VC - vital capacity
Vital capacity (VC): the volume change
of the lung between a full inspiration and a maximal expiration.
The maneuver may be performed in different ways:
|1. The maneuver is performed rather slowly
2. The maneuver is performed with
vital capacity is assessed during an inspiratory maneuver.
Starting from end-tidal volume the subject expires maximally
and subsequently makes a full inspiration. This is the inspiratory
vital capacity (IVC).
- The vital capacity is assessed during an expiratory maneuver.
Starting from end-tidal volume the subjects makes a full
inspiration and subsequently exhales maximally. This represents
the expiratory vital capacity (EVC),
or ‘slow vital capacity’ in the Anglo-American
- If the subject first fills the lung to the fullest (i.e.
to total lung capacity), and then exhales forcefully and
completely to residual volume, the volume change of the
lung is the forced vital capacity (FVC);
it would be more correct to speak of forced expiratory vital
- If the subject first exhales fully to residual volume,
and then inhales forcefully and fully to total lung capacity,
the volume change of the lung is the forced inspiratory
vital capacity (FIVC).
In healthy subjects the vital capacities
measured according to these different procedures are nearly the
same. In patient with obstructive lung disease, however, the vital
capacity obtained during expiratory maneuvers is smaller than when
obtained upon inspiration:
IVC > EVC > FVC.
You should therefore always note which
VC has been assessed.
- 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.
- Miller MR et al. Standardisation of spirometry. ATS/ERS task force: standardisation of lung function testing. Eur Respir J 2005; 26: 319-338.