Flow Volume Studies A Flashcards
PEF is measured with the patient starting at ___.
TLC.
PIF is measured with the patient starting at ___.
RV
Decreases in the ___ and ___ are indicative of obstructive disease.
FEF 50% and FEF 75%
The ___ correlates with the FEF 25%-75% for diagnosing early small airways disease.
FEF 50%
What is the definition of an FEFmax?
How is it used?
The highest flow achieved on the expiratory curve. (Basically the same thing as a PEF or PEFR.)
Evaluates pt expiratory effort.
The FIF 25%, 50%, and 75% are measured on the (top or bottom) of the flow volume loop.
They are useful when compared to the expiratory values for determining ___, particularly the ___.
Bottom
Site of large obstruction, particularly the 50% value.
What is the definition of the FEF 50% / FIF 50% ratio?
The ratio of forced expiratory flow and forced inspiratory flow at 50% of the vital capacity.
What is a normal FEF 50% / FIF 50% ratio?
Between 0.8-1.2
A variable extrathoracic obstruction would (increase/ decrease/ not change) the FEF 50% / FIF 50% ratio.
Increase the ratio (above 1.2)
Inhalation would be reduced.
A variable intrathoracic obstruction would (increase/ decrease/ not change) the FEF 50% / FIF 50% ratio.
Decrease the ratio (Below 0.8)
Exhalation would be reduced.
A fixed airway obstruction would cause (increase/ decrease/ not change) the FEF 50% / FIF 50% ratio.
Not change. (Flows would be decreased on inspiration and expiration.
In a variable extrathoracic obstruction, (inhalation/ exhalation/ both) would be reduced.
Inhalation
In extrathoracic, exhalation is normal.
In a variable intrathoracic obstruction, (inhalation/ exhalation/ both) would be reduced.
Exhalation
In intrathoracic, inhalation is normal
In a fixed airway obstruction, (inhalation/ exhalation/ both) would be reduced.
Both
What’s the formula for the FEF 50% / FIF 50% ratio?
FIF50%
These readings can only be determined directly from a flow volume loop. (x5)
FEF 25% FEF 50% FEF 75% PIFR PEFR
What does it mean if the PEFmax is less than the FEF25%?
The patient gave poor effort.
If the obstruction is located at the level of the upper airway, trachea, or mainstem bronchi, the ___ is useful in determining the site of the obstruction.
FEF 50%
Fixed airway obstruction appears as a decreased ___ and a decreased ___ with values being approximately equal.
FEF 50% and FIF 50%
What is an example of:
- A fixed airway obstruction?
- A variable extrathoracic obstruction?
- A variable intrathoracic obstruction?
- Tracheal stenosis
- Vocal cord paralysis
- Tumor near the carina
A flow volume loop of an asthma patient would cause a decrease in (inspiratory/expiratory) flow and a ___ appearance in the expiratory part of the loop.
Expiratory
“scooped out”
A flow volume loop of an asthma patient would cause a decrease in (inspiratory/expiratory) flow and a ___ appearance in the expiratory part of the loop.
Expiratory
“scooped out” more pronounced than asthma patients.
When should you give someone a bronchodilator? (x4)
If the FEV1 is below 80% on pre-bronchodilator.
Cough of unknown etiology (could be asthma)
Known asthmatic condition
Anytime airway hyperreactiviy is suspected.
What is the fastest acting bronchodilator?
What’s the major side effect?
Isoproterenol
Increases heart rate.
In a post-bronchodilator test, the FEV1 must improve by __% and __ liters to be considered a reversible condition.
12%
0.2 liters
What’s the formula to determine change in FEV1 during a pre/post bronchodilator test?
(Post FEV1 - Pre FEV1) / Pre FEV1 = % change
If patient states subjective improvement in breathing after bronchodilator test, he (may/may not) benefit from continued use of a bronchodilator.
The patient may benefit.
Name two tests that need not be repeated post-bronchodilator.
FRC and DLCO
Large increases in FVC following bronchodilation may cause the ___ to decrease.
May also cause the ___ to decrease.
FEV1/FVC
FEF 25%-75%
If FVC increases in the post-bronchodilator study, it is highly suggestive of ___.
Peripheral air trapping.
If a patient has a normal VC and decreased FEV1/FCV%, he has a (obstructive/restrictive) disease.
Obstructive
If a patient has a decreased VC and normal FEV1/FCV%, he has a (obstructive/restrictive) disease.
Restrictive
Children as young as ___ years old can do an spirometry.
5 years old
Children doing spirometry: Flow volume curves that meet the criteria for a good start of test and are free of artifact for at least ___ are called “usable.”
the first second
While a child is doing a spirometry, once the child feels that lungs are empty, what should they do?
Stop blowing.
If a child doing spirometry stops exhaling when the flow is within ___ of the ___, it is considered a premature termination and is unacceptable.
10% of peak flow
When children do spirometry, ___ may be better than an FEV1.
FEV0.5
When children do spirometry, increased results may be because they ___.
get better at it with practice.
When children do spirometry, if post-bronchodilator FVC increases proportionally with the FEV1, the increase is most likely a result of ___.
Increased effort.
When children do spirometry, if post-bronchodilator FVC remains the same but the FEV1 increases, the increase is most likely a result of ___.
the bronchodilator.
