Lung Function Test
Flow Volume Loop
The flow/volume loop represents the basic physiological description of the disease. This dynamic presentation provides an explanation as to why COPD patients become limited by pulmonary hyperinflation. As they exercise they breathe more rapidly and trap more air.
The first curve represents normal function with tidal breathing unencumbered.
The second curve represents the COPD/emphysema patient who is stacking air as he/she breathes more rapidly during exercise, and is thus unable to empty his/her lungs to make room for his/her subsequent inhalation.