Phys- Spirometry Flashcards
What is FVC?
Forced vital capacity = TOTAL volume forcibly expired after max inspiration
(FVC = FEV3; all expired air is exhaled within 3 seconds)
What is FEF-MAX? FEF 200-1200?
Forced expiratory flow-max = time to exhale 1 liter at greatest flow rate
Forced expiratory flow 200-1200 ml = flow rate between 200-1200 ml exhaled; synonymous with FEF-max
What is MMFR?
Mid-maximal expiratory flow rate
Another name for FEF 25%-75%
What are the 3 ways in which to express forced expiratory volume?
In L
As flow rate = L/s
As a % of VC
Why must the measured volumes be corrected?
The gas was at 37 degrees in the body but at a lower room temp when measured; thus, the gas measured is a smaller volume than what was in the body.
What correction for measured volumes did we use in lab?
Assumed T = 20 degrees, add 10% of the volume measured
Why does FEV1 provide diagnostic info?
Flow rate during expiration decreases almost linearly with lung volume; thus, if FEV1 decreases, you know lung volume must also be decreased.
What is the limitation of FEV1 as a diagnostic tool?
The gas expelled during the initial phase of expiration is effort-dependent (pt may not give much effort, making FEV1 falsely low); later phase is not effort-dependent.
What is a flow volume diagram?
The flow rate vs. expired volume
What 4 data points did we plot on the flow volume diagram?
Full inspiration, FEF-MAX, FEF 25-75%, full expiration
Time represented between two vertical lines of the kymographic paper?
1 sec
FEF 200-1200 is synonymous with:
FEF-Max
A reduced FEV1 indicates:
Airway obstruction
Normal FEV1/FVC in a healthy, young pt
85%
When would FEV1/FVC be expected to be reduced?
Older age
