Non-invasive blood component analyzer

• US 6,615,064 B1
• Filed: 02/28/2000
• Issued: 09/02/2003
• Est. Priority Date: 09/21/1998
• Status: Expired due to Fees

• Current Assignee: Essential Medical Devices
• Original Assignee: Essential Medical Devices
• Inventors: Aldrich, Thomas K.
• Primary Examiner(s): Winakur, Eric F.
• Application Number:
  US09/514,789
• Time in Patent Office: 1,282 Days
• Field of Search: 600/310, 600/315, 600/316, 600/319, 600/322, 600/323, 600/326, 600/329, 600/330, 600/335, 600/336, 600/407, 600/473, 600/476
• US Class Current: 600/316
• 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 5/1455 using optical sensors, e.g. spectral photometrical oximeters

Abstract

Claims

1. A non-invasive method for measuring the concentration of a blood component in a subject'"'"'s blood, said method comprising the steps of:

a. providing at least one light source for directing light of at least two wavelengths through a tissue of the subject in which light absorbances by arterial blood can be detected by measuring changes in absorbance during pulsatile flow of blood;

b. providing at least one detector for detecting the portion of the light transmitted through the tissue of the subject;

c. providing at least one detector for detecting a physical dimension of the tissue of the subject near or at the location of the at least one light source;

d. measuring the absorbance of the light at the first wavelength by the tissue at both the systolic and diastolic phases of the pulsatile flow;

e. measuring the absorbance of the light at the second wavelength by the tissue at both the systolic and diastolic phases of the pulsatile flow;

f. determining the rate of change over time of absorbance of light of the first wavelength during pulsatile flow;

g. determining the rate of change over time of absorbance of light of the second wavelength during pulsatile flow;

h. determining the rate of change over time in physical dimension during pulsatile flow at or near the location of the at least one light source;

i. calculating a ratio of the rate of change in light absorbance over time divided by the rate of change over time in physical dimension for the first wave length;

j. calculating a ratio of the rate of change in light absorbance over time divided by the rate of change over time in physical dimension for the second wave length;

k. calculating the concentration of the blood component in said subject'"'"'s blood by comparing the results of a formula employing the ratios determined in step i and j as independent variables to the results of the same formula in subjects with known blood component levels.