Patent Application
20080195131
The present invention relates generally to medical devices and procedures, and more particularly to lancing devices for sampling blood or other bodily fluids. The invention more particularly relates to an end cap for use in conjunction with a lancing device that allows for the collection of an increased volume of blood or bodily fluid to be sampled.
Many medical procedures require puncturing of the skin, and sometimes underlying tissues, of a human or animal subject. For example, a sharp lancet tip is commonly used to puncture the subject's skin for sampling of blood or other bodyfluid, as for example in blood glucose monitoring by diabetics. Generally, lancet blades or needles are much thinner than traditional hypodermic syringe needles, and therefore result in less pain to the patient. A lancet having a sharp lancing tip typically is mounted, permanently or releasably, to the drive mechanism of a lancing device. The drive mechanism includes one or more springs, cams, motors, or other mechanism(s) for moving the lancing tip from a retracted position shielded within a housing of the lancing device to an extended position outside of the housing for lancing the subjects skin. The lancing device may also include a cocking mechanism for arming the drive mechanism, and/or a triggering mechanism for firing the device. The housing of the lancing device typically includes an endcap with an opening through which the lancing tip extends in its extended position. The endcap may be releasably or permanently attached to the remainder of the housing, or can comprise an integral part of the housing.
One common problem that has been found to exist with many known lancets and lancing devices is the closure of the puncture site before an adequate volume of blood has been collected. Premature closure of the puncture requires additional blood to be drawn from the patient, often in a separate and sometimes less desirable location, resulting in an increase in pain and stress to the subject. Costs also increase, as multiple lancets are required to acquire an adequate sample. This is particularly the case when alternate lancing sites other than the fingertips, such as for example the forearm or earlobe, are lanced. Lancing at such alternate lancing sites may be desirable because repeated lancing of the fingertips can result in callous formation, leading to less consistent sampling and decreased sensitivity of the fingertips. In addition, the fingertips have a greater density of nerve endings than alternate lancing sites, resulting in greater pain sensation from fingertip lancing than lancing at alternate sites. To increase patient compliance with a prescribed sampling regimen, it is desirable to minimize pain resulting from the lancing operation. However, because alternate sites typically contain a lower density of capillaries or a deeper capillary bed than the fingertips, alternate lancing sites often yield insufficient sample sizes or are prone to premature closure.
Attempts have been made to provide lancing devices that inhibit premature closure of the puncture site and yield increased sample size. Such attempts have included the use of a stimulator member slideably mounted to the housing for cyclically pumping around the puncture site to “milk” the wound. Although utilizing the aforementioned pumping sequence may allow a larger sample to be collected before closure of the puncture site, occasionally a sample is still insufficient, and another lancing operation to collect blood or analytic fluid is required. Additionally, the repeated application and release of pressure from such pumping can result in contact between the sample and the lancing device, smearing and/or contaminating the sample and necessitating another lancing operation, and/or can lead to bruising of the tissue surrounding the lancing site. Also, the provision of a translationally mounted stimulator member results in increased complexity and cost of the lancing device.
Thus it can be seen that needs exist for improved lancing devices and methods to facilitate increased sample volume of blood or other analytic fluid, and to prevent premature closure of the sampling site. Needs further exist for such mechanisms and methods that are readily adaptable to current lancing devices and procedures, and which can be utilized for lancing at fingertip as well as alternate sample collection sites.
In example forms, the present invention is an endcap for a lancing device that enables collection of an increased volume of blood or other body fluid to be sampled from a lancing site of a human or animal subject. The device of the present invention is suitable for use at fingertip lancing sites, but is also well suited for use at alternate lancing sites such as the forearm and/or earlobe. In further embodiments, the invention is a sampling method for increasing collected sample size of blood or other body fluid from a lancing site.
In one aspect, the present invention is an endcap for a lancing device. The endcap preferably includes an opening for passage of at least a sharp tip portion of a lancet, a contact face surrounding the opening, and at least one surface feature on the contact face adjacent the opening for applying pressure to tissue surrounding a lancing site by rocking of the contact face in contact with the tissue surrounding the lancing site.
In another aspect, the invention is an endcap for a lancing device, the endcap preferably including an outwardly-curved contact face for rocking contact with tissue surrounding a lancing site, and at least one slotted opening through the outwardly-curved contact face, the slotted opening being narrower at a central portion than at extremities thereof.
In another aspect, the invention is a lancing device for collecting a sample of body fluid from a sampling site on the skin of a subject. The lancing device preferably includes a lancet and a housing comprising an endcap, the lancet being movable between a first position within the housing and a second position wherein at least a sharp tip portion of the lancet extends through an opening in the endcap. The endcap preferably includes a contact face surrounding the opening and at least one surface feature on the contact face adjacent the opening for applying pressure to tissue surrounding the sampling site by rocking of the contact face in contact therewith.
In still another aspect, the invention is a lancing device for collecting a sample of body fluid from a sampling site on the skin of a subject. The lancing device preferably includes a lancet and a housing comprising an endcap, the lancet being movable between a first position within the housing and a second position wherein at least a sharp tip portion of the lancet extends through an opening in the endcap. The endcap preferably includes an outwardly-curved contact face for rocking contact with tissue surrounding the sampling site, and at least one slotted opening through the outwardly-curved contact face.
In still another aspect, the invention is a method of collecting a sample of blood or other body fluid, the method preferably including the steps of lancing the skin of a subject at a lancing site with a lancing device having a contact face including one or more surface contour features surrounding an opening; and rocking the lancing device with the contact face in contact with the skin surrounding the lancing site.
These and other aspects, features and advantages of the invention will be understood with reference to the drawing figures and detailed description herein, and will be realized by means of the various elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following brief description of the drawings and detailed description of the invention are exemplary and explanatory of preferred embodiments of the invention, and are not restrictive of the invention, as claimed.
a and 2b show a perspective view and a side view, respectively, of an endcap for a lancing device according to another example embodiment of the present invention.
a and 3B show a perspective view and a side view, respectively, of an endcap for a lancing device according to yet another example embodiment of the present invention.
The present invention may be understood more readily by reference to the following detailed description of the invention taken in connection with the accompanying drawing figures, which form a part of this disclosure. It is to be understood that this invention is not limited to the specific devices, methods, conditions or parameters described and/or shown herein, and that the terminology used herein is for the purpose of describing particular embodiments by way of example only and is not intended to be limiting of the claimed invention. Also, as used in the specification including the appended claims, the singular forms “a,” “an,” and “the” include the plural, and reference to a particular numerical value includes at least that particular value, unless the context clearly dictates otherwise. Ranges may be expressed herein as from “about” or “approximately” one particular value and/or to “about” or “approximately” another particular value. When such a range is expressed, another embodiment includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another embodiment.
With reference now to the drawing figures,
In a preferred method of operation according to the present invention, after firing the lancing device, the user leaves the contact face of the endcap in contact with the skin around the lancing site, and rocks the lancing device, preferably in the plane of the slotted opening and raised rim. The outwardly curved or convex curvature of the contact face facilitates and guides this rocking motion. The device is preferably initially placed with its contact face in contact with the skin at the lancing site and held generally perpendicular to the skin surface during lancing, and then is rocked back and forth in contact with the skin in at least one plane of motion, wherein that plane of motion intersects a lengthwise axis of the overall lancing device and the center of the endcap's lancet opening. The endcap's lancet opening and/or the raised surface feature(s) on the endcap's contact face are preferably generally symmetric along either side of this plane of motion, and the endcap's contact face is curved along this plane of motion, whereby rocking of the lancing device in the plane of motion applies pressure symmetrically about the lancing site. For example, when the endcap embodiment of
a and 2b show an endcap 30 for a lancing device according to another embodiment of the present invention. The contact face 32 of this endcap defines a generally circular central opening 34 for allowing passage of the sharp lancet tip. Contact ribs 36 are preferably provided, extending across the contact face 32 along either side of the opening 34. The distal faces of the contact ribs 36 are preferably convexly curved to facilitate and guide rocking of the lancing device in contact with the skin in a similar fashion to that described above. The inner edges of the contact ribs 36 are preferably curved or angled to define a central channel 38 that is wider at its center, around the opening 34, than at its outer edges along the periphery of the endcap. The contours of the contact face 32 and the contact ribs 36 preferably direct subcutaneous fluid toward the puncture site and help prevent premature closure of the puncture site, as the device is rocked back and forth, preferably in a plane of motion extending through the center of the opening and central channel, thereby enhancing collection of increased volume of blood or other body fluid to be sampled.
a and 3b show an endcap 50 for a lancing device according to yet another embodiment of the present invention. The contact face 52 of this endcap defines a generally circular central opening 54 for passing the sharp lancet tip. The contact face 52 preferably comprises a plurality of alternating raised lobes 56 and depressions 58, forming a continuous, undulating or wave-like surface surrounding the opening 54. After firing, the user toggles, rocks and/or twists the lancing device with the contact face 52 in contact with the skin around the lancing site. The undulating contour of the contact face generates alternating tension and compression of the skin surrounding the lancing site, directing subcutaneous fluid toward the lancing site and helping prevent premature closure of the lancing site, thereby enhancing sample collection.
While the invention has been described with reference to preferred and example embodiments, it will be understood by those skilled in the art that a variety of modifications, additions and deletions are within the scope of the invention, as defined by the following claims.
This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/503,786, filed Sep. 18, 2003, the entirety of which is hereby incorporated herein by reference for all purposes.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/US04/24407 | 7/28/2004 | WO | 00 | 7/24/2007 |
