When your patient gets cold, hemoglobin holds onto oxygen tighter. Cooling shifts the oxyhemoglobin curve to the left, so at a given PaO2, you may see a higher SaO2, but less oxygen gets unloaded to the tissues. On ECMO, that means the “numbers” can look reassuring while perfusion and tissue oxygenation are not. If you’re fighting hypothermia, it’s worth thinking beyond the saturation and watching the whole picture: temperature, lactate trend, perfusion, and venous oxygen data if you have it.
Merry Christ-mas