ABGs

Question 1

The PaO2 should be … x the FiO2

Answer 1

3-5 x

E.g. a young person on 40% O2, PaO2 should be 200 mmHg

Question 2

A-a gradient

Answer 2

= (150 - (5/4 x PCO2)) - paO2

Question 3

What is the P/F index?
What is the normal value?
What value = severe respiratory failure?

Answer 3

PaO2/FiO2 e.g. 100/0.21 = 476
Normal = >=300
Severe resp failure <200

Question 4

What is rebound hypoxia?

Answer 4

If CO2 high, you need a high inspired O2 amount to get good stauration based on the alveolar gas equation. Put on BIPAP to help remove CO2.

Question 5

When does mixed acid base disorder occur?

Answer 5

When compensation does not occur

Question 6

what does serum lactate indicate?

Answer 6

Indicator of peripheral perfusion and O2 delivery.

Causes include hypoxia, anaemia, shock, sepsis and regional hypoperfusion

Question 7

How much should the HCO3 increase by in acute respiraotry acidosis?

Answer 7

1 mmol for every 10 mmHg rise in CO2

Question 8

How much should the CO2 increase by in chronic resp acidosis?

Answer 8

4 mmol/L for every 10 mmol/L rise

Question 9

How much should the HCO3 fall by in acute resp alkalosis?

Answer 9

2 mmol/L for every 10 mmHg fall in PCO2

Question 10

How much should the HCO3 fall by in chronic resp alkalosis?

Answer 10

5 mmol/L for every 10 mmHg fall in PaCO2

Question 11

How much O2 does 5L/min, 6, 8 O2 deliver ?

Answer 11

5= 35%
6= 40%
8 = 50%