Normal p50 is 27 mm Hg. Several factors can cause a right shift (increased unloading) in the oxyhemoglobin dissociation curve – acidemia, hypercarbia, increased temperature, and increased 2,3-DPG (all of which are more effective during hypoxemia, ex. at tissue levels). Changes in pH and pCO2 generally go hand-in-hand. This is know as the Bohr Effect, which is physiologically much more important). Note that 2,3-DPG levels can increase significantly during chronic hypoxemia, and that 2,3-DPG levels decrease substantially (preventing release of oxygen) after ~ 1 week of storage.
Oxyhemoglobin Dissociation Curve
- Normal p50: 27 mm Hg
- Right Shift: acidemia and hypercarbia (Bohr effect), increased temperature, 2,3-DPG
- Left Shift: alkalosis, hypocarbia, decreased temperature, carbon monoxide, methemoglobin, hypophosphatemia (critical care patients)