Calculate SpO₂ value from raw fingertip plethysmography (PPG)

1. How do you calculate SpO2 from PPG signal?
2. How do you calculate pO2 from SpO2?
3. Is a pulse oximetry a PPG?

How do you calculate SpO2 from PPG signal?

SpO₂ is calculated by taking the ratio of the AC to DC components of the photoplethysmograph (PPG) signal measured by the pulse oximeter. For accurate estimation of SpO₂, the AC component needs to be extracted from the signal through signal processing, where accurate peak detection is a crucial, difficult element.

How do you calculate pO2 from SpO2?

Example: Suppose a patient on 40% oxygen has a pulse oximetry SpO2 of 95%. Referring to the Table above, SpO2 of 95% is equal to a pO2 of 80mmHg. The P/F ratio = 80 divided by 0.40 = 200.

Is a pulse oximetry a PPG?

Photoplethysmography (PPG) is an optical technique that measures blood volume variations. The main application of dual-wavelength PPG is pulse oximetry, in which the arterial oxygen saturation (SpO₂) is calculated noninvasively.