Method and system for withdrawing blood

Abstract

A system for withdrawing blood from a body part that avoids formation of a drop of blood on the skin surface of the body part after blood removal. The system includes a collecting unit to withdraw blood, a lancing member configured for insertion into the body part and having a capillary to collect blood, and a pressure piece configured to apply pressure to the body part and having an actuator operably connected thereto. The pressure piece is movable relative to a support configured to exert pressure on the body part, and the actuator is configured to reduce the compressive force of the pressure piece after removing an amount of blood, whereby forming a drop of blood on the skin surface of the body part can be avoided.

Claims

1. A system for withdrawing blood from a body part, comprising: a pressure piece configured to apply pressure to a body part and having an actuator operably connected thereto; a lancing member configured for insertion into the body part and including a capillary to collect blood; a support configured to contact the body part; and the pressure piece being movable relative to the support in order to exert pressure on the body part, wherein the actuator is configured to reduce the compressive force of the pressure piece after removing an amount of blood, whereby forming a drop of blood on the skin surface of the body part can be avoided.

2. The system of claim 1, wherein the pressure piece is configured to be moved towards the support against a restoring force of the actuator by pressing the body part against the pressure piece.

3. The system of claim 1, wherein the actuator comprises a pretensioning element that further comprises a spring resting under pretension against the pressure piece.

4. The system of claim 3, wherein the actuator comprises a movable support to relax the pretensioning element.

5. The system of claim 1, wherein the actuator comprises a curve-controlled positioning drive for the movement of the pressure piece.

6. The system of claim 1, wherein the support comprises a positioning surface to which to apply the body part, the positioning surface being provided with an opening for the passage of the pressure piece.

7. The system of claim 1, wherein the pressure piece is formed as a ring and the lancing member is configured to be lanced through an opening in the ring into the body part.

8. The system of claim 1, wherein the pressure piece is formed by at least one bar configured to press down on the body part linearly or by a strut configured to press down on the body part in a punctiform manner.

9. The system of claim 1, wherein the pressure piece is elastically deformable.

10. The system of claim 1, further comprising a signal generator that is activated when a preset position is reached or when the support or the pressure piece is touched or reaches a stop position in order to generate a release signal for the activation of the lancing member.

11. The system of claim 1, comprising a capillary transport channel to transport the blood.

12. A system for withdrawing blood from a body part, comprising: a pressure piece having a surface configured to apply pressure to a body part and having an actuator operably connected thereto; a lancing member configured for insertion into the body part and including a capillary to collect blood; a support configured to contact the body part; and the pressure piece being movable relative to the support in order to exert pressure on the body part, wherein the actuator is configured to reduce the compressive force of the pressure piece after removing an amount of blood, whereby forming a drop of blood on the skin surface of the body part can be avoided.

13. The system of claim 12, wherein the pressure piece is configured to be moved towards the support against a restoring force of the actuator by pressing the body part against the pressure piece.

14. The system of claim 12, wherein the actuator comprises a pretensioning element that further comprises a spring resting under pretension against the pressure piece.

15. The system of claim 12, wherein the support comprises a positioning surface to which to apply the body part, the positioning surface being provided with an opening for the passage of the pressure piece.

16. The system of claim 12, wherein the pressure piece is formed as a ring and the lancing member is configured to be lanced through an opening in the ring into the body part.

17. The system of claim 12, wherein the pressure piece is formed by at least one bar configured to press down on the body part linearly or by a strut configured to press down on the body part in a punctiform manner.

18. The system of claim 12, wherein the pressure piece is elastically deformable.

19. The system of claim 12, further comprising a signal generator that is activated when a preset position is reached or when the support or the pressure piece is touched or reaches a stop position in order to generate a release signal for the activation of the lancing member.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The above-mentioned aspects of the present invention and the manner of obtaining them will become more apparent and the invention will be better understood by reference to the following description of the embodiments of the invention taken in conjunction with the accompanying drawings, wherein:

(2) FIG. 1 is a diagrammatic view of a device for withdrawing and analysing blood;

(3) FIG. 2 is a fragmentary perspective view illustrating the arrangement of a lancing unit, a pressure ring and a positioning surface of the device according to FIG. 1; and

(4) FIGS. 3a to 3h are fragmentary side views showing various positions of the elements shown in FIG. 2 during blood withdrawal.

(5) Corresponding reference numerals indicate corresponding parts throughout the several views.

DESCRIPTION

(6) The embodiments of the present invention described below are not intended to be exhaustive or to limit the invention to the precise forms disclosed in the following detailed description. Rather, the embodiments are chosen and described so that others skilled in the art may appreciate and understand the principles and practices of the present invention.

(7) The device shown in the drawing is designed as a hand-held device 10 for combined blood withdrawal and analysis. It includes an instrument housing 12 with a support 14 for a body part 16 of a user, a pressure ring 20 that can be moved by means of an actuator 18 relative to the support 14. A collecting unit 40 for blood withdrawal is provided with a lancing member 22, and a detection unit 24 for blood analysis is coupled to the collecting unit 40. Instead of a circular ring 20, a pressure piece 21 in the form of a bar configured to press down on the body part linearly or a strut configured to press down on the body part in the punctiform manner can be provided.

(8) The lancing movement of the collecting unit 40 with the lancing member 22 is carried out by a lancing drive 26 in a lancing axis 28 which extends through an opening 32 of the support 14. A processor unit 30 is provided for the process control of the actuator 18 and of the lancing drive 26 as well as to evaluate the measuring results.

(9) The pressure ring 20 can be moved by a linear guide 24 coaxially to the lancing member 22 along the lancing axis 28. During this process, the pressure ring 20 can be pressed back by pressing on the body part 16 against the force of a return spring 36 of the actuator 18 so that, as a reaction, the pressure on the body part increases during blood withdrawal. In order to subsequently enable a pressure reduction during the final phase of blood withdrawal, the actuator has a movable spring support 38 to relax the spring element 36. Alternatively, it is also possible that the actuator 18 includes, e.g., a curve-controlled positioning drive to control the course of movement of the pressure ring 20 (not shown). As a further alternative, it is also possible to provide a force element 23 as shown in FIG. 1 to regulate the compressive force.

(10) The collecting unit 40 has a capillary transport channel 25, also referred to herein as capillary 25, in order to automatically transport the body fluid removed at the collection site to the detection unit 24. This can be formed by an open rim capillary groove in order to simplify the manufacture. In order to detect glucose content in the blood, the detection unit 24 is, for example, aligned onto a suitable test field, for example, a reflection photometric unit. Such measuring systems with disposable test elements for blood sugar self-monitoring for diabetics are well-known.

(11) The basic arrangement for direct blood collection from the body part 16 is illustrated in FIG. 2. Blood is preferably removed from the finger pad 41 which is applied to the facing positioning surface 42 of the support 40 in the area of the opening 32. The pressure ring 20 can be moved through the opening 32 while the lancing member 22 as a capillary-active needle tip can be lanced through the ring opening 44 into the finger pad 41.

(12) FIG. 3 shows the sequence of the individual process steps for blood collection. According to FIGS. 3a and b the pressure piece 20 extended out of the instrument housing is moved towards the support 14 against a resisting force by pressing from the body part 16. Under the increased pressure, the body part 16 is bulged in the area of the finger pad or finger tip 41 so that additional blood accumulates.

(13) When the positioning surface 42 is reached, a release signal is generated by a touch sensor 46 (FIG. 3c), whereupon the user triggers the lancing process. The lancing member 22 is then rapidly inserted to a defined lancing depth (FIG. 3d) and then retracted or pulled back into a collecting position at a smaller lancing depth (FIG. 3e). In this position the lancing member is in the area of the skin (optionally also just above it) while the open puncture channel fills with blood. In this process, the blood flows automatically into the transport channel due to capillary forces (FIG. 3f). In this phase, the counter force exerted by the ring 20 may be modulated or varied in order to control the flow of blood.

(14) After removing a defined amount of blood which can be actively detected or empirically determined on the basis of an allocated withdrawal period, the compressing force of the pressure ring 20 is steadily or gradually reduced in order to prevent blood escaping from the puncture wound, such that no blood is visible on the skin surface. For this purpose the pressure ring 20 is retracted through the opening 32 of the support 14 into a position in the housing that is screened from contact by the body part 16. In this process, the collecting unit 40 is also completely retracted from the area of the body part 16 (FIG. 3g), which ends the blood collection. In the end position shown in FIG. 3h, the pressure ring 20 is positioned inside the housing behind the support 14. The collecting unit 40 is also retracted inside the housing so that the analysis can be carried out. The movement of the pressure ring 20 away from the body part 16 also provides a discernable and tactile signal to the user that the collection process has been completed.

(15) While exemplary embodiments incorporating the principles of the present invention have been disclosed hereinabove, the present invention is not limited to the disclosed embodiments. Instead, this application is intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.