Noninvasive blood chemistry measurement method and system

• US 6,113,541 A
• Filed: 06/30/1998
• Issued: 09/05/2000
• Est. Priority Date: 03/07/1997
• Status: Expired due to Term

• Current Assignee: Sanofi-Aventis Deutschland GmbH (Sanofi )
• Original Assignee: Agilent Technologies, Inc.
• Inventors: Mauze, Ganapati R., Dias, J. Fleming
• Primary Examiner(s): Nasser, Robert L.
• Application Number:
  US09/107,304
• Time in Patent Office: 798 Days
• Field of Search: 600/322, 600/323, 600/335, 600/338, 600/301, 600/345
• US Class Current: 600/301
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/1455 using optical sensors, e.g. spectral photometrical oximeters
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/6826 Finger
• CPC Class Codes: A61B 5/6838 Clamps or clips
• CPC Class Codes: A61B 5/6843 Monitoring or controlling sensor contact pressure

Abstract

A noninvasive blood chemistry measurement method and system isolate measurement contributions due to a patient'"'"'s blood to accurately measure blood chemistry. In accordance with a first preferred embodiment of the present invention a noninvasive blood chemistry measurement method decreases the blood volume within a patient'"'"'s body part relative to the normal blood volume in the body part and performs a baseline measurement. Blood volume is then increased and a second measurement is performed. Comparison of the second measurement to the baseline measurement isolates the measurement attributes of the patient'"'"'s blood. In accordance with a second preferred embodiment of the present invention a noninvasive blood chemistry measurement system decreases blood volume by applying mechanical pressure to a body part. In accordance with a third preferred embodiment of the present invention, blood volume in the body part is decreased using a pressure cuff. In a fourth embodiment, a noninvasive probe accurately measures blood chemistry and uses a suction cup to increase blood volume at the blood chemistry measurement site.

Claims

1. A method of isolating measurement attributes of blood in a noninvasive blood chemistry measurement, comprising:

performing a first alteration of blood volume in a human body part relative to a normal blood volume in the body part;

performing a first measurement of a noninvasive interaction with the body part after said first alteration of blood volume therein;

performing a second alteration of blood volume in the body part;

performing a second measurement of the noninvasive interaction with the body part after said second alteration of blood volume therein; and

comparing the first and second measurements;

wherein one of (i) said first alteration or (ii) said second alteration of blood volume comprises applying negative pressure to the body part.

2. The method of claim 1 wherein the noninvasive interaction with the body part comprises optical transmission through the body part.

3. The method of claim 2 wherein the other of (i) said first alteration or (ii) said second alteration of blood volume comprises applying a positive pressure to the body part.

4. The method of claim 3 wherein the step of applying positive pressure to the body part comprises inflating a cuff encasing the body part.

5. The method of claim 1 wherein the other of (i) said first alteration or (ii) said second alteration of blood volume comprises removing the negative pressure.

6. The method of claim 1 wherein the noninvasive interaction with the body part comprises optical scattering by the body part.

7. The method of claim 6 wherein the other of (i) said first alteration or (ii) said second alteration of blood volume comprises applying positive pressure to the body part.

8. The method of claim 7 wherein the step of applying positive pressure to the body part comprises inflating a cuff encasing the body part.

9. A method of isolating measurement attributes of blood in a noninvasive blood chemistry measurement, comprising:

decreasing blood volume in a human body part relative to a normal blood volume in the body part;

performing a baseline measurement of a noninvasive interaction with the body part;

using suction to increase blood volume in the body part;

performing a second measurement of the noninvasive interaction with the body part; and

comparing the baseline and second measurements.

10. A method of isolating measurement attributes of blood in a noninvasive blood chemistry measurement, comprising:

mechanically pressing a human body part to decrease blood volume in a human body part relative to a normal blood volume in the body part;

performing a baseline measurement of a noninvasive interaction with the body part by interrogating the body part with a light beam;

using suction to increase blood volume in the body part;

after increasing blood volume in the body part performing a second measurement of the noninvasive interaction with the body part by interrogating with a light beam; and

comparing the baseline and second measurements.