Lung Fuction Testing Flashcards
Definition of functional residual capacity
FRC
Volume of gas remaining in lungs at end of tidal expiration
Definition of forced vital capacity/vital capacity
FVC/ VC
Largest volume of gas expelled after full inspiration
Define tidal volume(TV)
Volume inhaled and exhaled during one cycle
Define inspiratory reserve volume
IRV
Amount of air inspired after tidal inspiration
Define expiratory reserve volume
ERV
Amount of air exhaled after tidal expiration
Define residual volume
RV
Volume remaining in lungs after maximal expiration
Define forced expiratory volume in one second
FEV 1
Volume of gas expelled in first second of forced exhaling
What is FVC/ TLC/ FRC (added)
FVC= IRV + TV+ ERV
FRC= ERV +RV
TLC= IRV+ TV+ ERV+ RV
Do you things lung function test’s provides us
1) Info about ventilatory function
- How much a moves
- How fast air moves
2) . Info about the gassiest exchange function of lungs
- Diffusion capacity of alveolar capillary
Three equipment types to test lung function
Spirometry (lab)
“ (portable)
Plethysmograph
Two ways to know if results are of good quality
1) Acceptable effort
- No cough
- No hesitation to start test
- Adequate Exhalation
2) Reproducible?
What is used to measure gaseous exchange
Diffusion capacity (DL)
What is diffusion capacity
# How old gases move from airway to blood #Test patients breath in CO #Difference between how much inhaled versus exhaled measured
What does diffusion capacity give us an idea of
How much CO diffused in bloodstream
And how much remains in lungs
Five things that influence diffusion capacity
1) Surface area: ⬇️ = ⬇️ DL
2) Volume of blood: ⬇️ = ⬇️ DL
3) Haemoglobin: ⬇️ = ⬇️ o2
Therefor affect on [ ] of gasses
4) Diffusion gradient: [ ] of gas in alveolar and blood affects how much difgion takes place
5) Thickness of the membrane: ⬆️= ⬇️ DL
