SM 174a, 175a - Pulmonary Function I, II

Question 1

Is the following characteristic of obstructive lung disease or restrictive lung disease?

FEV₁/FVC increases

Answer 1

Restrictive

(Even though both FEV₁ and FVC decrease, the ratio increases)

Question 2

What pressures contribute to P_alv?

Answer 2

P_alv = P_pl + P_el

Question 3

Which number labels Total Lung Capcity (TLC)?

Answer 3

8

Question 4

Is the following characteristic of obstructive lung disease or restrictive lung disease?

Decreased FEV₁

Answer 4

Both

But more decrease in obstructive than restrictive

Question 5

Expiratory airflow is decreased most by what combination of pathophysiologic conditions?

a) low Pel and high Raw
b) high Pel and high Raw
c) low Pel and low Raw
d) high Pel and low Raw

Answer 5

a) low Pel and high Raw

Question 6

Which number labels inspiratory capacity?

Answer 6

7

Question 7

Is the following characteristic of obstructive lung disease or restrictive lung disease?

Increased RV

Answer 7

Obstructive

Question 8

Is the following characteristic of obstructive lung disease or restrictive lung disease?

Increased FRC

Answer 8

Obstructive

Question 9

Is the following characteristic of obstructive lung disease or restrictive lung disease?

Decreased DLCO

Answer 9

Restrictive

(May also decrease in obstructive, or stay the same)

Question 10

Is the following characteristic of obstructive lung disease or restrictive lung disease?

Increased isovolume flow compared with a normal curve

Answer 10

Restrictive

Question 11

Flattening of the inspiratory loop suggests:

a) asthma
b) vocal cord paralysis
c) pulmonary fibrosis
d) pulmonary embolism

Answer 11

b) vocal cord paralysis

Inspiratory loop can be flattened by anythign that obstructs the upper (extrathoracic) airway, or inadequate strength of inspiration

Question 12

Which of the following test results suggests asthma?

1. Low FEV₁/FVC that normalizes after albuterol
2. Low FEV₁/FVC with low diffusing capacity
3. Normal FEV₁/FVC after an irritant challenge
4. Normal FEV₁/FVC with low diffusing capacity

Answer 12

a. Low FEV₁/FVC that normalizes after albuterol

Question 13

Is the following characteristic of obstructive lung disease or restrictive lung disease?

TLC decreases

Answer 13

Restrictive

Question 14

What is normal for FEV₁/FVC?

Answer 14

~75% in healthy people

Decreases with age

<70% indicates obstructive physiology

Question 15

How do people with obstructive airflow preserve their FVC, depite obstruction to expiratory air flow?

Answer 15

Time compensation

Healthy people can exhale their FVC in ~4 seconds, but people with obstructive physiology may take 8-10 seconds

Question 16

What does DLCO measure?

Answer 16

DLCO = diffusing capacity for carbon monoxide

Measures the diffusing capacity across the alveolar membrane

Measures inhaled CO uptake by hemoglobin
(Known [CO] in inhaled air - measured [CO] inexhaled air = uptaken by Hb

Question 17

Which curve represents an obstructive defect?

Answer 17

2

Question 18

Why are lung volumes lower in restrictive lung disease

(Ex: pulmonary fibrosis, asbestosis)

Answer 18

Restrictive lung diseases are characterized by fibrosis, which increases the elastic recoil pressure of the lung and decreases compliance

If the lungs do not want to expand and they are eager to recoil, lung volumes will not be as high

Question 19

What causes decreased DLCO?

Answer 19

Decreased DLCO = Decreased diffusing capacity

• V/Q mismatch
  
  • Empysema
• Blood loss
  
  • Anemia
• Loss of functional blood vessels
  
  • PE
  • Emphysema
  • ILD (Scarring and fibrosis -> loss of blood vessels)
• R- > L intracardiac shunt

Question 20

Which number labels Tidal Volume (VT)?

Answer 20

4

Question 21

What are the 3 tests that measure lung volume?

Answer 21

Helium dilution

Nitrogen washout

Body plethysmography

Question 22

Why are lung volumes increased in obstructive lung disease?

Answer 22

In obstructive lung disease, there is an impediment to expiratory airflow.

• Emphysema: decreased elastic recoil makes the lungs bad at pushing air out, and loss of teathering leads to airway collapse
• Chronic bronchitis, asthma: Increased airway resistance obstructs airflow

Air gets trapped in the lung, thus increasing lung volume

Question 23

Which number labels Inspiratory Reseve Voume (IRV)?

Answer 23

1

Question 24

Which number labels Residual Volume (RV)

Answer 24

6

Question 25

Is the following characteristic of obstructive lung disease or restrictive lung disease? ## Footnote **FEV₁/FVC decreases**

Answer 25

Obstructive FEV₁/FVC \<0.7 is indicative of an obstructive defect

Question 26

Which number labels Functional Residual Capacity (FRC)?

Answer 26

2

Question 27

Which curve represents an obstructive defect?

Answer 27

1

Question 28

Is the following characteristic of obstructive lung disease or restrictive lung disease? ## Footnote **Decreased Peak Expiratory Flow (PEF)**

Answer 28

Both

Question 29

Isovolume airflow is high in: ## Footnote a) asthma b) vocal cord paralysis c) pulmonary fibrosis d) pulmonary embolism

Answer 29

c) pulmonary fibrosis Isovolume air flow is high in restrictive lung disease

Question 30

Which number labels vital capacity (VC)?

Answer 30

3

Question 31

What is wrong with this flow-volume curve? What might be causing this?

Answer 31

The inspiratory part of the curve (below the x axis) is too flat Possible causes: * Inadequate strength, effort, or technique during forced inspiration * **Upper** airway obstruction * Croup * Racheal or laryngeal structures

Question 32

Emphysema is best characterized by: ## Footnote a) high FEV₁/FVC b) hyperinflation with low DLCO c) high Pel and low Raw d) fixed inspiratory and expiratory airflow obstruction

Answer 32

b) hyperinflation with low DLCO

Question 33

What causes increased DLCO?

Answer 33

Increased DLCO = more gas is uptaken by hemoglobin * Due to increased hemoglobin in areas of intact ventilation * Alveolar hemorrhage * Lupus * Cocaine * Legionella * Any condition that causes bleeding in the lung * Polycythemia = too many red blood cells * L-\>R intracardiac shunt

Question 34

Is the following characteristic of obstructive lung disease or restrictive lung disease? ## Footnote **Decreased FVC**

Answer 34

Restrictive | (May see some decrease in obstructive)

Question 35

Which curve represents a restrictive defect?

Answer 35

2

Question 36

Is the following characteristic of obstructive lung disease or restrictive lung disease? **Decreased RV**

Answer 36

Restictive

Question 37

Is the following characteristic of obstructive lung disease or restrictive lung disease? ## Footnote **Decreased FRC**

Answer 37

Restrictive

Question 38

What does spirometry measure?

Answer 38

Expiratory air flow rates FEV₁ FVC FEV₁/FVC PEF

Question 39

Describe the conditions of maximum expiratory flow

Answer 39

High P_el and low R_aw P_el = elastic recoil pressure R_aw = airway resistance

Question 40

Which curve represents a restrictive defect?

Answer 40

1

Question 41

Is the following characteristic of obstructive lung disease or restrictive lung disease? ## Footnote **TLC increases**

Answer 41

Obstructive

Question 42

Is the following characteristic of obstructive lung disease or restrictive lung disease? ## Footnote **Decreased isovolume flow compared with a normal curve**

Answer 42

Obstructive