About svc efforts – Welch Allyn CP 200 Spirometry Option - User Manual User Manual
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Chapter 4 Performing Spirometry Tests
Welch Allyn CP 200 Spirometry Option
During FVC testing, an animated incentive screen provides an alternative way to view the
data (
). This screen gives patients, usually children, a fun goal to achieve while
exhaling. (If the selected norm does not provide a valid FVC or PEF predicted value, the
system tries to use the Polgar norm; if Polgar does not fit the patient’s demographics, the
incentive screen is not available.)
Figure 22. FVC Incentive Screen
About SVC Efforts
“SVC” stands for slow (relaxed) vital capacity. Sometimes SVC testing is used when
forced breathing is impossible. The patient inhales and exhales as completely as possible,
as in FVC testing, but the breathing is not forced. The goal of an SVC effort is to measure
the volume of air inhaled and exhaled, not the air flow (speed).
When ready to begin an SVC effort, you coach the patient through these steps.
(If preferred, you may reverse the order of inhaling and exhaling.)
1.
Place the flow transducer in your mouth.
2.
Breathe normally several times (tidal breathing).
3.
Inhale fully — calmly fill your lungs as much as you can.
4.
Exhale fully — calmly empty your lungs as much as you can.
The parameters measured during SVC testing are always displayed in a volume/time
curve, as shown in
Figure 23. SVC Curve
The more forcefully the patient blows, the more
flames are extinguished.
Time (s)
Vol (L)
Tidal breathing