Lung Function Tests

Question 1

in obstructive disorders what will happen to the FEV/FVC ratio

Answer 1

it will decrease

Question 2

explain the FEV/FVC ratio in obstructive disorders

Answer 2

the ratio decreases because the FEV reduces. this is because it is harder to breath out and so the flow is lower, meaning less air is blown out immediately and instead takes a long time to be blown out

Question 3

what is the shape of the flow loop in obstructive disorders

Answer 3

scooped shape, lower peak, same FVC

Question 4

give 2 examples of obstructive disorders

Answer 4

asthma and COPD

Question 5

give an example of a restrictive disorder

Answer 5

fibrosis

Question 6

what happens to the FEV/FVC ratio in restrictive disorders

Answer 6

it increases or stays the same

Question 7

what is the FEV1

Answer 7

the amount of air blown out in 1 second of forced expiration - should be 80% of FVC

Question 8

what is the FVC

Answer 8

the amount of air that can be blown out in forced expiration

Question 9

what has the breathing of a patient with a restrictive disorder changed

Answer 9

the lungs are less compliant so can’t take in as much air or expel as much making inspiration and expiration both difficult

Question 10

describe a time-volume graph for obstructive disorders

Answer 10

the line will be lower (as air can’t be forced out as well) and longer (as all the air will eventually be blown out but just at a lower speed/flow)

Question 11

describe the time-volume graph for restrictive disorders

Answer 11

the line will initially be the same as initial exertion of air is normal - however, the line will then stop as no more air can be blown out

Question 12

describe a normal flow loop digram

Answer 12

above the line is the expiration flow - this should have a peak (fastest flow out expulsion of air) and then gradually decrease as the lungs empty of air

below the line is the inspiration flow - this should not be flat and loop back to the start

Question 13

describe a flow loop diagram in obstructive disorders

Answer 13

the peak is lower (as exertion of air is affected)
the FVC is the same so the loop will finish at the same point
has a scooped shape

Question 14

describe the flow loop diagram in restrictive disorders

Answer 14

the peak is smaller
the FVC is smaller so the loop finishes sooner (as they can’t blow as much air out)
inspiration flow is flatter