Lung function tests

Question 1

How is a peak flow test performed?

Answer 1

1) Patient wears noseclip
2) Patient inhales to TLC
3) Patient wraps lips round mouthpiece
4) Patient exhales as hard and fast as possible
5) Exhalation does not have to reach RV
6) Repeat at least twice. Take highest measurement

Question 2

1) Patient wears noseclip
2) Patient inhales to TLC
3) Patient wraps lips round mouthpiece
4) Patient exhales as hard and fast as possible
5) Exhalation does not have to reach RV
6) Repeat at least twice. Take highest measurement

Answer 2

1) Patient wears noseclip
2) Patient inhales to TLC
3) Patient wraps lips round mouthpiece
4) Patient exhales as hard and fast as possible
5) Exhalation continues until RV is reached or six seconds have passed

Question 3

What do volume time curves show?

Answer 3

1. FVC
2. FEV1
3. FVC/FEV1
4. Peak flow rate

Question 4

How do volume time curves change for restrictive and obstructive

Answer 4

Restrictive:
Rate initially same but volume less

Obstructive:
Less volume
Less rate

Question 5

What do flow volume loops show?

Answer 5

TV
VC
ERV
IRV
PEF

Question 6

How are flow volume loops conducted?

Answer 6

1) Patient wears noseclip
2) Patient wraps lips round mouthpiece
3) Patient completes at least one tidal breath (A&B)
4) Patient inhales steadily to TLC (C)
5) Patient exhales as hard and fast as possible (D)
6) Exhalation continues until RV is reached (E)
7) Patient immediately inhales to TLC (F)

• Peak expiration better than inspiration

Question 7

What happens to flow volume loop during mild and severe obstructive disease?

Answer 7

Mild:

• Moves up because lung volume increase
• Gradient of line slightly lower
• Coving/dipping to due lower flow rates in smaller airways

Severe:
- Everything gets slightly worse

Question 8

What happens to flow volume loops during restrictive disease?

Answer 8

Volumes lower
Less access to air
Peak lower or unchanged
• A filling problem not a moving gas problem

Question 9

How do flow volume loops change during extra thoracic and intrathoracic obstruction?

Answer 9

Extra: inspiratory flow rate limited
Intra: expiratory flow rate limited
Fixed airway: both limited

Question 10

How do lung volumes change during normal, obstructive and restritive lung disease?

Answer 10

Obstructive:

• Flow out of air into and out of lung obstructed
• Lungs operate at higher volumes
• Dec IRV, TV, ERV
• Inc. RV

Restrictive:

• Infl/defla restrited
• Lungs operate at lower volume
• Dec IRV, TV, ERV, IRV