Photoplethysmography

Photoplethysmography is an optical (often non-invasive) technique that can be used to detect blood volume changes in the microvascular bed of tissuewith each heart beat. Photoplythesmogram (PPG) is superimposed with a slowly varying baseline with lower frequency components attributed to respiration, sympathetic nervous system activity and thermoregulation. Till now, only few parameters of PPG are clinically used. PPG has a great potential for use in a wide range of clinical measurements as a biomarker for numerous pathologies. The shape of PPG and its derived parameters and their oscillations are biomarkers for cardiovascular and autonomic nervous diseases. A challenging problem by assignment of PPG in clinical diagnostic is the motion artifact, especially when it is superimposed with low perfusion. We have applied three types of adaptive filtering using fuzzy logic to get the best signals under the inconvenient conditions. We are able to design different PPG smart sensors in combination with other simple ones for the various clinical applications (e.g. camera PPG-system) that enable the early detection of cancer by measuring of tissue perfusion and local oxygen saturation. Applying other easy to use sensors and actuators for the detection of venous and arterial oxygen saturation as well as oxygen and glucose uptake in tissue, diabetes and cancerous cells can be detected in early stage. We consider important factors by our method for monitoring and diagnosis of dieses in clinical fields.

 Photopleth-Sensor