HLK Week 3

Question 1

Definition of ventilation:

Answer 1

Movement of air between alveoli and atmosphere by BULK FLOW. A mechanical process.

Question 2

Definition of respiration:

Answer 2

Movement of gases into and out of the body. Ventilation is part of the process but not exactly synonymous with it. Not to be confused with cellular respiration.

Question 3

Discuss anatomical vs. physiological dead space:

Answer 3

Anatomical:
- Refers to the amount of air that is always left inside the airways. Must be subtracted from tidal volume to obtain true alveolar ventilation.
Physiological:
- Refers to the amount of air that reaches the alveoli but which doesn’t participate in gas exchange because, e.g., of non-uniform capillary distribution in the alveoli.

Question 4

What does immediate orthopnea in an otherwise “healthy” person indicate?

Answer 4

Bilateral diaphragmatic weakness or paralysis

Question 5

Define trepopnea:

Answer 5

Dyspnea only in a lateral decubitus position

Question 6

Define platypnea:

Answer 6

Dyspnea only in an upright position

Question 7

What is the definition of ventilation/perfusion (V/Q) ratio?

Answer 7

The ratio of the amount of air reaching the alveoli (ventilation) to the amount of blood reaching the alveoli (perfusion).

Question 8

What is the classic imaging finding in a patient with acute hemoptysis?

Answer 8

Ground glass appearance on CXR

Question 9

What’s the mechanism of action of albuterol and other SABA drugs?

Answer 9

Stimulates beta 2 receptors, relaxing bronchial smooth muscle and promoting bronchodilation.

Question 10

According to lecture, what are the recommendations for theophylline?

Answer 10

Not recommended. Does not appear to control asthma but may be prescribed due to affordability.

Question 11

Discuss restrictive vs. obstructive diseases in regards to vital capacity and the FEV1 test:

Answer 11

Restrictive:
- Not due to airway narrowing but rather lung expansion
- Therefore, normal FEV1 but decreased vital capacity
Obstructive:
- Due to airway narrowing
- Therefore normal vital capacity but reduced FEV1

Question 12

The most common reason for inadequate oxygen movement between alveoli and capillaries:

Answer 12

Ventilation/perfusion inequality:

• Some alveoli may not be adequately ventilated, despite adequate blood supply (e.g., alveolar collapse)
• Some alveoli may be well ventilated but w/o adequate blood supply (e.g., due to a clot)

Question 13

Which is more affected by V/Q mismatch, O2 or CO2 transfer?

Answer 13

O2

Question 14

The neurons of the dorsal respiratory group (DRG) are responsible for which phase of respiration?

Answer 14

Inspiration

Question 15

What is the function of the ventral respiratory group (VRG) on respiration?

Answer 15

• Cells of the respiratory rhythm generator are located in the pre-Botzinger complex in the VRG. They set the basal respiratory rate.
• VRG neurons also control active expiration.

Question 16

What is the role of the pons in regulating breathing?

Answer 16

The apneustic and pneumotaxic centers fine tune the DRG’s activity and smooth the transition from inspiration to expiration

Question 17

How to airway stretch receptors affect breathing?

Answer 17

Hering-Breuer reflex occurs when stretch receptors are activated by inflated lungs, sending afferent signals that inhibit DRG activity

Question 18

Which chemoreceptors are most responsible for the regulation of breathing, and what are they most sensitive to?

Answer 18

• Carotid bodies (part of the peripheral chemoreceptors)

- H+, usually as a result of an increase in arterial CO2

Question 19

What is the primary spirometric tool used to diagnose obstructive lung disease?

Answer 19

FEV1/FVC ratio

Question 20

In a methylcholine (bronchoprovocation test) challenge, what result indicates asthma in a patient with normal pulmonary function tests?

Answer 20

At least a 20% reduction in FEV1.

Question 21

A few things to go on the DDx for a patient with dyspnea:

Answer 21

Obstructive: asthma, copd, cystic fibrosis
Infectious: pneumonia
Restrictive: obesity, interstitial lung disease, pleural effusion
Other: metabolic acidosis, PE, CHF, anemia

Question 22

Explain why hypoxia is more common in V/Q mismatch than hypercapnea?

Answer 22

The body can compensate for CO2 excess by increasing ventilation, causing you to blow off excess CO2. With low O2, increasing the ventilation only works when O2 is very low (this puts you on the steep part of the sat/PO2 curve). Plus, because O2 diffuses more slowly than CO2, increased ventilation can’t increase the alveolar PO2 enough to offset the V/Q mismatch happening elsewhere.

Question 23

Some common causes of pulsus paradoxus:

Answer 23

• Cardiac tamponade
• Pericarditis
• Asthma/COPD

Question 24

Examples of restrictive lung diseases/conditions:

Answer 24

• 2-ary to obesity
• Sarcoidosis
• Neuromuscular diseases
• Pleural effusion/pneumothorax
• Interstitial lung disease
• Pulmonary fibrosis

Question 25

Examples of obstructive lung diseases/conditions:

Answer 25

- Asthma - COPD - Bronchiectasis - Cystic fibrosis

Question 26

Complications of COPD:

Answer 26

- Cor pulmonale as a result of pulmonary HTN - Chronic respiratory failure - Right heart failure

Question 27

Describe the results of the FEV1/FVC test with respect to obstructive and restrictive diseases:

Answer 27

Obstructive: lower than normal ratio due to decreased ability to force air out. Restrictive: normal to higher than normal ratio due to lower vital capacity.

Question 28

Things that put cystic fibrosis on your differential:

Answer 28

- Chronic cough with thick sputum - Chronic respiratory infections - Chronic GI, liver, pancreas issues and malnourishment - Azoospermia - Bronchiectasis and scarring on CXR - Increased chloride in sweat

Question 29

Treatment for COPD:

Answer 29

- Oxygen therapy - Anticholinergic inhaler (ipratropium) - Inhaled or oral steroids for exacerbations - Quit smoking

Question 30

Things that put bronchiectasis on your differential:

Answer 30

- Chronic productive cough - CXR showing dilated, thickened airways (tram tracks) - Hx of cystic fibrosis

Question 31

Treatment for cystic fibrosis:

Answer 31

- Lung transplant - Inhaled bronchodilators - Chest percussion and postural drainage - Nutritional support - Abx for infections

Question 32

True or false: Asthma patients without sputum eosinophilia may be less responsive to steroids.

Answer 32

True

Question 33

Obesity hypoventilation syndrome treatment:

Answer 33

- Weight loss - Respiratory stimulants such as theophylline - Treatment of comorbid sleep apnea

Question 34

Acute respiratory distress syndrome (ARDS):

Answer 34

- Acute hypoxemic respiratory failure following pulmonary or systemic insult in the absence of heart failure. - Tx underlying cause