Lung Volumes

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Lung Volumes


the volume of the air contained in the lungs at various degrees of thoracic expansion.

With maximum exhalation, the gaseous contents of the lungs decrease to the residual volume (RV). The normal inhalation position adds to this the expiratory reserve volume (ERV), or the reserve air. The tidal volume (TV) is added by the end of inhalation (respiratory air). The inspiratory reserve volume (IRV), or complemental air, is added by the end of maximum inhalation.

The sum of the RV and the ERV is called the functional residual capacity (FRC); the sum of the TV and the IRV, the inspiratory capacity (IC); the sum of the ERV, the TV, and the IRV, the vital capacity (VC); and the sum of the RV, the ERV, the TV, and the IRV, the total capacity (TC) of the lungs. All lung volumes, with the exception of the RV and the TC, can be determined by measuring the volume of air exhaled into a spirometer or spirograph. The RV, the FRC, and the TC can be measured by inhaling an indicator gas, establishing its degree of diffusion in the lungs by gas analysis.

Lung volumes depend on height (directly), age (inversely, after age 30), sex (10–20 percent less in women than in men), and physical development (20–30 percent greater in athletes). Tables, nomograms, and formulas have been worked out for determining the VC and lung volumes expected in healthy persons (see Figure 1). Lung volumes are expressed as absolute (in ml) and relative (in percentages of the necessary volumes and TC) quantities. In men, the VC is 3,500–4,500 ml (in some cases reaching 6,000 ml); in women, 2,500–3,500 ml. Determination of the lung volumes is important in evaluating the condition of the external respiratory system. The volumes undergo characteristic changes with many diseases (especially diseases of the respiratory and cardiovascular systems).

Figure 1. Lung volumes and capacities in a healthy adult male


References in periodicals archive ?
Lung volumes are evaluated primarily by body plethysmography, during which a patient sits inside an airtight "body box" equipped to measure pressure and volume changes.
In particular, the reduced chest wall compliance plays an important role in reducing lung volumes and correlates closely with the Cobb's angle and with the decrease in FVC.
In order to detect the presence of air trapping in the lungs, lung volumes should be measured to determine the total lung capacity and the residual volume.
Table-1: Adjusted linear regression analysis of respiratory symptoms with absolute lung volume among textile workers.
The major types of pulmonary function tests include measurement of lung volume using spirometry and quantization of diffusing capacity.
Its EasyOne[R] and EasyOne Pro[R] portable instruments take up just 12 square inches of space to take lung function testing wherever it is needed, measuring DLCO, FRC, LCI, lung volumes and spirometry.
Such results are compatibles with the ones observed in a study with one hundred fifty six (156) asymptomatic volunteers thirty two (32) being eutrophics, thirty nine (39) overweight and eighty five (85) obese which did not detect correlation between obesity and FVC [20] also another study made with forty six college students aged between 20 and 40 years did not demonstrate changes on FVC and lung volumes in obese people classified by the MBI [21].
sup][5],[6] Chronically increased IAP may influence the diaphragm position as well as the lung volume, which might affect UA collapsibility.
In all cases, final reports should include name references to the predicted sets used for specific tests (spirometry, lung volumes, DLCO, etc.
Accurate assessment of lung volumes with plethysmography would define the pattern more clearly.
The first major finding of the present study is that lung volumes and capacities are not affected by the practice of football or judo in prepubertal boys; they are similar to the control group.
Results: Deteriorating effect of smoking was found on respiratory muscle strength, lung volumes and airflow parameters in our sample.