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Proceedings Paper

Development of optoelectronic monitoring system for ear arterial pressure waveforms
Author(s): Satoshi Sasayama; Yu Imachi; Tamotsu Yagi; Kou Imachi; Toshirou Ono; Masando Man-i
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Paper Abstract

Invasive intra-arterial blood pressure measurement is the most accurate method but not practical if the subject is in motion. The apparatus developed by Wesseling et al., based on a volume-clamp method of Penaz (Finapres), is able to monitor continuous finger arterial pressure waveforms noninvasively. The limitation of Finapres is the difficulty in measuring the pressure of a subject during work that involves finger or arm action. Because the Finapres detector is attached to subject's finger, the measurements are affected by inertia of blood and hydrostatic effect cause by arm or finger motion. To overcome this problem, the authors made a detector that is attached to subject's ear and developed and optoelectronic monitoring systems for ear arterial pressure waveform (Earpres). An IR LEDs, photodiode, and air cuff comprised the detector. The detector was attached to a subject's ear, and the space adjusted between the air cuff and the rubber plate on which the LED and photodiode were positioned. To evaluate the accuracy of Earpres, the following tests were conducted with participation of 10 healthy male volunteers. The subjects rested for about five minutes, then performed standing and squatting exercises to provide wide ranges of systolic and diastolic arterial pressure. Intra- and inter-individual standard errors were calculated according to the method of van Egmond et al. As a result, average, the averages of intra-individual standard errors for earpres appeared small (3.7 and 2.7 mmHg for systolic and diastolic pressure respectively). The inter-individual standard errors for Earpres were about the same was Finapres for both systolic and diastolic pressure. The results showed the ear monitor was reliable in measuring arterial blood pressure waveforms and might be applicable to various fields such as sports medicine and ergonomics.

Paper Details

Date Published: 1 February 1994
PDF: 8 pages
Proc. SPIE 2084, Biomedical Optoelectronic Devices and Systems, (1 February 1994); doi: 10.1117/12.167301
Show Author Affiliations
Satoshi Sasayama, Kyoto Univ. (Japan)
Yu Imachi, Kyoto Univ. (Japan)
Tamotsu Yagi, Kyoto Univ. (Japan)
Kou Imachi, Univ. of Tokyo (Japan)
Toshirou Ono, Narabunka Women's Junior College (Japan)
Masando Man-i, Kyoto Univ. (Japan)

Published in SPIE Proceedings Vol. 2084:
Biomedical Optoelectronic Devices and Systems
Nathan I. Croitoru; Riccardo Pratesi, Editor(s)

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