Cardiorespiratory Mechanics

Question 1

What happens to the flow-volume loops in mild obstructive disease?

Answer 1

• displaced to the left because the lungs in COPD have more air in (lungs are fuller but the amount of air that can be excessed is less)
• indented exhalation curve -‘coving’, the narrowing of the airways causing obstruction, also causing peak to be lower
• increased residual volume (x-axis)
• decreased VC

Question 2

What happens to the flow-volume loops in severe obstructive disease?

Answer 2

• shorter curve
• displace more to the left
• indented exhalation curve

Question 3

What happens to the flow-volume loops in restrictive disease?

Answer 3

• obstructive disorders obstruct airflow

- restrictive disorders restrict the chest’s ability to expand

Question 4

What is the difference between restrictive disorders and obstructive?

Answer 4

• obstructive disorders obstruct airflow
• restrictive disorders restrict the chest’s ability to expand (obesity as excess weight makes it harder to generate pressures for airflow)

Question 5

What happens to the flow-volume loops in variable extrathoracic obstruction?

Answer 5

-blunted inspiratory curve-blockage on inspiration
-otherwise normal
-

Question 6

What happens to the flow-volume loops in variable intrathoracic obstruction?

Answer 6

• blunted expiratory curve- blockage on expiration

- otherwise normal

Question 7

What happens to the flow-volume loops in fixed airway obstruction?

Answer 7

• blunted inspiratory curve
• blunted expiratory curve
• otherwise normal