Spirometry, lung volumes

Spirometry consists of the measurement of lung ventilation, the values obtained are important in the management of artificial lung ventilation and in the diagnosis of lung diseases. Ventilation parameters are measured by spirometers. We divide the measured parameters into:

• Static – the size of the alveolar space → inform about possible restriction disorders.
• Dynamic – the record of airflow in the airways → inform about obstructive disorders.

Static volumes

Spirometry - closing the nose with a peg, breathing only through the mouth through the spirometer attachment

Tidal Volume (TV)

• the amount of air that goes into the lungs with each inhalation (or the amount that is expelled with each exhalation);
• 0.5 l

Inspiratory Reserve Volume (IRV)

• air that is breathed in at maximal inspiratory effort above tidal volume;
• Men: 3 years
• Women: 2 yrs.

Expiratory reserve volume (ERV)

• volume expelled by active expiratory effort after passive expiration;
• Men: 1.2 l.
• Women: 0.7 l.

Vital Capacity (VC)

• the largest amount of air that can be exhaled after maximal inspiratory effort;
• it is often determined clinically as an index of lung function;
• Men: 5 l.
• Women: 3 yrs.

Dynamic volumes

Forced Expiratory Volume in one second (FEV1)

• the part of the vital capacity exhaled during the first second (also called the broken down vital capacity exhalation or forced expiratory volume in 1 s);
• it provides valuable information in diseases such as asthma, in which airway resistance is increased as a result of airway narrowing, vital capacity may be normal, but temporal vital capacity is significantly reduced.

Peak Expiratory Flow (PEF)

• 12 l/s.

Minute Pulmonary Ventilation - Respiratory Minute Volume (MPV, RMV)

• 6-8 liters/min (e.g. for 6 l – 500 ml/breath x 12 breaths/minute)

Maximum Free Ventilation (MFV)

• the largest volume of air that can be delivered to the lungs in one minute by voluntary effort;
• up to 200 liters/minute.

Cannot be measured by spirometry

Residual Volume (RV)

• air remaining in the lungs after maximum expiratory effort;
• 1.2 l;
• the dilution method is used for its measurement.

Dead volume (DV)

• the volume of air that does not participate in gas exchange;
• on exhalation, it mixes with alveolar air and cannot be distinguished;
• to determine, we must analyze the composition of exhaled air.

Links

Related articles

• Spirometry
• Lung volumes

Source

• KITTNAR, Otomar, et al. Lékařská fyziologie. 1. edition. Grada Publishing, 2011. 800 pp. ISBN 978-80-247-3068-4.

• KYMPLOVÁ, Jaroslava. Katalog metod v biofyzice [online]. [cit. 2012-09-20]. <https://portal.lf1.cuni.cz/clanek-793-katalog-metod-v-biofyzice>.