Method and Apparatus for Determining Blood Analytes

• US 20080198361A1
• Filed: 03/03/2006
• Published: 08/21/2008
• Est. Priority Date: 03/04/2005
• Status: Active Grant

• Current Assignee: Covidien LP (Medtronic Plc)
• Original Assignee: NIR Diagnostics Incorporated
• Inventors: MacIntyre, Duncan, Kaushal, Ashwani
• Granted Patent: US 8,406,839 B2
• Time in Patent Office: Days
• US Class Current: 356/39
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/14546 for measuring analytes not otherwise provided for, e.g. ions, cytochromes
• CPC Class Codes: A61B 5/1495 Calibrating or testing of in-vivo probes

Abstract

The present invention provides a method of measuring the concentration of a compound and a value of oxygen saturation in the blood of a part of a subject. Also provided is a device for carrying out the disclosed method. The method relates to measuring the concentration of a compound and a value of oxygen saturation in the blood part of a subject, and correlating the measured concentration of the compound and/or the value of oxygen saturation in the blood to a specific clinical condition. The device comprises a polychromatic light source, a receptor, a detector, and a processing system comprising a calibration algorithm.

Claims

1. A device for measuring a concentration of one or more than one compound and a value of oxygen saturation of blood in a part of a subject, comprising:

a polychromatic light source that emits a wavelength of light in the visible red spectrum, a wavelength of light in the infrared spectrum and a broad spectrum of light in the near infrared range, the light source being operatively coupled to a power source;

a receptor for receiving a part of the subject and comprising one or more than one input in operable association with the polychromatic light source, one or more than one output in operable association with a dispersing element, and a control device for measuring a value of blood volume in the part or a pulse of the subject, the one or more than one input and the one or more than output defining a light path within the receptor, wherein, the part of the subject when received by the receptor is placed within the light path;

a detector for measuring transmitted or reflected light received from the dispersing element, the detector operatively coupled to a processing system;

the processing system comprising one, or more than one calibration algorithm for determining a concentration for the one or more than one compound and the value of oxygen saturation of blood in the part, and an algorithm for controlling the detector based on the value of blood volume or the pulse measured by the control device.

2. The device according to claim 1, wherein said processing system comprises an oximeter.

3. The device according to claim 1, wherein the detector is a linear array detector.

4. The device according to claim 1, wherein the dispersing element is a grating.

5. The device according to claim 1, wherein the compound is selected from the group consisting of a fat, a protein, a glycoprotein, a lipoprotein, a carbohydrate, a steroid, an amino acid, nitrogen, carbon dioxide, cortisol, creatine, creatinine, a ketone, a lipid, urea, a fatty acid, glycosolated hemoglobin, alcohol, lactate, Ca²⁺, K⁺, Cl⁻

, HCO₃⁻

; and

HPO₄⁻

6. The device according to claim 1, further comprising a pulse detector for detecting a pulse within said part, said pulse detector being operatively coupled to said device to use measurements taken immediately subsequent to the detection of a pulse and prior to a next pulse so that all measurements upon which said concentration is based are taken between pulses.

7. The device according to claim 1, wherein said one, or more than one output comprises a lense, a fibre optic or a hologram.

8. The device according to claim 1, further comprising a collimator between said polychromatic light source and said receptor so that light from the polychromatic light source passes through said collimator before passing into said receptor.

9. The device according to claim 1, wherein the near infrared region in which measurements are taken extends from 650 nm to 2800 nm.

10. The device according to claim 1, wherein the near infrared region in which measurements are taken extends from 700 m to 1100 nm.

13. The device according to claim 1, wherein the dispersing element, the detector and the processing system are disposed on a microchip.

11. A method for determining a concentration of a compound and a value of oxygen saturation of blood, in a part of a subject, comprising:

(a) directing a broad spectrum of electromagnetic radiation (EMR) from the near-infrared spectrum onto the part;

(b) measuring a quantity of EMR reflected by, or transmitted through the part with a detector; and

(c) performing a quantitative mathematical analysis of the quantity of EMR using an algorithm, said algorithm correcting for changes in volume in the part, and

(d) determining the concentration of the compound and the value of oxygen saturation of blood in the part.

12. The method according to claim 12, wherein the compound is selected from the group consisting of a fat, a protein, a glycoprotein, a lipoprotein, a carbohydrate, a steroid, an amino acid, nitrogen, carbon dioxide, cortisol, creatine, creatinine, a ketone, a lipid, urea, a fatty acid, glycosolated hemoglobin, alcohol, lactate, Ca²⁺, K⁺, Cl⁻

, HCO₃⁻

, HPO₄⁻

, high density lipoprotein and low density lipoprotein.