Resp 2 - Ventilation Flashcards Preview

Respiratory System > Resp 2 - Ventilation > Flashcards

Flashcards in Resp 2 - Ventilation Deck (25)
Loading flashcards...
1
Q

What is Functional Residual Capacity (FRC)?

A

When the elastic inward recoil of the lungs and the outward recoil of the rib cage are in equilibrium.

Occurs at the end of tidal expiration.

2
Q

What is the pleural cavity?

A

Space between parietal and visceral pleura. It is a fixed volume.

Contains protein rich pleural fluid.

It is at negative pressure

3
Q

How does the pleura play a role in ventilation?

A

It is the negative pressure of the pleura that allows the chest wall to pull the lungs with it.

If chest wall/lung punctured, fixed volume of pleura is compromised - elastic recoil takes over and lung will collapse

4
Q

What happens if the pleural cavity is breached?

A

Intrapleural bleeding may occur - haemothorax.

If there is a perforated chest wall - air enters pleural cavity = pneumothorax

5
Q

Define tidal breathing.

A

Amount of inspiration/expiration that meets metabolic demand

6
Q

What is residual volume?

A

Volume of air in the lungs that cannot (and should not) be expelled.

7
Q

Explain:

  1. Total Lung Capacity (TLC)
  2. Vital Capacity (VC)
  3. Functional Residual Capacity (FRC)
  4. Inspiratory Capacity (IC)
A
  1. TLC = everything (including residual volume)
  2. VC = air within our maximal inspiration/expiration confines
    (VC = TLC - RV)
  3. Functional Residual Capacity (FRC) = Amount of air in the lungs at equilibrium
    (FRC = ERV + RV)
  4. Inspiratory Capacity (IC) = how much air you can take on top of FRC.
    (IC = TV + IRV)
8
Q

Transmural pressures?

A

Pressure across a tissue or several tisses

9
Q

Transpulmonary pressure?

A

Difference between alveolar and intrapleural pressure

10
Q

Transrespiratory pressure (important one)?

A

Tells us if Airflow into or out of lung

11
Q

Negative pressure breathing vs positive pressure breathing?

A

Negative = normal breathing

Positive = ventilator / CPR

12
Q

What is dead space?

A

Part of the airways and lung that doesn’t participate in gas exchange.

13
Q

The conducting zone is dead space. What other dead space can there be?

A

Alveolar dead space = parts of the lung that can participate in gas exchange but do not.

14
Q

What is physiological dead space equal to?

A

Physiological dead space = Anatomical Dead space + alveolar dead space.

In healthy adults, physiological dead space should roughy equal anatomical dead space (usually around 150mL)

15
Q

In normal patients, FEV1/FVC ratio should be 75% ish.

A

T

16
Q

What is FET?

A

Forced Expiratory Time.

Time taken to expel all the air from the lungs

17
Q

What is the pattern of Forced values for obstructive lung disease?

A
  1. FEV1 MUCH lower
  2. FET higher
  3. FVC lower
18
Q

What is the pattern of Forced values for restrictive lung disease? (e.g. sarcoidosis)

A
  1. FVC lower

2. FEV1 relatively high

19
Q

Difference between restrictive and obstructive disease?

A

Obstructive = mechanical obstruction to airflow

Restrictive = inability of chest to expand

20
Q

What are flow-volume loop features of mild obstructive disease?

A
  1. Displaced to the left

2. Coving

21
Q

What are flow volume loop features of a severe obstructive disease?

A
  1. Shorter curve
  2. Displaced to left
  3. Greater extent of coving
22
Q

What are flow volume loop features of restrictive disease?

A
  1. Displaced to the right

2. Narrower loop

23
Q

TLC may increase in people with obstructive disease. Why?

A

Air is trapped in the alveoli - because small airways linking alveoli to outside world have collapsed - causes increased residual volume.

Emphysema - degrades alveolar walls. Only a large alveolus instead of separate segments - increase in volume of the lungs.

24
Q

If airway obstructed, flow rate can be limited. Explain how extrathoracic and intrathoracic obstructions differ.

A

Extrathoracic obstruction = inspiratory curve flatten

Intrathoracic obstruction = expiratory curve flattened

25
Q

What does fixed airway obstruction do?

A

Both inspiratory and expiratory curves are blunted.