15 mm of duration as the cutting point reduced our conversion rate from 2.6 to 1.2%, identified a group who demonstrated continued large tuberculin reactions at repeat testing, and eliminated age dependency from our converter population. We propose the choice of 15 mm of induration as the appropriate cutting point in annual employee tuberculin skin testing programs in areas in which sensitivity to nontuberculous mycobacteria is common.
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The speed and accuracy of diagnosis of tuberculosis on general medical teaching services were retrospectively compared to that on a designated publicly funded tuberculosis service and to recent discouraging reports in the literature. The diagnosis was confirmed in all patients on the designated service and in 78.8% of patients not on the designated service within one week. No patient was discharged undiagnosed. Acid-fast smears done by the hospital laboratory showed a sensitivity of 82.5% and a specificity of 98.4%. Radiologic reports indicated the presence of tuberculosis or cavities in 85% of chest x-ray films in patients with pulmonary disease. These results may indicate that a publicly funded tuberculosis service, by providing emphasis on tuberculosis, allows more rapid and accurate diagnosis of tuberculosis in all patients. The impact of such training on future health care delivery should be recognized when decisions regarding allocation of public funds are made.
We prospectively compared the usefulness of a bronchoscopic protected catheter technique with the results from sputum cultures in the evaluation of moxalactam, a new beta-lactam antibiotic. The significance of a given isolate on protected catheter culture was determined by quantitative bacteriology. 32 patients with community-acquired pneumonia were enrolled in the study and 31 grew common lower respiratory tract pathogens from their protected catheter specimen. The most common single pathogens recovered were Streptococcus pneumoniae (11 patients) and Haemophilus influenzae (2). Mixed flora, predominantly anaerobes, were isolated from 15 patients, and 3 patients had mixed aerobic infections. All seven bacteremic cases had the identical organism isolated from the protected catheter specimen, confirming the accuracy of the technique. Comparisons with sputum cultures showed that the predominant organism on sputum culture was the same as that obtained from the protected catheter culture in only 13% of the cases. Sputum cultures revealed either no pathogen or a different pathogen in 23 cases, and no sputum could be obtained in 4. Compared to cultures of expectorated sputum, we found the protected catheter bronchoscopic culture technique to have the following advantages in the bacteriologic evaluation of moxalactam: 1) greater accuracy and sensitivity in bacteremic patients; 2) accurate delineation of the bacteriology of infections; and 3) a higher percentage of patients with evaluable bacteriology leading to greater efficiency during the investigation.
Quantitative bacteriology was performed on specimens collected by protected catheter fiberoptic bronchoscopy from 172 patients. Of the patients who had pneumonia, 75 of 78 (96%) had one or more species present at greater than or equal to 10(3) CFU/ml, whereas 2 of 35 (6%) control patients had organisms present in that quantity. In addition, 66% of the control specimens yielded no isolates by this technique. All of the 11 patients with bronchitis had greater than or equal to 10(3) CFU/ml. Quantitative bacteriology revealed high levels of colonization in patients without infection and endobronchial structural disease. The data suggest that bacterial counts of greater than or equal to 10(3) CFU/ml in suspended secretions collected with a protected catheter brush were diagnostic of the bacteriological etiology of lower respiratory tract infections in patients without endobronchial structural abnormalities.
Tuberculosis has declined in incidence over the past several decades, but disease due to nontuberculous mycobacteria has not. Although mycobacteria other than tuberculosis are commonly isolated in medical laboratories, isolation of such organisms does not necessarily imply disease. Generalizations concerning diagnoses and therapy of nontuberculous mycobacterial diseases are not possible because the various organisms differ greatly in ability to produce disease and response to therapy.
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Fiberoptic bronchoscopy using a protected brush catheter was done in 65 patients with suspected pulmonary infections to obtain uncontaminated specimens for culture. Quantitative aerobic and anaerobic cultures were done on each specimen. Forty-one patients had pneumonia. Ten bacteremic patients had the same organisms recovered from the catheter and blood cultures. Seven patients had received antibiotics before the procedure, and cultures grew no organisms in high concentration. In 23 of 24 remaining patients probable pathogens were recovered in high concentrations, and specific therapy resulted in clinical improvement in all of these patients. Five patients with lung abscesses and seven with necrotizing pneumonia had mixed aerobic and anaerobic organisms recovered. Twelve patients had final diagnoses of nonbacterial lung disease, and cultures were negative or revealed low concentrations of organisms. Quantitative cultures were necessary in distinguishing pathogens from nonpathogens. There were no complications. The results of this study indicate that fiberoptic bronchoscopy using a special protected catheter is an accurate and safe technique for identification of etiologic agents in lower respiratory tract infections.
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A case of a pulmonary intracavitary fungus ball composed of Syncephalastrum sp., a member of the class Zygomycetes not previously reported in association with human disease, is presented. The fungus was cultured preoperatively from bronchial secretions as well as from the fungal mass from the resected lung. This fungus appeared to behave in a saprophytic manner similar to that of the more common Aspergillus fungus ball.
A 26-year-old-man developed severe obstructive lung disease after inhalation of smoke from a house fire. Bronchography demonstrated changes characteristic of bronchiolitis. Despite intensive therapy with bronchodilators and corticosteroids, he continues to have severe obstructive lung disease nine months after the smoke inhalation.
The pathogenesis and treatment of diabetic ketoacidosis has been discussed. Insulin deficiency leads to increased rates of hepatic ketogenesis and gluconeogenesis with resultant hyperglycemia and ketonemia. Treatment consists of insulin and fluid replacement. Insulin therapy is titrated against the change in blood glucose concentration. Isotonic saline is the initial replacement fluid, and potassium is administered as required. Bicarbonate is employed in extreme acidosis, but its administration may contribute to the development of hypokalemia, CSF acidosis, and tissue hypoxia. It is hoped that a better understanding of the biochemical basis of ketoacidosis will permit the physician to develop a rational therapeutic regimen which will decrease the mortality associated with this condition.