T4 L4: Respiratory failure

Question 1

What is hypoxaemia?

Answer 1

Decrease in partial pressure of O2 in the blood

Question 2

Give an example of when hypoxia and hypoxaemia would not coexist

Answer 2

With cyanide poisoning. Cells are unable to utilise O2 even though the blood O2 levels are normal

Question 3

What is PaO2?

Answer 3

Arterial oxygen tension

Question 4

What is Sao2?

Answer 4

Arterial oxygen saturation (% of Hb saturated with O2)

Question 5

What is Type 1 respiratory failure?

Answer 5

V/Q Mismatch (reduction of PaO2 but no change in PaCO2)

Question 6

What is Type 2 respiratory failure?

Answer 6

Underventilation (Increase in PaCO2 and a reduction in PaO2)

Question 7

What are some mechanisms behind hypoxaemia?

Answer 7

V/Q Mismatch, right-to-left shunt, diffusion impairment, hypoventilation, low inspired pO2

Question 8

What is a right-to-left shunt?

Answer 8

An abnormal communication between the right and left sides of the heart. Less blood ends up being oxygenated

Question 9

What is an A-a gradient?

Answer 9

The difference between alveolar O2 (PAO2) and the arterial oxygen level (Pao2)

Question 10

What does an A-a gradient indicate?

Answer 10

The integrity of the alveolarcapillary membrane

Question 11

What are some clinical characteristics of shunt?

Answer 11

A-a gradient is elevated, pCO2 in normal, poor response to O2 therapy

Question 12

What condition is high PaCO2 a hallmark of?

Answer 12

Hypoventilation

Question 13

What is meant by a high V/Q ratio?

Answer 13

Ventilation is in excess to perfusion. Eg. PE

Question 14

What is hypercapnia?

Answer 14

Build up of CO2 in the bloodstream