Expansion
Acid, carbon dioxide, temperature and 2,3-DPG all shift it right
Expansion
Right shift (raised P50, reduced affinity, easier unloading) - CADET, face Right
- C - raised Carbon dioxide
- A - Acidosis (low pH), the Bohr effect
- D - raised 2,3-DPG
- E - Exercise
- T - raised Temperature
Left shift (lower P50, increased affinity, harder unloading)
- Alkalosis, low carbon dioxide, hypothermia, low 2,3-DPG
- Fetal haemoglobin, which binds 2,3-DPG poorly and so holds oxygen more tightly, allowing placental transfer
- Carboxyhaemoglobin and methaemoglobin
The logic is that a metabolically active tissue is warm, acidotic and carbon-dioxide-rich, so it automatically shifts the curve right where it is needed and unloads more oxygen.
Note the clinical trap in stored blood, which is depleted of 2,3-DPG, so transfused cells initially have a high affinity and release oxygen poorly until DPG is regenerated over 24 hours.