Method and apparatus for determining blood analytes

• US 8,406,839 B2
• Filed: 03/03/2006
• Issued: 03/26/2013
• Est. Priority Date: 03/04/2005
• Status: Active Grant

• Current Assignee: Covidien LP (Medtronic Plc)
• Original Assignee: Covidien LP (Medtronic Plc)
• Inventors: Kaushal, Ashwani, MacIntyre, Duncan
• Primary Examiner(s): HINDENBURG, MAX F
• Application Number:
  US11/885,537
• Publication Number:
  US 20080198361A1
• Time in Patent Office: 2,580 Days
• Field of Search: 600/326, 600/322, 600/323
• US Class Current: 600/322
• 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 within one or more than one tissue compartment of a body part of a subject, and a value of oxygen saturation of blood in the part of the 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 from 650 nm to 2800 nm, the light source being operatively coupled to a power source;

a receptor for receiving the 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, the one or more than one input and the one or more than one 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 pulse detector in operable association with the receptor for detecting a pulse within the part of the subject; and

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

the processing system configured to determine the concentration of the one or more than one compound in each of the one or more than one tissue compartments of the body part based on a calibration algorithm that accounts for the concentration of the one or more than one compound within one or more than one compartment, and the value of oxygen saturation of blood in the part, the processing system further configured to use measurements taken immediately subsequent to the detection of a pulse and prior to a next pulse so that all measurements upon which the concentration is based are taken between pulses.

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, wherein said one, or more than one output comprises a lense, a fibre optic or a hologram.

7. 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.

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

9. A method for determining a concentration of one or more than one compound within one or more than one tissue compartment of a body part of a subject, and a value of oxygen saturation of blood in the part of the subject, comprising:

(a) directing 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 (EMR) from 650 nm to 2800 nm onto the part;

(b) detecting a pulse in the body part of the subject;

(c) measuring a quantity of EMR reflected by, or transmitted through the part with a detector immediately subsequent to the detection of a pulse and prior to a next pulse so that all measurements upon which the concentration is based are taken between pulses;

(d) applying a calibration algorithm that accounts for concentration of the compound in each of the one or more than one tissue compartment of the body part; and

(e) determining the concentration of the one or more than one compound in each of the one or more than one tissue compartment of the body part and the value of oxygen saturation of blood in the part.

10. The method according to claim 9, 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.