P S - 2 1 5 2
Interpretation of PFT Data
5
®
012-08856B
Total Flow is the
net volume
of air that flows
out
from the lungs through the
Spirometer, equal to the total expired volume minus the total inspired volume. View
the graph of Total Flow vs. Time. Four specific lung volumes and two lung
capacities can be interpreted from this graph.
*
*Use the built in analysis tools in the data collection software to measure the quantities from the graph
Tidal Volume (TV) is the volume of one breath, or the amount of air moved into and
out of the lungs during quiet breathing (breathing without effort).
Expiratory Reserve Volume (ERV) is the amount of air moved out of the lungs
during a forced expiration, beyond the level of tidal expiration.
Inspiratory Reserve Volume (IRV) is the amount of air moved into the lungs during a
forced inspiration, beyond the level of tidal inspiration.
Forced Expiratory Volume in One Second (FEV
1.0
) is the volume of air moved out of
the lungs in the first second of a forceful expiration following a maximal inspiration.
Inspiratory Capacity (IC) is the maximum amount of air that can be inspired after a
normal expiration (IC = TV + IRV).
Vital Capacity (VC) is the maximum
movable
amount of air contained by the lungs
(VC = TV + IRV + ERV).
FEV
1.0
% = FEV
1.0
VC × 100% is a common comparison of FEV
1.0
to VC.