B-18 CASE Revision C
2060290-201
Miscellaneous: Spirometry Reference Value Equations, Interpretation Modes, Measurements
Impaired peripheral respiration
* If all four interpretation criteria are normal, the interpretative
statement Normal lung function values is displayed.
CHS
Interpretation mode based on the "American Thoracic Society
recommendations for disability testing." The most important criterion
used is the FEV1/FVC ratio; the changes of FEV 1 and FVC are also
considered. The underlying reference values are those published by
K
NUDSON.
Possible causes reduced pulmonary elasticity (emphysema), impaired
ventilatory distribution, peripheral airway obstruction
Criterion VC MAX/(2 x MEF50)
Definition Interpretative Statement
T50 % = < 0.8 s normal*
T50 % = 0.8 - 1 s mild expiratory flow limitation at deep expiration
T50 % = > 1 s moderate to severe expiratory flow limitation at deep
expiration
if > 0.8 s further lung function measurement recommended