Hypoxemia vs Hypoxia - False Hypoxemia and methemoglobinemia

Very helpful infographic:   / 1340822737284198400  

Hypoxemia = low PaO2 (partial pressure of oxygen)
Hypoxia = cells not receiving enough O2
Hypoxia cannot be directly measured but is inferred by elevated lactate (anaerobic metabolism).
It is possible to have hypoxia without hypoxemia (e.g., anemia, methemoglobinemia, hypoperfusion).

PaO2 only reflects 3% of the total content of arterial blood oxygen (CaO2)!! HgB (quantity and ability to release O2) and SaO2 accounts for 97% of available oxygen in the blood.

SpO2 reflects O2 sat based on pulse oximetry.

SaO2 is based on an arterial sample. It can be estimated based on the oxygen-hemoglobin dissociation curve or directly measured by CO-oximetry.

False hypoxemia based on SpO2 results from interference, cold hands, or altered hemoglobin.

Many more concepts (O2 saturation gap, metHgB, and carboxyhemoglobinemia) are taught in the video. We hope you enjoy it.