|VT tidal volume during normal, quiet breathing
ERV expiratory reserve volume
FRC functional residual capacity
EVC expiratory vital capacity
IVC inspiratory vital capacity
TLC total lung capacity
RV - residual volume
The volume of the lung after maximal exhalation started from the functional residual capacity.
- In children and adolescents residual volume grows slightly faster than the total lung capacity, mostly on account of changes in chest geometry (references below).
- In healthy adults RV increases with age since a maximal expiration is increasingly impeded by airway closure, preventing dependent alveoli from emptying. In contrast, the total lung capacity does not change with age in adults. As a result the VC decreases with age in healthy subjects.
- Small airway pathology (inflammation, accumulation of secretions, hypertrophy and hyperplasia of glands and smooth muscles) and loss of lung elastic recoil (and therefore diminished elastic stretch of small airways) lead to premature airway closure during a maximal expiration; this causes the RV to increase, and the VC to decrease. Any factors that influence the TLC also affect the VC.
In patients with airway obstruction an FVC maneuver usually ends at a higher lung volume than a maximal expiration started from FRC level; only in the latter instance should end-expiratory volume be called RV.
|RV grows faster than TLC in adolescents|
|1||Merkus PJFM, Borsboom GJJM, van Pelt W, Schrader PC, van Houwelingen JC, Kerrebijn KF, Quanjer PhH. Growth of airways and airspaces in teenagers is related to sex but not to symptoms. J Appl Physiol 1993; 75: 2045-2053.|
|2||DeGroodt EG, van Pelt W, Borsboom GJJM, Quanjer PhH, van Zomeren BC. Growth of lung and thorax dimensions during the pubertal growth spurt. Eur Respir J 1988, 1, 102-108.|
- Quanjer PhH, Tammeling GJ, Cotes JE, Pedersen OF, Peslin R, Yernault JC. Lung volumes and forced ventilatory flows. Official Statement of the European Respiratory Society. Eur Respir J 1993; 6 suppl. 16: 5-40. Erratum Eur Respir J 1995; 8: 1629.