Devices for Continuous Measurement of Glucose in Body Fluid

• US 20080269584A1
• Filed: 06/28/2005
• Published: 10/30/2008
• Est. Priority Date: 06/28/2004
• Status: Active Grant

• Current Assignee: G-Sense Ltd.
• Original Assignee: G-Sense Ltd.
• Inventors: Shekalim, Avraham
• Granted Patent: US 8,050,729 B2
• Time in Patent Office: Days
• US Class Current: 600/365
• 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 5/150076 by heating
• CPC Class Codes: A61B 5/150083 by vibration, e.g. ultrasound
• CPC Class Codes: A61B 5/150221 Valves
• CPC Class Codes: A61B 5/150229 Pumps for assisting the blood sampling
• CPC Class Codes: A61B 5/150389 Hollow piercing elements, e.g. canulas, needles, for piercing the skin
• CPC Class Codes: A61B 5/150503 Single-ended needles hollow piercing element tip design A61B5/150396, needle sets for catheters A61M25/06, needles for bringing media into the body A61M5/32
• CPC Class Codes: A61B 5/150526 Curved or bent needles
• CPC Class Codes: A61B 5/150809 by audible feedback
• CPC Class Codes: A61B 5/15087 short range, e.g. between console and disposable using implanted devices A61B5/150877
• CPC Class Codes: A61B 5/15105 Purely manual piercing, i.e. the user pierces the skin without the assistance of any driving means or driving devices
• CPC Class Codes: A61B 5/15142 Devices intended for single use, i.e. disposable
• CPC Class Codes: A61B 5/157 Devices characterised by integrated means for measuring characteristics of blood
• CPC Class Codes: B01L 2300/069 Absorbents; Gels to retain a fluid
• CPC Class Codes: B01L 2300/0838 Capillaries
• CPC Class Codes: B01L 2400/0406 capillary forces
• CPC Class Codes: B01L 2400/0439 ultrasonic vibrations, vibrating piezo elements
• CPC Class Codes: B01L 3/0268 using pulse dispensing or spraying, eg. inkjet type, piezo actuated ejection of droplets from capillaries
• CPC Class Codes: B01L 3/502715 characterised by interfacing components, e.g. fluidic, electrical, optical or mechanical interfaces
• CPC Class Codes: B01L 3/50273 : characterised by the means or forces applied to move the fluids micropumps F04B19/006, of the membrane type F04B43/043
• CPC Class Codes: G01N 2035/1041 : Ink-jet like dispensers
• CPC Class Codes: G01N 2035/1046 : Levitated, suspended drops
• CPC Class Codes: G01N 35/08 : using a stream of discrete samples flowing along a tube system, e.g. flow injection analysis

Abstract

A device for monitoring a constituent of body fluid continuously or repeatedly over a time period includes a body fluid sampling system and an optical sensor arrangement. The sampling system has a pumping arrangement which pumps body fluid from a cannula to a fluid sink. The optical sensor determines a concentration of at least one constituent of the body fluid. The pumping arrangement preferably ejects drops of body fluid from a fine nozzle. According to certain embodiments, optical sensor arrangements ensure that the optical paths do not pass through surfaces wetted by the fluid to be examined.

Claims

1. A device for monitoring a constituent of body fluid continuously or repeatedly over a time period, the device comprising:

(a) a body fluid sampling system including;

(i) a cannula for defining a fluid path for withdrawing body fluid from the body,

(ii) a fluid sink for storing a quantity of spent body fluid, and

(iii) a pumping arrangement for generating a net flow of body fluid from said cannula to said fluid sink; and

(b) an optical sensor arrangement associated with said body fluid sampling system and configured for determining a concentration of at least one constituent of the body fluid.

2. The device of claim 1, wherein said pumping arrangement includes at least one cyclically actuated piezoelectric transducer deployed to generate the net flow of body fluid.

3. The device of claim 1, wherein said pumping arrangement includes a nozzle arrangement for ejecting drops of the body fluid and a pulse generator for generating a pressure pulse within the body fluid so as to eject a drop from said nozzle arrangement.

4. The device of claim 3, further comprising a pressure regulating valve for maintaining a pressure above atmospheric pressure in said fluid sink.

5. The device of claim 3, wherein said nozzle arrangement is deployed so as to elect a drop from said nozzle arrangement towards a capillary uptake nozzle associated with said fluid sink.

6. The device of claim 3, wherein said nozzle arrangement is deployed so as to eject a drop from said nozzle arrangement towards an absorbent medium included within said fluid sink.

7. The device of claim 3, wherein said nozzle arrangement is deployed so as to eject a drop through a bubble trap arrangement.

8. The device of claim 3, wherein said pulse generator is deployed so as to generate a pressure pulse through said body fluid within said cannula.

9. The device of claim 8, her comprising a pressure wave augmenting configuration for augmenting a displacement of said pressure wave supplied to said cannula.

10. The device of claim 3, wherein said optical sensor arrangement is deployed for determining the concentration of said at least one constituent in the body fluid making up said ejected drop while said elected drop is in flight.

11. The device of claim 1, further comprising a pulse generator for generating a pressure pulse within the body fluid through said cannula.

12. The device of claim 11, further comprising a pressure wave augmenting configuration for augmenting a displacement of said pressure wave supplied to said cannula.

13. The device of claim 1, wherein said optical sensor arrangement includes an illumination source for illuminating at least a portion of the body fluid along an illuminating optical path and a sensor element sensitive to at least one wavelength of radiation received from said portion of the body fluid along a sensing optical path, and wherein said optical sensor arrangement is deployed such that at least one of said illuminating optical path and said sensing optical path does not pass through any surface which is wetted by the body fluid.

14. The device of claim 13, wherein said optical sensor arrangement is deployed such that at least one of said illuminating optical path and said sensing optical path does not pass through any container wall.

15. The device of claim 1, wherein said pumping arrangement includes a valveless pump configuration having:

(a) a pumping chamber for containing a quantity of the body fluid;

(b) a first directional flow impedance having a direction of minimum flow impedance from said cannula to said pumping chamber;

(c) a second directional flow impedance having a direction of minimum flow impedance from said pumping chamber towards said fluid sink; and

(d) a pulse generator for generating cyclic variations in volume of said pumping chamber, thereby generating said net flow of fluid.

16. The device of claim 15, further comprising a nozzle in fluid communication with said second directional flow impedance such that operation of said valveless pump configuration causes growth of a droplet at said nozzle.

17. The device of claim 16, wherein said optical sensor arrangement is configured to determine a concentration of said at least one constituent of said droplet at said nozzle.

18. The device of claim 16, wherein said fluid sink includes a capillary medium deployed in predefined spatial relation to said nozzle such that when said droplet grows to a predefined size, said droplet contacts said capillary medium and is drawn by capillary action into said fluid sink.

19. The device of claim 1, wherein at least said cannula, said fluid sink, and surfaces of said pumping arrangement coming in contact with the body fluid are implemented as part of a disposable cartridge, and wherein at least said optical sensor arrangement is implemented as part of a reusable housing configured for interchangeably receiving said disposable cartridge.

20. The device of claim 19, wherein said reusable housing includes a body contact portion configured for temporary attachment to a body surface of a subject and a cover removably attachable to said body contact portion.

21. The device of claim 1, further comprising a heating arrangement for locally heating at least part of said cannula.

22. The device of claim 21, wherein said heating arrangement includes an electrical heating element associated with at least part of said cannula.

23. The device of claim 21, wherein said heating arrangement includes a laser directed towards at least part of said cannula.

24. The device of claim 21, wherein said heating arrangement includes an actuator for generating vibration of at least part of said cannula.

25. A device for monitoring a constituent of body fluid continuously or repeatedly over a time period, the device comprising:

(a) a body fluid sampling system including;

(i) a cannula for defining a fluid path for withdrawing body fluid from the body,

(ii) a fluid sink for storing a quantity of spent body fluid, and

(iii) a pumping arrangement for generating a net flow of body fluid from said cannula to said fluid sink; and

(b) a sensor arrangement associated with said body fluid sampling system and configured for determining a concentration of at least one constituent of the body fluid,

wherein said pumping arrangement includes a nozzle arrangement for ejecting drops of the body fluid and a pulse generator for generating a pressure pulse within the body fluid so as to eject a drop from said nozzle arrangement.

26. A device for monitoring a constituent of body fluid continuously or repeatedly over a time period, the device comprising:

(a) a body fluid sampling system including;

(i) a cannula for defining a fluid path for withdrawing body fluid from the body,

(ii) a fluid sink for storing a quantity of spent body fluid,

(iii) a pumping arrangement for generating a net flow of body fluid from said cannula to said fluid sink amid

(iv) a pulse generator for generating a pressure pulse within the body fluid through said cannula; and

(b) a sensor arrangement associated with said body fluid sampling system and configured for determining a concentration of at least one constituent of the body fluid.

27. The device of claim 26, further comprising a pressure wave augmenting configuration for augmenting a displacement of said pressure wave supplied to said cannula.