Electronic module for photoplethysmography and pulse oximetry

Methods of pulse oximetry and photoplethysmography are widely used in clinical medicine and practice of biomedical research outside the clinic. The advantages of the method are high efficiency of preparation for the diagnostic procedure, non-invasive, complete safety for health. The method provides the possibility of unlimited long - term monitoring of the dynamics of saturation and desaturation of hemoglobin. In combination with the above, subject to the qualitative registration of photoplethysmograms, the method allows the calculation and analysis of a number of indicators of peripheral blood circulation: the total pulse blood flow to the study region, the tone of arterial vessels of different diameters, the state of capillary blood flow. Most modern foreign models of pulse oximeters are integrated devices that provide measurement of a very limited set of physiological parameters: the percentage of hemoglobin oxygen saturation and pulse rate. The range of pulse oximeters containing the interface with the personal computer and providing operational calculation of indicators of peripheral photoplethysmograms is small. Such devices have a fairlyhigh cost and are not portable.The development of domestic integrated electronic devices is extremely relevant, allowing along with obtaining information about blood oxygenation to perform continuous monitoring of peripheral blood circulation. The authors developed an electronic module that provides long-term registration of photoplethysmograms in the infrared and red areas of the light spectrum. The electronic module is made exclusivelywith the use ofdomestic active radio elements - discrete semiconductor devices and integrated circuits. The device was developed in full compliance with the import substitution policy pursued by the President and the Government of the Russian Federation.The advantage of the device is the "open architecture" of the electronic circuit, which provides four analog signals suitable for further digitization. The signals contain information about pulsating and non-pulsating components of the optical density of biological tissue in the infrared and red ranges of the spectrum. The device has an electronic filter of mains interference.Tests of the device demonstrated high quality of photoplethysmograms. This makes it possible tosuccessfullyuse the device for studies of hemoglobin oxygenation and peripheral hemodynamics.