Automatic Estimation of Skin Perfusion Pressure Based on Multi-wavelength Photoplethysmography Data.

Skin perfusion pressure (SPP) is a helpful test for assessing tissular perfusion in cases such as peripheral vascular disease. It is usually measured using modern imaging techniques, and although there are inexpensive options, these are not employed since they rely on visual inspections. In this work, we propose and evaluate using a plethysmography (PPG) sensor to estimate skin perfusion pressure automatically. Our proposal is a simple methodology based on derivatives and evaluates it using an occlusion and deflation protocol. We employ PPG measurements from three different wavelengths. This initial evaluation is applied to 10 participants who signed an informed consent. The results show that the data from the three wavelengths are highly correlated, and the SPP estimations are similar, with average measurements of 70 ± 8mmHg, 71 ± 7mmHg, and 75 ± 9mmHg for green, red, and infrared wavelengths, respectively. Future work will focus on further validation and the exploration of contactless methods to estimate SPP. Clinical Relevance—We propose an economical, quantitative, objective method for estimating SPP, which could aid physicians in assessing diseases such as peripheral vascular disease and making decisions regarding amputation in severe cases