Lung function studies. VIII. Analysis of alveolar ventilation by pulmonary N2 clearance curves.

A comprehensive analysis of pulmonary fuinction must include measurements of pulmonary ventilation, diffusion, and circulation. An accurate measurement of alveolar ventilation, independent of diffusion and circulation, is desirable. To date, no method has been wholly satisfactory (3). One approach has been by study of the time course of equilibration of alveolar gas with a "foreign" inspired gas, such as H2 (4), He (5-7) or pure 02 (8-15). A principal difficulty has been to differentiate between the effects of an enlarged respiratory dead space and of uneven alveolar ventilation, both of which can retard the completion of equilibration. The development by Lilly and Hervey of the N2 meter, for continuous analysis of N2 concentration of respired gas, permits an automatic breath-by-breath analysis of gas expired during and after the change from breathing air to uninterrupted breathing of 02. The ensuring progressive elimination of pulmonary N2 represents the process of equilibration with a N2-free gas, and may be analyzed in terms of alveolar ventilation. This paper presents the pulmonary N2 clearance curves obtained from healthy persons and patients with cardiorespiratory disease, and a method for analysis of these curves which yields a comprehensive picture of the volume and time characteristics of alveolar ventilation. The

[1]  A. Cournand,et al.  STUDIES ON THE INTRAPULMONARY MIXTURE OF GASES. III. AN OPEN CIRCUIT METHOD FOR MEASURING RESIDUAL AIR. , 1940, The Journal of clinical investigation.

[2]  W. S. Fowler,et al.  Lung function studies. VI. Detection of uneven alveolar ventilation during a single breath of oxygen. , 1951, The American journal of medicine.

[3]  Becklake Mr,et al.  Intrapulmonary mixing of helium in normal and emphysematous subjects. , 1951 .

[4]  W. S. Fowler.  Lung function studies; uneven pulmonary ventilation in normal subjects and in patients with pulmonary disease. , 1949, Journal of applied physiology.

[5]  Studies of lung volume and intrapulmonary mixing. Nitrogen clearance curves: apparent respiratory dead space and its significance. , 1950, Journal of applied physiology.

[6]  W. S. Fowler.  Lung function studies; the respiratory dead space. , 1948, The American journal of physiology.

[7]  W. S. Fowler.  Lung function studies. V. Respiratory dead space in old age and in pulmonary emphysema. , 1950, The Journal of clinical investigation.

[8]  G. Birath.  Lung Volume and Ventilation Efficiency. Changes in Collapse-treated and Non-Collapsed-treated Pulmonary Tuberculosis and in Pulmonectomy and Lobeetomy. , 1944 .

[9]  A. Cournand,et al.  STUDIES ON INTRAPULMONARY MIXTURE OF GASES. V. FORMS OF INADEQUATE VENTILATION IN NORMAL AND EMPHYSEMATOUS LUNGS, ANALYZED BY MEANS OF BREATHING PURE OXYGEN. , 1944, The Journal of clinical investigation.

[10]  Studies of pulmonary capacity and mixing with the nitrogen meter. , 1950, The Journal of clinical investigation.

[11]  G. Meneely,et al.  THE VOLUME OF THE LUNG DETERMINED BY HELIUM DILUTION. DESCRIPTION OF THE METHOD AND COMPARISON WITH OTHER PROCEDURES. , 1949, The Journal of clinical investigation.

[12]  J. Lilly.  Mixing of gases within respiratory system with a new type nitrogen meter. , 1950, The American journal of physiology.

[13]  Influence of Body Size on Gaseous Nitrogen Elimination During High Oxygen Breathing.∗ , 1941 .

[14]  J S ROBERTSON,et al.  Lung ventilation patterns determined by analysis of nitrogen elimination rates; use of mass spectrometer as a continuous gas analyzer. , 1950, The Journal of clinical investigation.