Positioning + Lung Function

Question 1

What does V/Q ratio stand for?

Answer 1

Ventilation and perfusion

Question 2

What factors influence ventilation? (6)

Answer 2

Pleural pressure
Altered lung expandibility
Altered airway resistance
Lung volume
Dead space
Shunt

Question 3

What factors influence perfusion? (2)

Answer 3

Wasted ventilation (e.g. pulmonary embolism)
Circulatory disorders

Question 4

What are the five uses of body positioning?

Answer 4

Maximise ventilation
Maximise diaphragmatic function
Optimise V/Q matching
Decrease work of breathing
Drain sputum

Question 5

What is the effect of giving more oxygen to a patient on a ventilator?

Answer 5

Decreased the nitrogen levels meaning alveoli are more likely to collapse

Question 6

Describe the mechanics of being on a ventilator (4)

Answer 6

The air is forced into the lungs
Pushing the diaphragm down passively
The airflow takes the path of least resistance (I.e. to the top of the lung)
Increased perfusion at lower regions and decreased ventilation so alveoli collapse

Question 7

What are the three types of dead space?

Answer 7

Anatomical, alveolar and physiological

Question 8

What is anatomical dead space?

Answer 8

Areas such as the trachea, bronchioles, nose and mouth where gas exchange does not take place

Question 9

What is alveolar dead space?

Answer 9

Alveoli that are ventilated but do not have a blood supply therefore cannot do gas exchange

Question 10

What is physiological dead space?

Answer 10

Anatomical and alveolar added together