The relation between arterial oxygen tension at rest (Pao2) and ventilatory performance (VC and FEV1.0) was studied (198 determinations) in a group of 156 patients (11 females) aged 31 to 76 (mean 52.1) years, with chronic non-specific lung disease (asthmatics non included). The average results were 72.7 mmHg for Pao2, 2.87 1 for VC, 1.32 1 for FEV1.0 and 44.9 % for the FEV1.0/VC ratio. Ninety per cent of the patients had ventilatory impairment (FEV1.0 less than 81 % predicted) and 2/3 had hypoxemia (Pao2 less than 75 mmHg). The Pao2 - spirometric variables linear correlation coefficients were of medium value (0.35 to 0.51), but highly significant due to the large number of observations. The correlation was high in patients with severe ventilatory defect (FEV1.0 less than 40% pred.), weak in those with moderate (FEV1.0 41-60 % pred.) and absent in those with minor or absent ventilatory impairment. In respect to the clinical type of obstructive disease, Pao2 and FEV1.0 showed a high correlation (r=0.69) in "bronchitics", a looser one (r=0.45) in "intermediate" patients, and no correlation for "emphysema" patients. The regression equation relating Pao2 and FEV1.0 (Pao2=64.4 + 5.9 X litres) had too high a standard error of estimate (20 % of the mean) to be of practical value.

Adult↗

PubMedDate not supplied

Impairment of pulmonary mixing in simple and complicated silicosis.

Two simple indices of pulmonary mixing (helium mixing time in a closed circuit, and mixing ventilation) were measured in 274 patients (mostly miners) with silicosis, aged 50 years or less (mean 42.4 years); the results were analysed in respect to silicosis category and type, presence of co-existent chronic bronchitis and ventilatory performance, and were compared to those of a group of normal subjects to assess statistical significance. The average results for the whole group were 5.81 min for mixing time (tmix) and 62.3 1 for mixing ventilation (Vmix), representing 1.8 times and 2.4 times the normal, respectively; the results were higher for patients with co-existent chronic bronchitis within each radiological category, except the last ("C" opacities), but the differences were significant only for patients with small opacities and with "suspect pneumoconiosis". Among patients with small rounded opacities the co-existence of healed tuberculosis (apical fibrous nodules) or of other X-ray changes did not influence the pulmonary mixing; no difference was found between the three types of small opacities. A slight tendency towards lower values in patients with early conglomeration ("A" opacities) allows the suggestion of conglomeration starting in "slow" lung spaces. The best results were those of patients with normal ventilatory function followed by those with a restrictive and then by those with an obstructive ventilatory impairment. The most severe mixing disturbance was found among patients with chronic bronchitis and obstructive defect with "suspect pneumoconiosis", who are not covered by occupational disablement compensation.

Adult↗

PubMedDate not supplied

[Pulmonary function in chronic bronchitis and emphysema. VIII. Alveolo-capillary diffusion (pulmonary transfer)].

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Bronchitis↗

PubMedDate not supplied

[Clear definitions of chronic bronchopulmonary diseases. Imperative for pneumological practice, teaching and research].

Important divergences in the definition of bronchial asthma, chronic bronchitis and pulmonary emphysema have persisted until the middle 1950's. Definitions were first standardized in 1958 by a group of British experts (CIBA symposium) and made clearer by the WHO Experts Group on Cor Pulmonale in 1961 and by the American Thoracic Society in 1962. The standardized questionnaire proposed by the British Medical Research Council has been widely adopted. For pulmonary emphysema, a precise definition based on anatomical data (dilatation of terminal air spaces with destruction of their walls) has been accepted. Chronic bronchitis is defined in clinical terms (almost daily productive cough 3 months each year, at least on 2 consecutive years; the terms "chronic cough" and "recurrent bronchitis" are still controversial. The greatest difficulties have been encountered in the definition of bronchial asthma; despite a second CIBA symposium (1971) devoted to this problem, it has not been possible to improve on the fairly wide physiological definition put forward in 1958 (bronchial obstruction that varies either spontaneously or under the influence of treatment). For about 15 years peripheral airways obstruction (PAO), sometimes called "small airways disease" has been recognized as a special anatomical and functional syndrome.

Asthma↗

PubMedDate not supplied

[Clinico-functional correlations in chronic obstructive bronchopneumopathy: dyspnea and arterial oxygenation].

The severity of dyspnoea was confronted to the value of the partial pressure of arterial oxygen at rest in a group of 51 patients with chronic non-specific pneumopathy associated to medium or severe ventilatory obstruction (VEMS under 1,5 I). The patients have been classified as "predominantly bronchitic" or "predominantly emphysematous" on the basis of clinical, radiological and biological criteria. In the group as a whole there was no relation between the partial pressure of arterial oxygen and the severity of the dyspnoea. The analysis of sub-groups evidenced a tendency to decrease of the oxygen pressure with accentuation of dyspnoea in the "bronchitis" group, although the coefficient value of this inverse correlation did not reach the treshold of statistical significance (r = -0,46; p greater than 0,05).

Adult↗

PubMedDate not supplied

Effects of chronic exposure to diisocyanates.

The pulmonary effects of chronic exposure to isocyanates (mainly MDI) at low levels (less than 0.02 ppm) were studied in a five year longitudinal survey of workers from two factories producing polyurethane foam. A respiratory questionnaire, flow volume curves and a single breath CO diffusion test were done at the beginning of the survey and repeated five years later; 318 workers (214 men, 104 women) of whom 83 (group I) were unexposed, 117 indirectly exposed (group II) and 118 directly exposed to isocyanates (group III) were examined. Five years later, half of the initial cohort only was still active and re-examined. The longitudinal analysis distinguished unexposed workers at both examinations (group A), indirectly at both examinations (group. B), directly exposed at both examinations (group. C) and workers exposed directly at first examination and retired from risk at the second (group. D). The decline of VC and FEV1 was not significantly different between exposed and unexposed. On the contrary, DLCO declined significantly in group C compared to the others. The results indicate that even at 'safe levels', chronic exposure to isocyanates involved a respiratory risk.

Air Pollutants, Occupational↗

PubMedDate not supplied

Comparative value of respiratory input and transfer impedances in field studies.

Total respiratory impedance was obtained from 4 to 30 Hz in 39 healthy males and in 140 iron miners by studying the relationship between transrespiratory pressure and mouth flow when forced oscillations were applied to the respiratory system in two different ways: by varying pressure at the mouth (input impedance, Zin); by varying pressure around the chest (transfer impedance, Ztr). Zin was characterized by the slope (S) and intercept (R0) of the resistance-frequency curve, by the resonant frequency (fn), and by total respiratory inertance (I) and compliance (C) obtained from the reactance. Transfer resistance and reactance curves were respectively analysed with a two-parameter (m1, m3) and a three-parameter (m0, m2, m4) equation. Significant correlations were found between impedance indices, particularly between m1 and both R0 (r = 0.931; p less than 0.001) and m2 (r = 0.739; p less than 0.001), and also between impedance indices and maximal expiratory flows. Nonsmoking miners (n = 40), compared to control nonsmokers (n = 16), had slightly lower maximal flows at high lung volumes (p less than 0.05) and higher values of m1 (p less than 0.001), R0, S, m3 (p less than 0.01) and m2 (p less than 0.05). In contrast, miners who smoked (n = 46) mainly differed from miners who did not smoke by lower flows at middle and low lung volumes (p less than 0.01) and larger m0 (p less than 0.01), m2 and m4 (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗