WO2007028200A1

WO2007028200A1 - Securing device for cannulas

Info

Publication number: WO2007028200A1
Application number: PCT/AU2006/001299
Authority: WO
Inventors: Hamish Meares
Original assignee: Hamish Meares
Priority date: 2005-09-07
Filing date: 2006-09-05
Publication date: 2007-03-15

Abstract

A device for securing a cannula arrangement at an insertion site (16) on a patient's skin is provided. The cannula arrangement has an input (72) via which intravenous fluid can be introduced. The input (72) is surrounded by a shoulder portion (76). The device includes a sheet material (30) having a surface including adhesive for attaching the sheet material (30) to the patient's skin. The surface is covered by a removable release liner (46). The sheet material (30) includes an aperture (32) therethrough. The aperture (32) is smaller in size than the shoulder portion (76) such that, operatively, the aperture (32) can be aligned with the input (72) to allow intravenous fluid to be introduced to the input (72), and prevent the shoulder portion (76) from moving through the aperture (32). In this manner, when the sheet material (30) is attached to the patient's skin, the cannula arrangement is substantially retained under cover of the sheet material (30) and is secured in position.

Description

SECURING DEVICE FOR CANNULAS FIELD OF THE INVENTION

The present invention relates to securing devices for securing in place an intravenous cannula at an insertion site on a patient's skin. BACKGROUND TO THE INVENTION

Intravenous cannulas, or catheters as they are otherwise known, are a ubiquitous medical device that is used for the infusion of fluids (e.g. normal saline, blood etc.) or drugs into a patient's vein. Cannulas typically consist of a small soft plastic tube 12 bonded to a hard plastic hub 14, see Fig. 1. In use, the tube 12 is inserted into the skin and lies mostly in the lumen of the vein. The hub 14 sits outside the insertion site 16 and allows for attachment of other devices, e.g. a one-way valve, bung or plastic tubing. Commonly, the hub is connected to a oneway valve 18 (see fig. 2) or bung, which in turn is connected to a length of plastic tubing known as a 'giving set'. The giving set acts a feed line to a syringe or bag of fluid and often an intermediary pump is provided to control the infusion.

To set up a cannula, the skin is first prepared with an alcohol swab to sterilise the skin and the insertion site. The cannula is inserted using a metal needle stylet. Upon removing the stylet, a one-way valve 18 or bung is attached to the cannula's hub 14 to prevent blood from flowing back out of the cannula. The cannula arrangement, consisting of the cannula and the valve 18, are then secured to the patient. Once the cannula arrangement is secured, the giving set is connected to the valve 18 and the infusion can begin. Most one-way valves and giving sets, in common use, have a standardised thread, known as a Luer lock, to screw-connect to one another. The most common practice for securing the cannula arrangement is to use a simple rectangular plastic adhesive membrane. The membrane is adhered to the cannula arrangement and the patient's skin around the insertion site 16. Part of the cannula arrangement is left extending from the side of the membrane to allow a giving set to be connected. Aside from securing the cannula arrangement, the membrane also acts as a dressing in order to prevent microbial access to the insertion site 16.

The manner in which the membrane secures the cannula to the patient can be categorised into two types of bonds, namely a cannula-to-membrane bond and a membrane-to-skin bond. The strength of each bond is dependent upon the surface area of contact between the respective surfaces.

In practice, during infusion, the cannula arrangement can easily get knocked or yanked, usually due to the giving set getting caught or snagged on some object. If these accidental forces exceed the strength of one of the types of bonds then the cannula can become dislodged. Clinical studies have found that there are 20-40% failure rate of cases, due to dislodgement, where this type of securing is used. The reason for this high failure rate is mainly attributable to the cannula-to-membrane bond. The cannula arrangement provides a very small surface area (typically less than 1cm²) to which the membrane adheres. This means that the cannula-to-membrane bond is very weak and fails to prevent accidental dislodgement.

When a cannula becomes dislodged it will be necessary to refit a new cannula. Not only is this a costly exercise in respect of wasting materials, as the old cannula cannot be re-used, but is also a waste of manpower. Furthermore, the act of fitting a cannula is not a very comfortable experience for the patient and, hence, it is not desirable to repeatedly put a patient through such an experience if it can be avoided. Additionally, there will be an unavoidable delay between the time the cannula becomes dislodged and the fitting of a new cannula. In certain cases of intravenous treatment this delay can be life- threatening.

An additional problem with this practice is the ability of the membrane to form an effective water-tight seal around the insertion site 16. Without such a seal, water carrying bacteria can access the insertion site 16, track down the course of the cannula into the patient and cause infection. This can, in fact, be a life-threatening problem. The problem arises because, when the membrane is placed over the cannula, initially as a flat sheet, the membrane tends to tent over the cannula. This tenting leaves a gap, between the cannula and the membrane at the patient's skin, where water can enter and track along the cannula to the insertion site 16.

Another known cannula securing device is called a Statlock. The Statlock is purely a securing device and does not act as a dressing. Hence, it is commonly used in conjunction with an adhesive membrane as dressing. The Statlock is a hard plastic locking device having an adhesive base that adheres the device to a patient's skin. Various versions of the locking device clamp on either the giving set or the cannula hub. The Statlock has been shown to have a very low dislodgement failure rate. This is due to its strong device-to-skin bond. However, the Statlock is quite a costly device to use in comparison with the adhesive membrane. Furthermore, Statlocks tends not to be adaptable for use with different types of cannulas; hence, in institutions where different types of cannulas are used, a number of associated types of Statlocks are required.

In practice, cannulas are required to be replaced within 48 hours. This can be a crucial time limit and, hence, it is important to accurately document the time when the cannula was inserted in order to know when it should be removed. Unfortunately, common current practices in this regard are highly inefficient.

A first common practice is to keep accurate documentation in a patient's medical notes. In practice, however, this is easier said than done. Aside from being a time consuming task in maintaining accurate documentation, unless the notes are constantly checked, which in a busy ward situation is impractical, the deadline can be easily missed. Furthermore, the notes can get confusing where a patient has more than one cannula, potentially in the same limb. It is not uncommon for the wrong cannula to get replaced in such confusion. A second common practice is to write a time of insertion on the dressing.

However, common dressings are water-resistant and non-absorbent which makes writing thereon very difficult.

It is an object of the present, invention to provide an efficient and cost- effective device for securing a cannula arrangement at an insertion site. It is an alternative object to provide a device for securing a cannula arrangement at an insertion site which assists in determining when the cannula needs to be removed. SUMMARY OF THE INVENTION

In its broadest form, the invention lies in an adhesive-backed sheet material which adheres to and covers a cannula arrangement, and adheres to a patient's skin. The sheet material has an aperture which is large enough to allow access to an input on the cannula arrangement, for the purpose of delivering intravenous fluid, and is small enough to prevent the cannula arrangement from moving through the aperture in order to secure the cannula arrangement against being dislodged.

According to a first aspect of the present invention there is provided a device for securing a cannula arrangement at an insertion site on a patient's skin, said cannula arrangement having an input via which intravenous fluid can be introduced, said input being surrounded by a shoulder portion, said device including: a sheet material having a surface including adhesive, for attaching said sheet material to said patient's skin, said surface covered by a removable release liner, said sheet material including an aperture there through, said aperture being smaller in size than said shoulder portion such that, operatively, said aperture can be aligned with said input, to allow intravenous fluid to be introduced to said input, and said shoulder portion is prevented from moving through said aperture; thereby when said sheet material is attached to said patient's skin surrounding said insertion site, said cannula arrangement is substantially retained under cover of the sheet material and is secured in position.

Preferably, in the case where the input projects from the shoulder portion, the aperture is sized to provide a close fit around the input. In certain embodiments, a portion of the surface surrounding the aperture is free of adhesive so that the sheet material does not adhere to the shoulder portion to allow the sheet material to be selectively rotated with respect to the input.

Preferably, a portion of the surface, surrounding the aperture, abuts and adheres to the shoulder portion. The insertion site and the cannula arrangement are ideally sealed within the cover of the sheet material. Preferably, the sheet material includes a transparent portion which allows the insertion site to be visually inspected when the sheet material is attached.

Ideally, the transparent portion is a separate transparent sheet which covers an inspection hole in the sheet material.

In exemplary embodiments, the sheet material includes a pair of slits extending from opposing sides of said sheet material towards one another and terminating proximate to said aperture, said slits allowing said sheet material to be folded back upon itself across the slits to avoid ridges being formed. Ideally, the slits terminate in circular holes which resist the formation of tears when the material is folded.

Preferably, the sheet material includes a pair of elongated portions extending from an edge of said sheet material, said elongated portions providing increased secureness against lateral forces relative to the direction of the portions.

According to another aspect of the present invention there is provided a device for securing a cannula arrangement at an insertion site on a patient's skin, said device including: a sheet material having an adhesive surface, for attaching said sheet material to said cannula arrangement and said patient's skin in order to secure said cannula arrangement in position, said adhesive surface covered by a removable release liner; and a plurality of adhesive-backed tabs, each tab including a visual indication of a different time and adapted to be selectively attached to said sheet material; wherein, at a time when the cannula arrangement is inserted and secured by said sheet material, a user may select an appropriate tab for the time and attach said appropriate tab onto said sheet material as an indication of when the cannula was inserted. Preferably, the visual indication is a colour coding and/or written text displaying the days of the week. Optionally, additional blank tabs could be included to allow a user to write additional information for display. Ideally, the tabs are provided on the release liner.

According to another aspect of the present invention there is provided a kit for securing a cannula arrangement at an insertion site on a patient's skin, said kit including: a sheet material having an adhesive surface, for attaching said sheet material to said cannula arrangement and said patient's skin in order to secure said cannula arrangement in position, said adhesive surface covered by a removable release liner; and a plurality of adhesive-backed tabs, each tab including a visual indication of a different time and adapted to be selectively attached onto said sheet material; wherein, at a time when the cannula arrangement is inserted and secured by said sheet material, a user may select an appropriate tab for the time and attach said appropriate tab onto said sheet material as an indication of when the cannula was inserted. Preferably, the kit is provided in a sterile package.

The present invention advantageously provides a reasonably cost-effective and efficient device for securing a cannula at an insertion site. Preferred embodiments provide further advantages in efficiently sealing the insertion site and therefore being self-dressing. Other embodiments advantageously provide effective means for indicating a time of insertion so that casual inspection would indicate whether the cannula needs to be removed. BRIEF DESCRIPTION OF THE DRAWINGS

A preferred embodiment of the present invention will now be described with reference to the accompanying drawings, in which: Fig. 1 is a view of a cannula inserted into a patient's skin;

Fig. 2 is the cannula of Fig. 1 additionally having a one-way valve attached;

Fig. 3 is an exploded view of a preferred embodiment of a securing device;

Fig. 4 is a perspective view of the device of Fig. 3; Fig. 5 is a top plan view of the device of Fig. 3;

Fig. 6 is a bottom plan view of the device of Fig. 3;

Fig 7 is a view of the device of Fig. 3 securing a cannula arrangement; and

Fig. 8 is a view of the secured cannula arrangement of Fig. 7 having a feed line attached. DESCRIPTION OF PREFERRED EMBODIMENT

In Figs 3-6, there is shown a preferred embodiment of a cannula securing device. The device essentially includes an adhesive-backed sheet material 30 having an aperture 32. The sheet material can be made from a variety of materials commonly used for medical purposes. Ideally, the sheet material is made from similar materials as used in wound dressings, for example, polyurethane or non-woven polyester. A reinforcing ring 34 may be provided around the aperture 32. The sheet material 30 ideally includes an inspection hole 36 which is covered by a separate transparent adhesive-backed sheet 38. In use, the inspection hole 36 is intended to surround, and the transparent sheet 38 cover, the actual insertion site16 on the patient's skin. Hence, when the sheet material 30 is adhered to the patient's skin, the insertion site 16 can be readily inspected for signs of infection etc. The sheet material 30 also includes a pair of slits 40 extending from opposing sides of the sheet material 30 towards one another. The slits each terminate with circular holes 42 proximate to the location of the aperture 32. The function of the slits will be explained later.

As shown in Figs. 3-5, the sheet material ideally has a C-shaped section which defines a pair of elongated portions 44, the significance of which will be explained later.

The adhesive back of the sheet material 30 and transparent sheet 38 are normally covered by two release liners 46, 48. Each liner 46, 48 is conveniently provided with a portion 50, 52 which can be gripped by a user to remove the liners 46, 48 before applying the device. It will be appreciated, that the device could be provided with only one release liner.

Release liner 46 is provided with a number of adhesive backed tabs 54. A number of the tabs 54 are provided with an indication of time, for example text indicating different days of the week, as shown. Optionally, the tabs 54 could instead, or additionally, be colour-coded to indicate different times. When a user applies the device, following cannula insertion, the user can select an appropriate tab indicating the insertion time and place the tab prominently on the upper surface of the sheet material 30. In this manner, a subsequent casual inspection of the tab will indicate when the insertion occurred and reveal whether it is time for the cannula to be removed or replaced. Optionally, as shown, a number of blank tabs could be provided to allow a user to write and display additional information, for example a precise time of insertion. Instead of providing the tabs on the release liner 46, the tabs could be provided on a separate release liner (not shown). To ensure that the tabs are convenient for use, the tabs and device would be provided as a kit and ideally be packaged together in a sterile package. The device is ideally suited for securing a cannula arrangement consisting of the cannula 12, 14 and an attached valve 18, as shown in fig. 2. Standard valves 18 include an input 72, to which a feed line 74 (or giving set) can be connected. The input 72 is surrounded by a shoulder portion 76. The shoulder portion 76 provides a convenient surface to which the portion of the sheet material 30 around the aperture 32 can adhere and allow the input 72 to extend through the aperture 32. Nevertheless, it is anticipated that the device could be used on just the cannula, as per fig. 1. The cannula hub 14 has an input hole 82 to which a one-way valve 18 can be connected. Provided there is sufficient area surrounding the input hole 82 to act as a shoulder portion, the sheet material, surrounding the aperture 32, could adhere to such a shoulder portion. In which case, the one-way valve 18 could be connected to the input hole 82 via insertion into the aperture 32.

In less preferred embodiments, it may be desired to apply the sheet material 30 before the cannula 12 has been inserted into the patient. In such cases, it would be preferred to allow the sheet material 30 to be capable of rotating with respect to the input 72 to allow the orientation of the sheet material 30 to be adjusted after inserting the cannula 12. The aperture 32 would need to be sized to provide a close fit around the input 72 to give an effective seal. Additionally, the portion of the surface surrounding the aperture 32 would need to be free of adhesive to prevent the sheet material 30 from adhering to the shoulder portion 76 and allow the sheet material 30 to be rotated about the input 72. To apply the device to an inserted cannula arrangement, as per Fig. 2, after the release liners 46, 48 are removed the aperture 32 is aligned with the input 72. The aperture 32 is sized to allow the input 72 to extend there through and is small enough so that the sheet material 30 surrounding the aperture 32 is adhered to the shoulder portion 76, thus sealing the shoulder portion 76 within the sheet material 30. Hence, the aperture 32 is small enough so that the shoulder portion 76 is unable to move through the aperture 32. The sheet material 30 is then adhered to the patient's skin with the transparent sheet 38 covering the insertion site 16. As the sheet material 30 is being applied, the front section of the material 30 is folded back across the slits 40 and adheres to the back section of the material 30. The circular holes 42 act to reinforce the material 30 against tearing during this folding process. The slits 40 and the folding process ensure that ridges are not formed as the sheet material 30 is applied, thus giving the device a more streamlined appearance. It has been found that the device effectively seals the insertion site 16 and the cannula arrangement within the cover of the sheet material 30. In other words the device is self-dressing. However, it is anticipated that an additional dressing could be applied over the device if desired. In less preferred embodiments having no slits 40, ridges can occur at the side of the sheet material 30 as it is applied. Although it has been found that these ridges do not necessarily affect the effectiveness of the sealing provided by the device, the ridges do not provide a pleasing look to the device.

Once the device is in place, the cannula arrangement is retained within and secured by the sheet material 30. A feed line 74 can be connected to the input 72. Given that in place, the sheet material 30 completely surrounds the cannula arrangement, the sheet-to-skin bond acts to secure the cannula in place and resist potential dislodgment forces. The elongated portions 44, which in place are arranged on either side of the input 72, provide additional secureness against lateral and vertical forces.

While the present invention has been described with reference to a specific embodiment, it will be appreciated that various modifications and changes could be made without departing from the scope of the invention. For example, some valves used with cannulas have more than one input so that a mixture of fluids can be applied to the cannula. In such circumstances, the device could include additional apertures located on the sheet material so as to align with the additional inputs.

Claims

CLAIMS:

1. A device for securing a cannula arrangement at an insertion site on a patient's skin, said cannula arrangement having an input via which intravenous fluid can be introduced, said input being surrounded by a shoulder portion, said device including: a sheet material having a surface including adhesive, for attaching said sheet material to said patient's skin, said surface covered by a removable release liner, said sheet material including an aperture there through, said aperture being smaller in size than said shoulder portion such that, operatively, said aperture can be aligned with said input, to allow intravenous fluid to be introduced to said input, and said shoulder portion is prevented from moving through said aperture; thereby when said sheet material is attached to said patient's skin, said cannula arrangement is substantially retained under cover of the sheet material and is secured in position.

2. The device according to claim 1 , wherein said input projects from said shoulder portion, said aperture being sized to, operatively, provide a close fit around said input.

3. The device according to claim 2, wherein a portion of said surface, surrounding said aperture, is free of adhesive to prevent said sheet material from adhering to said shoulder portion and allow said sheet material to be selectively rotated with respect to said input.

4. The device according to claim 1 or 2, wherein, operatively, a portion of said surface, surrounding said aperture, abuts and adheres to said shoulder portion.

5. The device according to any one of the preceding claims, wherein, operatively, said insertion site and said cannula arrangement are sealed within the cover of the sheet material.

6. The device according to any one of the preceding claims, wherein said sheet material includes at least one transparent portion to allow said insertion site to be visually inspected when said sheet material is attached to said patient's skin.

7. The device according to claim 6, wherein said transparent portion is a separate transparent adhesive-backed sheet covering an inspection hole in said sheet material.

8. The device according to any one of the preceding claims, wherein said sheet material includes reinforcing means.

9. The device according to claim 8, wherein said reinforcing means is a ring- shaped member surrounding said aperture.

10. The device according to any one of the preceding claims, wherein said sheet material includes a pair of slits extending from opposing sides of said sheet material towards one another and terminating proximate to said aperture, said slits allowing said sheet material to be folded back upon itself across the slits to avoid ridges being formed in said sheet material during application.

11. The device according to claim 10, wherein said slits terminate with circular holes which resist forming tears in said sheet material when said sheet material is folded.

12. The device according to any one of the preceding claims, wherein said sheet material includes a pair of elongated portions extending from an edge of said sheet material, said elongated portions providing increased secureness against lateral forces relative to the direction of the portions.

13. The device according to any one of the preceding claims, wherein said cannula arrangement includes a valve member having said input which is arranged to receive a feed line.

14. The device according to claim 13, wherein said valve member includes an additional input, said device including an additional aperture arranged to be aligned with said additional input.

15. The device according to any one of the preceding claims, wherein said surface is covered by more than one release liners.

16. A device for securing a cannula arrangement at an insertion site on a patient's skin, said device including: a sheet material having an adhesive surface, for attaching said sheet material to said cannula arrangement and said patient's skin in order to secure said cannula arrangement in position, said adhesive surface covered by a removable release liner; and a plurality of adhesive-backed tabs, each tab including a visual indication of a different time and adapted to be selectively attached onto said sheet material; wherein, at a time when the cannula arrangement is inserted and secured by said sheet material, a user may select an appropriate tab for the time and attach said appropriate tab onto said sheet material as an indication of when the cannula was inserted.

17. The device according to claim 16, wherein said visual indication includes written text indicating different days of the week.

18. The device according to claim 16 or 17, wherein said visual indication includes colour coding.

19. The device according to any one of claims 16 to 18, including at least one additional blank adhesive-backed tab, upon which a user may write additional information for display.

20. The device according to any one of claims 16 to 19, wherein said plurality of adhesive-backed tabs are provided on said removable release liner.

21. A kit for securing a cannula arrangement at an insertion site on a patient's skin, said kit including: a sheet material having an adhesive surface, for attaching said sheet material to said cannula arrangement and said patient's skin in order to secure said cannula arrangement in position, said adhesive surface covered by a removable release liner; and a plurality of adhesive-backed tabs, each tab including a visual indication of a different time and adapted to be selectively attached onto said sheet material; wherein, at a time when the cannula arrangement is inserted and secured by said sheet material, a user may select an appropriate tab for the time and attach said appropriate tab onto said sheet material as an indication of when the cannula was inserted.

22. The kit according to claim 21 , wherein said visual indication includes written text indicating different days of the week.

23. The kit according to claim 21 or 22, wherein said visual indication includes colour coding.

24. The kit according to any one of claims 21 to 23, including at least one additional blank adhesive-backed tab, upon which a user may write additional information for display.

25. The kit according to any one of claims 21 to 24, wherein said plurality of adhesive-backed tabs are provided on said removable release liner.

26. The kit according to any one of claims 21 to 24, wherein said plurality of adhesive-backed tabs are provided on a separate release liner.

27. The kit according to any one of claims 21 to 26, wherein said kit is provided in a sterile package.

28. A device for securing a cannula arrangement at an insertion site on a patient's skin substantially as herein described with reference to the embodiment illustrated in the accompanying drawings.

29. A kit for securing a cannula arrangement at an insertion site on a patient's skin substantially as herein described with reference to the embodiment illustrated in the accompanying drawings.