Lung Volumes

Lung volumes are the volumes of space occupied by the air in the lungs during respiration. The combination of individual volumes creates so-called lung capacities.

The measured parameters are divided into:


 * Static – the size of the alveolar space → inform about possible restriction disorders restriction disorders.


 * Dynamic – recording of air flow in the airways → inform about obstructive disorders.

All volumes reported in various publications are averages only. These volumes are individual. They are affected by height, weight, age, training, gender and health. In practice, therefore, an absolute value in liters and a relative percentage is given, which compares the measured results with persons of the same age, sex, height and weight.

Static volumes
Tidal volume (VT or TV) is the volume of one breath. It has a value of 0,5 l. It also contains the so-called dead space (anatomický mrtvý dýchací prostor), (anatomical dead airway), which indicates the volume of the airways up to the terminal bronchioles. Its volume is 150 to 200 ml. This volume can be further increased by the volume of such alveoli which are not capable of exchanging respiratory gases. Then this volume is called the total (functional) dead airway.

After exhaling, a person still has the opportunity to exhale hard and thus get breathing gases with a volume of about 1,7 l. This volume is called the reserve expiratory volume (ERV).

It is the same for inspiration.We can inhale even after a normal inhale even hard and inhale a volume of about 3 l vzduchu. This is called the reserve inspiratory volume (IRV).

Despite our best efforts, we are not able to completely empty our lungs. About 1,3 l of air always remain in them. This volume is then called the residual volume (RV).

Pro stanovení reziduálního objemu se využívá heliové diluční metody. helium dilution method is used to determine the residual volume.

Plicní objemy

Static capacities
Vital capacity (VC) – the sum of tidal volume, inspiratory reserve volume and expiratory reserve volume (maximum breath - maximum expiration);


 * VC = VT + IRV + ERV

Total lung capacity (TLC) – the sum of vital capacity and residual volume;


 * TLC = VC + RV = IRV + VT + ERV + RV

Functionoal residual capacity (FRC) – volume of air in the lungs after free expiration;


 * FRC = ERV + RV

Dynamické objemy
Minute ventilation (VE) – tidal volume (VT) multiplied by the frequency of breaths per minute, at rest it is about 8 l/min .;


 * Alveolar ventilation (VA) is munte ventilation of the lungs - minute ventilation of the dead space;
 * Maximum minute ventilation (MMV, Vmax) determines the largest possible minute exchange of breathing gases(max. 200 l/min );¨

One-second vital capacity (FEV1) - the volume of air that is exhaled with forced exhalation in the first second;

One-second vital capacity (FEV1) – the volume of air that is exhaled with forced exhalation in the first second;

The Tiffenea index is the ratio of FEV1 and VC. Helps diagnose obstructive and restrictive lung disease. The physiological value is reported to be 80 % (0,8). In restriction disease, the value of the Tiffenea index is usually normal to elevated. In the case of mixed diseases, both obstructive and restrictive, the value is reduced. eg FEV1 / VC = 0.7 -> at the site of suspected asthma, COPD, ...


 * In restriction diseases, the value of the Tiffenea index is usually normal to elevated.
 * In the case ofmixed disease, the value is reduced.
 * eg FEV1/VC = 0,7 -> at the site of suspected asthma, COPD,...

Související články

 * Funkční vyšetření kardiorespiračního systému
 * Restrikce dýchání/Repetitorium

Použitá literatura