Vital capacity

The vital capacity (VC) is a parameter for the function of the lungs and is used in spirometry . There are sizes for inhalation ( inspiratory vital capacity (IVC)) and for exhalation ( expiratory vital capacity (EVC)). Breathing takes place through a mouthpiece, breathing through the nose should be prevented by a nose clip. In addition to physical factors such as air pressure and turbulence, the measurement accuracy also depends on the participation of the test person, who has to inhale and exhale as much as possible, which is certainly subjective.

As forced (expiratory) vital capacity (FVC) is called the tidal volume that can be exhaled rapidly and completely after maximal inspiration.

The target values ​​of the vital capacity depend on gender, age and body size. The following equations can be used as a basis :, or 0.0481g - 0.020a - 2.81 (in liters)
${\displaystyle VC_{m}=(27.63-0.112a)\cdot g\quad ({\mathsf {in\ cm^{3}}})}$

${\displaystyle VC_{w}=(21.78-0.101a)\cdot g\quad ({\mathsf {in\ cm^{3}}})}$, or 0.0404g - 0.022a - 2.35 (in liters)

where g is the height in centimeters and a is the age in years.

Expiratory vital capacity

The expiratory vital capacity is the maximum amount of air that can be exhaled at once after maximum inhalation, and corresponds to the difference between total capacity and residual volume .

The measurement usually takes place in three steps:

1. maximum exhalation
2. slow maximum inhalation
3. maximum exhalation for measurement

See also

• Lung volume

Individual evidence

1. ↑ Reinhard Larsen: Anesthesia and intensive medicine in cardiac, thoracic and vascular surgery. (1st edition 1986) 5th edition. Springer, Berlin / Heidelberg / New York et al. 1999, ISBN 3-540-65024-5 , p. 474 f.