You just got done with the most precarious of intubations, but while patting yourself on the back, you note that beeping saturation tone is continuing its decline. Did the tube get dislodged? Was it ever in the cords? Take a step into the plight of oxygen and pulse oximetry with our physiologic guru Dr Steve CarletonRead More
First a bit of physics....
Both pulse oximetry and capnometry rely on the Beer-Lambert Law.
- In 1760, Johann Heinreich Lambert proved that the absorbance of light through a material is proportional to the thickness of the material.
- In 1852, August Beer proved that the absorbance of light through a material is proportional to the concentration of the attenuating substance in the material.