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The FTP or FEV test , this test is done to measure your lungs.
The FEV test says a lot about the state your lungs are in , below you
will see the information about the chart and its meaning.
FVC
- forced vital capacity , the amount of air you can blow out forcefully
and completely (ie until you feel there is none left) from a full breath
in.
(there is actually air left in your lungs - this is called residual
volume -this value goes up in CF as there is air trapping behind the mucous).
FEV1
- Forced expiratory volume in 1 second.
Normally someone should be able to get around 80% of the FVC out in
1 second.
FEV1/FVC
this ratio is a VERY broad indicator of obstruction in the airways (particularly
the larger airways) it does not often show it in the small airways.
FEF25-50
Forced expiratory Flow 25 - 50% (25-75 is common too) it doesn't have to
do with oxygen - but the flow rates (the speed of the air leaving your
lungs).
The percentages tell you at which time the flow measurement is taken.
(at 25% of the full breath out, 50% etc).
You can also have averages of these.
With FLOW
- The peak flow tells you about your large airways (bronchi- the ones with
smooth muscle , that's why this is useful with asthma).
As you get towards the 50,75% FEF's it's telling you about your middle
to smaller airways and how the flow is doing down there.
PEF(R)
Peak expiratory Flow (rate) the speed of the breath at the begining of
a breath out.
PIF
- same as above but for inspiration (breath in).
MVV
-Maximum Voluntary Ventilation (usually over a minute) - how much volume
you can move in 1 min going at top speed and with BIG breaths.
TLC
- Total lung capacity - usually measured by the "body box" or by dilution.
The box would work better with CF - because dilution might miss some
air stuck behind some mucous.
VC
- Vital capacity - is that thing from a deep breath in to the residual
volume (mentioned above) difference between TLC and RV.
RV/TLC
- tells you how much air is staying in your lungs after you breathe out
as far as you can - indicates how much "gas trapping" there is.
In CF - RV would go up with more air being trapped - so the RV/TLC
ratio would go up.
FRC
- Functional residual capacity - it's like the RV plus a little bit.
Instead of breathing all of the way out - this measure is only taken
from the end of a regular breath out.
Well thats about all , there are only a few things left out and those
are not regular anyway.
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