Lung Function Practical

Question 1

What are the levels of severity of obstructive disorders?

Answer 1

• mild obstruction = FEV1 is 50 - 80% of predicted best
• moderate obstruction = FEV1 is 30 - 49% of predicted best
• severe airflow obstruction = FEV1 <30% of predicted best

Question 2

What are the levels of severity of restrictive disorders?

Answer 2

• mild restriction = FVC 65 - 80%
• moderate restriction = FVC 50 - 65%
• severe restriction = FVC <50%

Question 3

What is a restrictive airway disorder?

Answer 3

where the ability of the lungs to actually expand is impaired

e.g. pulmonary fibrosis

Question 4

What is an obstructive airway disorder?

Answer 4

obstruction/narrowing of the airways

e.g. COPD, Bronchitis, Asthma

Question 5

What is FEV1?

Answer 5

the Forced Expiratory Volume in 1 second

hard, forced out breath into the peak flow/spirometer

Question 6

What is FVC?

Answer 6

the Forced Vital Capacity

hard, forced out breath

Question 7

What is VC?

Answer 7

the Vital Capacity

slow, long breath out to measure

Question 8

What are the diagnostic tests that suggest an obstructive airway disorder?

Answer 8

• FEV1 <80% of the predicted best
• FVC is reduced, but to a lesser extent than the FEV1

the air can still come out, but just takes longer to because of the narrowing

FEV1/FVC is REDUCED - less than 0.7

Question 9

What are the diagnostic tests that suggest a restrictive airway disorder?

Answer 9

• FEV1 <80% of the predicted best
• FVC is ALSO reduced <80% of the predicted best

the lungs have less overall volume because they are unable to expand, because BOTH are reduced, the FEV1/FVC ratio is NORMAL

Question 10

What suggests that a patient has asthma that is uncontrolled?

Answer 10

variable day - day readings

Question 11

How do you calculate the percentage of predicted best readings?

Answer 11

reading/predicted best x 100

Question 12

How do you calculate the FEV1/FVC ratio?

Answer 12

FEV1 reading/ FVC reading