Spirometry Mod 2 Flashcards
What is Spirometry?
- What values are observed?
Measures how an individual inhales and exhales volumes of air
- Measures Flow and Volume to Time (secondary)
- Spirometry is done fast (FVC)
- Slow flow is indicative of IC and VC
What does Spirometry measure?
- The function of the muscles of breathing
- Gas flow in and out of the lungs
What is being assessed in terms of muscle function from spirometry testing ?
- Diaprhagm, thoracic muscles
- Capability to expand and contract the thorax
What is being assessed in terms of Gas flow of the lungs from spirometry testing?
- Airway patency
- OBstructions to flow
What are 3 phases of Forced Vital Capacity (FVC)?
- Maximal inspiration
- Blast of exhalation
- Continued exhalation until end of test
What are the procedures for FVC?
- ATS guidlines…
- Prepare the subject
- Wash hands
- Instruct and demonstrate the test
- Perform Maneuverer (closed circuit method)
What is the maximum accepted leak value before beginning the test?
BEV <5% of FVC or 0.100 L; whichever is greater
What is the Acceptability and Usability criteria for Spirometry testing?
- 10 categories
- Add the specific ones outside of the table (slide 16)
How many attempts do you have at acquiring a usable test result
7-8 before test may be biased to pt fatigue
- aim for usable results rather than perfect acceptability
What does the between manoeuvre criteria (test) measure/performed/need to be met?
- (slide 24)
Ensures repeatable; of the 3 tests;
- the 2 largest values of FVC and FEV1 must be within 0.150 L of each other.
- The further the amount in litres, the lower the grade
How much of the FVC is blown out in the 1st second of the FEV1 (2 and 3 as well)
80% of air should be blown out within the 1st sec
What FVC results are reported to the doctor?
Largest FVC and FEV1
- Need at least 3 FVC to meet acceptability criteria
What is the Grading system for FEV1 and FVC
- i.e A-F
What is FEV1% also referred to as?
FEV1/FVC
On a flow volume loop; what points would the pt display effort dependant portion vs effort independant portion ?
- Slide 37
How does VC and IC test procedure differ from FVC tests?
Less forceful and effort needed
- usually performed before FVC because FVC could fatigue the pt before this test
- Still uses 3 tests
- Slow inhale and exhale flow rate
- tests TLC and RV? -> helps identify air trapping
Between manoeuvre evaluation for VC and IC?
Difference between largest and second largest manoeuvres should be no more than 150ml
- rest period of > 1 min between tests
- Needs 3 manoeuvres
What does Maximum Voluntary Ventilation (MVV) assess?
Used for exercise tolerance testing
- The max volume of air a subject can move in and out in the lungs in a specific period of time (within 12 sec)
- A alt if Spirometry testing is not viable (cannot test FEV1)
slide 70
We want their Vt to me half of VC?
What is differentiates upper and lower airway obstruction?
If the issue is derived above or below the carina
- If there’s time; break this table into other cards
What is Forced vital capacity (FVC)?
Max effort, rapid exhalation of VC
- validity = 3 maneuver variation <5%
How do airway obstructions affect FVC?
Airway obstructions = Increased airway resistance
- FVC exhalation requires more time due to decreased flow rate
- FVC test will have a 1 sec lag before flow starts regulating
How do Restrictive diseases affect FVC
Restrictive diseases typically infer low lung compliance and therefore limited lung expansion
- Small FVC exhaled quickly
What is the difference between FVC and FEVx?
Both are measures associated with volume-time measurements
- FVC = total forced exhalation of vital capacity
- FEV = Forced expiratory volume per time (x)
What is FEF (25-75*)
Forced expiratory flow
during middle half of FVC
- Dependent on the FVC
- Flow is from the medium to small airways
What information can you gather from FVC tests?
Helps reveal obstructive and restrictive conditions.
- Assess volumes + ability of Pt to forcefully exhale
What is the optimal test to assess restrictive conditions?
Slow vital capacity (SVC)
What information can Maximum Minute
Ventilation (MVV) testing provide and why do we use it?
Amount of air able subject can move in and out of the lungs over a specified period of
time.
- Used for obstructive disorders, can be a substitute for FEV1. (But FEV1 is
preferred). - Used when FEV1 is unattainable (FVC procedure too difficult to coordinate)
Main pulmonary characteristics of Obstructive Disease
Decreased Expiratory flow caused.
- High airway resistance will increased WOB
Main pulmonary characteristic of restrictive disease
Decreased volumes and capacities.
Decreased chest wall compliance (or lower lung compliance) will lead to increased WOB
Add this table later
What is EOFE?
End of Forced Exhalation
what is considered a
good Spirometry test?
Back Extrapolated Volume (BEV)
- Determines true start of test time
- Ensures accurate time zero for other measurements such as FEV1
- BEV must be <5% of FVC or 100 mL; whichever is greater
What is the max cut off time for 1 test/attempt?
15 seconds
Aside from accurate volumes; what other between maneuver criteria should be met before termination of testing
A total of 8 tests have been performed (max)
- fatigue can affect results
- Pt may tire and may not be safe to perform more testing
What information if measured and used when assessing FEV?
FEV1, FEV2, and FEV3 (forced exhalation within 1-3 seconds) is measured.
- FEV1 is the most important -> 80% of volume should be blown out here