Planning oxygen therapy:
This is how the pO2 and SpO2 are related (subject to many assumptions!)
Atmospheric pressure decreases with altitude (Boyle’s Law) in a non-linear relationship (because air is compressible, unlike water under which pressure is linearly related to depth):
The change in pO2 from sea level to a given altitude can be estimated using the ‘Gong’s nomogram’:
Eg. A patient with a pO2 on the ground of 80 mmHg will at an altitude of 5000 feet drop their pO2 to 60 mmHg:
Greater Sydney Area HEMS 