Implementation of a localized heating test in a portable PPG device

This is the authors' abstract. We don't add key points for this paper.

Microvascular dysfunction is a critical marker of serious pathological conditions, including diabetes mellitus, hypertension, etc. In the early stages of microvascular dysfunction, the risk of complications can be significantly reduced. From this point of view, the development of inexpensive and easy-to-use tests for microvascular dysfunction is of great importance. Today, wearable devices are routinely used for health monitoring. The objective of this work is to develop a prototype of a wearable device for the assessment of microvascular status. For perfusion measurement, we used an optical method photoplethysmography (PPG). For microcirculatory assessment, we integrated the well-known local heating test with PPG. Eight healthy young volunteers (age 25 ± 1 years) were recruited as controls. The perfusion index, defined as the amplitude of the oscillations of the PPG signal at the heartbeat frequency, showed a typical response to applied skin heating. The waveform is reproducible and shows little intragroup variation. In this pilot study, the prototype of a new portable device for the assessment of microvascular function proved to be a reliable technique. The further development of the presented portable device offers the possibility of predicting microcirculatory abnormalities, which can help prevent the progression of the pathology and provide a reference for the direction of wearable devices in microcirculatory health.