DESCRIPTION
The most frequently performed spirometry test is the forced expira-
tory vital capacity test, or FVC. It is commonly used for basic pulmo-
nary function testing as well as managing patients with chronic
obstructive pulmonary disease (COPD), asthma, emphysema,
bronchitis, or other lung diseases.
When doing a single maneuver, the patient inhales as much air as
possible, then exhales as rapidly and as completely as possible into
the spirometer. To perform a complete FVC spirometry test, the
patient should complete three or more acceptable FVC maneuvers
with a brief rest between each one.
MEASUREMENT PARAMETERS
Several characteristics of the FVC maneuver are helpful in evaluat-
ing the patient’s lung function.
The two most commonly used parameters are FVC and FEV 1 :
FVC
Forced Expiratory Vital Capacity, the total amount of air (in liters)
exhaled during an FVC maneuver.
FEVl
Forced Expiratory Volume in one second, the volume of air (in liters)
exhaled during the first second of the FVC maneuver. FEVl is also
the measure of the average flow rate during the first second of the
FVC maneuver.
Other commonly used FVC parameters include:
FEVl /FVC%
(also called RATIO) the ratio of the FEV 1 to the FVC, expressed as
a percentage.
FEF25%-75%
Forced Expiratory Flow between the 25% and 75% volume points
(also called Mean Mid Expiratory Flow or MMEF). A measurement
of the average rate of flow (in liters/second) during the middle 50%
of the FVC maneuver.
PEF
Peak Expiratory Flow, the highest rat
during the FVC maneuver.
Once an acceptable FVC maneuver I
results can be compared to establish1
determined. The norms are based
of the patient.
Lung disorders usually fall into one
lung diseases or restrictive disorders
Obstructive lung diseases are those
rates or airflow limitation, such as ast
Chronic Obstructive Pulmonary
Restrictive disorders are those that
reduced, such as congestive heart fa
pneumonia, pleural fibrosis, pneumoc
In general, it is possible to categorize
these two groups and gauge its seve
but it is usually not possible to identif
further information. The patient’s res
ment, response to various bronchodil
specific pulmonary tests may be
disorder.
NOTE:
During FVC maneuvers in
instrument assumes that air at body
saturated with water (BTPS) will be
applied.
