文摘
There is no generally accepted valid definition of pulmonary hyperinflation. Typical clinical and pulmonary functional signs should always be considered. Increased residual volume (RV) with a normal total lung capacity (TLC) is termed relative hyperinflation and an additional increase in TLC is called absolute hyperinflation. Furthermore, a differentiation is made between static and dynamic hyperinflation. Static hyperinflation is characterized by chronic destruction of the lung tissue and a decrease in lung compliance. Dynamic hyperinflation is situation-dependent, for example due to physical stress or exacerbation and plays a critical role in the pathophysiology of chronic obstructive pulmonary diseases. The most important parameter of pulmonary function is the functional residual capacity (FRC), which describes the amount of air remaining in the lungs after expiration of the tidal volume. The FRC can be measured using the washout method, helium dilution or whole body plethysmography. The various test methods can lead to deviating results, which should therefore be considered during interpretation and documentation.