Observation of Tissue Oxygenation Changes Using Remote Photoplesysmography with a Smartphone.

Background: Tissue oxygenation is a critical marker of tissue status and can be used to evaluate and track wound progress, the viability of transplanted tissue, and burns. Thus, the determination of tissue oxygenation (preferably remotely) is of great importance.

Aim: Explore the impact of oxygenation changes on tissue color.

Material And Methods: The rPPG of both hands was acquired using a stand-mounted smartphone (iPhone 8) placed about 10 cm above the hands. A 60 s baseline was followed by occlusion of one arm using a cuff inflated to 200 mmHg for approximately 2 min. The cuff was then rapidly deflated, followed by a 60 s recovery period. The reference muscle oxygenation signal (SmO) was acquired using the near-infrared contact Moxy device (Fortiori Design LLC) placed on the forearm distal to the occlusion. The data were collected on both hands of 28 healthy volunteers.

Results: rPPG can observe changes in tissue oxygenation, which was confirmed across 28 participants using a robust reference standard.

Conclusion: We have an initial confirmation of the notion that rPPG can monitor changes in tissue oxygenation. However, a spectrum of rPPG and SmO2 reductions is observed, which should be explored in future work.