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Results for “Maximal Expiratory Flow-Volume Curves”

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PubMed1979

Constancy of effort and variability of maximal expiratory flow rates.

In 14 normal subjects and in 13 patients with obstructive pulmonary diseases, we studied the variability within an individual of values for the maximal expiratory flow rate (Vmax) recorded simultaneously vs expired pulmonary volume (at the mouth) and vs thoracic volume (measured with a body plethysmograph). We found that the variance of Vmax within an individual at 25, 50, and 75 percent of the expired vital capacity did not differ statistically whether pulmonary volume was the expired or the thoracic gas volume. In ten healthy subjects on two occasions (at an interval of 12 days, on the average), we measured the peak expiratory flow rate and Vmax at different levels of inflation, with respect to either expired or thoracic volume. There was no statistical differences in Vmax between the first and the last day. A larger variability of Vmax measured vs expired volume implies a change in the expiratory effort from one forced expiration to another and a different degree of compression of intrathoracic air. Since this was not the case, we conclude that muscular effort during repeated forced expirations is similar. The good reproducibility of effort explains in great measure the good reproducibility of Vmax.

Adult↗
PubMed1978

Small airways of the lung. The importance of understanding and assessing the function of pulmonary bronchioles.

Recent findings have emphasized the importance of the bronchiole to the function of the lung. The surface of the bronchiole differs from that of the alveolus. Rather than being covered by a thin coat of phospholipid, the surface is covered with cilia that are surrounded by a low-viscosity fluid. This permits the removal of foreign particles. Surface forces are important to the function of the bronchiole. The diameter of the bronchiole is a function of the volume of the lung. When the lung is partially collapsed, the bronchiole acts as a capillary tube and is readily obstructed by fluid. In chronic bronchitis, obstruction is related to narrowing by fibrosis and inflammation, alteration in the secretion, and loss of traction on the walls. Obstruction of the bronchiole by fluid in edema of the lung contributes to hypoxemia. Positive end expiratory pressure may prevent obstruction by increasing the bronchiolar diameter.

Airway Obstruction↗
PubMed1979

A double blind cross-over study of maximal expiratory flows and arterial blood gas tensions in normals, asthmatics and bronchitics after salbutamol and ipratropin.

8 normals, 8 asthmatics and 8 bronchitics inhaled comparable doses of ipratropin and salbutamol. Five different flow-volume parameters were measured before and at intervals from 3 to 360 minutes after inhalation, on a total number of 2880 maximal effort expiratory flow-volume curves. Arterial blood gas tensions were measured before and 60 minutes after inhalation. In all parameters a significant larger effect (p less than 0.05) of ipratropin was found in normals, but in different time intervals. The parameter FEV1 and MEF at 50% of FVC showed the largest effect of salbutamol during the interval from 3 to 60 minutes in the asthma patients. None of the parameters showed significant difference in drug effects in the bronchitis patients. The findings suggested a more peripheral action of ipratropin than of salbutamol in the normals. No significant change in gas tensions were found after inhalation in any of the three groups.

Albuterol↗
PubMedDate not supplied

[Bonchodynamic tests in the study of bronchial asthma].

One characteristic of chronic obstructive bronchopneumopathies, especially bronchial asthma, is the slowing down of respiratory flow. Spirographic studies are therefore valued highly among specialists in respiratory pathology. All of those working in this field of physiopathology, however, agree that broncodynamic provocation tests are not fully specific for bronchial asthma. One important problem is the difficulty in determining the quantity of product inhaled by the patient, making the test even less precise. With our method, based on the broncotest developed by Piglowski, we are able to determine the quantity of inhaled material with a fairly high degree of accuracy. It thus represents a quantitative study and is much more specific. One hundred patients with bronchial asthma, whose ages ranged from 14 to 60 years, were selected for this study. We found that 100% of them (except for one 16-year-old patient whose case has been commented on) were positive for the acetylcholine aerosol test and for beta-2adrenergics (phenotherol). These results enabled us to establish diagnostic patterns for the severity of bronchial hyperactivity in relation to the number of micrograms needed to provoke a 20% variation in the VEMS. We consider it very important to determine the threshold does of acetylcholine, since it may serve in both diagnosis and prognosis. We believe that this method may represent a new direction in pharmacodynamic examination of asthma patients.

Acetylcholine↗
PubMed1979

Reproducibility of the response to diluent challenge in adult asthma.

The authors have demonstrated that patients with bronchial asthma may react to diluent provocative challenge. The pattern of airway response to diluent was found to be reproducible. The data herewith presented suggest that the baseline airway obstruction in adult asthma is highly variable but the degree of baseline obstruction is not related to the response to diluent challenge.

Administration, Intranasal↗
PubMed1979

Correlation between the function and structure of the lung in smokers.

To study the relationship between morphologic changes and alteration of lung function, the excised lobes of 21 smokers and one nonsmoker who required lobectomy for small peripheral tumors were inflated and fixed in formalin, and measurements of bronchiolar narrowing and degree of emphysema were made. All patients had comprehensive pulmonary function tests (including diffusing characteristics, the single-breath N2 test, measurements of elastic recoil, and flow-volume measurements with air and helium) performed before lobectomy. Eight of the lobes excised from the smokers had emphysema of grade 15 or more, the greatest being grade 50. Lobes from 11 patients had evidence of airway narrowing. There were 6 lobes with both emphysema and airway narrowing. Pulmonary function was abnormal in some aspect in all lobes except that from the nonsmoker. Whereas the tests of diffusing capacity, particularly the fractional uptake of CO, correlated with the degree of emphysema, the tests of elastic recoil were not predictive of this early degree of emphysema. The degree of small-airway narrowing correlated with maximal mid-expiratory flow rate and the single-breath N2 test. The maximal flow/static recoil pressure curves were the most sensitive indicators of airway abnormality in the patients with emphysema.

Aged↗