JOURNAL HOME CME HOME THIS MONTH PAST ISSUES ETOC COLLECTIONS
AUTHORS REVIEWERS EDITORIAL BOARD FEEDBACK RSS HELP
A&A International Anesthesia Research Society
QUICK SEARCH:   [advanced]


     

This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a colleague
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Aoyagi, T.
Right arrow Articles by Miyasaka, K.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Aoyagi, T.
Right arrow Articles by Miyasaka, K.

ARTICLE

Multiwavelength Pulse Oximetry: Theory for the Future

Takuo Aoyagi, EE, PhD*, Masayoshi Fuse, EE*, Naoki Kobayashi, EE*, Kazuko Machida, MD, PhD{dagger}, and Katsuyuki Miyasaka, MD, PhD{ddagger}

From the *Ogino Memorial Research Laboratory, Nihon Kohden Corporation; {dagger}Department of Respirology, National Tokyo Hospital, Tokyo; and {ddagger}Nagano Children’s Hospital, Nagano, Japan.

Address correspondence and reprint requests to: Takuo Aoyagi, PhD, Ogino Memorial Research Laboratory, Nihon Kohden Corporation, 1-31-4 Nishiochiai, Shinjuku-ku, Tokyo 161-8560 Japan. Address e-mail to tyaoyagi{at}s2.ocv.ne.jp.

Abstract

BACKGROUND: As the use of pulse oximeters increases, the needs for higher performance and wider applicability of pulse oximetry have increased. To realize the full potential of pulse oximetry, it is indispensable to increase the number of optical wavelengths. To develop a multiwavelength oximetry system, a physical theory of pulse oximetry must be constructed. In addition, a theory for quantitative measurement of optical absorption in an optical scatterer, such as in living tissue, remains a difficult theoretical and practical aspect of this problem.

METHODS: We adopted Schuster’s theory of radiation through a foggy atmosphere for a basis of theory of pulse oximetry. We considered three factors affecting pulse oximetry: the optics, the tissue, and the venous blood.

RESULTS: We derived a physical theoretical formula of pulse oximetry. The theory was confirmed with a full SO2 range experiment. Based on the theory, the three-wavelength method eliminated the effect of tissue and improved the accuracy of Spo2. The five-wavelength method eliminated the effect of venous blood and improved motion artifact elimination.

CONCLUSIONS: Our theory of multiwavelength pulse oximetry can be expected to be useful for solving almost all problems in pulse oximetry such as accuracy, motion artifact, low-pulse amplitude, response delay, and errors using reflection oximetry which will expand the application of pulse oximetry. Our theory is probably a rare case of success in solving the difficult problem of quantifying optical density of a substance embedded in an optically scattering medium.






Lippincott, Williams & Wilkins Anesthesia & Analgesia® is published for the International Anesthesia Research Society® by Lippincott Williams & Wilkins with the assistance of Stanford University Libraries' HighWire Press®. Copyright 2006 by the International Anesthesia Research Society. Online ISSN: 1526-7598   Print ISSN: 0003-2999 HighWire Press
Copyright © 2007 by the International Anesthesia Research Society.