scholarly journals A RAPID PLETHYSMOGRAPHIC METHOD FOR MEASURING THORACIC GAS VOLUME: A COMPARISON WITH A NITROGEN WASHOUT METHOD FOR MEASURING FUNCTIONAL RESIDUAL CAPACITY IN NORMAL SUBJECTS 1

1956 ◽  
Vol 35 (3) ◽  
pp. 322-326 ◽  
Author(s):  
Arthur B. DuBois ◽  
Stella Y. Botelho ◽  
George N. Bedell ◽  
Robert Marshall ◽  
Julius H. Comroe
Keyword(s):  
Functional Residual Capacity ◽  
Normal Subjects ◽  
Nitrogen Washout ◽  
Thoracic Gas Volume ◽  
Residual Capacity ◽  
Gas Volume

Measurement of high lung volumes by nitrogen washout method

1994 ◽  
Vol 77 (3) ◽  
pp. 1562-1564 ◽  
Author(s):  
Y. Sivan ◽  
J. Hammer ◽  
C. J. Newth
Keyword(s):  
Lung Volume ◽  
Human Infants ◽  
Lung Volumes ◽  
Nitrogen Washout ◽  
Thoracic Gas Volume ◽  
Residual Capacity ◽  
The Difference ◽  
Gas Dilution ◽  
Spontaneously Breathing ◽  
Gas Volume

Studies on human infants suggested that thoracic gas volume (TGV) measured at end exhalation may not depict the true TGV and may differ from TGV measured from a series of higher lung volumes and corrected for the volume added. This was explained by gas trapping. If true, we should expect the discrepancy to be more pronounced when functional residual capacity (FRC) and higher lung volumes are measured by gas dilution techniques. We studied lung volumes above FRC by the nitrogen washout technique in 12 spontaneously breathing rhesus monkeys (5.0–11.3 kg wt; 42 compared measurements). Lung volumes directly measured were compared with preset lung volumes achieved by artificial inflation of the lungs above FRC with known volumes of air (100–260 ml). Measured lung volume strongly correlated with and was not significantly different from present lung volume (P = 0.05; r = 0.996). The difference between measured and preset lung volume was 0–5% in 41 of 42 cases [1 +/- 0.4% (SE)]. The direction of the difference was unpredictable; in 22 of 42 cases the measured volume was larger than the preset volume, but in 17 of 42 cases it was smaller. The difference was not affected by the volume of gas artificially inflated into the lungs. We conclude that, overall, lung volumes above FRC can be reliably measured by the nitrogen washout technique and that FRC measurements by this method reasonably reflect true FRC.

Problems in measurement of thoracic gas volume in infancy

1982 ◽  
Vol 52 (4) ◽  
pp. 995-999 ◽  
Author(s):  
C. S. Beardsmore ◽  
J. Stocks ◽  
M. Silverman
Keyword(s):  
Functional Residual Capacity ◽  
Clinical Status ◽  
Pleural Pressure ◽  
Whole Body ◽  
Airway Closure ◽  
Lung Volumes ◽  
Airway Occlusion ◽  
Thoracic Gas Volume ◽  
Residual Capacity ◽  
Gas Volume

Thoracic gas volume (TGV) was measured with a whole-body plethysmograph in 20 infants at functional residual capacity (FRC) and at a series of higher lung volumes achieved by artificial inflation of the lungs with known volumes of air after airway occlusion. There was a discrepancy between the corrected values of TGV measured at high and low lung volumes in nine infants; in six cases TGV measured at high lung volumes exceeded that measured at FRC, and in three cases it was reduced when compared with the measurement made at FRC. These changes were not related to age, size, or clinical status and could be explained by airway closure at FRC, combined with an uneven distribution of pleural pressure.

Effect of uneven ventilation on pulmonary diffusing capacity

1961 ◽  
Vol 16 (4) ◽  
pp. 679-683 ◽  
Author(s):  
Benjamin M. Lewis ◽  
E. J. Hayford-Welsing ◽  
Akio Furusho ◽  
L. C. Reed
Keyword(s):  
Steady State ◽  
Functional Residual Capacity ◽  
Normal Subjects ◽  
Deep Breathing ◽  
Diffusing Capacity ◽  
Nitrogen Washout ◽  
Residual Capacity ◽  
Sample Technique ◽  
Uneven Ventilation ◽  
Absorption Theory

In four normal subjects measurements of steady state diffusing capacity for CO (DLCO) by an alveolar sample technique and of the degree of uneven ventilation by nitrogen washout were made simultaneously followed by measurement of DLCO by rebreathing. A methacholine-histamine aerosol was then given. After this aerosol uneven ventilation worsened and steady state DLCO fell, while rebreathing DLCO did not change. Relief of uneven ventilation by isoproterenol was followed by increase of steady state DLCO in two subjects. Alterations in rate and depth of breathing or changes in functional residual capacity do not explain the changes in steady state DLCO which are attributed to increase in uneven ventilation as predicted by the theory of CO absorption. Theory also predicts a lack of effect of uneven ventilation on the rebreathing DLCO, but these results must be accepted with caution because deep breathing may reverse the effects of the methacholine-histamine aerosol and O2 consumption during rebreathing rises after this aerosol. Submitted on December 30, 1960

Concurrent measurements of functional residual capacity by three methods

1962 ◽  
Vol 17 (6) ◽  
pp. 871-873 ◽  
Author(s):  
Donald F. Tierney ◽  
Jay A. Nadel
Keyword(s):  
Functional Residual Capacity ◽  
Total Lung Capacity ◽  
Open Circuit ◽  
The Body ◽  
Lung Capacity ◽  
Thoracic Gas Volume ◽  
Nitrogen Dilution ◽  
Residual Capacity ◽  
The Mean ◽  
Gas Volume

We made concurrent measurements of the functional residual capacity (FRC) with the body plethysmograph (thoracic gas volume) and by 7-min and prolonged open-circuit nitrogen dilution methods (communicating gas volume). The mean difference between the 7-min communicating gas volume and the thoracic gas volume in 13 healthy subjects was only 0.13 liters. The thoracic gas volume averaged 0.99 liters larger than the communicating gas volume after 7 min of O2 breathing in 13 patients with emphysema. The communicating gas volume at 12–18 min was the same as the thoracic gas volume in 11 of 13 patients but was smaller in the other 2. When the thoracic gas volume was used to measure FRC, the total lung capacity averaged 142% of predicted normal in 13 patients with emphysema. Submitted on January 4, 1962

Pulmonary response to threshold levels of sulfur dioxide (1.0 ppm) and ozone (0.3 ppm)

1985 ◽  
Vol 58 (6) ◽  
pp. 1783-1787 ◽  
Author(s):  
L. J. Folinsbee ◽  
J. F. Bedi ◽  
S. M. Horvath
Keyword(s):  
Sulfur Dioxide ◽  
Pulmonary Response ◽  
Rest Periods ◽  
Pollutant Concentrations ◽  
Thoracic Gas Volume ◽  
Exercise Ventilation ◽  
Before And After ◽  
Residual Capacity ◽  
Gas Volume ◽  
Male Subjects

We exposed 22 healthy adult nonsmoking male subjects for 2 h to filtered air, 1.0 ppm sulfur dioxide (SO2), 0.3 ppm ozone (O3), or the combination of 1.0 ppm SO2 + 0.3 ppm O3. We hypothesized that exposure to near-threshold concentrations of these pollutants would allow us to observe any interaction between the two pollutants that might have been masked by the more obvious response to the higher concentrations of O3 used in previous studies. Each subject alternated 30-min treadmill exercise with 10-min rest periods for the 2 h. The average exercise ventilation measured during the last 5 min of exercise was 38 1/min (BTPS). Forced expiratory maneuvers were performed before exposure and 5 min after each of the three exercise periods. Maximum voluntary ventilation, He dilution functional residual capacity, thoracic gas volume, and airway resistance were measured before and after the exposure. After O3 exposure alone, forced expiratory measurements (FVC, FEV1.0, and FEF25–75%) were significantly decreased. The combined exposure to SO2 + O3 produced similar but smaller decreases in these measures. There were small but significant differences between the O3 and the O3 + SO2 exposure for FVC, FEV1.0, FEV2.0, FEV3.0, and FEF25–75% at the end of the 2-h exposure. We conclude that, with these pollutant concentrations, there is no additive or synergistic effect of the two pollutants on pulmonary function.

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