US 5,515,847 A · Self-emission noninvasive infrared spectrophotometer

Abstract

A method and apparatus for monitoring glucose, ethyl alcohol and other blood constituents in a noninvasive manner. The measurements are made by monitoring infrared absorption of the desired blood constituent in the long infrared wavelength range where the blood constituent has a strong and distinguishable absorption spectrum. The long wavelength infrared energy emitted by the person as heat is monitored and the infrared absorption of particular constituents in the blood (such as glucose or blood alcohol) is measured at characteristic infrared absorption wavelengths for those constituents. The measurements are preferably synchronized with systole and diastole of the cardiac cycle so that the signal contribution caused by veins and tissues (which do not pulse) may be cancelled when a ratio of the detected signals is taken. The concentration of the blood constituents are then determined in accordance with a polynomial equation.

Claims22

Dependent claims

A noninvasive infrared spectrophotometer, comprising:

means for determining infrared absorption of at least one predetermined constituent of a person's blood from infrared emissions generated and emitted by the person's body;
and
processing means for calculating a concentration of said at least one predetermined constituent from the infrared absorption determined by said determining means.

A noninvasive infrared spectrophotometer for determining a concentration of at least one predetermined constituent in a person's blood, comprising:

means for detecting infrared energy generated and emitted by the person in a wavelength range including m different wavelengths of at least 2.0 .mu.m, said infrared energy containing energy at each of said n wavelengths which is differently absorbed by said at least one predetermined constituent whereby each predetermined constituent readily absorbs infrared energy at at least one of said m wavelengths and minimally absorbs infrared energy at another of said m wavelengths, said detecting means outputting at least one detection signal representative of infrared energy at said m wavelengths which has been emitted by said person and selectively absorbed by said at least one predetermined constituent;
synchronizing means for synchronizing the detection of said infrared energy emitted by the person with the systolic and diastolic phases of a cardiac cycle of the person;
and
means for determining the concentration of said at least one predetermined constituent of the person's blood from said at least one detection signal.

1 more element

A method of noninvasively measuring a concentration of at least one predetermined constituent in a person's blood, comprising the steps of:

detecting infrared energy generated and emitted by the person in a wavelength range including m different wavelengths of at least 2.0 .mu.m, said infrared energy containing energy at each of said n wavelengths which is differently absorbed by said at least one predetermined constituent whereby each predetermined constituent readily absorbs infrared energy at at least one of said m wavelengths and minimally absorbs infrared energy at another of said m wavelengths, and outputting at least one detection signal representative of infrared energy at said m wavelengths which has been emitted by said person and selectively absorbed by said at least one predetermined constituent;
synchronizing the detection of said infrared energy emitted by the person with the systolic and diastolic phases of a cardiac cycle of the person;
and
determining the concentration of said at least one predetermined constituent of the person's blood from said at least one detection signal.

1 more element

Dependencies are inferred from the claim text.

Self-emission noninvasive infrared spectrophotometer

Life of this patent

Self-emission noninvasive infrared spectrophotometer

Life of this patent

Abstract

Claims22