APPARATUS AND METHOD FOR LOCATING A CATHETER

Abstract: An apparatus for locating a catheter (10), the apparatus characterised in that it comprises at least two layers of material (18, 20) applied about the catheter (10), the layers (18, 20) being able to adhere together and thereby forming a sandwich, one layer of material (20) further being directly or indirectly adherable to the skin (12) of a patient, at least one of the layers of material (18, 20) having a durometer allowing same to conform substantially to the catheter (10) whereby contact between the layers (18, 20) and the catheter (10) is made about a substantial portion of the circumferential extent of the catheter (10).

Description: TITLE "Apparatus and Method for Locating a Catheter" FIELD OF THE INVENTION The present invention relates to an apparatus and method for locating a catheter. DISCUSSION OF THE PRIOR ART The present invention relates primarily to systems for securing to a patient a small diameter tube which enters any body cavity or the skin at any site, the tube then being used for the intermittent or continuous delivery of fluids and/or drugs. The invention has been particularly developed for use with epidurai catheters, and the following description of the invention will relate primarily to such catheters. However, it must be appreciated that the invention is not to be limited in its use to only epidurai catheters. Epidurai catheters are fine bore plastic tubes ranging in diameter from 1 mm to 3 mm, the tubes being soft and flexible and being inserted through a needle into the epidurai space. With this in mind, it will be appreciated that finer bore catheters may be used, such as those that are often taken through into the intrathecal space. There has recently been a rapid growth in the market for the use of epidurai catheters. In particular, for post-operative pain relief it is now possible to deliver local anaesthetic, or alternatively opiate solutions, which give good localised control of post-operative pain. There is also a moderate usage of epidurai catheters for the control of cancer pain. In this respect, post operative pain is usually present in a patient for three to five days, and it has been found that 30 to 40% of epidurai catheters will become displaced by the second or third day of normal use. Clearly, this causes significant frustration to the patient, who has been through an uncomfortable procedure to have the epidurai catheter inserted, and to the anaesthetist who has already performed the difficult procedure. Frequently, the patient is compromised and a less ideal method of pain relief is offered. In other circumstances, the anaesthetist will reinsert the epidurai catheter. The soft, flexible plastic tubes that comprise the epidurai catheters are made of a plastic that typically does not efficiently take up adhesive bonding to its surface, due primarily to the chemical nature and physical characteristics of soft plastics. In addition, the catheters are traditionally secured to the skin of a patient with a plaster dressing which lies over the catheter, the plaster dressing thus only providing a small area of contact upon the circular catheter tube. Moreover, the skin below the dressing tends to perspire, such that the perspiration interferes with the bonding between the tube and the dressing securing it to the patient. Some attempts have been made to provide catheter stabilising means which fix the catheter in position either at the puncture site or adjacent thereto. Such include adhesive transparent films that are adhered directly over a catheter and its puncture site. These devices suffer the same problem as that noted above in the use of plaster dressings. A further problem of the prior art is that associated with the need to periodtcally inspect, clean and possibly apply antibiotics or other topical drugs to the puncture site and its immediate surrounding area whilst at the same time preventing entry of infectious agents. Still further, adjustment of catheters is often necessary during use. Known catheter stabilising means do not generally allow quick adjustment as the entire means must be removed, the adjustment made, and the means re-adhered to the patient. There are additional problems associated with the securing of catheters to patients. One particular problem is the contamination of epidurai catheters with talc during their insertion because of talc coming from powdered gloves. Talc subsequently is able to enter the epidurai space with a concomitant risk of fibrosis and damage. It is an aim of the invention to provide an apparatus and method for locating a catheter which is not readily prone to displacement during the expected period of use. It is a further aim of the invention to provide an apparatus and method for locating a catheter that allows ready access to and inspection of a puncture site. It is a still further aim of the present invention to provide a catheter cleaning device able to decrease the risk of contamination of catheters. BRIEF DESCRIPTION OF THE INVENTION In accordance with the present invention there is provided an apparatus for locating a catheter, the apparatus characterised in that it comprises at least two layers of material applied about the catheter, the layers being able to adhere together and thereby forming a sandwich, one layer of material further being directly or indirectly adherable to the skin of a patient, at least one of the layers of material having a durometer allowing same to conform substantially to the catheter whereby contact between the adhering medium and the catheter is made about a substantial portion of the circumferential extent of the catheter. In referring to adhesive material, it will be appreciated that where two layers of material are provided, there being a need to bond the two layers of material together, it is equally possible to provide both layers of material with an adhesive surface, or merely provide one of the two layers of material with an adhesive surface. Furthermore, it will be appreciated that the same effect would be achieved by providing two layers of material without an adhesive surface, simply applying an adhesive shortly prior to bonding the two layers together. Indeed, the term adhesive material is to be interpreted to include those possibilities. It will also be appreciated that it may be possible to provide a single piece of material, folded over to locate the catheter therebetween, to still provide the sandwich-type arrangement referred to above. Furthermore, multiple pieces of material could be utilised to secure the two layers located immediately about the catheter, to the patient. Thus, it is envisaged that more than two layers of adhesive material may be utilised. Nonetheless, the preferred configuration is to simply provide two layers of adhesive material, a lower layer being a double-sided adhesive material (having an adhesive surface on both sides thereof) to be secured to the patient. The second layer of adhesive material may then simply be located across the first layer to secure the catheter therebetween, and thus to secure the catheter to the patient, at least one of the layers of adhesive material being provided in a material of sufficiently low durometer so as to conform substantially to the catheter. The provision of two layers of adhesive material, having the catheter located therebetween, will provide a significantly greater area of surface contact between the catheter and the adhering medium than would be obtainable simply by providing a single layer of a plaster dressing. As noted above however, the area of surface contact may be further increased by one or both of the layers of adhesive material beirig of a soft, foam-like material which is capable of moulding around at least a portion of the circumference of the catheter. Such a material would allow the catheter to be pressed into the material so that the material would mould around, and provide adhesive contact with, a large portion of the surface of the catheter. By forming both layers in such a material, when together the two layers may be compressed to mould around the catheter to allow adhesion with almost the full circumferential surface area of the catheter. In such a configuration, not only is strong adhesion provided, but the non- adhered space is small, thus ensuring only a small volume within which perspiration or other fluids may gather. Alternatively, it is envisaged that the adhering medium may be provided as two layers of adhesive material, one or both thereof bearing a semi-circular groove therein, the catheter being of a diameter or gauge complimentary to the size of the grooves, such that the two layers may be placed over the catheter, locating the catheter in the grooves, to again provide adhesive contact over a large proportion of the surface area of the catheter. It can thus be seen that the present invention may be advantageously applied by the use of a foam adhesive tape which is of sufficiently low durometer to mould around a catheter when the catheter is pushed firmly against it, or which has within it semi-circular grooves of a radius similar to the catheter radius, to provide a maximum area of contact between the catheter and the adhesive surface of the foam tape. In a particularly preferred form, the foam tape would be transparent such that epidurai catheter markings could be seen through the tape. Catheter location by the system of this invention may then allow the adhering medium to be placed around the catheter very close to where the catheter enters the skin, this being ideal for minimising the risk of movement of the catheter within the patient. An additional layer of material may be provided, the additional layer of material defining therein a aperture proportioned to surround the epidurai puncture site. The additional layer of material is preferably able to adhere to the skin of a patient. Further, a transparent cover film is preferably provided in a releasable manner over an upper surface of the additional layer and also over the aperture. Still preferably, the additional layer is provided in the form of an annulus. The transparent cover is further preferably adhered to the annulus with a releasable adhesive capable of multiple re-seals. In accordance with the present invention there is further provided a method for locating a catheter, the method comprising the steps of: • inserting or positioning a catheter in a patient; • adhering a first layer of material to the skin of the patient substantially adjacent a puncture site; • positioning a catheter on the first layer of material; • adhering a second layer of material over the catheter to the first layer of material, thereby sandwiching the catheter between the first and second layers of material; and • manipulating the second layer of material to ensure the layers of material conform substantially to the circumferential extent of the catheter. Preferably, the method of the present invention may further comprise the additional steps of: • after positioning of the catheter on the first layer of material, placing an additional layer of material having an aperture provided therein over the puncture site such that the aperture is positioned over that puncture site and the additional layer of material overlies in part the catheter and first layer of material; • adhering the second layer of material over the catheter and overlying portion of the additional layer to the first layer of material, thereby sandwiching the catheter and overlying portion of the additional layer between the first and second layers of material. In accordance with the present invention there is further provided a catheter cleaning device, characterised in that it comprises a plug and a membrane, the plug is proportioned to be received in the lock fitting of an epidurai needle and has a lumen extending therethrough and communicating with the bore of the needle, a distal end of the plug having the membrane received thereon, the membrane further having an aperture substantially smaller than the gauge of the catheter such that as the catheter is inserted through the aperture of the membrane the aperture grips the outside surface of the catheter and removes debris therefrom. DESCRIPTION OF THE DRAWINGS The present invention will now be described, by way of example only, with reference to three embodiments and the accompanying drawings, in which:- Figure 1 is a sectional view of an existing prior art technique for securing a catheter to a patient; Figure 2 is a sectional view of a first preferred embodiment of an apparatus for locating a catheter in accordance with the present invention; Figure 3 is a sectional view of a second preferred embodiment; Figure 4 is an upper perspective view of an additional layer of material to be utilised in a third preferred embodiment; Figure 5 is a lower perspective view of the additional layer of Figure 4 showing the peeling away of adhesive masking sheets; Figure 6 is an upper perspective view of the additional layer of Figure 4 showing the transparent cover layer being lifted; Figure 7a to 7f are diagrammatic representations of the fitting of the third preferred embodiment to a patient; Figure 8 is a top plan view of the third preferred embodiment showing the transparent cover being raised by a user to allow access to the puncture site; Figure 9 is a top plan view of the third preferred embodiment showing a loop of catheter held under the transparent cover; and Figure 10 is a sectional view through a catheter cleaning device shown received in the lock fitting of an epidurai needle. DESCRIPTION Illustrated in Figure 1 is a catheter 10 shown in cross-section lying across the skin 12 of a patient. A strip of traditional adhesive plaster 14 has been located across the catheter 10, secured at either end to the skin 12 of the patient. As will be seen, adhesion between the adhesive plaster 14 and the catheter 10 lies only in that region indicated by arrow A, there also being a large space 16 within which perspiration and other fluid may gather to the detriment of the bond between the plaster 14 and the skin 12. A similar sectional view of a preferred embodiment of the present invention is illustrated in Figure 2. The adhering medium is provided in the form of two layers (18 and 20) of a reasonably thick (in the order of 2 to 4 mm), soft foam material. The bottom layer 20 is coated on both sides with an adhesive so as to be adherable to the skin 12 and the top layer 18. By manipulating or forcing the two layers 18 and 20 together, paying particular attention to the region indicated by arrow B, a good adhesive bond may be created about almost the entire circumference of the catheter 10. An alternative embodiment is illustrated in Figure 3, where the adhering medium is provided by two layers 22 and 24 which include complimentary grooves 26 and 28 located therein. The grooves 26 and 28 are preferably such as to define an aperture through the combined layers of a size similar to the size of the catheter 10. Again, the layers 22 and 24 may be appropriately coated with an adhesive to provide the required bonding between layers, upon the catheter, and upon the skin 12. Referring to each of the embodiments of Figures 2 and 3, in use the catheter 10 may be firmly fixed to a patient's skin by simply providing the operator with two pre-cut pieces of material. After the epidurai catheter 10 is inserted, the first piece of material, being a double-sided, soft, relatively thick foam tape (20 and 24 in Figures 2 and 3) may be applied directly onto the skin of the patient adjacent the epidurai catheter site. It may then be pressed firmly down onto the skin to ensure that there is good contact between all parts of the material and the skin. Once firmly attached to the skin, a sealing cover on the other side of the double- sided adhesive tape may be removed, exposing the adhesive surface thereof. The epidurai catheter may then be carefully laid onto that adhesive surface (within the groove for the embodiment of Figure 3) to be secured thereto. The second matching piece of adhesive tape (being a single sided piece of tape) has its cover removed to reveal its adhesive surface. This second piece of adhesive tape is preferably of the same size as the first piece of adhesive tape and may be pressed over the first piece of adhesive tape to cover all of its surface and the epidurai catheter. Again, in the embodiment of Figure 3, the groove is carefully aligned so as to lie over and about the catheter. The second piece of adhesive tape is pressed firmly down onto the first, and onto the catheter, to ensure that there is good adhesive contact between both layers of the adhesive tape for the whole contact length of the catheter. In the embodiment of Figure-2, particular care is taken to press down firmly on the adhesive material about the region of the catheter tube. In Figures 4 to 6 there is shown an additional layer of material, provided in the form of an annulus 30. The annulus is similarly constructed so as to comprise two layers of adhesive material, one being a layer of soft foam material 32, the other being a transparent cover film 34 having a tab 35 provided thereon. The annulus 30 defines therein an aperture 36. The annulus 30 may be arranged so as to surround the epidurai puncture site and have that site located within the aperture 36. The foam material 32 of the .annulus 30 has an adhesive lower surface to which is applied a sealing cover 38 in two halves. Slight flexing of the annulus 30 allows peeling away of the sealing cover 38 to expose the adhesive, as is seen in Figure 5. The transparent cover film 34 provides an openable, resealable cover, as shown in Figure 6, that may be manipulated by a user and lifted away from the foam material 32. The transparent cover film 34 and foam material 32 are provided with a suitable resealable adhesive which is capable of multiple re-seals. It is to be understood that the annulus 30 may be utilised as an embodiment of the present invention, in that the foam material 32 may be adhered to a patient, the cover film 34 lifted and the catheter 10 applied thereacross. The cover film 34 may then be reapplied to the foam material 32 thereby forming a sandwich. Alternatively, the annulus 30 may be utilised in combination with the bottom 20, 24 and top 18, 22 layers of Figures 2 and 3. In Figures 7a to 9 there is shown the manner in which the annulus 30 is utilised in combination with the bottom 20 and top 18 layers of the first embodiment shown in Figure 2. In Figure 7a there is shown how, after the insertion of the epidurai catheter 10 through a puncture site 40 the first or bottom layer 20 is applied directly to the skin 42 of a patient 44 adjacent the epidurai puncture site 40. The bottom layer 20 is then pressed down firmly to ensure good contact between all parts of the layer 20 and skin 42. A sealing cover 46 provided on the other side of the bottom layer 20 may then be removed, exposing the adhesive surface thereof. The catheter 10 is then carefully laid onto that adhesive surface to be secured thereto, as is shown in Figure 7b. The sealing cover 38 of the annulus 30 is then removed from the lower surface thereof, as shown in Figure 5, and the annulus 30 adhered about the puncture site 40 such that the aperture 36 overlies the puncture site 40. Further, the annulus 30 also overlies in part the catheter 10 and the bottom layer 20, as can be seen in Figure 7c. A sealing cover (not shown) provided on one side of the top layer 18 is removed and such is pressed over the first or bottom layer 20 to cover its exposed surface, the epidurai catheter 10 and the overlying portion of the annulus 30, as is best seen in Figures 7d to 7f. A user may then use their hand 48 and fingernail to press down firmly along the margins of the catheter 10 so as to ensure good adhesive contact between the layers 18 and 20 along the whole contact length of the catheter 10, as is shown clearly in Figures 7e and 7f. This action, in combination with use of appropriate foam material of appropriate durometer for the layers 18 and 20, acts to accentuate contact between the adhering medium and the catheter 10 about a substantial portion of the circumferential extent of the catheter 10. The transparent cover film 34 may be gripped by the tab 35 provided thereon and opened, as shown in Figure 8. This action allows manipulation and adjustment of the catheter 10. In addition, this feature allows for the administration of antibiotics or other topical drugs through the aperture 36 to the area surrounding the puncture site 40, as well as allowing the release of any built-up moisture, sweat and/or other fluid. The transparent nature of the cover film 34 additionally allows observation or visualisation of the puncture site 40 and its surrounding area through the aperture 36. Additionally, in use, it may be necessary to pull the epidurai catheter 10 out an extra one or two centimetres. The form of the invention shown in Figures 8 and 9 of course easily allows for this due to there being ready access to the puncture site 40. If this is done, the extra catheter material is preferably gathered to form a small loop 50, and the loop 50 may be pulled to the side so that the catheter 10 may be secured to the upper surface of the annulus 30 by the adhesive interaction between it and the transparent cover film 34 (when replaced), as shown in Figure 9. This ensures a firm fixing or location of the catheter 10 in its new position, and allows for regular servicing of the catheter 10 without having to remove the adhesive from the patient's skin 42 each time. It is envisaged that, in this form of the invention, the transparent cover is of a size such that the contact (and location on the patient) between the annulus and the catheter is at a position only a few millimetres from the epidurai catheter entry site. However, this distance may be in the order of 1 to 15 millimetres and thus the diameter of the transparent cover may be in the order of 20 to 30 millimetres. Of course, some practitioners may require (or prefer) a larger window. Accordingly, it can be seen that the apparatus and method for locating a catheter of the present invention provides good adhesive contact between substantially all of the contact surface area of a circular epidurai catheter, easily provided by a sandwich of layers of a low durometer foam to provide an excellent method of catheter fixation. The fixation system may of course be applied to other fine bore tubes, although use of the invention with epidurai catheters provides particular advantages. In Figure 10 there is shown a catheter cleaning device 60 comprising a plug 62 and a membrane, fo.r_-example an elastomeric membrane 64. The catheter cleaning device 60 may be utilised in combination with the method and apparatus of the present invention. The cleaning device 60 is utilised during placement or insertion of the catheter 10 through the male luer lock fitting 66 of epidurai needles. The membrane 64 is received over, or fixed to, a distal end 68 of the plug 62 and has an aperture 70 provided therein. The plug 62 has a bore or lumen 72 passing therethrough and through which the catheter passes freely. The aperture 70 of the membrane 64 is however of significantly less diameter or gauge than the catheter 10. The discrepancy between .the diameter of the catheter 10 and aperture 70 causes the membrane 64 to grip and in effect clean the catheter 10 as it is inserted into and through the device 60. This cleaning action acts to prevent talc from powdered surgical gloves and other debris entering the epidurai space and possibly causing fibrosis and other damage. The plug 62 is preferably substantially solid other than the lumen 72 provided therein and acts as a support for the catheter 10 inside the typical 11 mm space in the hub of the epidurai needle. The plug 62 effectively provides a splinting system that makes it easier to introduce the epidurai catheter 10. Maximum splinting of the catheter 10 is provided if the plug 62 is able to extend right to the end 74 of the needle hub. Modifications and variations such as would be apparent to the skilled addressee are considered to fall within the scope of the present invention.

Claims: CLAIMS 1. An apparatus for locating a catheter, the apparatus characterised in that it comprises at least two layers of material applied about the catheter, the layers being able to adhere together and thereby forming a sandwich, one layer of material further being directly or indirectly adherable to the skin of a patient, at least one of the layers of material having a durometer allowing same to conform substantially to the catheter whereby contact between the layers and the catheter is made about a substantial portion of the circumferential extent of the catheter. 2. An apparatus according to claim 1 , characterised in that both layers of material have an adhesive provided on at least one surface thereof. 3. An apparatus according to claim 1 , characterised in that both layers are formed from a single piece or layer of material, arranged so as to be folded over to provide the sandwich with the catheter. 4. An apparatus according to claim 1 , characterised in that a lower layer of material is provided as a double-sided adhesive material able to be secured to the skin of a patient and have the catheter adhered thereto also. 5. An apparatus according to any one of the preceding claims, characterised in that at least one of the layers of material comprises a soft, foam-like material capable of moulding about at least a portion of the circumference of the catheter, thereby providing a small non-adhered space and a small volume within which perspiration and other fluids may gather. 6. An apparatus according to any one of the preceding claims, characterised in that at least one of the layers of material comprise a semi-circular groove therein so as to allow location of the catheter therein. 7. An apparatus according to claim 6, characterised in that the or each groove is of a size complimentary to the diameter or gauge of the catheter. 8. An apparatus according to any one of the preceding claims, characterised in that an additional layer of material is provided, the additional layer of material defining therein an aperture proportioned to surround a puncture site and able to adhere to the skin of the patient thereabout. 9. An aperture according to claim 8, characterised in that a releasable transparent cover film is provided over an upper surface of the additional layer and over the aperture. 10. An aperture according to claim 8 or 9, characterised in that the additional layer is provided in the form of an annulus. 11. An apparatus according to claim 9 or 10, characterised in that the cover film is adhered to the additional layer with a releasable adhesive capable of multiple re-seals. 12. An apparatus according to any one of claims 9 to 11 , characterised in that the cover film has provided thereon a tab for gripping by a user. 13. A method for locating a catheter, characterised in that the method comprises the steps of: inserting or positioning a catheter in a patient; • adhering a first layer of material to the skin of the patient substantially adjacent a puncture site; positioning a catheter on the first layer of material; • adhering a second layer of material over the catheter to the first layer of material, thereby sandwiching the catheter between the first and second layers of material; and manipulating the second layer of material to ensure the layers of material conform substantially to the circumferential extent of the catheter. 14. A method according to claim 13, characterised in that the method further comprises the steps of: after positioning of the catheter on the first layer of material, placing an additional layer of material having an aperture provided therein over the puncture site such that the aperture is positioned over that puncture site and the additional layer of material overlies in part the catheter and first layer of material; and adhering the second layer of material over the catheter and overlying portion of the additional layer to the first layer of material, thereby sandwiching the catheter and overlying portion of the additional layer between the first and second layers of material. 15. A method according to claim 14, characterised in that the method further comprises the steps of: • peeling a transparent cover film in part from the additional layer whilst such is maintained in position about the puncture site; and • ventilating and/or applying topical treatment to the puncture site. 16. A method according to claim 14, characterised in that the method further comprises the steps of: • peeling a transparent cover film in part from the additional layer whilst such is maintained in position about the puncture site; • adjusting the position of the catheter; and • if any extra length of catheter is now available, adhering such between the upper surface of the additional layer and the cover film, thereby avoiding the need to remove the additional layer from the patient's skin to make such an adjustment. 17. A method according to any one of claims 13 to 16, characterised in that the method further comprises the insertion or positioning of the catheter through a catheter cleaning device, the device comprising a plug and a membrane, the plug is proportioned to be received in the lock fitting of an epidurai needle and has a lumen extending therethrough and communicating with the bore of the needle, a distal end of the plug having the membrane received thereon or attached thereto, the membrane further having an aperture substantially smaller than the gauge of the catheter such that as the catheter is inserted through the aperture of the membrane the aperture grips the outside surface of the catheter and removes debris therefrom. 18. An apparatus for locating a catheter substantially as hereinbefore described with reference to Figures 2 and 4 to 9. 19. An ' apparatus for locating a catheter substantially as hereinbefore described with reference to Figures 3 and 4 to 9. 20. A method for locating a catheter substantially as hereinbefore described with reference to Figures 4 to 9. 21. A method for locating a catheter substantially as hereinbefore described with reference to Figures 4 to 10.

Inventors: O'NEIL ALEXANDER GEORGE BRIAN, O'NEIL, ALEXANDER, GEORGE, BRIAN
Applicants: ONEIL ALEXANDER G B, ONEIL CHRISTINE, O'NEIL, ALEXANDER, GEORGE, BRIAN, O'NEIL, CHRISTINE
Application year: 1997
Main classification: A61M25
IPC codes: A61M25, A61M39