US20060155316A1 - Methods and apparatus for expressing body fluid from an incision - Google Patents

Abstract

A sample of a body fluid such as blood or interstitial fluid is obtained from a body by lancing a portion of a user's skin, preferably in an area other than a finger tip, to form an incision. After the needle has been removed from the incision, a force is applied to depress the skin in a manner forming a ring of depressed body tissue in surrounding relationship to the incision, causing the incision to bulge and the sides of the incision to open, whereby body fluid is forced out through the opening of the incision. A stimulator member is mounted to an end of a lancet-carrying housing for applying the force. The stimulator member can be movable relative to the housing, and can be either heated or vibrated to promote movement of the body fluid.

Description

PRIOR APPLICATIONS
• The present application is a divisional of U.S. patent application Ser. No. 10/764,261 filed Jan. 23, 2004, which is a continuation of U.S. patent application Ser. No. 09/879,991 filed Jun. 14, 2001, now U.S. Pat. No. 6,706,000, which is a continuation-in-part of U.S. patent application Ser. No. 09/542,040 filed Mar. 31, 2000, now U.S. Pat. No. 6,464,649, which is a continuation of U.S. patent application Ser. No. 09/285,021 filed Apr. 1, 1999, now U.S. Pat. No. 6,066,103, which is a continuation of U.S. patent application Ser. No. 08/975,978 filed Nov. 21, 1997, now U.S. Pat. No. 5,964,718. The above-identified patent applications and patents are hereby incorporated by reference in their entirety.
FIELD OF THE INVENTION
• This invention relates to a body fluid testing device and methods for obtaining samples of blood fluid for analysis.
BACKGROUND OF THE INVENTION
• Many medical procedures in use today require a relatively small sample of body fluid, for example in the range of 0.1-50 micro liters. It is more cost effective and less traumatic to the patient to obtain such a sample by lancing or piercing the skin at a selected location, such as the finger or forearm, to enable the collection body fluid. With the advent of home use tests for the self monitoring of blood glucose, there is a requirement for a simple procedure which can be performed in any setting without a person needing the assistance of a professional.
• One device which is commonly utilized to form an opening in the patient's skin is a lancets. Lancets generally have a rigid body and a sterile lance which protrudes from one end. The lancet may be used to pierce the skin, thereby enabling the collection of a body fluid sample from the opening created. The body fluid sample is transferred to a test device or collection device. Body fluid is most commonly taken from the fingertips, where the supply is generally excellent. However, the nerve density in this region causes significant pain in many patient's. Sampling of alternative sites, such as earlobes and limbs is sometimes practiced to lessen the pain. These sites are also less likely to provide excellent body fluid samples and make body fluid transfer directly to test devices difficult. Examples of body fluids which may be utilized to test for glucose are blood and interstitial fluid.
• Repeated lancing in limited surface areas, such as fingertips, results in callous formation. This leads to increased difficulty in drawing body fluid and increased pain.
• To reduce the anxiety of piercing the skin and the associated pain, many spring loaded devices have been developed wherein the device automatically triggers in response to an applied force. Thus the user cannot anticipate the exact timing of the piercing, thus they are less likely to pull the device away during use. The following two patents are representative of the devices which were developed in the 1980's for use with home diagnostic test products.
• U.S. Pat. No. 4,503,856, Cornell et al., describes a spring loaded lancet injector. The reusable device interfaces with a disposable lancet. The lancet holder may be latched in a retracted position. When the user contacts a release, a spring causes the lancet to pierce the skin at high speed and the retract. The speed is important to reduce the pain associated with the puncture.
• Levin et al., U.S. Pat. No. 4,517,978 describes a blood sampling instrument. This device, which is also spring loaded, uses a standard disposable lancet. The design enables easy and accurate positioning against a fingertip so the impact site can be readily determined. After the lancet pierces the skin, a bounce back spring retracts the lancet to a safe position within the device.
• In home settings it is often desirable to collect a body fluid sample in order to enable a user to perform a test at home, such as glucose monitoring. Some blood glucose monitoring systems, require that the blood sample be applied to a test device which is in contact with the test instrument. In such situations, bringing the finger to the test device poses some risk of contamination of the sample with a previous sample that may not have been properly cleaned from the device. Glucose monitoring devices may utilize a blood sample in many ways, though the two most common methods for collection are a paper strip and a capillary tube. Monitors that utilize a paper strip, require the patient to pierce a finger or appropriate location, withdraw a small sample of blood from the pierced area, such as by squeezing, and then placing the paper strip in physical contact with the blood sample and waiting until the paper strip absorbs the blood. Monitors that utilize a capillary tube for fluid collection, require the patient to follow the process described above, except that a paper strip is not utilized, instead a small capillary tube is placed over the sample until a sufficient amount of blood is withdrawn into the capillary tube and to the glucose testing area of the testing device.
• Many times due to dexterity problems or poor eye site it can be difficult for the patient to either bring the body fluid sample to the testing area or to bring a capillary tube to the fluid sample. Additionally, some patient's have a fear of bodily fluids, such as blood, and would prefer not to see this type of body fluid.
• Amira Medical Inc. introduced a new method for home glucose testing. Amira's device AtLast 7, tests blood glucose levels by taking blood from the skin of the forearm, which is a much less sensitive than the fingertips. This device has been very well received by both the diabetic community as well as the blood glucose measurement industry.
• Haynes U.S. Pat. No. 4,920,977 describes a blood collection assembly with a lancet and micro-collection tube. This device incorporates a lancet and collection container in a single device. The lancing and collection are two separate activities, but the device is a convenient single disposable unit for situations when sample collection prior to use is desirable. Similar devices are disclosed in Sarrine U.S. Pat. No. 4,360,016 and O'Brian U.S. Pat. No. 4,924,879.
• Jordan et al., U.S. Pat. No. 4,850,973 and U.S. Pat. No. 4,858,607 disclose a combination device which may be alternatively used as a syringe-type injection device and a lancing device with disposable solid needle lancet, depending on configuration.
• Lange et al., U.S. Pat. No. 5,318,584 describes a blood lancet device for withdrawing blood for diagnostic purposes. This invention uses a rotary/sliding transmission system to reduce the pain of lancing. The puncture depth is easily and precisely adjustable by the user.
• Suzuki et al., U.S. Pat. No. 5,368,047, Dombrowski U.S. Pat. No. 4,654,513 and Ishibashi et al., U.S. Pat. No. 5,320,607 each describe suction-type blood samplers. These devices develop suction between the lancing site and the end of the device with the lancet holding mechanism withdraws after piercing the skin. A flexible gasket around the end of the device helps seal the end around the puncture site until adequate sample is withdrawn from the puncture sire or the user pulls the device back.
• Garcia et al., U.S. Pat. No. 4,637,403 discloses a combination lancing and blood collection device which uses a capillary action passage to conduct body fluid to a separate test strip in the form of a micro porous membrane. It is necessary to achieve a precise positioning of the upper end of the capillary passage with respect o the membrane in order to ensure that the body fluid from the passage is transferred to the membrane. If an appreciable gap exits therebetween, no transfer may occur.
• It is difficult for a user to determine whether a sufficiently large drop of body fluid has been developed at the incision for providing a large enough sample.
• Single use devices have also been developed for single use tests, i.e. home cholesterol testing, and for institutional use to eliminate the cross-patient contamination multi-patient use. Crosman et al., U.S. Pat. No. 4,869,249, and Swierczek U.S. Pat. No. 5,402,798, also describe disposable, single use lancing devices.
• The disclosures of the above patents are incorporated herein by reference.
• An object of the present invention is to provide a one-step procedure and device for testing glucose levels in body fluids.
• Another object of the present invention is to provide an apparatus that withdraws a body fluid sample and provides an individual with a body fluid glucose level reading.
• Even with the many improvements which have been made, the pain associated with lancing remains a significant issue for many patients. The need for blood sampling and the fear of the associated pain is also a major obstacle for the millions of diagnosed diabetics, who do not adequately monitor their blood glucose due to the pain involved. Moreover, lancing to obtain a blood sample for other diagnostic applications is becoming more commonplace, and a less painful, minimally invasive device is needed to enhance those applications and make those technologies more acceptable.
• An object of the present invention therefore, is to provide a device and a method for obtaining a sample of bodily fluid through the skin which is virtually pain free and minimally invasive, particularly by penetrating less sensitive areas of the skin.
• Furthermore, known lancing devices include manually actuable buttons for triggering the lance-driving mechanism once the user has placed the device against his/her skin. Because the user knows the precise instant when the lancet will be triggered and pain will be felt, there is a tendency for the user to jerk or raise the device at the instant of triggering, which can lead to inconsistent skin penetration, or possibly no penetration. Therefore, a further object of the invention is to provide a lancing device which eliminates such a tendency on the part of the user.
• Therefore, it is another object of the invention to provide a lancet carrier which eliminates the above-mentioned shortcomings.
• Another object of this invention is to provide a method which can result in a sample of either blood or interstitial fluid, depending on the sample site and the penetration depth utilized. While there are no commercially available devices utilizing interstitial fluid (ISF) at this time, there are active efforts to establish the correlation of analytes, such as glucose, in ISF compared to whole blood. If ISF could be readily obtained and correlation is established, ISF may be preferable as a sample since there is no interference of red blood cells or hematocrit adjustment required.
• Another object of this invention is to provide a method by which the drawn sample is collected and may be easily presented to a testing device, regardless of the location of the sample site on the body. This approach helps with infection control in that multiple patients are not brought in contact with a single test instrument; only the sampling device with a disposable patient-contact portion is brought to the test instrument. Alternatively, the disposable portion of a test device may be physically coupled with the sampler so the sample can be brought directly into the test device during sampling. The test device may then be read in a test instrument if appropriate or the testing system can be integrated into the sampler and the test device can provide direct results displayed for the patient.
• It is a further object of the invention is to provide a device for minimally invasive sampling comprising a reusable sampler and disposable sample lancet and collection device.
SUMMARY OF THE INVENTION
• The present invention involves a method of obtaining a sample of fluid from a body. The method comprises applying a skin-lancing medium against a skin surface to form an incision therein, removing the skin-lancing medium from the incision; and thereafter applying a force to depress the skin in a manner forming a ring of depressed body tissue in surrounding relationship to the incision, causing the incision to bulge and the sides of the incision to open, whereby body fluid is forced out through the opening of the incision.
• The invention also relates to a device for sampling body fluid which comprises a housing having an open end, and a skin lancing mechanism for applying a skin-lancing medium against a skin surface to form an incision therein and then remove the skin-lancing medium from the incision. A stimulator member is mounted to the housing at the open end thereof for movement relative to the housing. The stimulator member extends about a longitudinal axis of the housing and is adapted to engage the skin surface to bulge and open the incision in response to a pressing of the end face against the skin surface.
• The invention also relates to a device for expressing body fluid from a lanced skin surface, which comprises a housing, and a stimulator mechanism mounted to the housing at an end thereof. The stimulator mechanism includes a generally circular array of stimulator elements each mounted to the housing for movement toward and away from a longitudinal axis of the housing. An actuator is mounted to the housing for displacing the stimulator elements toward the axis.
• The invention also relates to a device for expressing body fluid from a lanced skin surface, which comprises a housing and a stimulator member mounted on the housing at an end thereof. The stimulator member comprises a coil spring which is compressible toward the housing in response to being pushed against a user's skin in surrounding relationship to a lanced portion thereof.
• Another aspect of the invention relates to a device for expressing body fluid from a lanced skin surface which comprises a housing and a hollow stimulator member mounted at an end of the housing and adapted to engage a user's skin surface in surrounding relationship to a lanced portion thereof. In order to promote the flow of body fluid, the stimulator member can be heated, or vibrated. If vibrated, the stimulator member applies an ultrasonic frequency to the skin surface.
• The invention also relates to a device for expressing body fluid from a lanced skin surface which comprises a housing and a hollow stimulator member mounted at an end of the housing for longitudinal movement relative to the housing and adapted to contact a user's skin surface in surrounding relationship to a lanced portion thereof. A motor is mounted in the housing and a reciprocatory mechanism is connected to the motor to be driven thereby, and is operably connected to the stimulator member for reciprocating the stimulator member along a longitudinal axis of the stimulator member.
BRIEF DESCRIPTION OF THE DRAWINGS
• The objects and advantages of the invention will become apparent from the following detailed description of preferred embodiments thereof in connection with the accompanying drawing in which like numerals designate like elements and in which:
• FIG. 1 is a longitudinal sectional view through a blood sampling device according to a first embodiment of the invention, with the lancet carrier in an unarmed condition;
• FIG. 2 is a view similar toFIG. 1, with the lancet carrier in an armed condition;
• FIG. 3 is a view similar toFIG. 2 after the lancet carrier has been triggered and a lancet is penetrating the skin;
• FIG. 4 is a fragmentary view similar toFIG. 1 after an incision has been formed;
• FIG. 5 is a view similar toFIG. 4 showing a stimulator member of the device being depressed to cause the incision to bulge and open;
• FIG. 6 is a view similar toFIG. 5 after a stimulating action has been performed to form a drop of blood at the open end of the incision;
• FIG. 7 is a fragmentary longitudinal sectional view through a second embodiment of the invention;
• FIG. 8 is a fragmentary longitudinal sectional view taken through a third embodiment of the invention;
• FIG. 9 is a side elevational view of a fourth embodiment of the invention pressed against a skin surface;
• FIG. 10 is an end view of the device depicted inFIG. 9;
• FIG. 11 is a view similar toFIG. 9 after the device has been compressed against the skin surface to bulge and open an incision;
• FIG. 12 is an end view of the device in the condition depicted inFIG. 11;
• FIG. 13 is a fragmentary longitudinal sectional view taken through a fifth embodiment of the invention while in a first state of operation;
• FIG. 14 is a view similar toFIG. 13 with the device in a second condition of operation;
• FIG. 15 is a fragmentary longitudinal sectional view taken through a sixth embodiment of the invention in a first condition of operation thereof;
• FIG. 16 is a view similar toFIG. 15 with the device in another condition of operation;
• FIG. 17 is a view similar toFIG. 16 of yet a further condition of operation of the device;
• FIG. 18 is a side elevational view, partly in longitudinal section of yet another embodiment of the invention;
• FIG. 19 is a longitudinal sectional view taken through still a further embodiment of the invention;
• FIG. 20 is a longitudinal sectional view of a blood lancing device according to a seventh embodiment of the invention while in a first condition or operation thereof;
• FIG. 21 is an end view of the device in the condition depicted inFIG. 20;
• FIG. 22A is a view similar toFIG. 20, with the lancet carrier in an armed condition;
• FIG. 22B is a partial cross-sectional side view of the lancing device wherein the lancet has penetrated the patient's skin;
• FIG. 22C is a view similar toFIG. 22A, illustrating the bulge which forms in the patient's tissue, wherein the stimulating member stretches the skin open for expressing a body fluid sample;
• FIG. 23 is an end view of an alternative embodiment of the stimulating member of the present invention;
• FIG. 24 is a cross-sectional side view of the alternative embodiment of the stimulating member illustrated inFIG. 23;
• FIG. 25 is an end view of another alternative embodiment of the stimulating member of the present invention;
• FIG. 26 is a partial cross-sectional side view of a lancing device including a stimulating member and a constricting member;
• FIG. 27 is a partial cross-sectional side view of the lancing device ofFIG. 26 in use;
• FIG. 28 is a partial cross-sectional side view of the lancing device ofFIG. 26 in use illustrating a bulge of tissue formed by the constricting member;
• FIG. 29 is a partial cross-sectional side view illustrating the lancing action and spreading of the formed incision by the stimulating member;
• FIG. 30 is a partial cross-sectional side view of an alternative embodiment of a lancing device including a stimulating member and a constricting member;
• FIG. 31 is a partial cross-sectional side view of the lancing device ofFIG. 30 illustrating the formation of an incision within a bulge of tissue;
• FIG. 32 is a partial cross-sectional side view of the lancing device ofFIG. 31 illustrating the spreading of the incision by the stimulating member; and
• FIG. 33 is a side view illustrating a glucose monitoring device in accordance with the present invention.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT
• A lancing device10 (seeFIG. 1) according to one preferred embodiment of the invention comprises an outer housing12 having upper andlower portions14,16 connected together, and aninner housing18 fixed to the outer housing.
• Mounted for vertical reciprocation in theupper portion14 of the outer housing12 is acocking mechanism20 comprising apull handle22 to which is fixedly secured a hollow draw tube24. Fixed to an inner wall of the draw tube24 is a draw ring26.
• Situated within the draw tube24 is adraw bar30 having a pair of flexible hooks32 at its upper end. The hooks are releasably latched to asleeve34 which is movably disposed within the draw ring26. A coil compression spring36 acts between a flange33 of thesleeve34 and an inner flange38 of the draw ring26.
• A trigger sleeve35 is mounted within the lower portion16 of the outer housing12. A lower end of the trigger sleeve rests upon a first outer flange37A of the inner housing, and a second outer flange37B of the inner housing rests upon aninner projection39 of the trigger sleeve.
• At its lower end thedraw bar30 frictionally holds a skin-lancing medium in the form of adisposable lancet40 in which aneedle42 is disposed. Thedraw bar30 includes a flexible latch finger44 that has aprojection45 adapted to be received in a hole46 of the inner housing18 (seeFIG. 2) when the device is armed. Atrigger member49 is mounted in a hole47 of the trigger sleeve35 and includes anarm48 extending partially into the hole46. Thetrigger member49 includes an inclinedcam follower surface50.
• Acoil compression spring52 acts between a top wall54 of theinner housing18 and ashoulder56 of the draw bar.
• Slidably disposed within a lower end of the lower portion of the outer housing is a firingtube60 which includes anupper cam surface62. Fixed to a lower end of the firingtube60 is an outer hollow stimulator member in the form of acylindrical ring64, having an end surface65 of generally frusto-conical shape so as to be oriented at a downward and inward inclination to generally face a longitudinal axis A of the device.
• Disposed coaxially within the firingtube60 andouter stimulator ring64 is an inner hollow stimulator member also in the form of a cylindrical ring66 having a frusto-conical end surface67 also oriented at a downward and inward inclination.
• The end surfaces65 and67 are of circular configuration when viewed along the axis A, other configurations, such as polygonal, oval, etc., are possible.
• Acoil compression spring68 acts between an upper end of theouter stimulator ring64 and a downwardly facing shoulder70 of the inner stimulator ring66.
• The inner stimulator ring66 includes a lance stop flange72 adapted to be engaged by a lance ring74 of thelancet40 as will be explained.
• The first flange37A of the inner housing rests upon a support sleeve80 which, in turn, rests upon an upper end of the inner stimulator ring66.
• In practice, when a fluid sample, such as blood or interstitial fluid, is to be taken from a user's body, a lancing device according to the present invention can be used to minimize pain. To do so, a region of the user's body having less sensitivity than, for example, a fingertip, is selected. Such a low-sensitivity region could be the user's forearm for example. Initially, thehandle22 is pulled up to raise thedrawbar30 until theprojection45 of the latch finger44 snaps into the hole44 of theinner housing18, as shown inFIG. 2. Simultaneously, thespring52 is compressed.
• If theouter stimulator ring64 is pressed against the user's skin S, e.g., on the selected forearm region FA, thering64 and itscam surface62 are moved upwardly to displace the trigger radially inwardly, whereupon theprojection45 of the latch finger44 is disengaged from the hole46. Accordingly, thespring52 expands to displace thedrawbar30 downwardly so that theneedle42 punctures the skin sufficiently deep to cut capillaries in the superficial vascular plexus, as shown inFIG. 3. Simultaneously, thespring68 is compressed. The extent of displacement of thedrawbar30 is limited
• by engagement between the lance ring74 with the lance stop72.
• Once lancing has occurred, thecompressed spring68 expands to raise the drawbar, as well as theneedle42 and inner stimulator ring66 from the skin (seeFIG. 4).
• The user then alternately applies and releases a downward force on the outer housing12. Each time that a downward force is applied, the end face65 of theouter stimulator ring64 exerts a downward force F which depresses a ring-shaped portion of the skin and body tissue which is disposed in surrounding relationship to the wound or incision I, causing the wounded area to bulge while pulling apart the sides of the wound (seeFIG. 5). Hence, fluid such as blood or interstitial fluid is trapped and pressurized so that it travels upwardly through the pulled-open end of the wound since the surrounding ring of depressed skin and body tissue restricts the outward flow of fluid. That action is enhanced by the fact that the force F is inclined inwardly toward the axis A to force the fluid toward the bulged area.
• When the downward force is released, the sides of the wound close, and fresh fluid flows toward the area of the wound to replace fluid which had been forced upwardly through the wound. As the downward force is reapplied, the above-described action is repeated and additional fluid is forced through the wound. Eventually, this “pumping” action results in the formation of a suitably large drop D of fluid (FIG. 6).
• It will thus be appreciated that the present invention enables an ample supply of blood, interstitial fluid or other body fluid to be obtained relatively painlessly from areas of the body which typically possess lesser amounts of such fluid as compared with the highly sensitive fingertip region.
• Note that each time that the downward force is applied to the outer housing, theouter stimulator ring64 moves upwardly relative to the inner stimulator ring66 so that the end surface67 of the inner ring66 also contacts the skin surface S at a location inwardly of the outer face65, thereby promoting the displacement of fluid inwardly toward the wound. However, the present invention can be practiced by a singlestimulator ring arrangement64A as shown inFIG. 8.
• While the surfaces65,67 are continuous, i.e., non-interrupted, it may be desirable to provide either or both of those surfaces with circumferentially spaced recesses80 as shown inFIG. 7. The surface(s)65A,67A will still depress a ring of body tissue surrounding the wound, but the areas of the ring corresponding to the location of the recesses will be depressed to a lesser extent than the other areas. Those lesser depressed areas will provide less resistance to fluid flow and will thus enable some fluid to leak past the ring, which would be beneficial in the event that the user neglects to release the downward pressure on the device.
• The stimulator member need not be in the form of a ring. As depicted inFIGS. 9-12, the stimulator member can be in the form of ahelical spring90 formed by aflat strip92. Such a spring would function in somewhat similar fashion to the double-ring arrangement ofFIGS. 1-7 in that a stimulator surface gradually comes into contact with the skin in a radially inward direction to aid in propelling blood or interstitial fluid toward the center axis. In that regard,FIGS. 9 and 10 depict a condition when thespring90 is uncompressed. In contrast,FIGS. 11 and 12 depict a condition wherein the spring is fully compressed. Shaded regions inFIGS. 10 and 12 represent contact between the spring and the skin. It will be appreciated that during compression of the spring, the contact region of the spring progresses gradually radially inwardly, causing blood or interstitial fluid to be pushed toward the axis A and thus toward the bulged area of the skin.
• Depicted inFIGS. 13 and 14 is yet another alternative embodiment wherein the outer stimulator ring64B is interconnected to theinner stimulator ring66B bylevers100 which are pivoted to the firing tube60B. Thus, upward sliding movement of the outer ring64B is transmitted as a downward force to theinner ring66B to slide the latter downwardly and intensify the pumping action.
• A further embodiment is depicted inFIGS. 15-17 wherein the firing tube60C has acarrier tube102 affixed at a lower end thereof. Pivotably mounted on thecarrier tube102 is a circular array oflevers104 each having an upper and lower end, each lower end carrying a stimulator element in the form of aroller106. Eachlever104 is rotatable about an axis extending orthogonally relative to the axis of the housing.
• Aninner ring110 is slidable up and down, either by manual force, or by a motor-driven cam (e.g., of the type disclosed later in connection withFIG. 19). Thatring110 has abeveled cam face112 formed on its lower end. When the device is pressed against the skin, following a lancing procedure, thering110 is moved downwardly so that thecam face112 engagesrollers108 mounted on upper ends of the levers. Hence, thelevers104 are rotated such that thelower rollers106 are displaced inwardly and upwardly at a location disposed below the open end of the bulged wound to open the wound and force blood or interstitial fluid toward the wound to form a drop D. When the levers are not contacted by thecam face112, therollers106 gravitate to a rest position shown inFIG. 15. Repeated applications of the downward force cause the drop to become gradually enlarged as explained earlier.
• Depicted inFIG. 18 is an alternative embodiment similar to that depicted inFIGS. 1-6, except that the lower end surface of the outer stimulator ring64D is provided with a hollow stimulator element114 which is electrically connected to a battery116 mounted in an upper end of the device. The element can be either an electrical resistance element (i.e., a heater) or a vibrator such as a piezoelectric transducer, intended to stimulate fluid flow. A heater will expand the capillaries and make the blood or interstitial fluid less viscous and thus more flowable, in order to increase the amount of the body fluid sample. On the other hand, if the element114 is a vibrator, such as a piezoelectric transducer, vibrations can be created which stimulate the flow of body fluid. This could be achieved by operating the transducer to produce frequencies below 28,000 cycles per second. Alternatively, ultrasonic frequencies, i.e., frequencies above 20,000 cycles per second, will create interferometric wave patterns inside the skin that cause contractions forcing fluid upwardly from the wound. The frusto-conical shape114A of the end face of the element will optimize the creation of such wave patterns. It may be further beneficial to employ a heater, such as an infrared emitter, mounted in the housing which vasodilates the capillaries to increase blood flow. Another advantage of the use of such frequencies is that only minimal downward force to the device may be necessary since the wave patterns may produce an ample pumping action.
• FIG. 19 depicts a device which is not automatically fired, but rather requires manual actuation of lever130 against a bias of a spring132 to force atrigger134 to push aprojection136 out of a hole138 (when the projection extends into that hole).
• Mounted in a housing140 of the device are a battery142 and electric motor144 connected to the battery to be actuated thereby. The motor144 rotates a sleeve146 about the axis A. The sleeve includes a cam surface148 which engages a follower roller150 mounted on atube152.
• As the sleeve146 rotates, the cam surface pushes thetube152 downwardly against the bias of a coil compression spring154, to push an inner stimulator ring156 repeatedly against a skin surface, thereby pumping blood to the top of an incision in the same manner described earlier herein. The inner stimulator ring156 reciprocates along the axis A within an outer stimulator ring155. This embodiment eliminates the need for the user to pulsate the device up and down; the pumping operation is achieved automatically in response to actuation of the lever130.
• The cam mechanism146 can be used in an automatically firing device, such as that disclosed in connection withFIG. 1.
• Referring now toFIG. 20, there is shown a seventh embodiment of theblood lancing device10 of the present invention, wherein like reference numerals have been utilized to denote the same or similar elements of the previous embodiments described above and shown inFIGS. 1-19. The lancingdevice10 according to a seventh embodiment includes an outer housing12 having upper andlower portions14,16 connected together, and aninner housing18 fixed to the outer hosing.
• Mounted for vertical reciprocation in theupper portion14 of the outer housing12 is acocking mechanism20 comprising apull handle22 to which is fixedly secured a hollow draw tube24. Fixed to an inner wall of the draw tube24 is a draw ring26.
• Situated with the draw tube24 is adraw bar30 having a pair of flexible hooks32 at its upper end. The hooks are releasably latched to asleeve34 which is movably disposed with the draw ring26. A coil compression spring36 act between a flange33 of thesleeve34 and an inner flange38 of the draw ring26.
• A trigger sleeve35 is mounted within the lower portion16 of the outer housing12. A lower end of the trigger sleeve rests upon a first outer flange37A of the inner housing, and a second outer flange37B of the inner housing rests upon aninner projection39 of the trigger sleeve.
• At its lower end, thedraw bar30 frictionally holds a skin-lancing medium in the form of adisposable lancet40 in which a needle orlancet42 is disposed. Thedraw bar30 includes a flexible latch finger44 that has aprojection45 adapted to be received in a hole46 of theinner housing18 when the device is armed. Atrigger member49 is mounted in a hole47 of the trigger sleeve35 and includes anarm48 extending partially into the hole46. The trigger46 includes an inclinedcam follower surface50.
• Acoil compression spring52 acts between a top wall54 of theinner housing18 and ashoulder56 of the draw bar.
• Slidably disposed within the lower end of the lower portion of the outer hosing is a firingtube60 which includes anupper cam surface62. Fixed to a lower end of the firingtube60 is astimulator member160 in the form of a flexible membrane, having atissue contacting surface161. Referring now toFIG. 21 there is shown an end view of the lancingdevice10 of the present invention illustrating thestimulator member160. As shown, thestimulator member160 includes circumferentially spacedinterruptions163.
• Referring now toFIGS. 22A through 22C, there are shown partial longitudinal cross-sectional side views of the present invention. Referring now toFIG. 22A there is shown the distal end of the lancingdevice10 as disposed over a potion of skin S to be lanced in preparation for a body fluid sample to be obtained. As shown inFIG. 22A, thetissue contacting surface161 of thestimulator member160 contacts the patient's skin. Thetissue contacting surface161 of thestimulator member160 may be formed having a raised area as shown inFIGS. 23-25, wherein the raised surface contact the skin S thereby providing a friction force f between thedistal surface161 and the skin S.
• Referring now toFIG. 22B, wherein a force F has been applied to the proximal end of the lancingdevice10, wherein the force F is translated to thelancet42 andlancet holder240, thereby advancing the lancet into the patient's skin.
• Referring now toFIG. 22C there is shown thelancet42 in a retracted position after thelancet42 has penetrated the skin S to a sufficient depth to cut capillaries in the superficial vascular plexis to form an incision I as shown.
• Thetissue contacting surface161 of thestimulator member160 remains in contact with the skin as after the lancet has formed an incision within the patient's skin and is thereby withdrawn from the incision I. The force F applied to the proximal end of the lancingdevice10 causes the sleeve280 to contact the skin, wherein the skin yields to the applied force as shown inFIG. 22C. The skin S forms a bulge about the incision I formed by the lancet. The friction force f between thedistal surface161 and the skin S retains the stimulator member upon the skin S. By retaining the contactingsurface161 upon the skin S, the incision I is stretched open, thereby allowing more body fluid to be expressed from the incision. In one embodiment, thesleeve180 causes fluid such as blood or interstitial fluid to become trapped and pressurized within the bulged area, so that the body fluid will travel upwardly through the pulled-open incision I.
• After a sufficient sample size has developed, the lancingdevice10 is removed from the patient's skin wherein the sample may then be utilized in any manner desirable.
• It shall be understood that thestimulator member160 and the lancingdevice10 produce a sufficiently sized sample between about 0.05 micro liters and 10 micro liters without the need for repetitive motion as described above with regard to the other embodiments of the present invention. In addition, the alternative embodiment of the lancing device illustrated inFIGS. 20-22C may be utilized with other methods and devices for producing a sufficiently sized sample. For example, the lancingdevice10 may include vibration means (not shown), heating means (not shown), vacuum means (not shown), each of which may be utilized to encourage blood flow within the area to be sampled. Alternatively, the area to be sampled may be stimulated using one of the methods described above prior to using the lancingdevice10.
• Thestimulator member160 may be constructed of bio-compatible materials such as polyvinyl chloride, silicon, urethane, or similar flexible materials which are adapted to grip and translate a frictional force between thetissue contacting surface161 and the patient's skin S thereby causing a wound to be stretched open thereby allowing a greater amount of body fluid to flow therefrom. In addition, thestimulator member160 may be formed of materials which are flexible such that a portion of thestimulator member160 will deform in use, though it shall be understood in a preferred embodiment, thetissue contacting surface161 remains substantially parallel with the skin surface as shown inFIGS. 22A-22C.
• Alternatively, it is contemplated that the stimulatingmember160 may be formed of a rigid material wherein the skin contacting surface of the rigid stimulating member is adapted to provide a friction force between the skin and the tissue contacting surface such that the skin will be retained upon the tissue contacting surface as described above. Additionally, the stimulating member may be pivotally affixed to the sleeve280 thereby allowing a rigid stimulator member to be utilized in the same manner as a flexible member.
• Referring now toFIGS. 23 and 24 thestimulator member260 illustrated therein may be formed in generally the same manner as that shown and described above, though thestimulator member260 is formed having a plurality ofrings261 disposed radially about an aperture266. In use, the plurality ofrings261 act on the skin S with a frictional force such as that described and shown above. The frictional force f retains thetissue contacting surface261 of thestimulator member260 upon the skin surface S, whereby causing the incision I to stretch open as described above.
• Referring now toFIG. 25 there is shown yet another alternative embodiment of thestimulator member460 of the present invention. Thestimulator member460 further includes a raised member462 extending from the tissue contacting surface461. The raised member462 is disposed upon the tissue contacting surface461 in a spiraling manner, such as that shown inFIGS. 9-11, and25. In practice, theleading edge463 of the spiraling raised member462 will contact the patient's skin first, thereafter as a greater downward force is applied the remaining portion of the spiraling raised member462 will contact the patient's tissue. The forced imparted by the spiraling raised member462 will cause the skin to bulge, in addition the constant spiraling motion will cause the fluid under the skin to become concentrated within the center of the bulge.
• Referring now toFIG. 26 there is shown yet another alternative embodiment in accordance with the present invention. The lancingdevice10 may further include a stimulatingmember160 as described in detail above with regard toFIGS. 21 through 25. In addition to the stimulatingmember160, a constricting member500 may be fixedly attached to thedistal end181 of thesleeve180. The constricting member500 may be constructed of a pliable material, wherein the constricting member500 will flex as shown inFIG. 28. Examples of materials which the constricting member500 may be constructed of plastics such as polyethylene, polysilicone, polyvinyl chloride, or alternatively of materials such as titanium, aluminum, steel, stainless steel.
• The constricting member500 may be constructed as a separate body which is then fixedly attached to thedistal end181 of thesleeve180 with an adhesive or mechanical fastener or other process such as melting or fusion welding. Alternatively, the constricting member500 may be pivotally attached to thedistal end181 of the sleeve180 (not shown).
• Methods of use relating to the lancingdevice10 will be described in relation toFIGS. 27-29. Referring now toFIG. 27 there is shown the lancingdevice10 as disposed over an area in which it is desired to express a sample of body fluid. As the force F is applied to the lancingdevice10 the force F is translated through the constricting member500 into component forces F′ and F″. As the force F increases, the component forces F′ and F″ cause the patient's skin in contact with the distal end501 of the constricting member500 to gather and form a pucker as shown inFIG. 28, wherein thetissue contacting surface161 of the stimulatingmember160 contacts the skin S.
• In addition to forming the puckered area of skin as shown inFIG. 28, when the force F is increased on the lancingdevice10, the pucker of skin is drawn into the distal end of the lancingdevice10. The pucker of skin is received by thetissue contacting surface161 of the stimulatingmember160, wherein the stimulating member may include a plurality of ridges to increase frictional contact between the skin and thetissue contacting surface161 of the stimulatingmember160. In addition to forming the pucker of skin, a second force F′″ is applied to thelance42, thereby driving the distal tip of a lance or needle into the pucker of skin to form an incision therein as shown inFIG. 28.
• The forces F′ and F″ which the constricting member500 applies to the skin cause the skin to form the pucker as described above. Additionally, the forces F′ and F″ cause body fluid to pool within the pucker because the forces constrict or tourniquet vessels under the surface of the skin thereby restricting the flow of body fluid from these areas. Thus, by constricting the flow of body fluid within the pucker a larger body fluid sample may be obtained from the incision formed by the lance or needle.
• Referring now toFIG. 29 there is shown the lancingdevice10 wherein the lance orneedle42 has been retracted by spring force K after an incision I has been formed in the patient's skin. As shown inFIG. 29 as a greater force F₂is applied to the lancingdevice10, this causes the constricting member500 to further pinch the skin in addition to causing the incision to be spread by the stimulatingmember160 due to a friction force f between the skin S and thetissue contacting surface161 of the stimulatingmember160.
• As a result of the stretching of the incision I, a greater amount of bodily fluid may be expressed from the incision I. Because a greater amount of body fluid may be expressed from the incision I, the lancet device may not require a repeated motion as described above in order to express a sufficiently sized sample of body fluid. Though not shown inFIGS. 27-29, the lancingdevice10 may include additional stimulating means such as heat, vibration, ultrasound or other similar known methods or devices which are utilized to increase body fluid flow within a localized area.
• Referring now toFIGS. 30-32 there is shown an alternative embodiment of a constrictingmember600. Wherein the constrictingdevice600 may be disposed about thesleeve180 of the lancingdevice10 and adjacent thedistal end181 to thesleeve180. The constrictingdevice600 includes a plurality ofarms610 having adistal end611 and aproximal end612, a biasingmember650 and apivot660.
• In accordance with the present invention, theproximal end612 of thearm610 may be pivotally attached to thesleeve180. Thearm610 may be pivotally attached to the sleeve through a pin and block configuration as shown inFIGS. 30-32 or alternatively theproximal end612 may be integrally formed with thesleeve180 and pivot through the use of a live hinge or similar arrangement.
• As described above the constrictingdevice member600 includes a biasingmember650. The biasingmember650 acts on thearms610 thereby directing thedistal tips611 of thearms610 to contact the skin S as shown and to provide forces F′ and F″.
• Referring now toFIGS. 31 and 32 there is shown the lancingdevice10 in use. The constrictingmember600 acts upon the patient's skin to form a pucker of skin which is received within the distal end of the lancingdevice10. It shall be noted that the constrictingmember600 acts upon the patient's skin in the same manner as the constricting device500 as described above with reference toFIGS. 26 through 29. Wherein the constrictingdevice600 and stimulatingmember160 act in conjunction with one another to express a greater amount of body fluid from an incision formed in the patient's skin.
• The lancing device in accordance with the present invention may be best utilized in areas where it is difficult to obtain a sufficient sample size, such as a forearm, though it is desirable to lance within this area because of the reduction in pain associated with the lancing.
• Referring now toFIG. 33, there is shown a further alternative embodiment of a lancing device700 in accordance with the present invention, wherein the lancing device700 further includes a body fluid sampling and testing device. The lancing device700 may be utilized upon a patient's forearm or similar area, wherein the stimulating member and constricting member in conjunction with a needle or lancet produce a sample size of sufficient volume wherein a test may be performed thereon. For example, the lancing device700 may be that which is shown and described in co-pending U.S. Provisional Patent Application No. 60/296,950 filed Jun. 8, 2001, now abandoned, Attorney Dkt. No. 018176-385 and to co-pending U.S. Provisional Patent Application No. 60/297,098 filed Jun. 8, 2001, now abandoned, Attorney Dkt. No. 018176-382, the entirety of which are hereby incorporated by reference.
• It will be appreciated that the present invention enables a sampling of blood or interstitial fluid to be taken from areas of the body, such as a forearm, that are less insensitive to pain, despite the fact that those areas typically have relatively less fluid as compared, for example, to fingertips (which are highly sensitive to pain).
• Therefore, there will be less reluctance on the part of users to have a sampling procedure performed. For example, diabetics who experience a relatively high fear of pain will be less likely to neglect monitoring their blood glucose levels.
• In lieu of using a lancet as a skin-lancing medium, other skin-lancing media can be used, such as a laser, or known pneumatic or hydraulic injectors of the type which inject pressurized gas or liquid against the skin. Such auto injectors are sold by Becton-Dickinson, for example, to inject insulin. By eliminating the insulin and merely injecting the gas (e.g., air or nitrogen) or liquid (e.g., water) at pressures above
• 30 psi. an incision could be formed in the skin for taking samples of body fluid. Advantageously, small particles could be mixed with the gas to promote the tissue-cutting action. The particles could comprise carbon particles of from 1 micron to 0.010 inches in diameter.
• In addition to that which is described above, it is contemplated that the lance or needle may remain within the incision during the collection of the sample. Additionally a force may be applied to the lance or needle to stimulate fluid flow from the incision, for example the lance or needle may be vibrated to express fluid from the incision. It shall be understood that the terms “remain within the incision” shall mean to include the instances where the lance or needle remains in contact with the patient's tissue inside of the incision, or where the lance or needle is withdrawn just distal the incision though remains in fluid contact with the body fluid expressed from the incision.
• Although the present invention has been described in connection with preferred embodiments thereof, it will be appreciated by those skilled in the art that additions, deletions, modifications, and substitutions not specifically described may be made without departing from the spirit and scope of the invention as defined in the appended claims. In addition, each of the methods and apparatuses described herein may be utilized with testing systems and devices such as those which are contained within the co-filed U.S. Patent Application having Ser. No. 60/297,187 filed Jun. 8, 2001, now abandoned, entitled “Control Solution Packet and Methods of Use for Bodily Fluid Sampling Devices;” U.S. Patent Application having Ser. No. 60/296,950 filed Jun. 8, 2001, now abandoned, entitled “Lancet Device Having Capillary Action;” U.S. Patent Application having Ser. No. 60/297,045 filed Jun. 8, 2001, now abandoned, entitled “Method of Sampling Interstitial Fluid for Glucose Monitoring;” U.S. Patent Application having Ser. No. 60/296,989 filed Jun. 8, 2001, now abandoned, entitled “Cassette for a Glucose Monitoring System;” and U.S. Patent Application having Ser. No. 60/296,949 filed Jun. 8, 2001, now abandoned, entitled “Test Media for Glucose Monitoring Systems;” the entirety of which are herein incorporated by reference.

Claims (8)

1. A sampling device, comprising:

a constricting member configured to pinch tissue to form a puckered area of the tissue;

a stimulating member positioned to contact the puckered area of the tissue;

a skin-lancing medium to form an incision in the puckered area of the tissue; and

wherein the stimulating member is configured to spread the incision open and the constricting member is configured to constrict fluid flow from the puckered area to enhance expression of the body fluid from the incision.

2. The device ofclaim 1, wherein the constricting member is constructed of a pliable material that flexes to pinch the tissue.

3. The device ofclaim 1, wherein the constricting member includes:

a plurality of pivot arms; and

a plurality of biasing members each coupled to a corresponding one of the pivot arms to pivot the pivot arms for pinching the tissue.

4. The device ofclaim 1, wherein the stimulator member includes circumferentially spaced interruptions.

5. The device ofclaim 1, wherein the stimulator member includes a flexible membrane.

6. The device ofclaim 1, wherein the stimulator members include first and second stimulator members that are interconnected to move axially in mutually opposite directions.

7. The device ofclaim 1, further including a second stimulator member chosen from the group consisting of, a heating mechanism for heating the stimulating member or constricting member, and a vibrator mechanism for vibrating the stimulating member or constricting member.

8. The device ofclaim 1, further comprising:

means for pinching the tissue, wherein the means for pinching the tissue includes the constricting member;

means for spreading the incision open, wherein the means for spreading the incision open includes the stimulating member; and

means for forming the incision, wherein the means for forming the incision includes the skin-lancing medium

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