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Biomedical subjects

G Methlin

Publications and source records attributed to G Methlin.

9 recordsLinked to original sources
PubMed1979

Radionuclide computerized ventilation studies.

Studies of regional lung function have developed rapidly in the last few years. Xenon -133 is the most frequently used isotope because of its physiocochemical and biologic properties. Fixed counters are being replaced by the scintillation camera interfaced to a computer allowing easy acquisition and interpretation of results and numerical data. The use of isotopes other than 133Xe, such as 81mKr, is less widespread. In this article, a method is described for studying regional ventilation in which the isotope used is 133Xe, the radioactivity is recorded by a scintillation camera, interfaced to a computer andsix (or 12) regions for both lungs are selected and investigated. The regional ventilation is expressed as an absolute value in ml/min/ml of ventilated volume as well as the relative contribution in percent of each zone to the total ventilation and volume. To illustrate this method, the results are reported for healthy subjects and for patients with chronic bronchitis and emphysema. Scintigraphs of individual cases are presented. Certain theoretic problems related to calculation of regional ventilation are discussed.

Bronchitis↗
PubMed1978

[The regional exploration of pulmonary function using xenon 133. Value of the gamma camera connected to a computer (author's transl)].

Regional isotopic exploration of ventilation and pulmonary perfusion is not yet widely applied in clinical practice, by virtue of the complexity of the equipment required, but also because of the complicated and lengthy analysis of the results. In this respect, connection of the scintillation camera to a computer represents a major advance which other authors have already emphasized. Our own experience in this area and our method of exploration are described. The results of regional exploration in a group of 43 cases of chronic obstructive lung disease (33 patients of the chronic bronchitis type, 10 patients with emphysema) are analysed and discussed. The results indicate the following : in chronic bronchitis, a very marked fall in ventilation of the bases with inversion of the normal vertical ventilation gradient, and a fall in the ventilation/perfusion ratio of the bases; in emphysema, a fall in ventilation, but also and above all in regional perfusion of all territories with preservation of normal or even increased regional ventilation/perfusion ratios. Regional exploration may also be of value in the detection of early stages of obstructive lung disease, and in pre-operative assessment in thoracic surgery.

Bronchitis↗
PubMed1977

Regional pulmonary function in sarcoidosis.

In 26 subjects with a confirmed histological diagnosis of thoracic sarcoidosis regional lung function was studied with Xenon 133. All subjects also underwent overall lung function studies including CO steady state (TCO SS) and single breath (TCO SB) diffusing capacity. Regional ventilation (Vr) was on the average increased in stages I (isolated hilar adenopathies) and II (pulmonary infiltration) and appeared normal in stage III (pulmonary fibrosis). Regional perfusion (Qr) was on the average normal in stages I and II and decreased in stage III. There were no appreciable differences between average values in stages I and II. Abnormalities of Vr and Qr were frequently found in individual cases. A distinction was made between the total number of abnormalities and deficiency abnormalities. The total number of abnormalties was high in all three stages. Deficiency abnormalities were relatively rare in stages I and II, and frequent in stage III. The correlation between radiological and regional functional abnormalities was low. TCO SB/VA was found significantly lower (P less than 0.005) in subjects with regional deficiency abnormalities (mostly perfusion abnormalities). These data probably indicate that a lowered diffusing capacity may be due to the loss of pulmonary capillaries and not only to ventilation - perfusion disparities.

Adolescent↗
PubMedDate not supplied

[Regional pulmonary function in hemidiaphragmatic paralysis (author's transl)].

Gaseous exchange and regional pulmonary function (using 133Xe) were studied in 10 subjects with hemidiaphragmatic paralysis; the paralysis was presumably idiopathic in nine subjects. Global and regional investigations were performed on the same morning, the subjects being studied in the sitting position. Six subjects were obese; nevertheless overweight was moderate except in one case. Lung volumes were moderately decreased (vital capacity ranged from 69 to 100 percent of the predicted value). PaO2 was normal or nearly normal: mean = 75.8 +/- 7.5 torr in the sitting position. PaO2 did not vary significantly in the supine, nor in the lateral recumbent position. AaDO2, breathing air or during hyperoxia, was slightly increased. Qs/Qt was markedly increased in only three cases. Regional lung function data suggest that the paralysed side still plays an appreciable part in pulmonary volume (43.5 +/- 6.3 percent), ventilation (39.1 +/- 8.2 percent) and perfusion (40.4 +/- 9.3 percent). Impairment of the paralysed side was mainly localized in the lower zone; in the middle zone only ventilation was significantly reduced. Results of regional ventilation and perfusion, expressed as absolute values, suggest a redistribution of ventilation and perfusion from the base towards the apex, not only for the paralysed side but also for the opposite side. This adjustment is probably due to the hemidiaphragmatic paralysis but the possible role of obesity (present in six cases) must be kept in mind. Possible therapeutic deductions are discussed.

Aged↗