Which is false regarding pulse oximetry?
High-Yield Explanation
Anaemia does not affect the reading of pulse oximetry. Factors affecting its accuracy- 1. Dyshemoglobins For example Met Hb absorb red and infrared wavelengths of light in a 1:1 ratio corresponding to an SpO2 of approximately 85%. Therefore, increases in Met Hb produce an underestimation when SpO2> 70% and an overestimation when SpO2 <70%. 2. Dyes (Methylene blue, indocyamine green) 3. Nail polish 4. Ambient light 5. Hypotension 6. Hypothermia 7. electrocautery