WO2008117078A1

WO2008117078A1 - Dressings

Info

Publication number: WO2008117078A1
Application number: PCT/GB2008/001114
Authority: WO
Inventors: Erik Keith Mayer; James Macalister Kinross; Ara Warkes Darzi; Edward Henry Goodwin; Richard Andrew Hartshorn
Original assignee: Imperial Innovations Limited
Priority date: 2007-03-28
Filing date: 2008-03-26
Publication date: 2008-10-02
Also published as: GB0705923D0

Abstract

The invention provides a dressing for supporting a tube (17) in an incision in a body. The dressing comprises a base (12) arranged to be located against the body and support means (10) arranged to support the tube (17) in position.

Description

DRESSINGS

FIELD OF THE INVENTION

The present invention relates to dressings for supporting a tube inserted in an incision in a patient's body. It can be used for drain tubes, such as for chest drains and ascetic drains, as well as percutaneous feeding tubes, and catheters such as suprapubic catheters and vascular catheters.

BACKGROUND TO THE INVENTION

Chest drains are commonly used in a variety of clinical scenarios including trauma, peri-operatively and as a distinct intervention. The insertion of chest drains is an invasive procedure, which has potential for a variety of complications. Indications however are often lifesaving such as collections of air, blood, or other fluids, in the cavity surrounding the lung, which can compress the lung and less frequently the heart and prevent their adequate function. Accurate fixation of the chest drain to the skin is therefore crucial to it performing its continuing role in treating the aforementioned conditions. Any accidental tube migration or complete dislodgement, resulting from inadequate fixation, will prevent resolution of the underlying disease process and can lead to secondary life threatening complications such as air being sucked into the chest cavity surrounding the lung, causing the lungs' collapse (pneumothorax), or the inappropriate transfer of air from the chest cavity to the tissue layers under the skin (surgical emphysema). There is a particularly high risk of migration or dislodgement during patients' mobilisation from their bed and at times of the drains dressing change. Despite the significant risks of an 'uncontrolled' drain removal, the patient will then have to endure the potential risks of a second chest drain insertion, which as for the primary insertion include inappropriate puncture of the lung, heart, major blood vessels and damage to important nerves and lymphatic channels. This is of course not forgetting the psychological and physical distress that the patient will experience with this sort of episode and the consequential delay in their recovery and discharge from hospital. The main working principle of chest drains is that all air must leave the chest cavity via the tube and no air should enter around the tube, thus any dressing must be 'airtight'. Additionally a waterproof dressing is normally required to prevent moisture entering the wound resulting in maceration and infection. Accuracy of chest drain position and a changing clinical picture often necessitate adjustments to be made to the tube after its initial placement. Presently, this involves removing significant quantities of adhesive dressings and gauze and removing and then reinserting fixation sutures. This is at best a cumbersome and time-consuming process. Any wound in which there is a foreign body present, e.g. a plastic tube, is particularly susceptible to bacteria tracking along the tube and causing a wound infection. It is imperative that wound infections are detected early to limit their progression and secondary complications. Daily visual inspection of a wound is therefore required, and this ideally should not involve dressing removal, as exposure increases the risk of infection.

There are presently no devices on the market specifically designed for the fixation of chest drains. The drain is commonly sutured to the chest wall using an intertwining suture configuration around the drain itself. A loose 'mattress' suture is additionally left in place for use at time of tube removal, being tightened to create an airtight seal. These 'mattress' sutures often get pulled out during dressing changes; meaning painful reinsertion at the bedside prolonging the process of tube removal. What is more, this suture technique tends to leave an unsatisfactory cosmetic result, and entails a visit to the GP practice 5-7 days after discharge for suture removal.

A current standard dressing, requires the use of a dressing pack, several large pieces of topper gauze, saline wash, and large quantities of a heavy adhesive Sleek™ tape, or suitable alternative, for the fixation of the tube into the required position on the chest wall, e.g. flush or perpendicular to the skin. This is costly, and time consuming to apply with often sub-optimal results. What is more, every time a dressing is changed the arduous process of removing the old dressing prior to new dressing application must be performed by a healthcare professional with specific training. This will remove a valuable clinical team member from other duties for up to 20 minutes, and this may have to be done several times in one day should the position need adjusting. The patients also find this problematic, as the tape used is particularly adhesive and can be painful to remove, especially if the patient is hirsute. It is also not possible to inspect the wound without taking the dressing down. If the dressing gets wet, and any holding sutures are not secure, the dressing may also then fail, allowing the potential for tube migration or dislodgement leading to dangerous pneumothorax, surgical emphysema and infection.

The removal of a chest drain can be perilous, as if not performed correctly, air can enter the chest cavity, and cause the very problem it has been used to treat. The mechanism employed requires coordination between the healthcare professional and the patient so that at the correct point in the breathing cycle, the tube is removed and the purse string is pulled tight in one movement, preventing air entering the chest cavity. If a pneumothorax does recur, negating the benefit of the previous tube, it may be necessary to re-insert a new tube to begin the whole process again.

Accordingly, the present invention provides a dressing for supporting a tube in an incision in a body, the dressing comprising a base arranged to be located against the body and support means arranged to support the tube in position.

The tube may be a single tube, or it may be one tube of many forming a single elongate object, such as a Yates' drain. As well as tubes, the dressing may be for use with other elongate objects which can be inserted into an incision in a patient body and retained there for a period of time. The support means may include gripping means arranged to grip the tube to prevent axial movement of the tube relative to the support means. The gripping means may be releasable to allow axial adjustment of the tube.

The support means may be resilient so as to retain the tube at a predetermined angle relative to the base, at least at the point of entry of the tube into the incision.

The support means may be flexible to accommodate bending of the tube. The support means may include limiting means arranged to limit the degree of bending of the support means thereby to limit the degree of bending of the tube.

The base may define a cavity for housing an absorbent material. The dressing may further comprise closing means arranged to close the cavity when the tube has been removed. The dressing may further comprise a closure arranged to be attached, directly or indirectly, to the base whereby the cavity can be opened to enable replacement of the absorbent material. The closure may comprise a cover which can be fitted onto or over the base to close the cavity, or it may be a closure member arranged to close an aperture formed in a cover, the cover being arranged to be fitted onto or over the base. The closure may be re-closable after it has been opened. The cover may be arranged to seal the cavity when closed, and to reseal it when re-closed.

Indeed the present invention further provides a dressing comprising a base arranged to be mounted against a patient body, and a closure, the base and closure at least partly defining a cavity in which absorbent material can be placed, wherein the closure is openable to allow replacement or removal of the absorbent material. The present invention further provides a dressing comprising: a base having an underside arranged to be adhered to a patient body around an incision, wherein parts of the base are movable between a plurality of positions to open or close the incision; and retaining means arranged to retain said parts in one of the positions.

The retaining means may comprise a cover arranged to cover a cavity defined, at least partly, by the base. The dressing may include two covers arranged to retain the base in two different configurations. Alternatively the retaining means may comprise a strap arranged to pull the parts of the base towards each other, or it may comprise a sliding or zip fastening arranged to pull parts of the cover together.

The dressing may further comprise valve means arranged to form a one- way valve arranged to resist the flow of air into the incision. For example the valve means may include at least one flexible sheet member arranged to extend at least partially over the incision, either in contact with the patient body or spaced above it.

The present invention further provides a method of inserting a tube in an incision in a patient body, the method comprising: providing a dressing, the dressing comprising a base and a support; locating the base against the patient body; inserting the tube into the incision; and supporting the tube in the support.

The tube may be inserted into the incision before or after the base is located against the body. The base may be pre-loaded onto the tube before the tube is inserted. The support may be pre-loaded onto the tube before the tube is inserted. Alternatively the base, or the support, may be put in place, for example by being slid over the tube, after the tube has been inserted. The present invention still further provides a method of dressing an incision in a patient body, the method comprising: providing a dressing comprising a base; adhering the base to the body around the incision; deforming the base to close, at least partially, the incision; and securing the base in the deformed position. The incision may be an incision made during surgery or it may be a wound.

Preferred embodiments of the invention will now be described with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a section through a dressing according to a first embodiment of the invention with a tube supported in it;

Figure Ia is a section through part of the dressing of Figure 1;

Figure 2 is a section through the dressing of Figure 1 with the tube removed;

Figure 3 is a perspective view of a dressing according to a second embodiment of the invention;

Figure 4 is a scrap section through a closure of the dressing of Figure 3 ;

Figure 5 is a scrap section through a seal of the dressing of Figure 3;

Figure 6 is a scrap view of a modification to a part of the dressing of Figure 3; Figures 7a to 7e are schematic views showing the dressing of Figure 3 in various stages of use;

Figure 8 is an exploded view of a dressing according to a third embodiment of the invention;

Figure 9 is a plan view of the dressing of Figure 8;

Figure 10 is a vertical section through the dressing of Figure 8, on line A-A of Figure 9, when in use;

Figure 11 is a perspective view of the dressing of Figure 8 when in use;

Figure 12 is a perspective view of a cover forming part of the dressing of Figure 8;

Figure 13 is a plan view of the base of the dressing of Figure 8;

Figure 14 is a plan view of the base of Figure 13 in a deformed condition

Figure 15 is a section through the base of a dressing according to a further embodiment of the invention with a tube in place;

Figure 16 is a section through the embodiment of Figure 15 with the tube removed;

Figure 17 is a section through the base of a dressing according to a further embodiment of the invention;

Figure 18 is a plan view of the base of a dressing according to a further embodiment of the invention; Figure 19 is a side view of a dressing according to a further embodiment of the invention;

Figure 20 is a section through the base of a dressing according to a further embodiment of the invention;

Figure 21 is a plan view of a cover of a dressing according to a further embodiment of the invention; and

Figure 22 is a section through a dressing according to a further embodiment o the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to Figure 1 a dressing according to an embodiment of the invention comprises a hollow moulded plastics support body or cuff 10 comprising a base portion 12 and a support portion 14. The support portion 14 is in the form of a support tube defining a channel 16 of elliptical cross section arranged to receive a chest drain tube 17 through it and to grip the drain tube 17. This forms an airtight and watertight seal around the drain tube 17 and tends to prevent axial movement of the drain tube 17 through the support tube 14. The side wall 18 of the support tube tapers, getting thinner towards its top end 20. The base portion 12 is at the bottom end of the support tube 14 and is formed by a flared portion or flange 18a of the side wall 18 which terminates in a flat annular underside 22. The channel 16 also widens out to form a chamber 24 within the base portion 12, which is of circular section and open towards the underside. A clamp 26 is attached to the top end 20 of the support portion 12 and is arranged to releasably grip the drain tube 17 to prevent the drain tube from moving axially through the dressing. Referring to Figure Ia, the clamp 26 comprises a cylindrical housing 27 with a pair of opposed internal surfaces 28 within it which are spaced apart by a distance which is less than the outer diameter of the tube 17. These surfaces therefore clamp the tube 17, unless the sides of the housing are compressed to force the clamping surfaces 28 apart to release the tube.)

The dressing further comprises a dressing cover 30 formed of flexible resilient sheet material. The dressing cover 30 comprises an annular portion 32 with adhesive underside 34 arranged to adhere to the body of the patient and to fit beneath the annular underside 22 of the base of the support body 10. The top surface 35 of the annular portion 32 has adhesive thereon so that the underside 22 of the base of the support body can be adhered to it. The dressing cover 30 also comprises a side wall 36 arranged to extend upwards from the inner edge of the annular portion 32 inside the chamber 24, defining a cavity 37 within it. Finally the dressing cover 30 also comprises a top portion 38 arranged to cover the cavity 37 and including a pair of sealing flaps 40 which can be deflected upwards into the tubular support portion 16 to allow the tube 17 to pass through the support portion 16 and, but which tend towards a sealing position as shown in Figure 2 in which they cover and seal the cavity 37. The dressing also comprises an absorbent pad 42 which fits within the cavity 37 and therefore also inside the chamber 24. The pad 42 is annular having a central aperture 44 through it so that it can fit around the drain tube 17 while the drain tube is inserted in the body as shown in Figure 1.

The dressing further comprises an adhesive sheet 50 the outer part 52 of which is flat and annular and arranged to adhere to the patient body around the support body 10, and the inner part 54 of which is arranged to adhere to the outer surface of the support body 10. An annular adhesive anchor 56 is arranged to be adhered to the patient body around the support body 10. This adhesive anchor is more highly adhesive than the adhesive sheet 50 and has an upper surface 58 which is also adhesive and to which the outer edge of the adhesive sheet 50 can be adhered. This allows the adhesive sheet to be removed and replaced, without removing the adhesive anchor 56 from the patient body.

In use, in order to apply the dressing to the body of the patient, the dressing cover 30, with the absorbent pad 42 is placed in the chamber 24 in the base of the support body. Initially the sealing flaps 40 will be in the closed condition as shown in Figure 2. The chest drain tube 17 is then pushed upwards through the pad until it reaches the sealing flaps 40. It is then pushed further upwards so that it moves into the support tube 14, opening the sealing flaps 40 so that it can pass through the dressing cover 30. Finally it is pushed upwards until its end passes through the clamp 26 and out of the top end of the dressing, reaching the position shown in Figure 1. Then the lower end of the drain tube 17 is inserted through an incision in the body of the patient until the underside of the dressing cover 30 and the absorbent pad 42 contact the patient body around the incision. The adhesive anchor is then adhered to the patient body around the incision and the support body 10, and the adhesive sheet 50 adhered to the support body 10, the patient body and the adhesive anchor 56 as shown in Figure 1. In this position adhesion of the dressing cover 30 to the patient body, and of the support body 10 to the dressing cover 30, provides an airtight and watertight seal between the dressing and the patient body. The support tube 14 is sealed against the drain tube 17 as described above. Physical support of the support body 10 to retain the support tube 14 at the desired angle relative to the patient body is provided both by the adhesion to the dressing cover 30 and the patient body, and by the adhesive sheet 50.

Once the dressing is in place, the position of the drain tube 17 can be adjusted. In order to do this the clamp 26 is released, the drain tube 17 moved axially through the dressing to the desired position, and the clamp re-applied to secure the drain tube in the new position.

When the chest drain tube 17 needs to be removed it can be simply pulled out through the dressing by releasing the clamp 26. When this is done, the sealing flaps 40 on the dressing cover 30 will move to the closed position thereby sealing the cavity 37 within the dressing cover 30 so that it is watertight and airtight. After the drain tube has been removed, the adhesive sheet 50 can be removed, leaving the anchor 56 in position, and the support body 10 removed from the dressing cover 30. This leaves the dressing cover 30 in a sealed condition with the absorbent pad 42 inside it. If the absorbent pad 42 needs to be replaced the sealing flaps 40 on the dressing cover can be opened, and the old pad 42 removed and replace with a clean one.

Referring to Figure 3, according to a second embodiment of the invention, a chest drain dressing comprises a base 130, a cover 150 and a chimney 170. The base 130 is formed from moulded resilient plastics material, in this case polypropylene, and comprises four straight side walls 131 of equal length defining a cavity 137 within them. The walls are joined at the corners of the cavity 137 by flexible portions 132 which form live hinges, which enable the angles between the side walls 131 to be varied. The side walls 131 therefore form an equal sided parallelogram, i.e. a rhombus, the corner angles of which can be varied by flexing of the hinges 132. A mounting flange 133 projects outwards from the base of each of the side walls 131. The flanges 133 extend along substantially the whole length of the side walls 131, but do not extend around the corner hinges 132 as that would reduce their flexibility. The mounting flanges 133 have flat undersides, which are in a common plane, arranged to be placed against the patient body. A sheet of elastic adhesive material 134 has a square aperture 135 in it which has four sides the length of which is equal to the length of the side walls 131. The base 130 is attached to the adhesive material by adhering the undersides of the flanges 133 to the top of the adhesive material 134 around the edges of the aperture 135. The adhesive material will therefore flex with the base 130 as its shape is changed.

The cover 150 comprises a flat top 152 in the shape of a parallelogram with four straight side walls 153 of equal length depending from it. The side walls 153 of the cover 150 are slightly shorter than those on the base 130 so that the parallelogram that they form fits just inside the side walls 131 of the base. Because of the flat top 152, the side walls 153 of the cover are at fixed angles to each other, and the parallelogram that they form has two internal angles greater than 90°, in this case around 110°, and two internal angles less than 90°, in this case around 70°. As shown in Figure 5, the side walls 131 of the base have an inwardly projecting lip 136 at their top edge, and the side walls 153 of the cover have an outwardly projecting lip 154 on their bottom edge. These lips 136, 154 are arranged to interlock with each other to releasably retain the cover on the base. The cover 150 therefore releasably closes the cavity 137 and the interlocking lips 136, 154 provide a seal between the base 130 and cover 150.

Referring to Figure 4, the top 152 of the cover has a round hole 156 through its centre, surrounded by an upwardly projecting rim 158. A cap 160 is also provided comprising a flat top 162 and a downwardly projecting circular wall 164 which is an interference fit within the rim 158 of the hole 156 so that the cap 160 can be inserted to seal the hole 156, and removed to open it. Therefore when the cap 160 is inserted and the cover 150 is on the base, the cavity 137 is sealed and airtight, preventing ingress of fluids and pathogens. Referring back to Figure 3, the chimney 170 is formed of resilient plastics material and comprises a clip portion 172 at its base and a helical support portion 174 extending upwards from the clip portion. The clip portion 172 is in the form of a split ring and is arranged to clip onto the rim 58 of the hole 156. Various modifications can be made to the basic clip shown, for example with a screw threaded or ratcheting clamping arrangement to make the connection between the chimney 170 and base more secure and easy to release. The helical support portion 174 tapers gradually towards its upper end. The resilience of the support portion allows it to grip around a drain tube whilst allowing axial adjustment of the tube through it.

In use, the base 130 is adhered to the patient body 180 around an incision 182 by means of the adhesive material 134. The chest drain tube is then inserted through the chimney 170, with the chimney attached to the cover 150, so that the tube, chimney and cover are pre-assembled. An absorbent pad or dressing, with a central hole to allow the drain tube to pass through it, is placed in the cavity 137. The tube is inserted into the body 180 through the incision 182, and the cover 150 pushed onto the base 130 so that the interlocking lips 136, 154 seal the cover onto the base. Further axial adjustment of the drain tube is then possible without removing the cover 150. The cover 150 can be removed and replaced without removing the drain tube, allowing replacement of the absorbent pad in the cavity 137.

In practice the tube, chimney and cover may be supplied as an assembly so that the surgeon does not need to perform the pre-assembly step. Similarly the absorbent pad may be supplied pre-loaded into the base. Alternatively one or more of the components, in particular the chimney and cover but optionally also the base, can be pushed over the tube after the tube is inserted in the incision. Referring to Figure 6, in a modification to the embodiment of Figure 3, grip portions 188 having concave outward facing grip surfaces 189 are formed on two of the corners of the base 130 to facilitate gripping of the corners while they are being pushed together.

Referring to Figure 7a, when the drain tube 190 is to be inserted into the patient body, the incision 182 is made in the form of a linear cut so that it has two sides 184, 186 that can be pulled apart to allow the tube 190 to pass through the incision. When the base 130 is first applied to the body it is applied in the shape of a parallelogram with the two corners 132a of larger internal angle aligned on the imaginary line which is an extension of the line of the incision 182. Therefore when the cover 150 is put onto the base 130 it is also orientated so that its larger angled corners are aligned with the line of the incision. An absorbent pad or dressing can be placed within the base 130 around the tube 190. When the drain tube 190 is to be removed, the cover 150 and chimney 170 are removed as shown in Figure 7a and the drain tube 190 removed from the incision 182. Then the narrower angle corners 132b of the base are pushed together until the side walls 131 form a parallelogram which is the same shape as when originally applied, but with the smaller angled corners 132b having widened to become the larger angled corners, and the wider angled corners 132a having narrowed to become the narrower angled corners, as shown in Figure 7b. The grip portions 188 of Figure 6 would be used for this if present. Because the base is adhered to the patient body around the incision 182, this pushes the sides 184, 186 of the incision together, and pulls the ends of the incision apart in the direction parallel to the incision, to close the incision. The chimney 170 is then removed from the cover 150 as shown in Figure 7c, a new absorbent dressing placed inside the base if required, and the cover pushed onto the base 130 as shown in Figure 7d, the cover having been rotated through 90° so that it fits onto the base in its modified shape. The cap 160 is then placed over the hole 156 to seal the cover as shown in Figure 7e.

The base 130 and cover 150 can then be left in place while the incision heals. If the absorbent dressing needs to be replaced, the cover 150 can be removed to enable the old dressing to be removed and replaced, and then the cover replaced.

Referring to Figure 8 to 11 a third embodiment of the invention is similar to the second, and corresponding parts are indicated by the same reference numerals increased by 100. The third embodiment functions in a similar way as the second, and only the major differences will be described.

In this embodiment, the chimney 270 has a thin-walled section 272 at its base which is arranged to allow a fastening strap, such as a zip tag, to be tightened around it to secure the tube 290 longitudinally in the chimney 270. The location of this securing mechanism at the base of the chimney 270, rather than at the top as in the first embodiment, gives a more secure location of the tube 290 as flexing of the chimney 270 cannot cause axial movement of the tube through the incision in the patient body. Also, as well as securing the tube in position, the fastening strap is also arranged to seal the base of the chimney 270 against the outer wall of the tube 290. In practice a more secure fastening mechanism might be preferred to locate the tube 290 in the chimney 270. For example a releasable clamp similar to that of the embodiment of Figure 1 could be used. Alternatively a clamp can be used of the type comprising a number of jaw members spaced around the tube, and a locking ring that can be screwed or pushed axially over the jaw members to force them inwards to clamp the tube. Also in this embodiment the chimney 270 has a series of slots or openings 271 formed in it. Each slot 271 extends circumferentially around the chimney 270, the slots being arranged in pairs, each pair being aligned with each other in the longitudinal direction with narrow pillars 273 between the ends of the slots. The pairs of slots 271 are alternately offset by 90°, in the circumferential direction, so that each pair of pillars 273 is aligned with the centres of the adjacent pair of slots. This allows the chimney 270 to flex, with the width of the slots 271 setting a minimum radius of curvature to which the chimney can easily flex before the sides of the slots 271 come together and inhibit further flexing, except what is possible due to the flexibility of the material of which the chimney is made.

One of the purposes of the chimney 270 is to prevent buckling of the tube. Therefore the width of the slots 271 is set so that the largest tube that can fit within the chimney 270 will not buckle at the minimum radius of curvature. This ensures that, if smaller tubes are used which are not a tight fit within the chimney 270, such tubes will also not buckle as, generally, they can withstand an even smaller radius of curvature without buckling. It will also be appreciated that the chimney will maintain the tube, at its point of entry into the incision, perpendicular to the base and therefore perpendicular to the surface of the body around the incision.

It will be appreciated that if the chimney were formed of a continuous tube without slots, the bending could be limited in a similar way by providing a series of annular ribs or flanges projecting from the outer surface of the tube, the spacing and outer diameter of which could be chosen to control the minimum radius of curvature to which the tube could bend. The base 230 includes four securing tags 236 each extending from the outer edge of one of the mounting flanges 233. These tags 236 have no adhesive on them and are connected to the mounting flanges 233 by thin flexible strips of the polypropylene material which form live hinges 238. The tags 236 have apertures 236a through them, and the cover 250 has four hooks 254, one projecting from the centre of each of its side walls 253. When the cover 250 is placed over the base 230, it can be releasably secured in place by pulling the tags 236 over the hooks 254.

In this embodiment, the sides 231 of the base 230 naturally tend towards a square configuration as shown in Figure 13. However, the cover 250 has a parallelogram shape, with two wider angled corners at angles of about 110° and narrower corners at angles of about 70°. When the base is first adhered to the patient body, it is in its square configuration, with two of its corners 232a on the line of the incision, and the other two 232b, at which the grip portions 288 are located, on either side of that line. In order to put the cover 250 onto the base 230, the grip portions 288 are pushed together so that the corners of the base correspond to those of the cover 250. The undersides of the base, which are adhered to the patient body, tend to close the incision slightly as this is done. This is done while the tube 290 is already at least partially inserted, so the incision tends to close around the tube 290, and to be held in this position when the cover 250 is fixed in place on the base, securing it in the partially compressed condition.

Referring to Figure 12, in this embodiment, the dressing further comprises a separate second cover 250a, which is in the same basic form as the main cover 250, but has no hole in the top, and is in a narrower parallelogram, with wider angle corners at about 150° and narrower angle corners at about 30°. When the tube is removed, the main cover 250 is removed also and replaced by the second cover 250a, the base 230 having first been compressed further, as shown in Figure 14, so that its angles correspond to those of the second cover. This provides further closing of the incision, which is maintained by the dressing as it heals. A further set of absorbent pads can also be provided that fit in the more narrowly compressed dressing.

In a modification to this embodiment, the cover of Figure 12 can include a sealable door or closure in its top surface that can be opened to allow access to, and replacement of, the absorbent pad. This allows the cavity within the dressing to be opened and closed independently of the retaining mechanism which holds the base in its compressed condition in which it holds the incision closed for healing. The cover 150 of Figure 3 could also include such a closure.

In a further modification to this embodiment some form of locking mechanism to secure the cover 250, or the further cover 250a, to the base can be provided. This can be in the form of a tamper-proof locking mechanism, tamper-proof adhesive tape over the cover, or sutures securing the cover to the base.

It will be appreciated that the base 230 of the third embodiment of the invention together with the further cover 250a can be used as a general purpose wound dressing arranged to provide a closing force to the wound and retain an absorbent dressing against the wound.

Referring to Figure 15, in a fourth embodiment, which is otherwise similar to the third embodiment, the base 330 has a pair of flexible sheet members 331, 332 each of which is joined at one of its edges to one side of the base 330. The sheet members 331 , 332 extend across the aperture defined within the base, and overlap in a region 333 in the centre of that aperture. When the tube 390 is in place, the sheet members 331, 332 are deflected upwards against the sides of the tube so that the tube 390 can pass between them as shown in Figure 15. When the tube is removed, the sheet members 331, 332 fall back against the patient body to which the base is attached, with the overlapping region 333 being arranged to lie over the incision 382 as shown in Figure 16. In this position the sheet members 331, 332 form a one-way flap valve, which allows air or other fluid to escape from the incision 382 but prevents, or at least inhibits, air from entering the incision from outside the patient body. This is particularly advantageous in chest drain incisions in which it is important for air and fluid to be able to escape from the incision, but also important to prevent air from entering the body through the incision when the patient inhales. This valve mechanism, which closes on removal of the tube, is therefore advantageous as it avoids the incision being left unsealed and uncovered for a period after the tube is withdrawn.

In a modification to this embodiment, a single sheet member can be used to form the flap valve that closes the incision.

Referring to Figure 17 in a fifth embodiment, the sheet members 431, 432 are formed of a slightly resilient material and shaped such that, rather than overlapping where they meet in the centre of the base 430, they both turn upwards so that their undersides 435 are in contact with each other and their free edges 436 lie parallel to each other and raised up above the surface of the patient body, and over the incision 482. It will be appreciated that the sheet members 431, 432 can flex apart to allow the tube to pass between them, and will come together on removal of the tube to form a one-way valve arrangement which operates to allow air to escape from the incision 482 but to prevent ingress of air into the incision. Referring to Figure 18, in a sixth embodiment of the invention, the base 530 is again in the form of a flexible rhombus, but the retaining mechanism for holding the rhombus in a compressed condition takes the form of a diagonal strap 532. The strap 532 has one end 533 attached to one corner 534 of the base 530, and extends through an aperture 535 in the opposite corner 536. The strap has a series of projections 537 along its length which narrow towards the free end 538 of the strap. These projections are slightly wider than the aperture 535 so that they form a ratchet mechanism allowing the strap to be pulled through the aperture 535 in the direction of the arrow A to draw the two corners 434, 436 together, but resisting movement of the strap back through the aperture 535. This allows the rhombus to be compressed from an initial fully open position, through a large number of increasingly closed positions until the required degree of compression is reached. It will be appreciated that it may be desirable to locate the strap 532 so that it is offset from the diagonal of the rhombus, so that the incision and tube can be located at approximately the centre of the base.

In some embodiments, rather than a ratchet mechanism on the strap, it may be preferable to have a releasable locking mechanism that can be released to enable the strap to be pulled to pull the sides of the rhombus together, and then locked to secure it in position. This enables the locking mechanism then to be released again to allow the rhombus to open again, for example if it has been closed too far or if it simply needs to be adjusted.

Referring to Figure 19, in a seventh embodiment of the invention the base 630, cover 650 and chimney 670 correspond to those of the third embodiment, but the dressing further comprises an anchor 680 for the tube which is located remotely from the cover 650 and supported on an extension of the adhesive material 634. The anchor 680 comprises a simple clip mechanism 682 which is arranged to releasably secure the tube 690 to it at a position on the tube which is remote from the chimney 670 and therefore remote from the incision, and to prevent movement of the tube longitudinally through the anchor when it is fastened. Operation of the dressing is the same as that of the third embodiment, but when the tube is in place in the incision and located longitudinally within the chimney 670, the tube 690 can be flexed over as shown in Figure 19, within the constraints of the flexibility of the chimney 670 which is arranged to prevent buckling of the tube, and secured in the anchor 680. The anchor can then be fastened around the tube 690 to prevent the tube from sliding through it. The anchor 680 then serves to isolate the base 630, cover 650 and chimney 670 from any forces applied to the tube 690 beyond the anchor 680, for example if it is accidentally pulled.

In a modification to this embodiment the anchor 680 may be provided on its own separate adhesive base rather than attached to the same base material as the rest of the dressing. This allows greater freedom as to the location of the anchor on the patient.

Referring to Figure 20, in an eighth embodiment the base 730 has a capsule 740 of adhesive release fluid attached to the inside of one of its side walls. This capsule can be ruptured when the base is to be removed from the patient body, allowing the release fluid to act on the adhesive on the underside of the adhesive material 734, allowing the base to be removed without undue discomfort to the patient. Because the capsule 740 is located inside the side walls of the base, the fluid is released into the cavity 737 when the capsule is ruptured, and therefore will be contained at least partially within the base and in contact with the adhesive as the adhesive material 734 is removed. It will be appreciated that the release fluid could be stored in other ways. For example it could be stored in a chamber formed within the base 730 itself, with a removable closure over the chamber which can be removed to allow the fluid to come out. Again the chamber can open into the interior of the base 730. Alternatively, in some cases it may be preferable to keep the release fluid away from the incision. In this case the capsule 740 can be located on the outside of the base, or it can be arranged to be removable from the base so that it can be removed with the fluid in it, held close to the first part of the adhesive material that is to be removed, and ruptured to release the fluid in that location.

Referring to Figure 21, in a further embodiment of the invention, the cover 850 comprises four side walls 853 with hinges 832 at the corners to form a flexible rhombus as in previous embodiments. However the top 852 of the cover is formed in two halves 852a, 852b separated by a split along one of the diagonals of the rhombus, each half being formed of a sheet of flexible material. The free edges 852c of the sheets 852a, 852b have interlocking seals 855 formed along them, and a slide fastener 854 is arranged to slide along the edges 852c in one direction to secure them together and in the other to release them. The sheets 852a, 852b are arranged together to make up a rhombus with its longer diagonal being that on which the edges 852c of the sheets lie. Therefore when the fastener is done up, it pulls the sides of the cover together, and therefore also pulls the sides of the base together. In use the split in the cover is aligned with the incision so that closing the split causes closing of the incision.

Referring to Figure 22, in a further embodiment, the cover 950 has a generally tubular membrane 960, formed of elastic sheet material, located in the central aperture 956 over which the chimney 970 is located. The membrane 960 has a wide lower end 960a which flares outwards and is secured to the underside of the cover 950 around the aperture 956. The membrane 960 extends upwards through the aperture 956 with the sides of its upper end 960b arranged to come together to form a closed slit. The drain tube is pushed upwards through the membrane 956 which stretches around it to seal the cover to the tube. When the tube is pulled out of the chimney in the upward direction, the sides of the upper part of the membrane come together, sealing the cavity within the cover, and forming a one-way valve which allows air to escape from the incision, through the cavity within the cover and through the membrane, but prevents air from entering the cavity from above, and therefore prevents air from outside the cover 950 from entering the incision. The membrane 960 therefore serves the multiple purposes of sealing the cover to the tube when the tube is in place, sealing the cavity within the cover when the tube is removed, and preventing air from entering the incision when the tube is removed.

Claims

1. A dressing for supporting a tube in an incision in a body, the dressing comprising a base arranged to be located against the body and support means arranged to support the tube in position.

2. A dressing according to claim 1 wherein the support means includes gripping means arranged to grip the tube to prevent axial movement of the tube relative to the support means.

3. A dressing according to claim 2 wherein the gripping means is releasable to allow axial adjustment of the tube.

4. A dressing according to any foregoing claim wherein the support means is resilient so as to retain the tube at a predetermined angle relative to the base.

5. A dressing according to any foregoing claim wherein the support means is flexible to accommodate bending of the tube.

6. A dressing according to claim 5 wherein the support means includes limiting means arranged to limit the degree of bending of the support means thereby to limit the degree of bending of the tube.

7. A dressing according to any foregoing claim wherein the base defines a cavity for housing an absorbent material.

8. A dressing according to claim 7 further comprising closing means arranged to close the cavity when the tube has been removed.

9. A dressing according to claim 8 wherein the closing means is arranged to close on removal of the tube.

10. A dressing according to claim 8 or claim 9 wherein the closing means is further arranged to seal the cavity.

11. A dressing according to claim 10 wherein the closing means can be opened to allow the tube to pass through it and closed to form a sealed enclosure over the incision when the tube has been removed.

12. A dressing according to any foregoing claim wherein the support means is releasably attached to the base such that the support means can be removed from the base.

13. A dressing according to any of claims 7 to 12 further comprising a closure arranged to be openable whereby the cavity can be opened to enable replacement of the absorbent material.

14. A dressing according to any foregoing claim wherein the base has an underside arranged to be adhered to the body around the incision, and parts of the underside are movable relative to each other to enable opening or closing of the incision.

15. A dressing according to claim 14 wherein said parts of the underside are movable between a plurality of positions and the dressing further comprises retaining means arranged to retain said parts in one of the positions.

16. A dressing according to any foregoing claim further comprising an anchor arranged to anchor the tube to the body at a position remote from the incision.

17. A dressing comprising: a base having an underside arranged to be adhered to a patient body around an incision, wherein parts of the base are movable between a plurality of positions to open or close the incision; and retaining means arranged to retain said parts in one of the positions.

18. A dressing according to claim 16 or claim 17 wherein the base has four sides arranged to form a parallelogram and the sides are movable so that the angles between the sides can change as the sides are moved.

19. A dressing according to claim 18 wherein the sides are all of the same length.

20. A dressing according to any of claims 16 to 19 wherein the retaining means comprises a cover arranged to cover a cavity at least partly defined by the base.

21. A dressing according to claim 20 including two covers arranged to retain the base in two different configurations.

22. A dressing according to any foregoing claim further comprising valve means arranged to form a one-way valve arranged to let air out of the incision but to inhibit the flow of air into the incision.

23. A dressing according to claim 22 wherein the valve means includes at least one flexible sheet member arranged to extend at least partially over the incision.

24. A method of inserting a tube in an incision in a patient body, the method comprising: providing a dressing, the dressing comprising a base and a support; locating the base against the patient body; inserting the tube into the incision; and supporting the tube in the support.

25. A method of dressing an incision in a patient body, the method comprising: providing a dressing comprising a base; adhering the base to the body around the incision; deforming the base to close, at least partially, the incision; and securing the base in the deformed position.

26. A dressing substantially as hereinbefore described with reference to any one or more of the accompanying drawings.