Exploring the Bias: How Skin Colour Influences Oxygen Saturation Readings via Monte Carlo Simulations

The main of this study is to gain theoretical insights into the effect of skin tone on SpO2 - R curves by using a three-dimensional, four-layer finger tissue model. The purpose was to understand the the root cause of reported oxygen saturation overestimation in heavily pigmented skin types to devise solutions toward enabling equity in pulse oximeter design. A finger tissue model, containing the epidermis, dermis, two arteries and a bone was developed using a Monte Carlo based approach in the MCmatlab software tool. Two different skin tones were simulated - light and dark skin by adjusting the optical properties within the epidermal layer. Based on this SpO2 vs R curves were produced in various tissue configurations, including transmission and reflection mode using red and infrared wavelengths. Further to this, the influence of source-detector separation distances on both light and dark skin tissue models were investigated.