Bulletin de physio-pathologie respiratoire最新文献

The authors examine the respiratory tests performed during a two years-period in 676 pneumoconiotic miners. Spirography was normal in 8% of the cases; a mixed ventilatory impairment, with an obstructive prevalence of variable extent, was present in 2/3 of the cases. Pharmacodynamic tests in 353 subjects showed a frequent non-specific bronchial sensitivity (34.2% of the whole group). Hypoxaemia (PaO2 below 75 mmHg) with normo- or hypocapnia was observed in 379 patients; hypercapnia was relatively uncommon (9.9%) and occurred mainly in bronchitic patients. The breath holding CO lung transfer test was very often disturbed, as the diffusing capacity (DLCO) was below the predicted value in about 80% of the population. Radiofunctional comparisons were carried out in an homogeneous group of 212 subjects. The data clearly demonstrate that functional abnormalities were not exclusively seen in extensive radiological forms. As far as it goes beyond a simple ventilatory study, the measurement of the breath holding lung transfer factor for CO has proved to be a valuable element in the functional statement of anthracosilicosis. The polymorphism of the pulmonary repercussions of dust exposure explains individual differences between the results of the main investigations, and this emphasizes the need for a series of diversified tests.

Many types of dust, including cigarette smoke, cause an impairment of lung function. This lung function impairment does not affect working capacity provided the dust is not fibrogenetic. Quartz, normally present in coal mine dust in concentrations between 2 and 10% is claimed to be responsible for coal workers' pneumoconiosis (CWP) by some writers. However the evidence is conflicting and firm conclusions cannot be drawn at present. From the clinical point of view CWP is characterized by an increased airway resistance. All correlations between airway resistance, arterial oxygen and carbon dioxide pressure and intrathoracic gas volumes (IGV) in patients having CWP and obstructive airway disease are similar to those in non-dust exposed patients with obstructive ariway disease. Patients with CWP, at equivalent values of airway resistance have smaller mean values of IGV. The relationship between arterial oxygen pressure and pulmonary arterial pressure is the same in patients with CWP and obstructive airway disease as in patients with chronic obstructive airway disease but without CWP. The effect of therapy in CWP with obstructive airway disease corresponds very well to that seen in patients without CWP.

Pulmonary gas exchange was measured at rest and during exercise in 30 normal males (14 smokers) and 43 coal workers free of obstructive syndrome, at three levels of oxygenation: hypoxia, normoxia and hyperoxia. The main results are the following: a) in normoxia PaO2 and (A--a)DO2 are slightly abnormal in coal workers at rest and during exercise; b) in hyperoxia (A--a)DO2 and venous admixture are higher in the miners at rest but not during exercise; c) in hypoxia (A--a)DO2 and DLO2 are abnormal in miners as compared with the control subjects; during exercise there is however no difference between the miners and the smokers of the control subjects; d) there is a correlation between PaO2 and (A--a)DO2 during exercise in normoxia and the various diffusion indices; e) (a--A)DCO2 and VD/VT show relatively slight increases in the miners; f) there are several differences between the miners with pin-head images and those with micronodular ones; g) at rest, (a--A)DCO2 and VD/VT are influenced by the degree of oxygenation. These various findings are discussed.

Tests of lung function have a number of important roles in occupational medicine but the results need to be of high technical quality if they are to be useful. On this account, as well as careful supervision and scrutany of results, only appropriate tests should be applied. The choice will vary with circumstances; it is likely to be made from a limited number of procedures including those recommended in Respiratory function tests in pneumoconioses (I.L.O., 1966). Tests of maximal and near maximal exercise are seldom indicated. Care should be taken over the selection of reference values and of mathematical treatments for the results.

Lung function profiles were defined in over 1,000 Quebec chrysotile asbestos workers using five standard tests of lung function, and were related to dust exposure and smoking. Close to half the men (44.3%) had a normal lung function profile and a further 26.5% some function changes but no definite profile. Amongst the remainder restrictive and obstructive function profiles occurred with equal frequency (12.8 and 12.2% respectively). Both were associated with radiologic asbestosis; both occurred infrequently in the absence of the smoking habit. These findings suggest an association between the smoking habit and the harmful effects of asbestos exposure on lung function, and by implication on the development of lung fibrosis. A similar association has been recognized in respect of bronchogenic carcinoma. This experience, in the primary mining and milling of pure chrysotile asbestos, may not be directly applicable to secondary industries concerned with the further processing of this fibre.

Fifty-seven patients, all with chronic respiratory insufficiency and hypoxemia, have been classified in five groups according to their acid-base status, determined by the intra-erythrocytic pH (pHi) : A. normal acid-base balance ; B. chronic alkalosis ; C. acute alkalosis ; D. acute acidosis ; E. chronic acidosis. We have measured in the arterial blood : Po2, PCO2, plasmatic pH (pHp1), pHi, P50(7,40) and 2,3-DPG. From these values. the base-excess (B.E.) and the P50 to real pH [P50 I.V.] have been computed. There is a good correlation between 2,3-DPG and P50 (r = 0.707), none between P50 and Pao2. For a normal acid-base balance, P50 and 2.3-DPG also are normal. Increased in chronic alkalosis, the amount of DPG is decreased in chronic acidosis. The DPG-pHi correlation is very good (r = 0.691 ; pless 0.001) and the changes of the acid-base balance seem to be the main factors for controlling the DPG synthesis : it increases it in chronic alkalosis and reduces it in chronic acidosis. Thus the P50(I.V.) returns to the normal range on account of the Bohr effect adjustement. On the contrary, in acute acidosis and alkalosis, the amount of DPG is normal and the P50(I.V.) is increased or reduced. Therefore the duration of the acid-base lack of balance also interfers.

In 84 conscious mongrel dogs weighting 19.0 +/- 3.2 kg (x +/- s), the mean pressure in the pulmonary artery was found to be 14.2 +/- 3.1 mmHg. In 102 anaesthetized dogs weighting 19.9 +/- 3.2 kg, pulmonary arterial pressure was 14.3 +/- 2.8 mmHg and pressure in the abdominal aorta 121.3 +/- 16.9 mmHg ; the O2 saturation in the arterial blood recorded oximetrically at the same time was 91.9 +/- 1.3%. Statistical analysis of the data derived from a selection of 87 of these anaesthetized dogs (body=weight : 15-25 kg ; Sao2 : 90-94 % ; mean aortic pressure : 80-150 mmHg ; mean pulmonary arterial pressure : 9-19.5 mmHg) revealed a significant relation between pulmonary pressure and O2 saturation. No significant relation was demonstrable, however, between these pressures and the animals' body-weight. The lower limit of the normal range of mean pulmonary pressure was 8 mmHg and the upper limit 20 mmHg.

We are convinced on the basis of experiments made on animals and on the basis of observations made during pneumonectomies operations, that the expired CO2 does not originate only from the arterial pulmonary system. Our experineces prove that the expired CO2 originates in a not negligible quantity from the blood of the bronchial arteries and the metabolism of the lung.

Oxygen dilution devices (Venturi 3 and 4) with Multi-VentTM mask, using an oxygen flow rate of 6 1/min, are insufficient when subjects' ventilation is increased : inspired oxygen concentration is lower than predicted. This can be detrimental to patients who could benefit by oxygenotherapy during exercise.

In a group of 140 asthmatic children (6-15 years old) followed up for six months, the authors compared : (1) the daily transcription of asthmatic symptoms, of their intensity and of the use of antibiotics or corticosteroids ; (2) the peak expiratory flow rate measured daily at nine a.m. ; (3) the clinical history, coded every fifth day. A clinical score was computed by multiple linear correlation between (1) and (3), with a correlation coefficient of 0.84 (p less than 0.001), showing that the propounded quantification of symptoms and treatments was very good for estimating the clinical history. The coefficient of simple linear correlation between peak expiratory flow rate and score (r = --0.41) and between peak expiratory flow rate and clinical history (r = --0.65) was statistically significant ; however a further computation by stepwise multiple linear correlation showed that the peak expiratory flow rate was essentially correlated to the intensity of the symptoms, and to a lesser degree to the presence of breathlessness and prescription of corticosteroids. The correlation coefficient was -- 0.55 (p less than 0.01). Thus the peak expiratory flow rate does not very well account for the clinical state of asthmatics ; useful for the fast but superficial monitoring of patients, it cannot replace the daily transcription of symptoms and treatments : both methods are complementary.