Respiratory failure

Question 1

What is the control of breathing?

Answer 1

Ventral surface of medulla detects pH of CSF

Question 2

What is the control of breathing in hypoxic drive?

Answer 2

Receptors in carotid bodies detect changes in O2- has to be dramatic to kick in

Question 3

What is type 1 respiratory failure?

Answer 3

Low O2 <8kPa

Failure to oxygenate

Question 4

What causes type 1 respiratory failure?

Answer 4

V/Q mismatch e.g. PE
Diffusion impairment e.g. pulmonary fibrosis, pneumonia
Hypoventilation e.g. neuromuscular disease
Shunt e.g. right left shunt

Question 5

What is type 2 respiratory failure?

Answer 5

Low O2 (<8) and high CO2 (>6.7)
Failure to ventilate

Question 6

What can cause type 2 respiratory failure?

Answer 6

Increased airway resistance e.g. COPD, asthma
Reduced breathing effort e.g. drugs, brainstem lesion, obesity
Decreased surface area e.g. emphysema, bronchiolitis
Neuromuscular e.g. MND, GBS
Chest wall deformity

Question 7

What investigations are done to detect respiratory failure?

Answer 7

Pulse ox= only estimation, don’t rely on!

ABG

Question 8

In what situation is pulse ox esp not reliable?

Answer 8

CO poisoning

Question 9

What is the management of respiratory failure?

Answer 9

Treat cause

Give appropriate oxygen

Question 10

What are the risks of over oxygenating?

Answer 10

Can disrupt auto regulation and perfusion
Free radical formation
Can mask that they’re getting worse

Question 11

What is the risk of over oxygenating in hypoxic drive?

Answer 11

Will stop breathing if oxygen high