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