PFT Flashcards
What are a few indications for performing a PFT?
- Evaluate signs of lung disease
- Assess progression of lung disease
- Monitor effectiveness of therapy
- Evaluate preoperative patients
- Monitor for toxic effects of drugs or chemicals
- Screen patients at risk for pulm dx
what is FVC?
- Forced Vital Capacity is when the patient inhales as deep as possible and then exhales for as long with as much force as possible
What is FEV1?
- Amount of air exhaled during the first second of the FVC
- FEV1/FVC ratio should be ~80%
An anemic patient comes into the office, what can we expect of their diffusing capacity?
Decreased as blood can’t bind the diffusing gas
With a patient who has emphysema what can we expect of their diffusing capacity?
Expect it to be decreased as the surfae area for gas exchange is decreased
For a 68 yo woman with SOA, no cough or wheeze
Lower limit of normal:
- FVC: 2.39 L
- FEV1: 1.80 L
- FEV1/FVC ratio: 67.3%
- TLC: 4.12 L
Patient Values:
- FVC: 1.85 L
- FEV1: 1.64
- FEV1/FVC ratio: 88.6
- TLC: 2.74 L
Is this restrictive or obstructive?
- Is the ratio less than normal limit? no
- Is FVC less than lower limit of normal? yes
- This is a restrictive pattern
Is this restrictive or obstructive?
- Is ratio less than lower limit normal? yes,, it is 58.2% lower than predicted
- Is FVC less than lower limit normal? no
- This is an obstructive pattern
What happens to FVC, FEV1, ratio, and TLC with an obstructive pattern?
- FVC is decreased or normal
- FEV1 is decreased
- Ratio is decreased
- TLC is normal or increased
Lungs have high compliance so they can fill easy, but they have low elastic recoil so pushing air out is an issue
What happens to FVC, FEV1, ratio, and TLC with a restrictive pattern?
- FVC is decreased
- FEV1 is decreased or normal
- Ratio is normal or elevated
- TLC is decreased
Lungs have low compliance so they do not easily fill, and high elastic recoil so pushing air out is easier
