Body fluid sampling device with a capacitive sensor

• US 20090024009A1
• Filed: 07/25/2008
• Published: 01/22/2009
• Est. Priority Date: 04/19/2002
• Status: Active Grant

• Current Assignee: Sanofi-Aventis Deutschland GmbH (Sanofi )
• Original Assignee: Sanofi-Aventis Deutschland GmbH (Sanofi )
• Inventors: Alden, Don, Freeman, Dominique, Briggs, Barry Dean
• Granted Patent: US 8,784,335 B2
• Time in Patent Office: Days
• US Class Current: 600/309
• CPC Class Codes: A61B 5/1411 by percutaneous method, e.g. by lancet
• CPC Class Codes: A61B 5/150022 for capillary blood or interstitial fluid
• CPC Class Codes: A61B 5/150061 Means for enhancing collection
• CPC Class Codes: A61B 5/150068 by tissue compression, e.g. with specially designed surface of device contacting the skin area to be pierced
• 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 5/150106 Means for reducing pain or discomfort applied before puncturing; desensitising the skin at the location where body is to be pierced
• CPC Class Codes: A61B 5/150152 by an adequate mechanical impact on the puncturing location
• CPC Class Codes: A61B 5/150167 Adjustable piercing speed of skin piercing element, e.g. blade, needle, lancet or canula, for example with varying spring force or pneumatic drive
• CPC Class Codes: A61B 5/150175 Adjustment of penetration depth
• CPC Class Codes: A61B 5/15019 Depth adjustment mechanism using movable stops located inside the piercing device housing and limiting the travel of the drive mechanism mechanisms using distal end caps A61B5/150183, mechanisms at the piercing element carrier proximal end A61B5/150198
• CPC Class Codes: A61B 5/150358 Strips for collecting blood, e.g. absorbent optical reagent test strips G01N21/8483; chemical reagent test strips G01N33/4875, G01N33/52
• CPC Class Codes: A61B 5/150427 Specific tip design, e.g. for improved penetration characteristics
• 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 5/150572 Pierceable protectors, e.g. shields, caps, sleeves or films, e.g. for hygienic purposes
• CPC Class Codes: A61B 5/150748 Having means for aiding positioning of the piercing device at a location where the body is to be pierced means for aiding positioning of devices for bringing media into the body A61M5/427, locating blood vessels A61B5/489
• CPC Class Codes: A61B 5/15109 Fully automatically triggered, i.e. the triggering does not require a deliberate action by the user, e.g. by contact with the patient's skin
• CPC Class Codes: A61B 5/15113 Manually triggered, i.e. the triggering requires a deliberate action by the user such as pressing a drive button
• CPC Class Codes: A61B 5/15115 Driving means for propelling the piercing element to pierce the skin, e.g. comprising mechanisms based on shape memory alloys, magnetism, solenoids, piezoelectric effect, biased elements, resilient elements, vacuum or compressed fluids
• CPC Class Codes: A61B 5/15117 comprising biased elements, resilient elements or a spring, e.g. a helical spring, leaf spring, or elastic strap
• CPC Class Codes: A61B 5/15123 comprising magnets or solenoids
• CPC Class Codes: A61B 5/15126 : Means for controlling the lancing movement, e.g. 2D- or 3D-shaped elements, tooth-shaped elements or sliding guides
• CPC Class Codes: A61B 5/15146 : Devices loaded with multiple lancets simultaneously, e.g. for serial firing without reloading, for example by use of stocking means. multiple simultaneous cutting or piercing A61B5/150977
• CPC Class Codes: A61B 5/15153 : Multiple piercing elements stocked in a single compartment
• CPC Class Codes: A61B 5/15169 : Characterized by a rolled strip
• CPC Class Codes: A61B 5/15171 : Characterized by propelling the piercing element perpendicular to the direction of movement of the strip
• CPC Class Codes: A61B 5/15174 : Piercing elements stocked in the form of a stack or pile
• CPC Class Codes: A61B 5/15176 : Stocking means comprising cap, cover, sheath or protection for aseptic stocking
• CPC Class Codes: A61B 5/15178 : Stocking means comprising separate compartments or units for new and for used piercing elements separate compartments for used piercing elements in piercing devices A61B5/15184
• CPC Class Codes: A61B 5/15184 : Piercing device comprising a separate compartment or unit for used piercing elements separate compartments for used piercing elements in stocking means A61B5/15178
• CPC Class Codes: A61B 5/15186 : Devices loaded with a single lancet, i.e. a single lancet with or without a casing is loaded into a reusable drive device and then discarded after use; drive devices reloadable for multiple use
• CPC Class Codes: A61B 5/15194 : fully automatically retracted, i.e. the retraction does not require a deliberate action by the user, e.g. by terminating the contact with the patient's skin
• CPC Class Codes: A61B 5/157 : Devices characterised by integrated means for measuring characteristics of blood
• CPC Class Codes: A61B 5/7485 : Automatic selection of region of interest
• CPC Class Codes: A61M 5/42 : having means for desensitising skin, for protruding skin to facilitate piercing, or for locating point where body is to be pierced
• CPC Class Codes: A61M 5/427 : Locating point where body is to be pierced, e.g. vein location means using ultrasonic waves, injection site templates
• CPC Class Codes: A61M 5/46 : having means for controlling depth of insertion

Abstract

A body fluid sensing device with a body fluid capture structure and a body fluid measurement sensor positioned in the body fluid capture structure. A capacitance sensor is coupled to the body fluid measurement sensor. The capacitance sensor is used to assist in the positioning of a body part relative to the body fluid capture structure.

Claims

1. A body fluid sensing device, comprising:

a body fluid capture structure;

a body fluid measurement sensor positioned in the body fluid capture structure; and

a capacitance sensor coupled to the body fluid measurement sensor.

2. The device of claim 1, wherein the capacitance sensor is integrated with the body fluid measurement sensor.

3. The device of claim 2, wherein the capacitance sensor is integrated by sharing an electrical element used with the body fluid measurement sensor.

4. The device of claim 3, wherein the capacitance sensor is integrated with an independent electrical element for capacitance sensing

5. The device of claim 1, wherein the capacitance sensor is in direct contact with the body fluid measurement sensor.

6. The device of claim 1, wherein the capacitance sensor is positioned near the body fluid measurement sensor.

7. The device of claim 1, wherein the capacitance sensor is coupled to electronics that measure capacitance and interpret a capacitance value as either a position of the body part relative to the measurement sensor or as positive contact between the body part and the measurement sensor

8. The device of claim 1, wherein a presence of a body part in contact with or in close proximity to the body fluid measurement sensor causes a change in a bulk capacitance of the sensing element.

9. The device of claim 1, wherein the capacitive sensor includes an electrified plate sensing surface.

10. The device of claim 1, further comprising:

driver electronics coupled to the capacitive sensor.

11. The device of claim 10, wherein the driver electronic includes an driver integrated circuit.

12. The device of claim 10, wherein the driver electronics continually change a voltage applied to the electrified plate sensing surface.

13. The device of claim 11, wherein an amount of current required to change a voltage is measured by the circuit and indicates an amount of capacitance between the capacitive sensor and the skin.

14. The device of claim 10, wherein the capacitive sensor is a printed circuit board with a plurality of traces.

15. The device of claim 10, further comprising:

a capacitance digital converter that converts capacitive input signals into a digital value.

16. The device of claim 15 wherein the digital value is stored at an on-chip register.

17. The device of claim 15 further comprising:

a host controller with an interface coupled to the capacitive sensor.

18. The device of claim 17, wherein the host controller is coupled to a human interface.

19. The device of claim 16 wherein the host controller includes logic that implements a serial interface and an interrupt service routine.

20. The device of claim 17 wherein the host controller reads results over the serial interface.

21. The device of claim 15, wherein a capacitance ambient value is measured and stored.

22. The device of claim 15, wherein the capacitance sensor is active when a measured capacitance value is exceeds at least one of an upper or lower threshold limit.

23. The device of claim 15, further comprising:

an on-chip logic circuit configured to address changing ambient capacitance levels.

24. The device of claim 23, wherein a high and low threshold levels track changes in an ambient capacitance level.

25. A method for sampling blood, comprising:

providing a sensing device that includes a body fluid capture structure, a body fluid measurement sensor and a capacitance sensor coupled to the body fluid measurement sensor;

determining if a selected body part is in contact with or in close proximity to the sensing device.

26. The method of claim 25, further comprising:

determining a change in a bulk capacitance of the capacitance sensor.

27. The method of claim 25, further comprising:

measuring capacitance and interpreting a measured capacitance value as either a position of the body part relative to the sensing device or as positive contact between the body part and the sensing device.

28. The method of claim 25, wherein the measured capacitance is used to align the body part with the sensing device.