Oxygen dissociation curve ad O2 therapy

Question 1

The oxygen dissociation curve describes the relationship between what two variables

Answer 1

% of saturated haemoglobin

partial pressure of oxygen in the blood.

Question 2

Hb concentration does not affect the oxygen dissociation curve. TRUE/FALSE?

Answer 2

TRUE

Question 3

What happens if the oxygen dissociation curve shifts to the LEFT

Answer 3

• increased saturation of Hb with oxygen
  => DECREASED oxygen delivery to tissues

Question 4

What happens if the oxygen dissociation curve shifts to the RIGHT

Answer 4

• reduced saturation of Hb with oxygen

=> INCREASED oxygen delivery to tissues

Question 5

What causes lower oxygen delivery to tissues when the curve shifts left?

Answer 5

Low [H+] (alkali)
Low pCO2
Low 2,3-DPG
Low temperature

Question 6

Give examples of clinical conditions which make the O2 dissociation curve shift LEFT

Answer 6

Polycythaemia
Cyanosis
haemolytic anaemia

Question 7

Oxygen saturation targets in acutely unwell patients

Answer 7

94-98%

Question 8

Oxygen saturation targets in patients at risk of hypercapnia

Answer 8

88-92%
(via venturi mask)

Question 9

Clinical situations where oxygen should not be used routinely if there is no evidence of hypoxia?

Answer 9

myocardial infarction/ ACS
stroke
obstetric emergencies
anxiety-related hyperventilation