System and method for continuous analyte monitoring

• US 7,384,396 B2
• Filed: 05/08/2003
• Issued: 06/10/2008
• Est. Priority Date: 07/21/1998
• Status: Expired due to Fees

• Current Assignee: ​Passport Technologies, Inc.
• Original Assignee: Spectro Incorporated (Spectro Scientific, Inc.)
• Inventors: Hatch, Michael R., Samuels, Mark A., Eppstein, Jonathan A., Smith, Alan, Faupel, Mark
• Primary Examiner(s): Winakur; Eric
• Assistant Examiner(s): Berhanu; Etsub D
• Application Number:
  US10/435,221
• Publication Number:
  US 20030191376A1
• Time in Patent Office: 1,860 Days
• Field of Search: 600/309, 600/322, 600/361, 600/583
• US Class Current: 600/309
• CPC Class Codes: A61B 10/0045 Devices for taking samples of body liquids devices for taking blood samples A61B5/15
• CPC Class Codes: A61B 2010/008 Interstitial fluid
• CPC Class Codes: A61B 5/00 Measuring for diagnostic purposes radiation diagnosis A61B6/00; diagnosis by ultrasonic, sonic or infrasonic waves A61B8/00; Identification of persons
• CPC Class Codes: A61B 5/0002 Remote monitoring of patients using telemetry, e.g. transmission of vital signals via a communication network A61B5/07 takes precedence; transmission systems for measured values G08C; transmission H04B; transmission of digital information H04L; wireless communication networks H04W
• CPC Class Codes: A61B 5/14514 using means for aiding extraction of interstitial fluid, e.g. microneedles or suction
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/150022 for capillary blood or interstitial fluid
• CPC Class Codes: A61B 5/150099 by negative pressure, other than vacuum extraction into a syringe by pulling on the piston rod or into pre-evacuated tubes
• CPC Class Codes: A61B 5/150809 by audible feedback
• CPC Class Codes: A61B 5/150816 by tactile feedback, e.g. vibration
• CPC Class Codes: A61B 5/150824 by visual feedback
• CPC Class Codes: A61B 5/150862 intermediate range, e.g. within room or building
• CPC Class Codes: A61B 5/150969 Low-profile devices which resemble patches or plasters, e.g. also allowing collection of blood samples for testing
• CPC Class Codes: A61B 5/150984 Microneedles or microblades
• CPC Class Codes: A61B 5/15134 Bladeless capillary blood sampling devices, i.e. devices for perforating the skin in order to obtain a blood sample but not using a blade, needle, canula, or lancet, e.g. by laser perforation, suction or pressurized fluids
• CPC Class Codes: A61B 5/155 Devices specially adapted for continuous or multiple sampling, e.g. at predetermined intervals devices loaded with multiple lancets simultaneously A61B5/15146
• CPC Class Codes: A61B 5/157 Devices characterised by integrated means for measuring characteristics of blood

Abstract

A system and method for extracting a biological fluid from an organism and continuously monitoring its characteristics. The system includes a tissue interface device suitable for positioning on or about the surface of the biological membrane of the organism and a monitor and control unit coupled to the tissue interface device. The tissue interface device includes a sensor positioned in a flow path of the fluid for continuously sensing a characteristic of the biological fluid as it flows out from the one or more artificial openings formed in the biological membrane. The sensor generates a sensor signal representative thereof. The monitor and control unit electrically or optically reads the sensor to obtain a measurement of a characteristic, such as concentration of a particular analyte, of the biological fluid on a continuous basis.

Claims

1. A system for continuously monitoring a characteristic of a biological fluid extracted from an organism, comprising:

a tissue interface device suitable for positioning on or about a surface of a biological membrane of the organism, the tissue interface device comprising a sensor positioned in a flow path of the fluid for continuously sensing a characteristic of the biological fluid as it flows out from one or more artificial openings formed in the tissue and in the flow path; and

a monitor and control unit coupled to the tissue interface device that reads the sensor to derive a measurement of a characteristic of the biological fluid on a continuous basis and wherein said tissue interface device is capable of detecting a shift in pH, so that potential contamination of the biological fluid can be detected, and

further comprising a connector that connects the monitor and control unit to the tissue interface device, wherein the connector includes a tube extending the length thereof, wherein the monitor and control unit comprises a suction source that is coupled to the tube and provides suction to the tissue interface device so as to draw biological fluid from the one or more artificial openings and through the fluid collection and sensor device and wherein said tissue interface device further includes means for rinsing the sensor of biological fluid so that it may accurately assay fresh biological fluid.

2. The system of claim 1, wherein the sensor comprises an analyte sensor.

3. The system of claim 1, wherein the monitor and control unit comprises a controller that controls when readings are made from the sensor.

4. The system of claim 3, wherein the controller compares data obtained from the sensor with stored values and generates an alarm signal upon determining a deviation from the stored values.

5. The system of claim 4, and further comprising an alarm device that is responsive to the alarm signal to generate an audio and/or visual alarm.

6. The system of claim 1, and further comprising electrical lead lines coupling the sensor to the monitor and control unit, wherein the sensor in the tissue interface device generates an electrical sensor signal representing the characteristic of the biological fluid, the electrical lead lines coupling the electrical sensor signal to the monitor and control unit and wherein the sensor, upon detecting abnormal changes in pH, report same to the control unit, so that the user may determine if reported characteristics of the biological fluid are reliable.

7. The system of claim 1, wherein the sensor changes its optical characteristics in response to a characteristic of the biological fluid.

8. The system of claim 7, wherein the monitor and control unit comprises means for optically reading the sensor.

9. The system of claim 8, and further comprising at least one optical fiber coupled between the means for optically reading the sensor.

10. The system of claim 7, and further comprising electrical lead lines coupling the sensor to the monitor and control unit, wherein the tissue interface device comprises means to optically read the sensor and generate an electrical sensor signal representative thereof, the electrical lead lines coupling the electrical sensor signal to the monitor and control unit.

11. The system of claim 1, wherein the monitor and control unit comprises a controller that controls the level of the suction.

12. The system of claim 1, and further comprising a pressure sensor for measuring the suction applied to the tissue interface device, the pressure sensor generating as output a pressure signal representative thereof, wherein the monitor and control unit reads the pressure signal.

13. The system of claim 1, wherein the tissue interface device comprises one or more elements for forming one or more artificial openings in the biological membrane and for applying a sweat control substance to the biological membrane to reduce contamination by sweating.

14. The system of claim 1, wherein the tissue interface device is attached to the surface of the biological membrane for a period of time to continuously collect biological fluid and sense characteristics thereof during the period of time, while periodically flushing the sensor of biological fluid.

15. The system of claim 1, and further comprising one or more electrical conductors that are connected between the tissue interface device and the monitor and control unit to communicate signals therebetween.

16. The system of claim 1, wherein the monitor and control unit is contained within a body wearable or attachable housing.

17. The system of claim 1, wherein the monitor and control unit comprises a memory coupled to the controller for storing data obtained from the sensor on a programmable periodic basis.

18. A system for continuously monitoring a characteristic of a biological fluid extracted from an organism, comprising:

a tissue interface device suitable for positioning on or about a surface of a biological membrane of the organism, the tissue interface device comprising a sensor positioned in a flow path of the fluid for continuously sensing a characteristic of the biological fluid as it flows out from one or more artificial openings formed in the tissue and in the flow path; and

a monitor and control unit coupled to the tissue interface device that reads the sensor to derive a measurement of a characteristic of the biological fluid on a continuous basis and wherein said tissue interface device is capable of detecting a shift in pH, so that potential contamination of the biological fluid can be detected, and

further comprising a connector that connects the monitor and control unit to the tissue interface device, wherein the connector includes a tube extending the length thereof, wherein the monitor and control unit comprises a suction source that is coupled to the tube and provides suction to the tissue interface device so as to draw biological fluid from the one or more artificial openings and through the fluid collection and sensor device and wherein said tissue interface device further includes means for rinsing the sensor of biological fluid so that it may accurately assay fresh biological fluid and further including a sweat control substance that functions by incapacitating the sweat glands.

19. The system of claim 18, wherein an optical energy source is contained within the monitor and control unit, and further comprising an optical fiber that couples a beam of optical energy to an optically absorbent material on the tissue interface device.

20. The system of claim 18, wherein the monitor and control unit comprises a display coupled to the controller that displays measurement data.