Publications

@article{Narayana_Swamy2024-la,

title = {Exploring the bias: how skin color influences oxygen saturation  readings via Monte Carlo simulations},

author = {Suvvi K Narayana Swamy and Chong Liu and Ricardo Correia and Barrie R Hayes-Gill and Stephen P Morgan},

doi = {10.1117/1.JBO.29.S3.S33308},

year  = {2024},

date = {2024-06-01},

urldate = {2024-06-01},

journal = {J. Biomed. Opt.},

volume = {29},

number = {Suppl 3},

pages = {S33308},

publisher = {SPIE-Intl Soc Optical Eng},

abstract = {Significance: Our goal is to understand the root cause of 

 reported oxygen saturation ( SpO 2 ) overestimation in heavily 

 pigmented skin types to devise solutions toward enabling equity 

 in pulse oximeter designs. Aim: We aim to gain theoretical 

 insights into the effect of skin tone on SpO 2 - R curves using 

 a three-dimensional, four-layer tissue model representing a 

 finger. Approach: A finger tissue model, comprising the 

 epidermis, dermis, two arteries, and a bone, was developed using 

 a Monte Carlo-based approach in the MCmatlab software. Two skin 

 tones-light and dark-were simulated by adjusting the absorption 

 and scattering properties within the epidermal layer. Following 

 this, SpO 2 - R curves were generated in various tissue 

 configurations, including transmission and reflection modes 

 using red and infrared wavelengths. In addition, the influence 

 of source-detector (SD) separation distances on both light and 

 dark skin tissue models was studied. Results: In transmission 

 mode, SpO 2 - R curves did not deviate with changes in skin 

 tones because both pulsatile and non-pulsatile terms experienced 

 equal attenuation at red and infrared wavelengths. However, in 

 reflection mode, measurable variations in SpO 2 - R curves were 

 evident. This was due to differential attenuation of the red 

 components, which resulted in a lower perfusion index at the red 

 wavelength in darker skin. As the SD separation increased, the 

 effect of skin tone on SpO 2 - R curves in reflection mode 

 became less pronounced, with the largest SD separation 

 exhibiting effects similar to those observed in transmission 

 mode. Conclusions: Monte Carlo simulations have demonstrated 

 that different light pathlengths within the tissue contribute to 

 the overestimation of SpO 2 in people with darker skin in 

 reflection mode pulse oximetry. Increasing the SD separation may 

 mitigate the effect of skin tone on SpO 2 readings. These trends 

 were not observed in transmission mode; however, further planned 

 research using more complex models of the tissue is essential.},

keywords = {Melanin, Monte Carlo, Occult hypoxemia, oxygen saturation, pulse   oximeter, Racial bias, skin color, transmission mode},

pubstate = {published},

tppubtype = {article}

}