Pulmonary Function Tests Flashcards
Is mucus hypersecretion obstructive or restrictive?
obstructive
What does it mean if someone is emphysemic?
Emphysema is a lung condition that causes shortness of breath. In people with emphysema, the air sacs in the lungs (alveoli) are damaged. Over time, the inner walls of the air sacs weaken and rupture — creating larger air spaces instead of many small ones
- break down tissue
is COPs more compliant or elastant?
It is more compliant but has less elastance
What are restrictive disorders?
disorders that restrict the ability for the lungs to fill
- extra-airway diseases
What are obstructive disorders?
disorders associated with obstructed airflow
- airway diseases
What can be used to measure the peak expiratory flow rate (L/min)
peak flow meter
What is FVC?
forced vital capacity
What is FEV1?
forced expired volume in 1 second
What is the protocol to use peak flow meters to make volume time curves?
1) Patient wears noseclip
2) Patient inhales steadily to TLC
3) Patient wraps lips round mouthpiece
4) Patient exhales as hard and fast as possible
5) Exhalation continues until RV is reached
6) Visually inspect performance and volume time
curve and repeat if necessary. Look out for:
a) Inconsistencies with clinical picture
b) Interrupted flow data
What is the normal FEV/FVC ratio, and what is it in obstructive and restrictive diseases?
Calculating the FEV1/FVC ratio
Normal 4.3/5.1= 84%
Restrictive 3.3/3.3= 100%
Obstructive 1.0/1.9= 53%
so obstructive is lower, restrictive is higher
In the flow-volume loop, when does A-F occur in the steps of using a peak flow meter?
What do the flow volume loops look like for mild obstructive, severe obstructive and restrictive diseases?
What is left and right displacement dependent on in flow volume loops?
x-axis direction
What does an extra-thoracic obstruction cause?
decreased inspiration, bluntening
normal expiration
Due to pressure gradient
What does intrathoracic obstruction cause?
expiratory bluntening
What does the flow-volume loop of a
- variable extrathoracic obstruction
- variable intrathoracic obstruction
- fixed airway obstruction
look like?
What are pulmonary function tests useful for?
in the diagnosis, management and evaluation of lung diseases
What are obstructive diseases associated with?
impaired airflow in the airways (e.g., COPD and asthma)
What are restrictive diseases associated with?
limitation of chest expansion and the causes are usually extra-airway (e.g., pulmonary fibrosis, chest burns, obesity)
What affects the propensity of airways collapsing during expiration?
pressures in the airway, pleural space combined with mechanical properties
What is PERF?
gradient of the line in the volume-time spirometry
What is the FVC in a volume-loop spirometry?
width of loop
What is FEV1 in a flow-volume loop?
volume indicated by separate marker
What is PERF in a flow-volume loop?
highest point of upper portion of loop
