Week 3 - Positioning

Question 1

Give four factors affecting V/Q

Answer 1

Pleural pressure 
Altered lung compliance
Altered airway resistance
Airflow resistance
Lung volume
Physiologic dead space
Shunt

Question 2

Give two possible problems with V/Q and a potential cause

Answer 2

Shunt - atelectasis, consolidation

Wasted ventilation - PE

Question 3

Describe VQ in ventilated and side lying

Answer 3

Perfusion is mainly occurring in the lower most lung
Ventilation is mainly occurring in upper lung
You cannot get VQ match

Question 4

Describe VQ in non-ventilated, side lying

Answer 4

Perfusion in lower lung

Ventilation most potential to occur in lower lung as well

Question 5

Define TLC - total lung capacity

Answer 5

Total volume of gas in lungs after max inspiration (3-8l)

Question 6

Define Vital Capacity

Answer 6

Volume of gas exhaled after full inspiration (3-6l)

Question 7

Define Residual Volume

Answer 7

Volume of gas remaining in lungs after full expiration (1l)

Question 8

Define Expiratory Reserve Volume

Answer 8

Extra volume of gas you can exchange forcibly after end tidal volume

Question 9

Define FRC - Functional Residual Capacity

Answer 9

Amount of gas remaining after end tide volume exhalation (2l- position dependent)

Question 10

Define Inspiratory Reserve Volume

Answer 10

Extra volume of gas that can be inhaled voluntarily after Inspiratory Tidal Volume (3l)

Question 11

Define Tidal Volume

Answer 11

Volume of air exhaled and inhaled during on respiratory cycle (300-800ml)

Question 12

Describe the changes to FRC with different body positions

Answer 12

The closer to supine we become, the lower the FRC

Question 13

Define dead space

Answer 13

Volume of air inhaled but not used in gas exchange; can be anatomical or alveolar dead space