15. Blood gas analysis and pulse oximetry

Question 1

What is the rule of thumb for working out O2 kPa based on % inspired oxygen?

Answer 1

O2 kPa = % inspired O2 - 10

Question 2

What are potential sources of error with pulse oximetry?

Answer 2

1. Presence of other haemoglobins
2. Surgical and imaging dyes
3. Nail varnish
4. High ambient light levels
   5.Motion artefact
   6.Reduced pulse volume