# Patent

## Title
Device for channeling fluid and methods of use

## Abstract

Method and apparatus for channeling fluid away from an insertion site having a channel guiding the fluid flow from the insertion site, and a channeling compartment containing absorbent material to wick the fluid such as blood away from the insertion site is provided.

## Background
BACKGROUND
Glucose monitoring systems generally include a sensor such as an analyte sensor for detecting analyte levels such as glucose levels, a transmitter (such as an RF transmitter) in communication with the sensor and configured to receive the sensor signals and to transmit them to a corresponding receiver unit by for example, using RF data transmission protocol. At least a portion of the sensor is inserted through the skin of the patient so as to be in fluid contact with the patient's analyte. The receiver may be operatively coupled to a glucose monitor that performs glucose related calculations and data analysis.
The transmitter may be mounted or adhered to the skin of a patient and also in signal communication with the sensor, at least a portion of which may be inserted in the patient. Generally, the sensor is configured to detect and measure the glucose levels of the patient over a predetermined period of time, and the transmitter is configured to transmit the signals related to the analyte (e.g., current signal) over the predetermined period of time for further analysis. To initially set up the sensor so that the sensor contacts and electrodes are in fluid contact with the patient's analyte fluids, it is important to properly insert the sensor through the patient's skin and securely retain the sensor during the time that the sensor is configured to detect analyte levels.
When the sensor is pierced through the skin of the patient with, for example, an introducer to properly position the sensor to be in fluid contact with the patient, the sensor insertion site on the patient's skin will typically bleed. The amount of blood that would be drawn as a result of the sensor insertion using the sharp introducer depends at least upon the insertion site. For example, if the insertion site of the sensor is near capillary vessels or other blood vessels, it is likely that more blood will be drawn out of the insertion site at the time of the sensor insertion process. On the other hand, if the sensor insertion site is located in an area of the patient's skin that has less capillary vessels or other blood vessels, it is likely that less blood will result in response to the piercing process of the skin with the sensor introducer.
Given that the analyte sensor location will be positioned at the insertion site, and the likelihood of blood pooling at the insertion site due to the disturbance of the tissues and the blood vessels by the sharp introducer, it is important to ensure that the drawn-out blood does not have significant impact upon the sensor functions including the sensor signals generated by the sensor (for example, using the various electrodes of an electrochemical analyte sensor), so that the detected signals accurately reflect the patient's analyte level.
In view of the foregoing, it would be desirable to have a method and apparatus which would allow for minimizing the amount of blood pooling at or near the insertion site of the analyte sensor. It would also be desirable to have a device or method to draw the blood away from the insertion site of the skin so that it may help facilitate the healing process of the skin wound resulting from the piercing of the skin with the sharp introducer.
SUMMARY OF THE INVENTION
Embodiments of the subject invention include devices that retain biological fluid at a location distanced from a skin opening, e.g., draw and keep the fluid away from the site. The devices may include a substrate having one or more fluid-retaining compartments and/or absorbent material, e.g., positioned within the one or more compartments or otherwise. A substrate may be configured to hold an analyte sensor transmitter and/or infusion set cannula in a fixed position on a skin surface.
In one embodiment, a method and apparatus for channeling fluid away from an insertion site having a channel guiding the fluid flow from the insertion site, and a channeling compartment containing absorbent or absorption material to wick the fluid such as blood away from the insertion site is provided.
More particularly, in accordance with embodiments of the present invention, there is provided a device and method for effectively wicking or drawing blood or other fluid away from the sensor insertion site to minimize the potential interference in the sensor-transmitter connection and thus, providing accurate data associated with the sensor signals, and also, to minimize blood or fluid pooling at or near the sensor insertion site to provide faster wound healing time and less likelihood of blood clots, for example.
In addition, within the scope of the present invention, insertion sets of infusion devices such as insulin pumps, may be provided with similar channeling compartments provided with absorbent material to wick the blood or other fluids away from the insertion site of the patient.



BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates a perspective view of the fluid channeling device for use in an analyte monitoring system in accordance with one embodiment of the present invention;
FIGS. 2A-2B illustrate a frontal view along the directional arrow A of FIG. 1 of the fluid channeling device in accordance with respective alternate embodiments of the present invention;
FIG. 3 is a side view of the fluid channeling device in accordance with one embodiment of the present invention;
FIG. 4 is a bottom view of the fluid channeling device in accordance with one embodiment of the present invention; and
FIG. 5 is a side view of the fluid channeling device after the insertion of the sensor at the insertion site in accordance with one embodiment of the present invention.



DETAILED DESCRIPTION
FIG. 1 illustrates a perspective view of the fluid channeling device for use in an analyte monitoring system in accordance with one embodiment of the present invention. Referring to the Figure, there is provided a transmitter mount unit 100 including a first or base section 101 and a second or upper section 102 which in this embodiment extends substantially transversely to the first section, but which may be otherwise in other embodiments. The transmitter mount unit 100 is configured to operatively couple with a transmitter (not shown). More specifically, during or after the insertion of a sensor, the transmitter is configured to couple to the sensor at the base section 101 of the transmitter mount unit 100 such that the transmitter and the sensor are in electrical communication with each other.
As shown in FIG. 1, the transmitter mount unit 100 includes a hollow cavity 104 substantially positioned where the base section 101 and the upper section 102 meet. As will be discussed in further detail below, a sensor introducer is operatively coupled with the transmitter mount unit 100 substantially at the hollow cavity 104 so as to pierce the skin of the patient through the hollow cavity 104 using, for example, a sharp sensor introducer (not shown). Thus, after the sensor insertion process, at least a portion of the sensor is positioned under the skin layer of the patient, while the remaining portion of the sensor is positioned through the hollow cavity 104 of the transmitter mount unit 100.
Referring again to FIG. 1, also shown is a channel 103 provided substantially towards the lower section of the upper section 102 of the transmitter mount unit 100 such that the hollow cavity 104 on the base section 101 of the transmitter mount unit 100 and the channel 103 are substantially collocated and in fluid connection. In other words, it can be seen from FIG. 1 that a frontal side 105 of the upper section 102 includes thereon the channel 103 so that the channel 103 is also contiguous with the hollow cavity 104 of the base section 101 of the transmitter mount unit 100. In this manner, in one embodiment of the present invention, the blood or other fluid drawn onto the surface of the skin as a result of the skin piercing with the sensor introducer is channeled or guided into the channel 103 of the upper section 102 of the transmitter mount unit 100. As such, there is less blood or fluid remaining at the skin surface around the hollow cavity 104 area where the sensor is configured to maintain electrical communication with the transmitter.
While glucose is described as examples of analytes that is detected by the sensor in the monitoring system, within the scope of the present invention, additional analytes that may be monitored or detected include, for example, acetyl choline, amylase, bilirubin, cholesterol, chorionic gonadotropin, creatine kinase (e.g., CK-MB), creatine, DNA, fructosamine, glucose, glutamine, growth hormones, hormones, ketones, lactate, peroxide, prostate-specific antigen, prothrombin, RNA, thyroid stimulating hormone, and troponin. The concentration of drugs, such as, for example, antibiotics (e.g., gentamicin, vancomycin, and the like), digitoxin, digoxin, drugs of abuse, theophylline, and warfarin, may also be monitored.
FIGS. 2A-2B illustrate a frontal view along the directional arrow A of FIG. 1 of the fluid channeling device in accordance with respective alternate embodiments of the present invention. Referring to FIG. 2A, the upper section 102 of the transmitter mount unit 100 includes a plurality of channeling compartments 201, each of which is in fluid connection with the channel 103. Each compartment may have its own channel or two or more may share a common channel. More specifically, the upper section 102 of the transmitter mount unit 100 in one embodiment of the present invention includes five discrete channeling compartments 201, each of which is configured to house or contain an absorbent material. In this manner, when blood or other fluid is channeled into the channel 103 of the transmitter mount unit 100, the absorbent material contained within the channeling compartments 201 draw the blood or fluid therein and thus away from the sensor insertion site on the skin of the patient.
Within the scope of the present invention, the transmitter mount unit 100 may be configured with more or less than five channeling compartments 201. Indeed, the transmitter mount unit 100 may comprise of a single channeling compartment 201 provided with the absorbent material. Some considerations regarding the number of the channeling compartments 201 include, but are not limited to, the ease and/or cost of manufacturing as well as design considerations.
Referring now to FIG. 2B, in contrast to the embodiment shown in FIG. 2A, there is provided one substantially larger channeling compartment 202 which is configured to be in fluid contact with the channel 103 of the transmitter mount unit 100. As shown in FIG. 2B, the channeling compartment 202 is configured to house or retain the absorbent material similar to the embodiment shown in FIG. 2A such that the blood or other fluid that is channeled into the channel 103 will be drawn into the channeling compartment 202 by the absorbent material when in fluid contact with the blood or other types of fluid.
FIGS. 3 and 4 are side and bottom views respectively, of the fluid channeling device in accordance with one embodiment of the present invention. Referring to FIGS. 3-4, it can be seen that the inner space of the channeling compartment 201 (FIG. 2A), 202 (FIG. 2B) may be loosely filled with absorbent material 301 so that there is sufficient space to hold the biological fluid, (blood, interstitial fluid, or the like) and to facilitate the wicking process (or drawing the fluid into the inner space of the channeling compartment 201 (FIG. 2A), 202 (FIG. 2B). Within the scope of the present invention, the absorbent material 301 may be placed within the channel compartment 201, 202 so as to not completely fill the compartments 201, 202. Such configuration may be desirable when it is anticipated that the expected amount of blood or other fluids is relatively less, and further, to reduce the cost of manufacture. Moreover, by not completely filling the compartments 201, 202 with the absorbent material 301, there is provided sufficient room to absorb blood or other fluid at or around the insertion site.
FIG. 5 is a side view of the fluid channeling device after the insertion of the sensor at the insertion site in accordance with one embodiment of the present invention. Referring to FIG. 5, it can be seen that the introducer 501, which contains at least a portion of the sensor 502 in a pre-deployed state within the sharp needle portion of the introducer, upon withdrawal from the insertion site 504 of the skin, draws blood or other fluids through the insertion site 504 onto the skin of the patient. FIG. 5 further illustrates the deployed and subcutaneously (or otherwise) placed portion of the sensor 502 in the patient at the insertion site 504.
Referring to FIG. 5, the absorbent material 301 is thus contacted with the blood or other fluids 503 that are drawn onto the surface of the patient's skin at the insertion site 504, and draws in the blood or other fluids 503 into the channeling compartment 202 so as to displace the blood or other fluids away from the insertion site 504.
It has been observed that patients typically bleed less than 10 μL of blood during the sensor insertion process. As such, the channeling compartments 201, 202 as shown above in accordance with various embodiments of the present invention having absorbent material contained therein, effectively draws or wicks the blood away from the insertion site, thus minimizing potential interference with the sensor functionality and the sensor communication or electrical contacts with the transmitter. The absorbent material may be able to absorb some or all of the biological fluid at the sensor insertion site, e.g., may be configured to absorb as much as about 10 μL (or more in certain embodiments) of fluid.
In accordance with the various embodiments of the present invention, the absorbent material 301 may include sponge like material, super absorbent materials such as polyacylites, for example, and any other suitable absorbent material such as, but not limited to, polyester, nylon, cellulose, and cellulose derivatives such as nitrocellulose. The absorbent material may include an anti-bacterial agent and/or anti-fungal agent. In certain embodiments, the transmitter mount may be maintained in position on the skin of a subject for one or more days, e.g., one or more weeks, even one or more months in certain instances. The inclusion of an agent may be useful to retard or inhibit the growth of harmful organisms that may be the source of infection, especially in the event the transmitter is used for a prolonged period of time.
In the manner described above, in accordance with the various embodiments of the present invention, there is provided devices and methods for effectively wicking or drawing blood, interstitial fluid or other fluid away from the sensor insertion site to minimize the potential interference in the sensor-transmitter connection and thus, providing accurate data associated with the sensor signals, and also, to minimize blood or fluid pooling at or near the sensor insertion site to potentially provide faster wound healing time and less likelihood of blood clots, for example. In addition, users or patients will likely prefer to draw blood or other fluid away from the sensor insertion site so as to have a clean or biological fluid-free area substantially surrounding the sensor insertion site on their skin.
In addition, within the scope of the present invention, insertion sets of infusion devices such as insulin pumps, may be provided with similar channeling compartments provided with absorbent material to wick the blood or other fluids away from the insertion site of the patient.
Indeed, in accordance with one embodiment of the present invention, there is provided an apparatus including a housing having a base portion and a side portion, the side portion including at least one compartment, the base portion including an opening positioned to substantially surround an insertion site on the skin of a patient, the compartment configured to draw a fluid substantially from around the insertion site.
The apparatus further includes in one embodiment an absorbent material positioned substantially within the compartment, where the absorbent material draws the fluid from away the insertion site.
In one aspect of the present invention, the absorbent material includes one or more of polyester, nylon, cellulose, cellulose derivative, nitrocellulose, an anti-bacterial agent or anti-fungal agent.
Further, the absorbent material may be in fluid contact with the fluid substantially surrounding the insertion site, so as to draw the fluid away from the insertion site.
Moreover, in a further embodiment, a portion of a sensor is provided under the skin of the patient at the insertion site, where the insertion site substantially corresponds to the transcutaneous position of the sensor on the skin.
The sensor in one embodiment is an electrochemical sensor, and in particular, a glucose sensor.
Moreover, at least the portion of the sensor may be in fluid contact with biological fluid of the patient.
In one embodiment, a transcutaneously positioned cannula of an infusion device may be provided, where the insertion site of the cannula substantially corresponds to the transcutaneous position of the sensor on the skin. In an alternate embodiment, the infusion device may be wholly implantable.
The infusion device in one embodiment includes an insulin pump. An apparatus in a further embodiment of the present invention includes a housing comprising a compartment, the housing including an opening positioned to substantially surround an insertion site on the skin of a patient, an absorbent material provided substantially within the compartment.
Moreover, the apparatus may further include a sensor with at least a portion of the sensor provided under the skin of the patient, the insertion site substantially corresponding to a transcutaneous location of the sensor on the skin.
A method in a further embodiment of the present invention includes the steps of positioning at least a portion of an analyte sensor, a cannula, or both an analyte sensor and a cannula, at an insertion site on the skin of a patient, and drawing a fluid substantially away from the insertion site of the patient.
The method in one embodiment may further include the step of contacting an absorbent material with the fluid to draw the fluid substantially away from the insertion site.
The fluid may be one or more of an interstitial fluid or blood.
An apparatus in still a further embodiment includes an analyte sensor, and a substrate for retaining a transmitter in electrical contact with the analyte sensor, the substrate comprising at least one compartment for retaining biological fluid.
The at least one compartment comprises absorbent material, and further, where the at least one compartment comprises an agent to at least inhibit growth of harmful organisms.
In a further embodiment, the substrate may comprise a first section and a second section, the second section further including the at least one compartment, where the second section may be substantially transverse to the first section.
Further, the substrate may be attachable to the skin of a subject in still another embodiment.
A system in accordance with yet still another embodiment includes a housing comprising a compartment, the housing including an opening positioned to substantially surround an insertion site on the skin of a patient, an absorbent material provided substantially within the compartment, a sensor substantially located at the insertion site, and a transmitter unit coupled to the housing, and electrically coupled to the sensor.
An insertion kit in accordance with yet still a further embodiment includes a housing comprising a compartment, the housing including an opening positioned to substantially surround an insertion site on the skin of a patient, an absorbent material provided substantially within the compartment, a sensor, and an introducer coupled to the sensor configured to place the sensor at the insertion site on the skin of the patient so that at least a portion of the sensor is placed under the patient's skin.
Various other modifications and alterations in the structure and method of operation of this invention will be apparent to those skilled in the art without departing from the scope and spirit of the invention. Although the invention has been described in connection with specific preferred embodiments, it should be understood that the invention as claimed should not be unduly limited to such specific embodiments. It is intended that the following claims define the scope of the present invention and that structures and methods within the scope of these claims and their equivalents be covered thereby.

## Claims

1. An apparatus, comprising:
a housing comprising at least one compartment, and including an opening positioned to substantially surround an insertion site on a skin surface and to accommodate a sensor coupled to a sensor introducer for inserting the sensor under the skin surface, wherein at least a portion of the sensor is adapted to be placed under the skin surface at the insertion site, the at least one compartment configured to draw a fluid substantially from around the insertion site and away from the sensor after the introducer has inserted at least the portion of the sensor under the skin surface and the introducer has been removed from the insertion site.

2. The apparatus of claim 1, further including an absorbent material positioned substantially within the at least one compartment.

3. The apparatus of claim 2, wherein the absorbent material draws the fluid away from the insertion site and away from the sensor.

4. The apparatus of claim 2, wherein the absorbent material includes one or more of polyester, nylon, cellulose, cellulose derivative, nitrocellulose, an anti-bacterial agent, or an anti-fungal agent.

5. The apparatus of claim 2, wherein the absorbent material is in fluid contact with the fluid substantially surrounding the insertion site, so as to draw the fluid away from the insertion site and away from the sensor.

6. The apparatus of claim 1, wherein the sensor is an electrochemical sensor.

7. The apparatus of claim 1, wherein the sensor is a glucose sensor.

8. The apparatus of claim 1, wherein the at least a portion of the sensor is in fluid contact with biological fluid under the skin surface.

9. The apparatus of claim 1, further including a cannula of an infusion device provided at a cannula insertion site, the insertion site of the cannula substantially corresponding to the insertion site of the sensor on the skin surface.

10. The apparatus of claim 9, wherein the infusion device includes an insulin pump.

11. The apparatus of claim 1, wherein the housing comprises a plurality of compartments.

12. The apparatus of claim 1, wherein the at least one compartment is positioned laterally from the opening and the insertion site.

13. A system, comprising:
a housing comprising a compartment, the housing adapted to be maintained in position on a skin surface for one or more days and including an opening positioned to substantially surround an insertion site on the skin surface;
a sensor with at least a portion of the sensor adapted to be placed under the skin surface, the insertion site substantially corresponding to a transcutaneous location of the sensor on the skin surface; and
an absorbent material provided substantially within the compartment and configured to draw fluid away from the sensor, across the opening and into the housing.

14. The system of claim 13, wherein the absorbent material includes one of polyester, nylon, cellulose, cellulose derivative, nitrocellulose, an anti-bacterial agent, or an anti-fungal agent.

15. The system of claim 13, wherein the sensor includes an electrochemical sensor, and a first end of the sensor is adapted to be placed in fluid contact with an interstitial fluid under the skin surface.

16. The system of claim 13, further including a cannula of an infusion device provided at a cannula insertion site, the cannula insertion site substantially corresponding to the insertion site of the sensor on the skin surface.

17. The system of claim 13, wherein the housing comprises a lower section configured for positioning on the skin surface and an upper section extending substantially transverse to and laterally from the lower section.

18. The system of claim 17, wherein the opening is located within the lower section and the compartment is located within the upper section.

19. A method, comprising:
positioning a housing including a compartment on a skin surface, the housing adapted to be maintained on the skin surface for one or more days, wherein the housing further includes an opening positioned to substantially surround an insertion site on the skin surface;
positioning at least a portion of an analyte sensor, a cannula or both an analyte sensor and a cannula under the skin surface at the insertion site;
removing one or more introducers used for positioning the portion of the analyte sensor, the cannula or both the analyte sensor and the cannula under the skin surface from the insertion site; and
drawing a fluid substantially away from the sensor and from the insertion site of the patient skin surface using an absorbent material provided substantially within the compartment of the housing to a location inside the housing after the removal of the one or more introducers from the insertion site.

20. The method of claim 19, further including contacting the absorbent material with the fluid to draw the fluid substantially away from the insertion site.

21. The method of claim 19, wherein the absorbent material includes one or more of polyester, nylon, cellulose, cellulose derivative, nitrocellulose, an anti-bacterial agent, or an anti-fungal agent.

22. The method of claim 19, wherein the fluid is one or more of interstitial fluid or blood.

23. The method of claim 19, wherein the location inside the housing is laterally positioned with respect to the insertion site.

24. The method of claim 19, wherein the housing comprises a base portion configured for positioning on the skin surface and a lateral portion extending substantially transverse to and at a side edge of the base portion.

25. An apparatus, comprising:
an analyte sensor;
a base for retaining a transmitter in electrical contact with the analyte sensor when at least a portion of the analyte sensor is placed under a skin surface and a sensor introducer is removed from the skin surface, the base positionable entirely above the skin surface; and
at least one compartment for retaining biological fluid away from the analyte sensor, the at least one compartment positioned at a periphery of the base.

26. The apparatus of claim 25, wherein the at least one compartment comprises an absorbent material.

27. The apparatus of claim 25, wherein the at least one compartment comprises an agent to at least inhibit growth of harmful organisms.

28. The apparatus of claim 25, wherein the base includes a first section and a second section, the second section including the at least one compartment, and further, wherein the second section is substantially transverse to the first section.

29. The apparatus of claim 25, wherein the base is attachable to the skin surface.

30. A system, comprising:
a housing wholly positionable on a skin surface, the housing comprising an opening positioned to substantially surround an insertion site on the skin surface and comprising at least one fluid channel entirely within the housing;
a sensor substantially located at the insertion site, wherein the at least one channel is configured to wick fluid away from the sensor;
an introducer coupled to the sensor configured to place the sensor at the insertion site so that at least a portion of the sensor is placed under the skin surface upon removal of the introducer from the insertion site; and
a transmitter unit coupled to the housing and electrically coupled to the sensor.

31. The system of claim 30, wherein the at least one channel comprises a notch in the housing.

32. The system of claim 30, wherein the at least one channel is in fluid communication with at least one fluid compartment within the housing.

33. The system of claim 32, wherein the housing comprises a base portion configured for positioning on the skin surface and a lateral portion extending substantially transverse to and at a side edge of the base portion.

34. The system of claim 33, wherein the at least one channel and the at least one compartment are located within the lateral portion of the housing.