Multi-channel non-invasive tissue oximeter

Abstract

A method and apparatus for spectrophotometric in vivo monitoring of blood metabolites such as hemoglobin oxygen concentration at a plurality of different areas or regions on the same organ or test site on an ongoing basis, by applying a plurality of spectrophotometric sensors to a test subject at each of a corresponding plurality of testing sites and coupling each such sensor to a control and processing station, operating each of said sensors to spectrophotometrically irradiate a particular region within the test subject; detecting and receiving the light energy resulting from said spectrophotometric irradiation for each such region and conveying corresponding signals to said control and processing station, analyzing said conveyed signals to determine preselected blood metabolite data, and visually displaying the data so determined for each of a plurality of said areas or regions in a comparative manner.REEXAMINATION RESULTSThe questions raised in reexamination proceeding No. 90 / 010,128, filed Mar. 31, 2008, have been considered, and the results thereof are reflected in this reissue patent which constitutes the reexamination certificate required by 35 U.S.C. 307 as provided in 37 CFR 1.570(e) for ex parte reexaminations, or the reexamination certificate required by 35 U.S.C. 316 as provided in 37 CFR 1.997(e) for inter partes reexaminations.

Description

[0001]This application is a national stage of International Application No. PCT / US99 / 22940, filed Oct. 13, 1999, which claims the benefit of U.S. Provisional Application Ser. No. 60 / 103,985, filed Oct. 13, 1998.[0002]This invention relates generally to in vivo spectrophotometric examination and monitoring of selected blood metabolites or constituents in human and / or other living subjects, e.g., medical patients, and more particularly to spectrophotometric oximetry, by transmitting selected wavelengths (spectra) of light into a given area of the test subject, receiving the resulting light as it leaves the subject at predetermined locations, and analyzing the received light to determine the desired constituent data based on the spectral absorption which has occurred, from which metabolic information such as blood oxygen saturation may be computed for the particular volume of tissue through which the light spectra have passed.[0003]A considerable amount of scientific data and writings,...

AI Technical Summary

Benefits of technology

Enables precise, real-time monitoring of brain oxygenation at different brain regions, providing critical information for surgical procedures by overcoming previous limitations of low signal quality and imprecision, allowing for direct comparison and immediate clinical guidance.

Problems solved by technology

This information was not previously available, despite its great importance, since there really is no detectable arterial pulse within brain tissue itself with respect to which pulse oximetry could be utilized even if it could be effectively utilized in such an interior location (which is very doubtful), and this determination therefore requires a substantially different kind of apparatus and determination analysis.

In addition, there are a number of uniquely complicating factors, including the fact that there is both arterial and venous vasculature present in the skin and underlying tissue through which the examining light spectra must pass during both entry to and exit from the brain, and this would distort and / or obscure the brain examination data if excluded in some way.

In addition, the absorption and scatter effects on the examination light spectra are much greater in the brain and its environment than in ordinary tissue, and this tends to result in extremely low-level electrical signal outputs from the detectors for analysis, producing difficult signal-to-noise problems.

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