forced spirometry Flashcards
measured volumes
FVC
FEV1
measured flow rates
peak expiatory flow
FEF-25-75% flow rate during the middle 50% of the FVC tracing
FEF200-1200 forced expiratory flow between 200 and 1200 ml
the spiromery is?
highly effort depended test and good instruction must be given
technical test
initial speed at 32 mm/min and patient breath comfortably and at the end of inspiration the patient signal and you turn on 1920 mm/min and patient exhales forcefully to and test stop when patient can no longer continue
may take up to 20 seconds for severely obstructed patients
end of test criteria
six second expiatory time
plate of 1 second at RV
patient cannot exhale further
minimal detectable volume change at rv less than 30ml
acceptability criteria
maximal effort with a smooth continue effort
no cough
back extrapolation ,150mL or 5% whichever greater
producibility criteria
three acceptable criteria
three acceptable test plus or minus 5% or 200 mL
best test
greatest sums of the FVC and FEV1
FEV1 should be
75-85% of the FVC in one second
fev2
should be 94% of FVC in 2 seconds
fev3
normal individual can exhale 94% of FVC in 3 seconds
in obstructive patient the FEV1/FVC
65% and in restrictive disease it maybe normal or increases
FEF25-75%
flow during the middle portion of FVC
sensitive to small airway obstruction
FEF200 and 1200
indicative of large airway obstruction
and flow is between 200 to 1200 on the FVC
Peak expiatory flow rate
steepest portion of the tracing,, usually near the upper most part of the FVC curve
