Device intended to be attached to the skin
The present invention relates to a device which is intended to be attached directly or indirectly to skin.
The invention also relates to an apparatus for removing a device from skin, wherein the device is attached to the skin by means of a first layer of the device.
The invention also relates to an apparatus for attaching a device to skin, wherein the device is intended to be attached to the skin by means of a first layer of the device .
The invention also relates to a method for removing a device from skin, wherein the device is attached to the skin by means of a first layer of the device.
The invention also relates to a method for attaching a device to skin, wherein the device is intended to be attached by means of a first layer of the device.
A patient who undergoes a dialysis treatment is bound to a dialysis machine three to four times a week. The cannulas used are designed and dimensioned to be capable of handling the flows in question which may occur during dialysis . Careful securing is required in order to enable the cannulas to maintain an exact position in a fistula also when the cannula is subjected to external influence. If it is not secured the cannula can penetrate too deeply into a blood vessel, or be pulled out and come loose. An external pulling action which occurs is the one from blood- filled sets of tubes between the patient and the dialysis machine. The set of tubes has such an intrinsic weight that it has to be secured.
Today, different types of surgical tape and preformed adhesive plasters which are applied together with the cannula, are often used for securing a cannula. There is no routine or standardized technique for how this should be done. Medical staff will do it differently and individually according to what suits them best. This is not optimal, and does not provide the desired safety.
In the two published specifications US 2002/0156423A1 and WO 00/12165, some variants of different appliances for securing cannulas in the skin are shown. Common for these is that they are glued and/or taped onto the patient's skin. In removing, this is done by "tearing off" and/or by applying alcohol in order to dissolve the adhesive. This implies that the adhesion should not be too strong since the cannula should be possible to remove without causing problems or discomfort to the patient.
Another way of detaching adhesive plasters and tapes from skin is to use a special type of adhesive which loses its adhesiveness when it is illuminated with visible light. The adhesive plaster is covered by a light-protecting film. The film is then removed to let light in when it is desired to remove the adhesive plaster. The purpose of this adhesive plaster is to facilitate the removal of the adhesive plaster from a sensitive skin and to minimize the risk of the wound being torn open in connection with the removal .
The object of the present invention is to provide a device intended to be attached to the skin, and which does not have the problems associated with US 2002/0156423A1 and WO 00/12165.
The device according to the invention comprises
- a first layer which comprises an electrochemically active adhesive, said first layer comprising a first
surface which is intended to be directly or indirectly- attached to the skin, as well as a second surface which faces away from the first surface,
- a second layer which has a first surface which is in electrical contact with the second surface of the first layer, as well as a second surface which faces away from the first surface of the second layer, and
- a kit which is directly or indirectly arranged on the second surface of the second layer.
The apparatus according to the invention for removing the device from skin comprises a first contact member which is electrically connected to a first terminal of a current source, and a second contact member which is electrically connected to a second terminal of the current source, wherein the first contact member is intended to be brought into electrical contact with the second layer of the device, and wherein the second contact member is intended to be brought into electrical contact with the skin, so that electrical current in a first current direction is caused to flow between the contact terminals and through the first layer of the device .
The apparatus according to the invention for attaching the device to skin comprises a first contact member which is electrically connected to a second terminal of a current source, and a second contact member which is electrically connected to a first terminal of the current source, wherein the first contact member is intended to be brought into electrical contact with the second layer of the device, and wherein the second contact member is intended to be brought into electrical contact with the skin so that electrical current in a second current direction is caused to flow between the contact members and through the first layer of the device.
The method according to the invention for removing the device from skin comprises
- connecting the second layer of the device to a first terminal of a current source and connecting the skin to a second terminal of the current source, and
- causing the current source to generate a current in a first current direction, which flows between the second layer and the skin and through the first layer in order to break and/or weaken the adhesive bonds of the electrochemically active adhesive so that the first layer releases from the skin and/or from the second layer .
The method according to the invention for attaching the device to skin comprises
- positioning the device on the skin so that the first layer of the device abuts directly or indirectly against the skin,
- connecting the second layer of the device to a second terminal of a current source and connecting the skin to a first terminal of the current source, and
- causing the current source to generate a current in a second current direction, which flows between the second layer and the skin and through the first layer, in order to reinforce the adhesive bonds of the electrochemically active adhesive so that the first layer adheres to the skin and/or the second layer.
Electrochemically active adhesive, as used herein, refers to an adhesive having adhesive and electrically conductive properties. The adhesive bonds of the electrochemically active adhesive are broken, weakened or reinforced when it is subjected to an electrical impulse and electrical current flows through the electrochemically active adhesive. This technique is sometimes called CDM (Controlled Delamination Material) .
The electrochemically active adhesive used in the present
invention is to a large extent similar to the properties exhibited by the electrochemical composition in WO 2007/142600.
The invention will be described more closely in the following with reference to the drawings .
Figure 1 shows a device according to a first embodiment of the invention, wherein the device is attached directly to skin.
Figure 2 shows the device according to a second embodiment of the invention, wherein the device is attached to a conductive layer which is applied to the skin.
Figure 3 shows an apparatus which is intended to remove and/or attach the device to skin.
Figure 4 shows some different exemplary embodiments of different kits which can be comprised by the device.
Figure 5 shows another exemplary embodiment of a kit which can be comprised by the device.
The device described in the following comprises a first active surface which is attached to a second active surface. The active surfaces act as electron and/or ion transmitters and receivers . The surfaces are connected to each other through a binding layer which comprises an electrochemically active adhesive. When a voltage is applied between the active surfaces an electrical DC current is caused to flow through the electrochemically active adhesive. This implies that the adhesive bonds of the electrochemically active adhesive is broken, weakened or reinforced in or between the binding layer and at least one of the active surfaces . The properties of the
electrochemically active adhesive are controlled by the current direction of the DC current. When the DC current flows in a first current direction the adhesive bonds are weakened and/or broken in such a way that the electrochemically active adhesive releases from at least one of the active surfaces. When the DC current flows in a second current direction, said second current direction being opposite to the first current direction, the adhesive bonds are reinforced in such a way that the electrochemically active adhesive hardens and adheres to at least one of the active surfaces .
A preferred composition of the electrochemically active adhesive of the invention comprises hydrogels, which can absorb a lot of water, a matrix, e.g. made of polyester, and an electrolyte consisting of e.g. a salt, an ionic liquid and/or a conductive polymer. A preferred composition of the electrochemically active adhesive has Ag/AgCl as a redox pair at the active surface.
The conductivity of the electrochemically active adhesive can advantageously be achieved by an addition of an ionic liquid which is disclosed in greater detail in WO 2007/142600. Preferably, the conductivity of the electrochemically active adhesive is entirely constituted of this ionic liquid.
DC current, as used herein, refers to an electrical current with a constant current direction. Examples of different DC currents are pure DC current, which can be obtained from, for example, a battery, and pulsed DC current which can be obtained from, for example, an apparatus which converts AC current to DC current. The invention is applicable to all kinds of electrical DC currents with a constant current direction.
Figures 1 and 2 show preferred embodiments of a device according to the invention, said device being intended to be attached directly or indirectly to the skin 1 of a person. The device comprises a first layer 2 which comprises an electrochemically active adhesive 3. The first layer 2 has a first surface 4 which is intended to be attached directly or indirectly to the skin 1. The first layer 2 further has a second surface 5 which faces away from the first surface 4.
The device further comprises a second layer 6. The second layer 6 has a first surface 8 which is in electrical contact with the second surface 5 of the first layer 2. The second layer 6 furthermore has a second surface 9 which faces away from the first surface 8 of the second layer 6. The second layer 6 is electrically conductive across at least parts of the first surface 8, preferably the entire first surface 8 is electrically conductive. The first surface 8 can thus act as an active surface.
Finally, the device comprises a kit 17, 18, 20, 21 which is directly or indirectly arranged on the second surface 9 of the second layer 6.
Figure 1 shows a first preferred embodiment of a device according to the invention, wherein the first surface 4 of the first layer 2 is attached directly to the skin 1. In this embodiment, the first surface 8 of the second layer 6 and the skin 1 act as active surfaces . When removing the device from the skin 1 an electrical DC current in first current direction is applied across the first layer 2 by using an electrical DC current source 13, for example a battery 13. The first terminal 14 of the DC current source 13 is then brought into electrical contact with the first surface 8 of the second layer 6, and the second terminal 15 of the DC current source 13 is brought into electrical contact with the skin 1. An
electrical DC current is then caused to flow in the first current direction through the first layer 2 and the electrochemically active adhesive 3. The adhesive bonds of the electrochemically active adhesive 3 are then weakened and/or broken so that the first layer 2 releases from the skin 1 and/or from the first surface 8 of the second layer 6.
Electrical DC current can also be used in attaching the device to the skin 1 (not shown) . The first terminal 14 of the DC current source 13 is then brought into electrical contact with the skin 1, and the second terminal 15 of the DC current source 13 is brought into electrical contact with the first surface 8 of the second layer 6. An electrical DC current is then caused to flow in a second current direction, said second current direction being opposite to the first current direction, through the first layer 2 and the electrochemically active adhesive 3. The adhesive bonds of the electrochemically active adhesive 3 are then reinforced so that the first layer 2 adheres to the skin 1 and/or to the first surface 8 of the second layer 6.
The fact that the skin 1 has a certain electrical conductivity is utilized in the above embodiments.
However, sometimes it might be necessary to increase the electrical conductivity of the skin. One method is to apply to the skin an electrically conductive layer in the form of an electrically conductive printing ink which increases the electrical conductivity of the skin. There are primarily three different types of conductive printing inks: metal-based, carbon-based, and polymer-based. All these inks consist of some kind of intrinsically conductive particles. Common to them is also that these particles have to get close enough to each other in the dried ink to render the ink conductive.
The above-mentioned printing inks are well known and are available on the market. Examples of leading printing inks are BAYTRON P from BAYER and SUN TRONIC from SUN CHEMICALS .
Figure 2 shows a second preferred embodiment, where an electrically conductive layer 10, in the form of conductive printing ink, is applied to the skin 1. The electrically conductive layer 10 has a first surface 11, which is attached to the skin 1. The electrically conductive layer 10 has a second surface 12 which faces facing away from the first surface 11. The first surface 4 of the first layer 2 is directly attached to the second surface 12 of the electrically conductive layer 10. In this embodiment, the first surface 8 of the second layer 6 and the second surface 12 of the electrically conductive layer 10 act as active surfaces. In removing the device from the skin 1, the first terminal 14 of the DC current source 13 is brought into electrical contact with the first surface 8 of the second layer 6 and the second terminal 15 of the DC current source is brought into electrical contact with the second surface 12 of the electrically conductive layer 10. An electrical current is then caused to flow through the first layer 2 and the electrochemically active adhesive 3. The adhesive bonds of the electrochemically active adhesive 3 are then weakened and/or broken, so that the first layer 2 releases from the second surface 12 of the electrically conductive layer 10 and/or from the first surface 8 of the second layer 6.
Also here, electrical DC current can be used when attaching the device to the skin 1 (not shown) . The first terminal 14 of the DC current source 13 is then brought into electrical contact with the second surface 12 of the electrically conductive layer 10, and the second terminal 15 of the DC current source 13 is brought into electrical
contact with the first surface 8 of the second layer 6. An electrical DC current is then caused to flow in a second current direction, said second current direction being opposite to the first current direction, through the first layer 2 and the electrocheraically active adhesive 3. The adhesive bonds of the electrochemically active adhesive 3 are then reinforced so that the first layer 2 adheres to the skin 1 and/or to the second layer 6.
Figure 3 shows an apparatus 22 which is intended to remove the device from the skin 1 by generating a voltage between the second layer 6 and the skin 1. The apparatus 22 comprises a first contact member 23 which is connected to the first terminal 14 of the DC current source 13, and a second contact member 24 which is electrically connected to the second terminal 15 of the DC current source 13. The contact surface 25 of the first contact member 23 is intended to be brought into electrical contact with the second layer 6 of the device, and the contact surface 26 of the second contact member 24 is intended to be brought into electrical contact with the skin 1. During use, a voltage is applied between the second layer 6 and the skin 1 so that a DC current in a first current direction is caused to flow through the first layer 2. The adhesive bonds of the electrochemically active adhesive 3 are weakened and/or broken so that the first layer 2 releases from the skin 1 and/or from the first surface 8 of the second layer 6.
The apparatus 22 is also intended for attaching the device to the skin 1. In one embodiment not shown in the figures, the apparatus 22 comprises a means for switching the electrical connections of the apparatus 22 so that the first contact means 23 becomes electrically connected to the second terminal 15 of the DC current source 13, and the second contact member 24 becomes electrically
connected to the first terminal 14 of the DC current source 13. The contact surface 25 of the first contact member 23 is intended to be brought into electrical contact with the second layer 6 of the device, and the contact surface 26 of the second contact member 24 is intended to be brought into electrical contact with the skin 1. During use, a voltage is applied between the second layer 6 and the skin so that a DC current in a second current direction which is opposite to the first current direction, is caused to flow through the first layer 2. The adhesive bonds of the electrochemically active adhesive 3 are reinforced so that the first layer 2 adheres to the skin 1 and/or to the first surface 8 of the second layer 6.
In order not to risk that the respective contact surfaces 25, 26 of the contact members 23, 24 are positioned on an erroneously active surface, the contact surfaces 25, 26 should be designed differently. The contact surface 25 of the first contact member 23 which is intended to abut in electrical contact against the second contact surface 8 of the second layer 6, should be substantially smaller than the contact surface 26 of the second contact member 24 which is intended to abut in electrical contact against the skin 1.
In order not to risk causing personal damage to the user, the operating voltage of the DC current source 13 can be limited to 10V, preferably to 5V.
In the following some exemplary embodiments of what the kit 17, 18, 20, 21 can be constituted of will be described.
Figure 4 shows some exemplary embodiments of how different types of kits 17, 18, 20 can be fixed to the arm of a dialysis patient by means of a device according
to the invention. In order to secure the position of a cannula tube 16 against external pulling influence, e.g. arm movements, rapid, involuntary movement, heavy- dialysis tubes, etc., a kit in the form of a fixing device 17 which is fixed to the wrist of the patient, is used. The fixing device 17 surrounds at least parts of the cannula tube 16 so that the cannula tube 16 is prevented from moving in the longitudinal direction relative to the fixing device 17. The fixing device 17 is directly or indirectly arranged on the second layer 6 of the device (not shown in Figure 4) . The first surface 8 of the second layer 6 is in electrical contact with the second surface 5 of the first layer 2. The first surface 4 of the first layer 2 is directly or indirectly arranged against the skin of the patient in accordance with one of the above-described embodiments according to Figure 1 and Figure 2.
In order to secure the position of the cannula tube 16 so that the cannula tube 16 does not move in the lateral direction, a kit in the form of a supporting device 18 can be used. The cannula tube 16 extends through a frame on the supporting device 18, wherein the frame prevents the tube 16 from being displaced in the lateral direction. The supporting device 18 is directly or indirectly arranged on the second layer 6 of the device (not shown in Figure 4) . The first surface 8 of the second layer 6 is in electrical contact with the second surface 5 of the first layer 2. The first surface 4 of the first layer 2 is directly or indirectly arranged against the skin of the patient in accordance with one of the above-described embodiments according to Figure 1 and Figure 2.
In order to ensure that a cannula 19 in a vein or artery does not move, a kit in the form of a securing device 20 can be used. The securing device 20 surrounds the cannula
19 so that the cannula 19 is prevented from moving in the longitudinal direction and lateral direction relative to the securing device 20. The securing device 20 is directly or indirectly arranged on the second layer 6 of the device (not shown in Figure 4) . The first surface 8 of the second layer 6 is in electrical contact with the second surface 5 of the first layer 2. The first surface 4 of the first layer 2 is arranged directly or indirectly against the skin of the patient in accordance with one of the above-described embodiments according to Figure 1 and Figure 2.
Figure 5 shows an exemplary embodiment of securing a cannula tube 21 from moving in the longitudinal direction and the lateral direction. The cannula tube 21 is rigidly arranged directly or indirectly on the second layer 6 of the device. The first surface 8 of the second layer 6 is in electrical contact with the second surface 5 of the first layer 2. The first surface 4 of the first layer 2 is arranged directly or indirectly against the skin of the patient in accordance with one of the above-described embodiments according to Figure 1 and Figure 2.
In the foregoing, the invention has been described on the basis of some specific embodiments within dialysis treatment. It is appreciated, however, that other embodiments and variants are possible within the scope of the following claims. For instance, the invention can be used for fixing a cannula of a diabetic, wherein the diabetic has an insulin pump and a tube between the insulin pump and the cannula. Another field of use of the invention is when attaching devices in the form of body sensors to the skin, such as e.g. ECG electrodes, pulse electrodes, etc. These are often attached with an electrically conductive adhesive gel such as, for example, TAC GEL. These sensors are normally removed by tearing the sensors from the skin, and can in some cases
cause a redness to the skin. The skilled person will of course appreciate that the invention is also applicable in many other fields, where devices are attached to skin. Further examples of kits can be number signs in competition situations, which are glued to the skin, or pulse sensors which are attached to the body for measuring the pulse during physical activity.
Above all, by means of the invention, the advantages are achieved that devices which are attached to the skin adhere very well, and that the removal from the skin can be done without using solvents or tearing off. This is achieved in that the adhesive bonds of the electrochemically active adhesive of the invention are broken and/or weakened when a current is applied across the adhesive. This enables the device to be removed without any major discomfort to the person.