Device and method for variable speed lancet

• US 20040010279A1
• Filed: 04/21/2003
• Published: 01/15/2004
• Est. Priority Date: 04/19/2002
• Status: Active Grant

• Current Assignee: Sanofi-Aventis Deutschland GmbH (Sanofi )
• Original Assignee: Pelikan Technologies, Inc.
• Inventors: Boecker, Dirk, Freeman, Dominique M.
• Granted Patent: US 7,258,693 B2
• Time in Patent Office: Days
• US Class Current: 606/182
• 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 5/150152 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 5/150427 Specific tip design, e.g. for improved penetration characteristics
• CPC Class Codes: A61B 5/150435 Specific design of proximal end
• 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 5/15123 comprising magnets or solenoids
• 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 5/15161 Characterized by propelling the piercing element in a radial direction relative to the disc

Abstract

A method of penetrating tissue is provided. The method comprises using a lancet driver to advance a lancet into the tissue; advancing the lancet at a first desired velocity in a first layer of tissue; advancing the lancet at a second desired velocity in a second layer of tissue; and advancing the lancet at a third desired velocity in a third layer of tissue. In one embodiment, the method may including using a processor having logic for controlling velocity of the lancet in each layer of tissue.

Claims

1. A method of penetrating tissue comprising:

using a lancet driver to advance a lancet into said tissue;

advancing said lancet at a first desired velocity in a first layer of tissue;

advancing said lancet at a second desired velocity in a second layer of tissue; and

advancing said lancet at a third desired velocity in a third layer of tissue.

2. The method of claim 1 further comprising using a processor having logic for controlling velocity of the lancet in each layer of tissue.

3. The method of claim 1 wherein said lancet achieves a lancet velocity between about 4 to 10 m/s while in at least one of the layers of tissue.

4. The method of claim 1 wherein said lancet achieves a penetration depth, as measured from a surface of the tissue, of between about 0.5 to about 2.0 mm.

5. The method of claim 1 wherein said second desired velocity is sufficient to minimize nerve stimulation while maintaining cutting efficiency.

6. The method of claim 1 wherein said second velocity is the same as the first velocity.

7. The method of claim 1 wherein said first velocity is at least partially determined based on hydration of the stratum corneum.

8. The method of claim 1 wherein said second velocity is at least partially determined based on hydration of the stratum corneum.

9. The method of claim 1 further comprising determining hydration of the stratum corneum.

10. The method of claim 1 wherein said lancet driver is electromech anical.

11. The method of claim 1 wherein said lancet driver is coupled to position sensor for determining lancet position during lancet actuation.

12. The method of claim 1 further comprising adjusting lancet penetration depth based on stratum corneum hydration.

13. The method of claim 1 wherein a four edge algorithm is used to control lancet velocity.

14. The method of claim 1 wherein there are at least 30 different decision points to change lancet velocity during penetration.

15. The method of claim 1 wherein there are at least 30 different decision points to change lancet velocity prior to the lancet reaching a stopped position in the tissue.

16. The method of claim 1 further comprising a position sensor to resolve position of the lancet within the skin to an accuracy of about ±

17 microns.

17. The method of claim 1 further comprising a position sensor having a 360 strip per inch encoder strip.

18. The method of claim 1 further comprising using a first detection algorithm on. a lancet inbound phase and a second detection algorithm on a lancet outbound phase.

19. The method of claim 1 controlling lancet velocity to within 1 % at a speed of 5 m/s.

20. The method of claim 1 lancing according to regional velocity profiles based on variation of cell type.

21. The method of claim 1 lancing according to regional velocity, said velocity base on changes of regional cell types and the resistance they provide.

22. The method of claim 1 lancing according to regional velocity profiles based on location to pain sensors.

23. The method of claim 1 wherein position and velocity are determined based on cell population and distribution in the different zones of tissue.

24. The method of claim 1 wherein the processor measures differences between normal and hydrated stratum corneum and determines what proportion of electrical power consumption is related to the increase in stratum corneum thickness.by.

25. The method of claim 1 wherein said lancet has a maximum velocity through a stratum corneum, has a velocity in the epidermis sufficient to reduce shock waves to pain sensor in dermis, and a velocity through in the dermis sufficient for efficient cutting of blood vessels without stimulating pain sensors.

53. The method of claim 1 further comprising characterizing tissue using a method such as OCT.

54. The method of claim 1 further comprising adjusting velocity to account for up to 150 micron thickness change in stratum corneum when hydrated.

26. A method of penetrating tissue having a plurality of layers, the method comprising:

using a drive force generator to advance a penetrating member along a penetration path into said tissue, said penetrating member having a penetrating member velocity equal to a first velocity in a first layer of tissue;

determining penetrating member velocity at a plurality of locations along said penetration path; and

adjusting penetrating member velocity at a plurality of locations along said penetration path prior to the penetrating member coming to a stop in said tissue.

27. The method of claim 26 wherein said penetrating member achieves a penetrating member velocity between about 4 to 10 m/s while in at least one of the layers of tissue.

28. The method of claim 26 wherein said penetrating member achieves a penetration depth, as measured from a surface of the tissue, of between about 0.1 to about 2.0 mm.

29. The method of claim 26 wherein said penetrating member is sufficient to minimize nerve stimulation while maintaining cutting efficiency.

30. The method of claim 26 wherein said second velocity is the same as the first velocity.

31. The method of claim 26 wherein said first velocity is at least partially determined based on hydration of the stratum corneum.

32. The method of claim 26 wherein said second velocity is at least partially determined based on hydration of the stratum corneum.

33. The method of claim 26 further comprising determining hydration of the stratum corneum.

34. The method of claim 26 wherein said penetrating member driver is electromechanical.

35. The method of claim 26 wherein said penetrating member driver includes a position sensor for determining penetrating member position during penetrating member actuation.

36. The method of claim 26 further comprising adjusting penetrating member penetration depth based electrical parameters to compensate for stratum corneum hydration.

37. The method of claim 26 wherein a four edge algorithm is used to control penetrating member velocity.

38. The method of claim 26 wherein there are at least 30 different decision points to change penetrating member velocity during penetration.

39. The method of claim 26 wherein there are at least 30 different decision points to change penetrating member velocity prior to reaching.

40. The method of claim 26 further comprising a position sensor to resolve position of the penetrating member within the skin to an accuracy of about 117 microns.

41. The method of claim 26 further comprising a position sensor having a 360 strip per inch encoder strip.

42. The method of claim 26 further comprising using a first detection algorithm on a penetrating member inbound phase and a second detection algorithm on a penetrating member outbound phase.

43. The method of claim 26 controlling penetrating member velocity to within 1 % at a speed of 5 m/s.

44. The method of claim 26 lancing according to regional velocity profiles based on variation of cell type.

45. The method of claim 26 lancing according to regional velocity, said velocity based on changes of regional cell types and the resistance they provide.

46. The method of claim 26 lancing according to regional velocity profiles based on location of pain sensors.

47. The method of claim 26 wherein position and velocity are determined based on cell population and distribution in the different zones of tissue.

48. The method of claim 26 wherein the processor adjusting penetrating member penetration depth based electrical parameters to compensate for stratum corneum hydration.

49. The method of claim 26 wherein said penetrating member has a maximum velocity through a stratum corneum, has a velocity in the epidermis sufficient to reduce shock waves to pain sensor in dermis, and a velocity through in the dermis sufficient for efficient cutting of blood vessels without stimulating pain sensors.

50. A method of penetrating tissue having a plurality of layers, the method comprising:

using a lancet driver to advance a lancet into said tissue, said lancet having a lancet velocity equal to a first velocity in a first layer of tissue;

adjusting lancet velocity to achieve a desired velocity based on the layer of tissue through which the lancet is cutting.

51. The method of claim 50 further comprising:

adjusting the lancet velocity to achieve a second velocity in a second tissue layer, said adjusting based upon characteristics of the second tissue layer and said adjusting selected from one of the following;

increasing velocity from said first velocity, decreasing velocity from said first velocity, or maintaining a velocity equal to said first velocity;

adjusting the lancet velocity to achieve a third velocity in a third tissue layer, said adjusting based upon characteristics of the third tissue layer and said adjusting selected from one of the following;

increasing velocity from said second velocity, decreasing velocity from said second velocity, or maintaining a velocity equal to said second velocity.

52. A method of penetrating tissue comprising:

using a lancet driver to advance a lancet into said tissue;

adjusting the lancet velocity based on stratum corneum hydration.

55. A lancing system configured to drive a lancet during a lancing cycle and used on a tissue site, the system comprising:

a lancet driver;

a processor coupled to said lancet driver, said processor configured to adjust lancet velocity to achieve a desired velocity based on the layer of tissue through which the lancet is cutting.

56. The system of claim further comprising a user interface on said lancet driver allowing a user to adjust penetration depth based on stratum corneum hydration.

57. The system of claim further comprising a user interface on said lancet driver allowing a user to adjust lancet velocity based on user pain.

58. The system of claim further comprising memory for storing at least one of the following to determine a skin profile:

energy consumed per lancing event;

;

time of day.

59. The system of claim wherein:

said processor has logic for using a lancet driver to advance a lancet into said tissue, said lancet having a lancet velocity equal to a first velocity in a first layer of tissue;

adjusting lancet velocity in the skin to achieve a desired velocity based on the layer of tissue through which the lancet is cutting.

60. A lancing system configured to drive a lancet during a lancing cycle and used on a tissue site, the system comprising:

a drive force generator coupled to an energy sensor sufficient for measuring energy used to drive said lancet into the tissue site;

a processor on said lancet driver, said processor calculating lancet velocity and sending signals to said drive force generator to adjust lancet velocity based at least in part on characteristics of tissue being cut by the lancet

61. The system of claim 60 further comprising memory for storing advancing said lancet at a first desired velocity in a first layer of tissue;

advancing said lancet at a second desired velocity in a second layer of tissue; and

advancing said lancet at a third desired velocity in a third layer of tissue.

62. A lancing system configured to drive a lancet during a lancing cycle and used on a tissue site, the system comprising:

a drive force generator;

a controller with logic for controlling the drive force generator to advance a penetrating member along a penetration path into said tissue, said penetrating member having a penetrating member velocity equal to a first velocity in a first layer of tissue;

wherein said controller has logic for determining penetrating member velocity at a plurality of locations along said penetration path; and

wherein said controller has logic for adjusting penetrating member velocity at a plurality of locations along said penetration path prior to the penetrating member coming to a stop in said tissue.

63. A method of driving a lancet into a tissue site, said method comprising:

calculating stratum corneum thickness based on energy consumed and depth of lancet penetration on a previous lancing cycle;

driving the lancet into the tissue site, wherein the lancet does not penetrate more than a desired beyond the stratum corneum thickness, said stratum corneum thickness determined by an inflection point of energy consumption when the lancet exits that layer.

64. The method of claim 63 further comprising:

stopping said lancet at a desired depth without multiple oscillations against tissue in the tissue site, wherein said desired depth is less than a sum of the stratum corneum thickness and a predetermined depth from the stratum corneum.