Patent Application
20090012472
The present invention generally relates to a device which is adapted for application to a skin surface of a subject and comprises a cannula in combination with an insertion needle, the insertion needle serving as an insertion aid for the cannula which typically is more flexible than the insertion needle. In embodiments of the invention the cannula may be replaced with a sensor.
In the disclosure of the present invention reference is mostly made to the treatment of diabetes by injection or infusion of insulin, however, this is only an exemplary use of the present invention.
Portable drug delivery devices for delivering a drug to a patient are well known and generally comprise a reservoir adapted to contain a liquid drug and having an outlet in fluid communication with a hollow infusion needle, as well as expelling means for expelling a drug out of the reservoir and through the skin of the subject via the hollow needle. Such devices are often termed infusion pumps.
Basically, infusion pumps can be divided into two classes. The first class comprises infusion pumps which are relatively expensive pumps intended for 3-4 years use, for which reason the initial cost for such a pump often is a barrier to this type of therapy. Although more complex than traditional syringes and pens, the pump offer the advantages of continuous infusion of insulin, precision in dosing and optionally programmable delivery profiles and user actuated bolus infusions in connections with meals.
Addressing the above problem, several attempts have been made to provide a second class of drug infusion devices that are low in cost and convenient to use. Some of these devices are intended to be partially or entirely disposable and may provide many of the advantages associated with an infusion pump without the attendant cost and inconveniences, e.g. the pump may be prefilled thus avoiding the need for filling or refilling a drug reservoir. Examples of this type of infusion devices are known from U.S. Pat. Nos. 4,340,048 and 4,552,561 (based on osmotic pumps), U.S. Pat. No. 5,858,001 (based on a piston pump), U.S. Pat. No. 6,280,148 (based on a membrane pump), U.S. Pat. No. 5,957,895 (based on a flow restrictor pump (also know as a bleeding hole pump)), U.S. Pat. No. 5,527,288 (based on a gas generating pump), or U.S. Pat. No. 5,814,020 (based on a swellable gel) which all in the last decades have been proposed for use in inexpensive, primarily disposable drug infusion devices, the cited documents being incorporated by reference. U.S. Pat. No. 6,364,865 discloses a manually held infusion device allowing two vial-type containers to be connected and a pressure to be build up in one of the containers to thereby expel a drug contained in that container.
The disposable pumps generally comprises a skin-contacting mounting surface adapted for application to the skin of a subject by adhesive means, and with the infusion needle arranged such that in a situation of use it projects from the mounting surface to thereby penetrate the skin of the subject, whereby the place where the needle penetrates the skin is covered while the appliance is in use. The infusion needle may be arranged to permanently project from the mounting surface such that the needle is inserted simultaneously with the application of the infusion pump, this as disclosed in U.S. Pat. Nos. 2,605,765, 4,340,048 and in EP 1 177 802, or the needle may be supplied with the device in a retracted state, i.e. with the distal pointed end of the needle “hidden” inside the pump device, this allowing the user to place the pump device on the skin without the possibility of observing the needle, this as disclosed in U.S. Pat. Nos. 5,858,001 and 5,814,020.
As an alternative to a needle, a cannula in combination with an insertion needle which is withdrawn after insertion thereof may be used. Typically, the cannula is in the form of a relatively soft infusion cannula (e.g. a Teflon® cannula) and a there through arranged removable insertion needle. This type of cannula and needle arrangement is well known from so-called infusion sets, such infusion sets typically being used to provide an infusion site in combination with (durable) infusion pumps. However, recently a disposable pump has been disclosed comprising an insertable soft cannula in combination with an insertion needle. More specifically, WO 03/090509 shows a skin mountable drug delivery device comprising an initially concealed soft cannula through which an insertion needle is arranged. With the device mounted on a skin surface the cannula can be released and inserted angled through the skin, the pointed distal end of the insertion needle projecting from the distal end of the cannula. When the cannula is fully inserted the insertion needle is withdrawn.
For all of the above the following has to be considered. When a needle enters the subcutaneous tissue, the cutting edge will cause lesions to this tissue; cells are punctured, the fine blood vessels are damaged and nerve connections are cut, causing hemorrhage and trauma to the patient. Further, such hemorrhage triggers an immune reaction in the tissue, causing the chemical environment in the skin at the insertion site to change. This can influence the effect of the injected substance, which of course is undesirable. This is especially an issue for obliquely inserted soft cannulas as these are normally inserted with a long travel to reach the desired depth of insertion in the subcutaneous space.
Having regard to the above-identified problems, it is an object of the present invention to provide a skin mountable medical device or system as well as components therefore, which allow such a device or system to be used in a convenient and cost-effective manner, yet allowing safe and reliable treatment of a medical condition.
In the disclosure of the present invention, embodiments and aspects will be described which will address one or more of the above objects or which will address objects apparent from the below disclosure as well as from the description of exemplary embodiments.
Thus, a medical device is provided comprising a housing adapted for application towards the skin of a subject, a cannula having a distal end portion adapted to be arranged through the skin of the subject and having a distal opening, and an insertion needle (in the following also denoted as a needle for short) arranged coaxially with and being axially moveable relative to the cannula, the needle comprising a pointed distal end. The medical device is transformable between (1) a first state in which the cannula and the needle are retracted within the housing, (2) a second state in which the cannula and the needle are extended relative to the lower surface with the distal end of the needle projecting relative to the distal opening of the cannula thereby allowing the cannula to be introduced through the skin of the subject, (3) a third state in which the distal end of the needle is positioned short of the distal opening, the cannula not being fully extended relative to the housing, (4) a fourth state in which the cannula is fully extended relative to the housing, and optionally (5) a fifth state in which the needle is retracted from the portion of the cannula extending from the housing.
The cannula will typically be in the form of a flexible, relatively soft polymeric tube having a relatively blunt distal end (often designated a catheter or soft catheter), with the needle typically being formed from medical grade stainless steel providing the pointed distal end, however, the needle may also be formed from a polymeric material.
The term “housing” merely denotes a supporting structure for supporting the different elements as described. The housing may be a traditional partially or fully closed structure, however, it may also be in the form of an open structure, e.g. a platform.
Corresponding to a first aspect, the needle is arranged within the cannula such that in the fourth state the distal end of the needle can be positioned within the cannula short of the distal opening. The above arrangement allows the upper leathery layer of the skin to be penetrated with the insertion needle projecting from the cannula. Thereafter the distal ends of the cannula and the needle “shift positions”, e.g. the needle stops and the cannula continues the insertion until the distal end is a short distance in front of the needle end, e.g. 1-5 mm. After this the cannula and the needle together continue the insertion through the relatively soft subcutaneous tissue, the needle providing directional guidance as well as support against kinking, until the cannula is fully inserted. As appears, the combined cannula and needle assembly has a blunt tip when penetrating the sub-cutis thereby causing reduced damage to the subcutaneous tissue. Compared with traditional infusion sets in which the needle penetrates the dermis as well as sub-cutis, less damage can be expected. Once the cannula is fully inserted, the needle is retracted.
To provide the relative motions between the cannula, the needle and the housing, an exemplary embodiment comprises an inserter assembly for moving the cannula and the insertion needle between the different states as defined above. The inserter assembly comprises the cannula, an inserter for moving the cannula, the needle, and a needle holder attached to the needle. The inserter assembly has (a) an initial state in which the needle holder is locked to the inserter in an initial position with the distal end of the needle projecting from the distal opening of the cannula, (b) an intermediate state in which the needle holder is locked to the inserter in an intermediate position with the distal end of the needle positioned within the cannula short of the distal opening, and optionally (c) a retracted state in which the needle is retracted from the portion of the cannula extending from the housing. This arrangement allows the inserter to function as the primary vehicle for moving the cannula and the needle, the “shift” between the initial and the intermediate state allowing the relative movement between the cannula and needle after the initial insertion through the outer layer of the skin.
More explicitly, the above arrangement provides a medical device wherein (i) the inserter assembly is transformable from the first to the second state with the inserter assembly in its initial state (e.g. the entire inserter assembly is moved forward), (ii) the inserter assembly is transformable from the second to the third state when the inserter is transformed from its initial to its intermediate state (e.g. the needle holder is released from its initial position whereby movement of the needle stops as the inserter and the cannula move forward, the needle holder thereafter being locked in its intermediate position after which it will be moved together with the cannula), (iii) the inserter assembly is transformable from the third to the fourth state with the inserter assembly in its intermediate state (e.g. the entire inserter assembly is moved forward with the needle locked in its intermediate state), and (iv) the inserter assembly is transformable from the fourth to the fifth state when the inserter is transformed from its intermediate to its retracted state (e.g. the needle is retracted from the cannula, either by retracting the needle holder or by retracting the inserter with the needle holder locked in place).
To prevent displacement of the inserted cannula, the fully extended cannula may be locked in place relative to the housing. For example, in case the inserter is left in place and only the needle is withdrawn, locking means (e.g. barbs or hooks) may be provided between the housing and the inserter. Alternatively, the cannula may be attached to a cannula which can be moved by the inserter from a retracted to a fully extended position, the cannula holder and the housing comprising cooperating fastening means for locking the cannula in its extended position, this allowing the inserter to be withdrawn after insertion.
To provide swift and minimally painful insertion, a user-releaseable actuator for actuating the inserter assembly from state 1-4 may be provided, i.e. until the cannula has been fully inserted. For example, the actuator may comprise a spring urging the inserter from an initial position to an extended position corresponding to the first respectively the fourth state. Further, a retractor for retracting the needle from its fully extended to a retracted position may be provided, e.g. a handle or a strip allowing the needle to be pulled back, or a further spring actuated mechanism. The latter may be coupled to a first actuator to provide fully automatic insertion corresponding to states 1-5.
In an exemplary embodiment the medical device comprises first and second housing portions coupled to each other, wherein the cannula in its extended position can be locked to the first housing portion. When the needle is retracted into the second housing portion, the second housing portion can be detached from the first housing portion with the needle being arranged there within. Preferably a lock is provided locking the needle safely within the second housing after use, this preventing unintended needle sticks. This concept may also be utilized in a medical device comprising a second housing with a “traditional” combination of a cannula and a needle, i.e. an arrangement in which the cannula and needle assembly is moved to their extended position with the needle projecting from the cannula.
The medical device may be provided with a flexible sheet member with a lower surface adapted to be arranged on a skin surface of a subject (e.g. comprising an adhesive), and an upper surface to which the first housing portion is arranged. In this way the cannula can be securely held in place after insertion.
After the cannula has been inserted it may be coupled to a desired fluid source, e.g. tubing to supply fluids or drugs from an IV bag or bottle. The medical device may also be provided as part of an assembly comprising a medical device as described above and a delivery device adapted to be coupled to the first housing portion. Such a delivery device comprising a reservoir adapted to contain a fluid drug, and an expelling assembly adapted for cooperation with the reservoir to expel fluid drug out of the reservoir and through the skin of the subject via the cannula when the delivery device has been coupled to the first housing portion after the cannula has been inserted and the second housing portion removed. As appears, in case fluid is supplied directly to the cannula, the needle has to be removed before attachment of the delivery device.
Alternatively, the needle may be hollow and comprise a proximal end, with the distal end of the needle being in sealed fluid communication with the interior of the cannula when the needle has been arranged in its retracted position. By this arrangement a fluid communication can be provided between the proximal end of the needle and the cannula. In this case a delivery device would supply drug to the cannula via the hollow needle.
Corresponding to a further aspect, the needle is hollow and arranged outside the cannula, this allowing for a smaller diameter cannula as it does not have to accommodate the needle. On the other hand the needle will have a larger diameter. Thus the needle may be arranged to be fully extended corresponding to the third state, i.e. the outer needle is only used to penetrate the uppermost layer of the skin and does not support the cannula during the further insertion in the subcutis.
Accordingly, in a further embodiment a medical device is provided comprising an inserter assembly for moving the cannula and the insertion needle between the different states. The inserter assembly comprises the cannula, the needle, an inserter attached to the needle, a cannula holder attached to the cannula and adapted for moving the cannula relative to the inserter and thereby the needle. The inserter assembly has (a) an initial state in which the cannula is positioned within the needle and with the distal end of the needle projecting relative to the distal opening of the cannula, and (b) an intermediate state in which the cannula holder has been moved to extend the cannula from the needle. The inserter assembly may have (c) a further extended state in which the cannula holder has been moved to further extend the cannula from the needle. Further, the inserter assembly has (d) a retracted and (e) an extended position.
More explicitly, the above arrangement can provide a medical device wherein (i) the inserter assembly is transformable from the first to the second state when the inserter assembly is moved from the retracted to the extended position with the inserter assembly in its initial state (i.e. the entire inserter assembly is moved forward), (ii) the inserter assembly is transformable from the second to the third state when the inserter is transformed from its initial to its intermediate state (i.e. the cannula is extended from the needle), and (iii) the inserter assembly is transformable from the third to the fourth state with the inserter assembly in its intermediate state (i.e. the cannula is further extended from the needle). The inserter assembly may further (iv) be transformable from the fourth to the fifth state when the inserter is transformed from its intermediate to its extended state and when the inserter assembly is moved from the extended to the retracted position (i.e. the cannula is fully extended from the needle and the entire inserter assembly is retracted).
As for the above described embodiment, the medical may comprise a flexible sheet member with a lower surface adapted to be arranged on a skin surface of a subject, and an upper surface to which the housing is arranged. Such a medical device may also be provided as part of an assembly further comprising a delivery device adapted to be coupled to the housing, the delivery device comprising a reservoir adapted to contain a fluid drug, and an expelling assembly adapted for cooperation with the reservoir to expel fluid drug out of the reservoir and through the skin of the subject via the cannula when the delivery device has been coupled to the first housing portion after the cannula has been inserted and the second housing portion removed. The assembly may also be provided as a unitary device.
In the above embodiments the subcutaneously introduced element has been in the form of a cannula suitable for drug delivery, however, the cannula may be replaced by a sensor and the delivery device may be in the form of an assembly adapted to transmit and/or process data acquired via the sensor, see for example U.S. Pat. No. 5,482,473 which is hereby incorporated by reference. A penetrating sensor may allow a body parameter to be sensed in the subcutaneous space, e.g. by using a needle formed sensor as discussed in the introduction, or by transporting fluid from the subcutaneous space to detection assembly by means of a conduit, this principle being known as micro-dialysis. An example of a penetrating needle-sensor and a corresponding process unit is shown in U.S. Pat. No. 6,809,653 (hereby incorporated by reference) which discloses a characteristic monitor system including a data receiving device, a transcutaneous needle sensor for producing signal indicative of a characteristic of a subject (e.g. a blood glucose value), and a processor device. The processor device includes a housing, a sensor connector, a processor, and in the shown embodiment a transmitter. In the shown embodiment the processor coupled to the sensor processes the signals from the sensor for transmission to the remotely located data receiving device, however, the processed data could also be shown directly on a display provided on the processor device. The data receiving device may be a characteristic monitor, a data receiver that provides data to another device, a wireless programmer for a medical device (e.g. a remote control), a medication delivery device (such as an infusion pump), or the like.
In a further aspect a method of inserting a cannula into the subcutaneous tissue of a subject is provided, comprising the steps of (a) providing a cannula having a distal end portion adapted to be arranged through the skin of the subject and having a distal opening, and a needle arranged coaxially with and being axially moveable relative to the cannula, the needle comprising a pointed distal end, (b) advancing the cannula with the distal end of the needle projecting there from through the dermis of the subject, and (c) further advancing the cannula into the sub-cutis of the subject with the distal end of the cannula projecting relative to the needle. During the advancement of the cannula into the sub-cutis the distal end of the needle may be arranged short of the distal end of the cannula during, this supporting and directing the cannula during insertion. 29. The needle may be arranged either within the cannula or the needle may be hollow and arranged outside the cannula.
In a yet further aspect an assembly is provided comprising a transcutaneous device unit and a process unit. The transcutaneous device unit is adapted for application towards a skin surface of a subject and comprises a housing, and an extendable transcutaneous device having a distal end portion adapted to be arranged through the skin of the subject at an inclined angle relative to the skin surface. The process unit is adapted to be releasably coupled to the housing, the process unit comprising a process assembly adapted for cooperation with the transcutaneous device, wherein the process unit in a situation of use in which the assembly has been applied towards the skin of a subject covers the cannula in its extended position, and wherein at least partial removal of the process unit from the transcutaneous device unit allows inspection of the introduction site of the transcutaneous device through the skin surface.
In an exemplary embodiment the transcutaneous device unit comprises a transcutaneous drug delivery device, and the process unit comprises a reservoir adapted to contain a fluid drug, and an expelling assembly adapted for cooperation with the reservoir to expel fluid drug out of the reservoir and through the skin of the subject via the transcutaneous drug delivery device when the two units are coupled to each other.
The transcutaneous drug delivery device may be in the form of e.g. a pointed hollow infusion needle or a combination of a relatively flexible per se blunt cannula with a penetrating insertion needle, the insertion needle being retractable after insertion of the blunt portion of the transcutaneous device. The cannula is advantageously soft and flexible relative to the insertion needle which may be a solid steel needle arranged inside the cannula or a hollow needle arrange outside the cannula. The length of the transcutaneous device may be chosen in accordance with the actual application, e.g. 4-20 mm. Indeed, the housing may comprise more than one transcutaneous drug delivery device.
To reduce the likelihood of transcutaneous device injuries, the distal end of the transcutaneous device may be moveable between the extended position in which the end projects relative to the mounting surface, and a retracted position in which the end is retracted relative to the mounting surface.
The term expelling assembly covers an aggregation of components or structures which in combination provides that a fluid can be expelled from the reservoir. The expelling assembly may e.g. be a mechanical pump (e.g. a membrane pump, a piston pump or a roller pump) in combination with electronically controlled actuation means, a mechanically driven pump (e.g. driven by a spring), a gas driven pump or a pump driven by an osmotic engine. The expelling assembly may also be in the form of an aggregation of components or structures which in combination provides that a fluid can be expelled from the reservoir when the expelling assembly is controlled or actuated by a controller external to the expelling assembly.
In a further exemplary embodiment the transcutaneous device unit comprises a transcutaneous sensor device and the process unit is adapted to transmit and/or process data acquired via the sensor. The penetrating sensor may allow a body parameter to be sensed in the subcutaneous space, e.g. by using a needle formed sensor as discussed in the introduction, or by transporting fluid from the subcutaneous space to detection assembly by means of a conduit, this principle being known as micro-dialysis. An example of a penetrating needle-sensor and a corresponding process unit is shown in U.S. Pat. No. 6,809,653 (hereby incorporated by reference) which discloses a characteristic monitor system including a data receiving device, a transcutaneous needle sensor for producing signal indicative of a characteristic of a subject (e.g. a blood glucose value), and a processor device. The processor device includes a housing, a sensor connector, a processor, and in the shown embodiment a transmitter. In the shown embodiment the processor coupled to the sensor processes the signals from the sensor for transmission to the remotely located data receiving device, however, the processed data could also be shown directly on a display provided on the processor device. The data receiving device may be a characteristic monitor, a data receiver that provides data to another device, a wireless programmer for a medical device (e.g. a remote control), a medication delivery device (such as an infusion pump), or the like.
The devices described above in accordance with individual aspects of the invention can be used both independently of each other and in combination with elements and features in accordance with other aspects of the invention.
As used herein, the term “drug” is meant to encompass any drug-containing flowable medicine capable of being passed through a delivery means such as a hollow needle in a controlled manner, such as a liquid, solution, gel or fine suspension. Representative drugs include pharmaceuticals such as peptides, proteins, and hormones, biologically derived or active agents, hormonal and gene based agents, nutritional formulas and other substances in both solid (dispensed) or liquid form. In the description of the exemplary embodiments reference will be made to the use of insulin. Correspondingly, the term “subcutaneous” infusion is meant to encompass any method of transcutaneous delivery to a subject. Further, the term needle (when not otherwise specified) defines a piercing member adapted to penetrate the skin of a subject.
In the following the invention will be further described with reference to the drawings, wherein
In the figures like structures are mainly identified by like reference numerals.
When in the following terms such as “upper” and “lower”, “right” and “left”, “horizontal” and “vertical” or similar relative expressions are used, these only refer to the appended figures and not to an actual situation of use. The shown figures are schematic representations for which reason the configuration of the different structures as well as there relative dimensions are intended to serve illustrative purposes only.
Firstly, with reference to
More specifically,
The needle unit comprises a flexible patch portion 10 with a lower adhesive mounting surface adapted for application to the skin of a user, and a housing portion 20 in which a hollow infusion needle (not shown) is arranged. The needle comprises a pointed distal end adapted to penetrate the skin of a user, and is adapted to be arranged in fluid communication with the reservoir unit. In the shown embodiment the pointed end of the needle is moveable between an initial position in which the pointed end is retracted relative to the mounting surface, and an extended position in which the pointed end projects relative to the mounting surface. Further, the needle is moveable between the extended position in which the pointed end projects relative to the mounting surface, and a retracted position in which the pointed end is retracted relative to the mounting surface. The needle unit further comprises user-gripable actuation means in the form of a first strip-member 21 for moving the pointed end of the needle between the initial and the second position when the actuation means is actuated, and user-gripable retraction in the form of a second strip-member 22 means for moving the pointed end of the needle between the extended and the retracted position when the retraction means is actuated. As can be seen, the second strip is initially covered by the first strip. The housing further comprises user-actuatable male coupling means 31 in the form of a pair of resiliently arranged hook members adapted to cooperate with corresponding female coupling means on the reservoir unit, this allowing the reservoir unit to be releasable secured to the needle unit in the situation of use. A flexible ridge formed support member 13 extends from the housing and is attached to the upper surface of the patch. In use a peripheral portion 12 of the patch extends from the assembled device as the reservoir unit covers only a portion 11 of the upper surface of the patch. The adhesive surface is supplied to the user with a peelable protective sheet.
The reservoir unit 5 comprises a pre-filled reservoir containing a liquid drug formulation (e.g. insulin) and an expelling assembly for expelling the drug from the reservoir through the needle in a situation of use. The reservoir unit has a generally flat lower surface adapted to be mounted onto the upper surface of the patch portion, and comprises a protruding portion 50 adapted to be received in a corresponding cavity of the housing portion 20 as well as female coupling means 51 adapted to engage the corresponding hook members 31 on the needle unit. The protruding portion provides the interface between the two units and comprises a pump outlet and contact means (not shown) allowing the pump to be started as the two units are assembled. The lower surface also comprises a window (not to be seen) allowing the user to visually control the contents of the reservoir before the two units are connected.
First step in the mounting procedure is to assemble the two units by simply sliding the reservoir unit into engagement with the needle unit (
After the device has been left in place for the recommended period of time for use of the needle unit (e.g. 48 hours)—or in case the reservoir runs empty or for other reasons—it is removed from the skin by gripping and pulling the retraction strip 22 which leads to retraction of the needle followed by automatic stop of drug infusion where after the strip which is attached to the adhesive patch is used to remove the device from the skin surface.
When the device has been removed the two units are disengaged by simultaneously depressing the two hook members 31 allowing the reservoir unit 5 to be pulled out of engagement with the needle unit 2 which can then be discarded. Thereafter the reservoir unit can be used again with fresh needle units until it has been emptied.
In the shown embodiment the patch portion has the same general shape as the combined device albeit somewhat larger. In alternative embodiments the patch may comprise openings or cut-out portions. For example, an area between the two support legs may be cut out allowing the underlying skin to better breath.
As seen is the user gripable portion 551 of the release member initially covered by a portion of the actuation member, this reducing the probability that the user erroneously uses the release member instead of the actuation member. Further, the actuation and release members (or portion thereof) may be colour coded to further assist the user to correctly use the device. For example, the actuation member may be green to indicate “start” whereas the release member may be red to indicate “stop”.
To actuate the needle the user grips the flexible strip forming the user gripable portion 541 (which preferably comprises adhesive portions to hold it in its shown folded initial position) and pulls the needle actuation portion 542 out of the housing, the actuation member 540 thereby fully disengaging the housing. More specifically, when the ramp surface 544 is moved it forces the latch 527 away from the lower arm to thereby release it, after which the release portion 528 disengages the ramp allowing the two legs to be pulled out of the housing. As seen in
In the shown embodiment the release member is in the form of a strip formed from a flexible material and having an inner and an outer end, the strip being threaded through an opening 512 in the housing, the strip thereby forming the user gripable portion 551 and the needle retraction portion 552, the inner end of the strip being attached to the housing and the outer end of the strip being attached to a peripheral portion of the sheet member 570 or, alternatively, a peripheral portion of the housing. In the projection shown in
When the user decides to remove the needle unit from the skin, the user grips the user gripable portion 551, lifts it away from the housing and pulls it upwardly whereby the loop shortens thereby forcing the lower arm upwardly, this position corresponding to an intermediate release state. By this action the lower arm engages the inclined edge portion 529 of the catch 527 thereby forcing it outwardly until it snaps back under the lower arm corresponding to the position shown in
Advantageously, the actuation and release members may be formed and arranged to communicate with the reservoir unit (not shown). For example, one of the legs of the actuation member may in its initial position protrude through the housing to thereby engage a corresponding contact on the reservoir unit, this indicating to the reservoir unit that the needle unit has been attached, whereas removal of the actuation member will indicate that the needle has been inserted and thus that drug infusion can be started. Correspondingly, actuation of the release member can be used to stop the pump.
In
The control and actuation means comprises a pump actuating member in the form of a coil actuator 581 arranged to actuate a piston of the membrane pump, a PCB or flex-print to which are connected a microprocessor 583 for controlling, among other, the pump actuation, contacts 588, 589 cooperating with the contact actuators on the needle unit, signal generating means 585 for generating an audible and/or tactile signal, a display (not shown) and an energy source 586. The contacts are preferably protected by membranes which may be formed by flexible portions of the housing.
In
In the above described embodiments, the transcutaneous device has been in the form of a unitary needle device (e.g. an infusion needle as shown or a needle sensor (not shown)), however, the transcutaneous device may also be in the form of a cannula or a sensor in combination with an insertion needle which is withdrawn after insertion thereof. For example, the first needle portion may be in the form of a (relatively soft) infusion cannula (e.g. a Teflon®(cannula) and a there through arranged removable insertion needle. This type of cannula needle arrangement is well known from so-called infusion sets, such infusion sets typically being used to provide an infusion site in combination with (durable) infusion pumps.
Thus,
In a situation of use the assembly is moved downwardly, either manually or by a releasable insertion aid, e.g. a spring loaded member acting through an opening in the housing (not shown) whereby the cannula with the projecting insertion needle is inserted through the skin of a subject. In this position the lower member engages the coupling member 657 to thereby lock the cannula in its extended position, just as the coupling member 667 is released by the release member 622 thereby allowing the upper member to return to its initial position by means of the first spring.
When the user intends to remove the delivery device from the skin surface, the user grips the gripping portion of the tab and pulls it in a first direction substantially in parallel with the skin surface, by which action the flexible strip 677 releases the coupling member 657 from the lower member whereby the lower member and thereby the cannula is retracted by means of the second spring. When the cannula has been withdrawn from the skin, the user uses the now unfolded tab to pull off the entire delivery device from the skin surface, for example by pulling the tab in a direction away from the skin surface.
With reference to
More specifically, the patch unit comprises a flexible sheet 721 with a lower adhesive surface and an opening 722 for the cannula, a patch housing with top 723 and base 724 portions, the base portion being attached to the upper surface of the sheet. The patch housing comprises an opening 725 for the cannula arranged just above the opening in the sheet, as well as a coupling in the form of two flexible arms 726 allowing the inserter to be attached.
The inserter unit comprises an inserter housing with top 733 and base 734 portions, the base portion comprising two walls 735 with upper inclined edges serving as a ramp 736 for an inserter assembly 740. The inserter assembly comprises an inserter 750, a needle holder 760 comprising a needle 761 protruding there from, a cannula holder 770 with a cannula 771 protruding there from, the cannula comprising a proximal needle penetratable septum, two springs 751 mounted on respective spring guides 752 on the inserter, and a release and retraction strip 780 (see
Next, with reference to
At this point the soft catheter has been placed at the desired place and what remains is for the user to withdraw the needle and remove the remaining inserter assembly and housing. In the shown embodiment the inserter is locked in place in its foremost position. The needle holder is released from the inserter and the needle is retracted by the user pulling the strip attached to the needle holder until the needle has been locked in its fully retracted position with the distal pointed end arranged within the inserter housing (see
With reference to
With reference to
Turning to an exemplary embodiment, the medical device is in the form of a unitary patch unit 800 comprising a housing mounted on a patch of flexible sheet material, the inserter housing comprising the entire insertion mechanism including the cannula.
More specifically, the patch unit comprises a flexible sheet 821 with a lower adhesive surface and an opening 822 for the cannula (in this embodiment a flexible soft catheter), a patch housing with top 823 and base 824 portions (823′ indicates a top portion shown upside down), with the base portion being attached to the upper surface of the sheet, wherein the top portion comprises a 45 degrees guide 825 for the cannula holder (see below). The patch housing comprises an opening for the cannula and needle arranged just above the opening in the sheet, as well as a coupling in the form of two flexible arms 826 allowing a delivery device to be attached. The base portion comprises two walls 835 with upper inclined edges serving as a ramp 836 for an inserter assembly 840. The inserter assembly comprises an inserter 850 with an attached needle 861 and a cannula holder 870 attached to a cannula 871 and adapted for moving the cannula relative to the inserter and thereby the needle (see
To save space in the patch housing, the soft catheter introducing mechanism is placed perpendicular in respect of the direction of introduction. The soft catheter 871 is placed in a groove 855 in the inserter that guides the soft catheter, the groove having a 90 degrees bend to change the direction of the soft catheter during the introduction. As appears from
Next, with reference to
As the proximal end of the soft catheter is stationary, it may be provided with a pointed hollow needle which would allow a reservoir unit basically as shown in
Indeed, the concept of a medical device comprising an angled insertable cannula which in its inserted position is covered by a detachable portion of the device can be used in combination with any type of cannula-needle arrangement, not only the embodiments disclosed above. The assembly may also be provided as a unitary device in which an opening may be formed allowing the insertion site to be inspected during use.
Although it is believed that the above-disclosed medical devices can be manufactured in a cost-effective manner, frequent changes of cannula or needle devices, e.g. infusion sets, is one of the cost drivers and poor convenience factors in CSII (continuous subcutaneous insulin infusion) treatment. It is today generally not recommended to wear an infusion set for more than 2 days before changing it, but in practice pump users wear them for a longer time—on average 3.3 days. One of the limiting factors in wear time is that the risk of bacterial growth at the infusion site increases with longer wear times. The preservatives in insulin are anti-bacterial, but since they don't get in touch with the outside of the infusion needle they have no effect on this bacterial growth.
With a porous infusion needle or cannula having a pore size between the molecular size of the preservatives (typically small molecules like meta-cresol and phenol) and the molecular size of insulin (rather large molecules), some of the preservatives will move to the outside of needle where they can reduce bacterial growth and potentially increase the safe wear time of the infusion needle. For a polymeric cannula the entire tube or portions thereof thus can advantageously be made from a polymeric material allowing the preservatives to diffuse from the cannula and into the subcutis. A cannula may also be made from a fibrous material as used in micro tubes for dialysis. For a steel needle laser drilling of micro side openings would allow preservatives together with insulin to diffuse out in the subcutis along the needle (unless the side openings are made so small that they would be an effective barrier to the insulin molecules). The porous portion of the needle may be uniformly porous or it may be adapted to cause weeping at a non-uniform flow rate along the length of the porous portion. A porous portion may e.g. be located at the portion of the needle or cannula intended to cross the skin barrier.
US 2004-0220536, which is hereby incorporated by reference, discloses a surgical needle with a porous distal portion from which a liquid injectate will weep or ooze multidirectionally under injection pressure while the porous distal portion of the needle is inserted into a body surface. More specifically, it is disclosed how a needle or cannula can be provided with pores from which a liquid will ooze. For example, the porous portion of the needle can be fabricated from any of a number of different “open cell” porous materials (i.e., materials in which the pores are interconnecting). For example, a distal portion can be fabricated from a porous sintered metal, such as forms a non-woven matrix of metal fibers selected from such metals as stainless steel, tantalum, elgiloy, nitinol, and the like, and suitable combinations of any two or more thereof. Generally, the metal fibers will have a diameter in the range from about 1.0 micrometer to about 25 micrometer. A non-woven matrix of metal fibers having these desired properties that can be used in manufacture of the porous distal portion of the invention needle is available from the Bekaeart Corporation (Marietta, Ga.), and is sold under the trademark, BEKIPOR® filter medium. A porous portion of the needle can also be fabricated from such porous materials as a porous polymer, such as a porous polyimide, polyethylene, polypropylene, polytetrafluroethylene, and the like. Such porous polymers are disclosed, for example, in U.S. Pat. No. 5,913,856, which is hereby incorporated by reference in its entirety. Alternatively, a porous ceramic can be used, such as is known in the art for use in ceramic filters and separation membranes, or a porous metal (also known as an expanded metal) or carbon, such as is known in the art for use in filters or bone grafts. For example, Mott Corporation (Farmington, Conn.) manufactures porous metals for use in various types of filters. If the porous filter medium is flexible, a porous portion of a needle can be fabricated by wrapping the filter medium, which is available commercially as a flat sheet, one or more times around an axis while creating a hollow central core. The porous portion of the needle can then be fused in fluid-tight fashion (e.g. welded) to a non-porous hollow needle shaft using methods known in the art. To create a porous portion of the needle having decreasing impedance to fluid flow, a porous filter medium or metal mesh having an appropriate porosity gradient can be employed in fabrication of the porous portion. Alternatively, a porous portion can be created from a non-porous material (e.g., a metal) using a cutting laser and techniques known in the art to punch pores into the needle segment (i.e. by a process of laser etching). For example, the nonporous hollow shaft, porous portion, and point of a needle can be fabricated of metal in a single piece, for example, from a conventional hypotube. In this scenario, a metal-cutting laser is used to create a segment of the needle that has appropriate porosity, for example, a porosity gradient within a portion of the needle to equalize fluid impedance along the length of the porous portion of the needle.
The direct advantage of the above principle is a reduced bacterial growth at the infusion site compared with standard infusion needles. This increases user convenience, since an infusion set can be worn longer before it needs to be replaced—a replacement that can be painful especially for soft infusion needles where a large diameter steel needle is used to guide the soft infusion needle into the skin. Since infusion sets are typically rather expensive, increased wear time will furthermore be cost-attractive to pump users.
In the above description of the preferred embodiments, the different structures and means providing the described functionality for the different components have been described to a degree to which the concept of the present invention will be apparent to the skilled reader. The detailed construction and specification for the different components are considered the object of a normal design procedure performed by the skilled person along the lines set out in the present specification.
| Number | Date | Country | Kind |
|---|---|---|---|
| PA 2004 01434 | Sep 2004 | DK | national |
| PA 2004 01894 | Dec 2004 | DK | national |
| PA 2005 00115 | Jan 2005 | DK | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP2005/054758 | 9/22/2005 | WO | 00 | 4/11/2008 |
