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Proceedings Paper

Test of a processing algorithm for NIR-laser-diode-based pulse oximetry
Author(s): Sonnia Maria Lopez Silva; Juan Pedro Silveira; Maria Luisa Dotor
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Paper Abstract

Pulse oximeters are used for the non-invasive monitoring of arterial blood hemoglobin oxygen saturation. This technique is based on the time variable optical attenuation by a vascular bed due to the cardiac pumping action (photoplethysmography) and the differential optical absorption of the oxy- and deoxy-hemoglobin. The photoplethysmographic (PPG) signals measured at two specific wavelengths are decomposed into its variable or pulsating component (EAC) and the constant or non-pulsating component (EDC) for deriving a parameter related to the arterial blood oxygen saturation (So2). Previously it has been reported a signal processing algorithm for a near infrared (NIR) laser diodes based transmittance pulse oximetry system. The main difficulties in the extraction of the information from the PPG signals are the small value of the signals variation related to their constant values, and the presence of artefacts caused by macro- and micro- movements of the part under analysis. The proposed algorithm permits the numeric separation of the variable and constant parts of the signals for both wavelengths. The EDC is obtained by a low pass filtering, and EAC by a pass-band one, followed by a non-linear filtering based on histogram reduction. In the present work is exposed the analysis of the influence of processing parameters like filters cut-off frequencies and histogram reduction percentage, on the derived So2 values. The test has been conducted both on real and simulated PPG signals. The real PPG has been recorded through experimental studies with human subjects using the NIR laser diodes based transmittance pulse oximetry system. The sources of artefacts and noise in the laser diodes PPG signals are discussed.

Paper Details

Date Published: 18 April 2003
PDF: 11 pages
Proc. SPIE 5119, Bioengineered and Bioinspired Systems, (18 April 2003); doi: 10.1117/12.499067
Show Author Affiliations
Sonnia Maria Lopez Silva, Univ. de Las Palmas de Gran Canaria (Spain)
Juan Pedro Silveira, IMM-Ctr. Nacional de Microelectronica (Spain)
Maria Luisa Dotor, IMM-Ctr. Nacional de Microelectronica (Spain)


Published in SPIE Proceedings Vol. 5119:
Bioengineered and Bioinspired Systems
Angel Rodriguez-Vazquez; Derek Abbott; Ricardo Carmona, Editor(s)

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