Pulmonary function Test Flashcards
What are the 3 pulmonary function tests?
Effort dependent
Effort independent
Gas diffusion. Slide 5
What does the effort dependent test measure and how is it measured?
Forced expiratory volume and is measured by spirometry. Slide 5
What does the effort independent test measure and how is it measured?
Relaxed vital capacity and is measured by spirometry during static lung volumes. Slide 5+16
What does the gas diffusion test measure and how is it measured?
The CO transfer factor and is measured by SaO2 during exercise. Slide 5
In spirometry what is the difference in results between asthma, normal and COPD?
Normal - breath out the most in 1 second and have a high FVC.
Asthma - Not as steep a curve as normal but will reach the same FVC.
COPD - Even shallower curve and has a lower FVC. Slide 7
What is the flow-volume curve and what does it show?
Flow rate plotted against FEV(TLC to RV).
If there is a deviation from the normal graph then it can show volume and pressure dependent airway closure. Slide 10
If a patient has asthma or chronic bronchitis, what will the pattern of the flow volume curve pattern look like?
A slightly more curved line declining as the airway closes before most the air can get all out quickly. Slide 10
If a patient has emphysema, what will the pattern of the flow volume curve pattern look like?
A very small curve which a very steep decline and small incline. Slide 10
What is the PEFR in obstructive and restrictive diseases compared to normal?
O = decreased
R = normal
Slide 11
What is the FEV1 in obstructive and restrictive diseases compared to normal?
O = decreased
R = decreased
Slide 11
What is the FVC in obstructive and restrictive diseases compared to normal?
O (asthma) = normal
O (COPD) = decreased
R = decreased
slide 11
What is the FEV1/FVC ratio in obstructive and restrictive diseases compared to normal?
O = <75%
R = >75%
Slide 11
What is the FEV1 response to Beta-agonist in obstructive and restrictive diseases compared to normal?
O (asthma) = >15%
O (COPD) = <15%
R = No response
Slide 11
What is bronchial challenge testing?
Exercise and using a specific concentration of a airway hyper-responsiveness marker to cause a 20% decrease in FEV1. Slide 13
When do you diagnose asthma in the bronchial challenge test?
If the concentration of the airway hyper-responsiveness marker is less than 8mg to cause a 20% fall in FEV1. Slide 13
What is the transfer factor and how can the result be interpreted?
The ability of CO to diffuse across the alveolar-capillary barrier.
If there is a low TLCO then it can show anaemia, emphysema, DPLD. Slide 19
How is airway resistance measured?
By whole body plethysmography or more commonly oscillometry. Slide 20
What does exhaled breath condensate show?
Allows the exhaled breath nitric oxide to be measured and if there is >35ppb then it shows asthma but not COPD. Slide 21
