HYPOXIC HYPOXIA (e.g. High Altitude)
- PaO2 is reduced ( as FiO2 is low)
- So more extraction of O2: So PvO2 is reduced
- Based on the above formula, both arterial and venous oxygen content also will be reduced
ANAEMIC HYPOXIA (e.g. haemorhhage)
- PaO2 will be normal
- But arterial oxygen content will be reduced due to lower values of Hb, as per the above formula reducing the oxygen delivery to tissues and increasing the cardiac work
- So there will be more oxygen extraction leading to a low PvO2 and venous oxygen content.
STAGNANT HYPOXIA (e.g. Cardiogenic shock)
- PaO2 is normal
- PvO2 is also normal
- There is no reduction in the arterial and venous oxygen content too.
- However, circulatory dysfunction results in inadequate oxygen delivery to organs
HISTOTOXIC HYPOXIA (e.g. Cyanide poisoning)
- PaO2 is normal. Arterial oxygen content also will be normal.
- But cells are unable to utilise oxygen resulting in high venous saturations