Development of optical probes for arterial pulse wave assessment

Abstract

Three optical probes based on different photo-diodes: lateral effect (LEP), planar (PPD) and avalanche (APD) photodiodes, were developed to measure the arterial pressure waveform and access clinically relevant information. The pressure wave propagates through the arterial tree and is measured in the peripheral arteries. The probes were evaluated in dedicated test setups and in vivo, at the carotid. For the PPD and APD probes, an ultrasound system was used as a source of data for comparison. Two different light sources were tested: visible and infrared, which performance was evaluated in a test setup, simulating the fatty deposits seen in the obese. Although the LEP probe lacks of temporal resolution, PPD and APD probes show a good overall performance, measuring waveforms with <;8% error, with higher resolution than the ultrasound system. The probes lit with infrared light show better resolution and definition in the test setup and at in vivo conditions.