The units for PaCO2 and PaO2 are given in mmHg in some establishments.
Normal values can differ slightly on different machines.
If the patient is receiving supplemental oxygen, then you need to take this into account for the PaO2 value. A deficit in oxygenation will be present if the PaO2 and inspired oxygen concentration have a difference more than 10 kPa. For example a patient on 50% oxygen should have a PaO2 of 40 kPa.
