Non-invasive system and method for measuring skin hydration of a subject

• US 8,043,227 B2
• Filed: 12/26/2006
• Issued: 10/25/2011
• Est. Priority Date: 12/28/2005
• Status: Expired due to Fees

• Current Assignee: Koninklijke Philips N.V.
• Original Assignee: Koninklijke Philips N.V.
• Inventors: Van Gogh, Antonius Theodorus Marinus, Van Herpen, Maarten Marinus Johannes Wilhelm
• Primary Examiner(s): Lucchesi; Nicholas D
• Assistant Examiner(s): Snyder; Melissa A
• Application Number:
  US12/158,714
• Publication Number:
  US 20080275319A1
• Time in Patent Office: 1,764 Days
• Field of Search: 600/555, 600306-309, 600/316, 600346-348, 600365-366
• US Class Current: 600/555
• CPC Class Codes: A61B 5/0095 by applying light and detecting acoustic waves, i.e. photoacoustic measurements
• CPC Class Codes: A61B 5/01 Measuring temperature of body parts ; Diagnostic temperature sensing, e.g. for malignant or inflamed tissue clinical contact thermometers G01K13/20
• 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 5/441 Skin evaluation, e.g. for skin disorder diagnosis
• CPC Class Codes: A61B 5/4869 Determining body composition

Abstract

A non-invasive system and method for measuring skin hydration of a subject includes a thermistor used in transient mode to obtain a measurement of the thermal conductivity of the skin of the subject and a processor for determining a skin hydration value from the thermal conductivity measurement. The system for measuring skin hydration further includes a non-invasive system for detecting blood analyte concentration, such as glucose, with a spectroscopic device having e.g., an infrared source which generates infrared beam and detector for detecting transmitted radiation through portion (e.g., finger) of a subject. The system may also include skin hydrator which moisturizes the skin and is connected in a control loop to the system for measuring skin hydration. The system for detecting blood analyte concentration may include a photoacoustic device or a metabolic heat conformation device.

Claims

1. A non-invasive system for measuring hydration of at least one of a skin and exterior mucosa and detecting a blood analyte concentration of a subject comprising:

a thermal conductivity measuring apparatus for obtaining a measurement of a thermal conductivity of the at least one of the skin and the exterior mucosa of the subject; and

a processor configured to determine a hydration value from the thermal conductivity measurement and to determine the blood analyte concentration, wherein the processor is further configured to postpone determination of the blood analyte concentration until the hydration value is within a predetermined range,

further comprising a hydrating device for providing a hydrating agent to the least one of the skin and the exterior mucosa and a hydration controller connected to the hydrating device so the hydration controller maintains the hydration value at a predetermined level within the predetermined range.

2. The non-invasive system according to claim 1, wherein the thermal conductivity measuring apparatus comprises:

a thermistor in thermal connection with the at least one of a skin and exterior mucosa of the subject in use; and

a current supply for supplying current to the thermistor sufficient to maintain the resistance or temperature of the thermistor at a predetermined level,

wherein the thermal conductivity measuring apparatus obtains a measurement of the thermal conductivity in dependence upon the current supplied to the thermistor.

3. The non-invasive system according to claim 1, wherein the system for detecting the analyte blood concentration comprises one or more of:

a spectroscopic device;

a photoacoustic device; and

a device for determining blood glucose concentration based on the metabolic heat conformation method.

4. The non-invasive system according to claim 1, wherein the analyte concentration is glucose concentration.

5. The non-invasive system of claim 1, wherein the processor is further configured to continuously compare the determined hydration value with the predefined range until the determined hydration value is within the predefined range.

6. The non-invasive system of claim 1, wherein the processor is further configured to determine the blood analyte concentration from a radiation detected by a detector, wherein the radiation is emitted by a source and transmitted through a portion of the subject.

7. The non-invasive system of claim 1, wherein the processor is further configured to determine the blood analyte concentration from a pressure wave detected by an acoustic sensor in response to a pulsed radiation emitted by source to cause a temperature rise that generates the pressure wave.

8. A method for measuring hydration of at least one of a skin and exterior mucosa and a blood analyte concentration of a subject, the method comprising the acts of:

non-invasively measuring a thermal conductivity of the at least one of the skin and the exterior mucosa;

determining a hydration level of the at least one of the skin and the exterior mucosa from the thermal conductivity;

monitoring the hydration level until the hydration level is within a predetermined range;

when the hydration level is within the predetermined range, determining by a processor the blood analyte concentration; and

maintaining the hydration level within a predetermined range using a hydration controller for controlling a hydrator for providing a hydrating agent to the least one of the skin and the exterior mucosa.

9. The method of claim 8, wherein the monitoring act includes continuously comparing the determined hydration level with the predefined range until the determined hydration value is within the predefined range.

10. The method of claim 8, wherein the act of determining the blood analyte concentration is performed using a radiation detected by a detector, wherein the radiation is emitted by a source and transmitted through a portion of the subject.

11. The method of claim 8, wherein the act of determining the blood analyte concentration is performed using a pressure wave detected by an acoustic sensor in response to a pulsed radiation emitted by source to cause a temperature rise that generates the pressure wave.

12. The method of claim 8, wherein the analyte concentration is glucose concentration.