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.
