L18 - Intro to Pulmonary Physiology

Question 1

Part of the lung where there is:

• Bulk air movement
• Anatomic dead space (no alveoli)
• No gas exchange

Answer 1

Conducting Zone

Includes: trachea, bronchi, bronchioles, terminal bronchioles

Question 2

Part of the lung where there is:

• Increasing number of alveoli
• Air distribution by diffusion
• Alveolar-capillary unit; Gas exchange takes place

Answer 2

Transitional / Respiratory Zone

Includes: respiratory bronchioles, alveolar ducts, alveolar sacs

Question 3

Describe normal lung histology

Answer 3

Large spaces between alveoli and thin alveolar walls

Question 4

A. What are the 2 sources of blood to the lungs and what are their primary roles?

B.How does this impact lung infarctions?

Answer 4

A.

1. Pulmonary artery - responsible for gas exchange (pulm aa –> alveoli –> alveolar ducts –> RBC picks up and drops off CO2 –> pulm vv)
2. Bronchial artery - gives nutrition to lungs

B. Lung rarely infarcts since it has 2 sources of blood

Question 5

Tidal Breathing: Inspiration Which is false?

A. Brain initiates inspiratory signal

B. Inspiratory muscles contract

C. Thoracic volume increases - diaphragm flattens

D. Intrapleural pressure increases

E. Alveoli expand

F. Alveolar pressure less than atmospheric

G. Air gradient so air flows into airways until Alveolar = atmospheric pressure

Answer 5

D. decreases

Question 6

Tidal Breathing: Expiration Which is false?

A. Brain ceases inspiratory signal

B. Inspiratory muscles relax - diaphragm returns to normal shape

C. Alveoli recoil (elastic)

D. Thoracic volume decreases

E. Alveolar pressure much less than atmospheric

F. Air flows out of airways until Alveolar = atmospheric pressure

Answer 6

E. Alveolar pressure much greater than atomospheric

Question 7

T/F Restrictive lung diseases or rib cage abnormalities will impair normal tidal breathing?

Answer 7

T

Question 8

Which is not a common pulmonary symptoms?

1. Dyspnea
2. Syncope
3. Hemoptysis
4. Cough
5. Nausea

Answer 8

5. Nausea is not a common symptom Chest pain is the other pulmonary symptom

Question 9

On physical exam: Whistle noise made during exhalation due to narrow tubes

Answer 9

Wheezing

Question 10

On inspection what do you look for in someone with impaired pulmonary function?

Answer 10

1. ability to finish a sentence
2. cyanosis
3. use of accessory muscles

Question 11

On physical exam: Static-like sound due to alveoli filled with fluid.

Answer 11

Rales (crackles)

Question 12

On physical exam: Sound made on inspiration as if one was breathing through a straw. This is due to upper airway obstruction causing turbulent flow

Answer 12

Stridor

Question 13

What physical exam sign may indicate chronic lung disease?

Answer 13

Clubbing

Question 14

On percussion a pleural effusion will sound _____?

Answer 14

Dull (due to fluid around lungs)

Question 15

On percussion a pneumothorax will sound _____?

Answer 15

Hyperresonant around the pleural space

Question 16

Spirometry is a test used to:

A. Exam lung function

B. Differentiate obstructive from restrictive lung diseases

C. Evaluate symptoms such as dyspnea, cough and wheezing

D. monitor response to therapy

E. Stage the severity of lung disease

F. Detect bronchial hyporesponsiveness

Answer 16

F. Hyperresponsiveness

Question 17

Describe the technique of how patients must breathe during spirometry.

Answer 17

Inhale to TLC, then forcibly exhale to RV. (e.g. VC)

Question 18

Volume of air exhaled in first second by forced expiratory effort

Answer 18

FEV1 (Forced Expiratory Volume at the first second)

Question 19

Total volume of air exhaled by forced expiratory effort

Answer 19

FVC (Forced Vital Capacity)

Question 20

• Expressed as a percentage
• Above 70% to be normal

Answer 20

FEV1/FVC (ratio of FEV1 to FVC)

Question 21

Reference (normal) values of spirometry tests are NOT based on:

A. Weight

B. Height

C. Sex

D. Age

E. Ethnicity

Answer 21

A. Weight is not used

Question 22

Breathing volume at rest (includes normal inhalation and exhalation)

Answer 22

Tidal volume

Question 23

Additional air that can be forcibly inhaled after the inspiration of a normal tidal volume

Answer 23

Inspiratory reserve volume

Question 24

Max volume of air that can be expelled from the lungs after normal expiration

Answer 24

Expiratory reserve volume

Question 25

Maximum amount of air a person can expel from the lungs after a maximum inhalation

Answer 25

Vital capacity

Question 26

Normal range for FEV1 & FVC

Answer 26

80-120% predicted

Question 27

What does a FEV1/FVC less than 70% indicate?

Answer 27

Airflow obstruction

Question 28

Post-bronchodilator response is used to determine reversibility of airflow obstruction after given albuterol. 1. Which is reversible (aka will give a positive response), asthma or COPD? 2. What % and volume increase is considered a positive response?

Answer 28

1. Asthma 2. 12% and 200ml increase from pre (FEV1 or FVC)

Question 29

1. FEV1/FVC in healthy nonsmokers (increases/decreases) with age in M and F. 2. This results in (over/underdiagnosis) of COPD in the elderly 3. This results in (over/underdiagnosis) of asthma in the young

Answer 29

1. decreases 2. overdiagnosis (false positives) 3. underdiagnosis (can have preserved FEV1 even with asthma) - false negatives This is a limitation of the FEV1/FVC ration

Question 30

COPD and asthma are examples of (obstructive/restrictive) disorders

Answer 30

obstructive

Question 31

pleural, interstitial, neuromuscular, thoracic/extrathoracic are examples of (obstructive/restrictive) disorders

Answer 31

restrictive

Question 32

Obstructive or restrictive? 1. Expiratory difficulty, cannot get air out. 2. Increased lung compliance (“floppy” airways) 3. Reduction in air-flow \>\> reduction in lung volume 4. Reduced FEV1 (out of proportion to reduction in FVC) 5. Reduced FEV1/FVC ratio (

Answer 32

Obstructive

Question 33

Obstructive or restrictive? 1. Inspiratory difficulty, cannot get air in. 2. Decreased lung compliance (“stiff” airways) 3. Reduction in lung volume \>\> reduction in air-flow 4. Diagnosis by lung volume test, not spirometry 5. Decreased FVC (out of proportion to reduction in FEV1) 6. Normal or elevated FEV1/FVC ratio 7. Decreased RV, FRC, and TLC

Answer 33

Restrictive

Question 34

Flow volume loop is lower and more prolonged

Answer 34

Obstructive

Question 35

Flow volume loop has decreased volume

Answer 35

Restrictive

Question 36

used to measure lung volumes and capacities Volume/Pressure calibrated sealed box Patient tidal breathes around FRC When expiratory tube closed ̏ V1̏ P1 ≈ ̏ Vx̏ P2

Answer 36

Body Plethysmography

Question 37

used to measure lung volues and capacities equilibrate FRC (functional residual capacity) with He V1 x [He]i = (V1 +Vx) x [He}f

Answer 37

Helium Dilution

Question 38

Obstructive/restrictive? over time due to chronic airflow obstruction, will inc reserve volume (air trapping) and hyperinflation --\> inc TLC

Answer 38

Obstructive

Question 39

Obstructive/restrictive? lung volume compressed - RV, TLC decreased

Answer 39

Restrictive

Question 40

T/F: You can diagnose obstructive physiology (FEV1/FVC ratio \< 70%), but not restrictive physiology using spirometry

Answer 40

True: To diagnose restrictive physiology, lung volume needs to be measured

Question 41

(surface area \* pressure gradient across the membrane) / diffusion distance = ?

Answer 41

Gas diffusion

Question 42

What are 3 ways in which gas diffusion is decreased in the alveoli?

Answer 42

1. decreased surface area (e.g. alveolar destruction, lose capillaries, alveolar filling defect) 2. Decreased pressure (e.g. bronchial obstruction, alveolar filling defect) 3. Increased diffusion distance (e.g. wide alveolar-capillary space; fibrosis, edema)

Question 43

process of oxygen diffusing passively from the alveolus to the pulmonary capillary, where it binds to hemoglobin in red blood cells or dissolves into the plasma

Answer 43

Oxygenation

Question 44

Which mechanism of impaired alveolar oxygen diffusion results in pulmonary embolism? A. Decreased surface area for diffusion B. Decreased driving pressure C. Increased diffusion distance

Answer 44

A. Decreased surface area for diffusion - Less capillaries

Question 45

Which mechanism of impaired alveolar oxygen diffusion results in COPD/emphysema? A. Decreased surface area for diffusion B. Decreased driving pressure C. Increased diffusion distance

Answer 45

A. Decreased surface area for diffusion - due to alveolar destruction

Question 46

Which mechanism of impaired alveolar oxygen diffusion results in Pneumonia? A. Decreased surface area for diffusion B. Decreased driving pressure C. Increased diffusion distance

Answer 46

A. Decreased surface area for diffusion B. Decreased driving pressure (pus)

Question 47

Which mechanism of impaired alveolar oxygen diffusion results in pulmonary fibrosis? A. Decreased surface area for diffusion B. Decreased driving pressure C. Increased diffusion distance

Answer 47

3. Increased diffusion distance Dec matrix around alveoli and the capillaries. As you increase this difference - gas diffusion will decrease

Question 48

Reduced partial pressure of oxygen in the alveolus results in \_\_\_\_\_\_\_

Answer 48

hypoxia

Question 49

Reduced oxygen content in arterial blood is referred to as \_\_\_\_\_

Answer 49

hypoxemia

Question 50

Blood oxygenation is described in three ways: 1. Amount of hemoglobin bound to oxygen (%) referred to as \_\_\_\_\_\_\_\_\_. 2. Dissolved oxygen content (mmHg) referred to as \_\_\_\_\_\_\_\_\_. 3. Sum of bound and dissolved oxygen (mL O2/dL) referred to as \_\_\_\_\_\_.

Answer 50

1. Saturation - normal \>95% 2. Partial pressure - normal for pao2 = 104 - (0.3 x age) ; sea level, room air 3. Content

Question 51

A-a gradient helps us with the differential of what causes arterial hypoxemia. What does a normal A-a gradient indicate?

Answer 51

1. Pure hypoventilation (hypercapneic failure) 2. Reduced Inspired Oxygen Tension (altitude) o2 making it to capillaries and blood but still low o2 bc hyperventilation (resp failure) or living at high elevations.

Question 52

A-a gradient helps us with the differential of what causes arterial hypoxemia. What does an increased A-a gradient potentially indicate?

Answer 52

1. Decreased surface area 2. Decreased pressure 3. Increased diffusion distance

Question 53

Alveolar - arterial Oxygen Difference

Answer 53

P[A-a]O2 = Alveolar oxygen content - arterial oxygen content P[A-a]O2 = PAO2 - PaO2 or: P[A-a]O2 = [(FiO2 \* {Patm - PH2O}) - (PaCO2 / R)] - PaO2 or: P[A-a]O2 = [150 - (PaCO2/0.8)] - PaO2: this is the A-a gradient Normal P[A-a]O2 \< 15 (age \< 60)

Question 54

This is the difference between estimated alveolar oxygen content and the measured arterial oxygen content (determined by arterial blood gas.)

Answer 54

Alveolar-arterial oxygen difference

Question 55

1. The “A-a” difference (increases/decreases) in lung diseases. 2. The (larger/smaller) the P(A-a)O2 difference, the more severe the oxygenation impairment.

Answer 55

1. The “A-a” difference **increases** in lung diseases. 2. The **larger** the P(A-a)O2 difference, the more severe the oxygenation impairment.