HAEMOSTATIC DRESSINGS

Abstract: A dressing (10) for effecting haemostasis at the site (32) of a vascular puncture after withdrawal of a needle or cannula comprises a base strip (12) having an adhesive undersurface protected by removable panels (14, 16) and having mounted thereon a pad (18). An eye (26) is secured above the strip (12) and has passing therethrough the shank (44) of a draw strip (20) which, after being drawn to approximate the end portions of the strip (12), may have its free and (20b) adhered to the upper surface of its root portion (20a). After application of the dressing (10) the skin (36) under the pad (18) is subjected to a pressure sufficient to restrict flow through the punctured vessel (32) and achieve haemostasis. Alternatively the end portions of the base strip (12) may be approximated by opposed draw members. Other arrangements for generating a pressure over the puncture site are disclosed.

Description: HAEMOSTATIC DRESSINGS This invention relates to haemostatic dressings. In the practice of medicine it is frequently necessary to puncture blood vessels, for example to supply blood, blood products or.a solution intraveneously by means of a drip and cannula, or a drug by direct injection with a hypodermic syringe through an indwelling needle which is maintained in place and enables successive injections to be made without the need for further venepuncture. Other frequent reasons for performing venepuncture are to take blood samples and blood donations, while arterial puncture is performed to take arterial blood samples, for radiology and for monitoring of arterial blood pressure. When the needle or catheter is withdrawn there will naturally ensue a loss of blood from the site of vascular puncture. The usual method of achieving haemostasis, i.e. stopping the blood flow, is by the exertion of local pressure by means of the thumb, frequently with the interposition of any convenient small pad. Maintaining digital pressure in this way is a tedious and sometimes physically demanding task which is frequently not properly carried out, particularly when other urgent matters arise. However, unless such pressure is applied and maintained for several minutes blood escapes into the sub-cutaneous tissue and haematomata (bruises) occur. Another method of achieving haemostasis is to hold a pad for example a folded or rolled up cotton swab, or a ball or cylinder of cotton wool, tightly in place by means of adhesive strapping. Taking, for example, ■ the case of a venepuncture site at the back of the hand, one end of the tape should be applied to the side of the hand and tension must subsequently be maintained in the tape as the other end is stuck down to the other side of the hand. During these operations the pad must at least be held in position, and sometimes pressed firmly against the puncture site, usually, but not always, after the needle has been withdrawn, making it a matter of some difficulty to extract the digit from underneath the sticky undersurface of the tape at precisely the right moment. It will thus be apparent that considerable dexterity and an appreciation of the principles involved are needed to perform this technique effectively; and that the conven¬ tional haemostatic dressing consisting of a pad and an adhesive tape or surgical plaster must be skilfully and conscientiously applied in order to achieve the required results. In practice haematomata again frequently occur due to failures to apply the technique effectively. The occurrence of haematomata is undesirable for the reasons that they are 1. Unsightly; 2. A cause of concern and distress to the patient, particularly when in a prominent position such as on the back of the hand; 3. Sometimes the only visible effect of an operation 5. and thus an inappropriate symbol of its general success; 4. Capable of obscuring the vessel by swelling or discolouration and thus preventing its further use; and 0 5. Sometimes large enough, in the case of arterial puncture, to cause significant blood loss and discomfort through the pressure of the extra- vasated blood. An adhesive pressure dressing for minimizing 5 haemotomata has been disclosed in US Patent Specification No. 3 490 448 comprising a backing having an adhesive surface to which a compressible pad is secured. A first flap of backing on one side of the pad is protected by a first removable strip which extends across the pad. 0 in use the first flap is adhered to the skin on one side of the puncture site and as the needle is withdrawn the exposed surface of the pad is pressed by the operator against the puncture site. After withdrawal the second' strip is removed and the second flap adhered to the skin on 5 the opposite side of the puncture site. It will be noted that the application of the dressing requires digital, e.g. thumb, pressure and for the second flap to be held taut while it is applied to the skin. Because of the elasticity of the skin which is not much counteracted by the recommended "slightly elastic" nature of the backing, much of the digital pressure applied to the pad is lost when the digit is removed, and the dressing has not proved successful. The aim of the present invention is to render the achievement of haemostasis easy and consistently effective, independently of the skill of the operator. According to the present invention there is provided a haemostatic dressing for applying local pressure to the site of a vascular puncture comprising a base piece of flexible sheet material coated on one face with adhesive for adhering the material to the skin of a patient at least in a area adjacent said site, and pressure-means incorporated in, or attached to, the Base piece which are manually operable independently of application of the base piece to generate or release pressure against said site. (The base piece may take forms other than an oblongate strip, for example square or circular, but will for convenience be referred • to hereinafter simply as a "strip".) The use of a dressing according to the present invention enables the application of the dressing to be separated into two discrete steps, namely 1) The application of a base strip over the site of the vascular puncture and surrounding areas; and 2) The operation of the pressure means which exert local pressure over the puncture site which is sufficient to effect haemostasis and is independent of the pressure used when applying the base strip. The dressing may be ' applied before, during or immediately after withdrawal of the vascular insert. In a simple but effective form of haemostatic dressing according to the present invention the manually- operable pressure generating means take the form of a pad secured in a medial position on the non-adhesive surface of the base strip, and a tensionable strip permanently secured at one end to the strip on one side of the pad and having the other, free end portion, extending on the other side of the pad, provided with attachment means, for example, adhesive on its undersurface, a "Velcro" touch and close fastener, a jamming cleat or a hook and eye. To prevent any tendency for the base strip to be pulled away from the skin by the tension applied to the tensionable strip, the secured end of the tensionable tape is preferably secured to the base strip at a position inset from the end thereof. To allow the skin under the base strip to bunch or ruck freely to allow the maximum tension to be applied to the tensionable strip, the base strip should be of thin and flexible material. Where the attachment means take the form of an adhesively-coated area, it is important that the area of the tensionable tape,over the pad should be free of adhesive, with a view to allowing the maximum tension to be applied without any impediment. Not only will this plain area allow the tensionable tape to be drawn over the pad and the pad to accommodate itself, so that the inward force exerted by the tensioned tape is normal to the skin, but also ensures that if temporary digital pressure, e.g. with the thumb, has to be applied to the pad before the tensionable tape is stuck down, the thumb can be removed more easily. It may be advantageous for the adhesively-coated free end portion of the tensionable tape to extend beyond the end of the base strip so that it may be stuck directly to the skin as well as to the upper surface of the base strip on said other side of the pad. In a more sophisticated arrangement the manually- operable pressure generating means may take the form of a pivotable, rotatable or deformable member attached to the base strip. The pivotable member may be a leaf hinged at one end to the base strip and provided with attachment means at the distal end. The medial portion may be formed with a trough, depression or blister so that when the distal end is pressed down onto the base strip the medial portion exerts pressure over the puncture site. Conversely, if the leaf is planar or convex the base strip may be provided with a suitable pad through which pressure is exerted over the puncture site. In a slight modification the leaf with a medial depression may be constituted by a rotatable cylinder or semi-cylinder attached to the base strip along a narrow area extending in the axial direction and having a flange bearing attachment means extending in a dia¬ metrically opposite direction. In use, the flange would thus be rotated through some 90° to 180° to exert pressure over the puncture site and then be secured to the base strip. Again, the cylinder or semi-cylinder may be duplicated so that in use the flanges are each pivoted upwardly in opposite senses and secured together at their distal edges or over substantially their entire areas. - 3 - The deformable member is made from resilient sheet material and is generally U- or C-shaped in side elevation, a transverse medial portion of the base strip being secured to the convex surface of the arcuate portion of the member. When the projecting end portions of the member are squeezed or pinched together the curve of the medial arcuate portion tends to become more pronounced exerting a pressure against the puncture site. Alternatively, the. deformable member may be planar and reliance placed on the skill of the operator and the resistance of the skin to obtain an outwardly concave curve. On the other hand the member may be given a slight set in the correct direction or provided with- protrusions on its outer surface which allow it to bend in one direction only. In other forms of embodiment incorporating a deformable member, the member may be polygonal or circular and pressure generated by approximating opposed peripheral portions, for example the diagonally opposed corners of a square, and securing them together. It will be appreciated that in all the above- described embodiments the pressure generated over the puncture site in a direction generally normal to the plane of the base strip and transmitted by the pad or member, is developed by reaction against the anchorages provided by the one or more areas of adhered base strip. In fact, it is not necessary for there to be any element transmitting such a normal force and the pressure exerted over the puncture site may be developed generally in the plane of the base strip. For example the base strip may be provided with an overlying draw member resembling the tensioning member in the first-described embodiment, with the free end of the draw member preferably passing through an eye, but with the omission of a pad for producing a normal force. The eye is preferably narrow and does not extend across the width of the base strip; and the draw member is doubled back on. itself, after passing through the eye, and secured to the base strip and/or skin, for example by exposure and application of an adhesive area, on the same side of the eye as the secured end. A thin, fairly hard pad or a piece of foam may be incorporated between the base strip and the tensioning member; preferably an absorbent pad on the adhesive face of the base strip may be adapted to perform a similar function of assisting skin to bunch on each side thereof rather than immediately over the puncture site, and enhancing the normal component of the pressure generated by the draw member. In general, however, any absorbent pad on the under side of the strip should be narrow since adhesion of the base strip over a large area is necessary for it to function efficiently. Alternatively, tensioning members may be woven into the base strip in the manner of gatherable curtain tape and connected at their free ends by a tab which is pulled and subsequently .secured by the operator. Another example of this type of dressing according to the present invention is one comprising a circular base piece provided with a circular drawstring inset from the perimeter, and preferably arranged around a central circular core. As indicated previously, in these forms of dressings haemostasis is achieved by approximating the two end portions of the base strip by pulling one or more draw members in the same direction and thus bunching together the skin and subcutaneous tissue lying under at least part of the medial portion of the strip in order to apply pressure to the puncture site. Such approximation •may also be achieved by (usually simultaneously) tensioning a draw member attached to each end portion of the base strip, at least one draw member having securing means at its free end for securing it to the other end portion of the base strip and/or the patient's skin adjacent thereto. Preferably the securing means take the form of a layer of pressure-sensitive adhesive on the underside of the member. To ensure as far as practicable that the approximating forces applied to the end portions of the base strip are mutually opposed, it is preferred to attach more than one draw member to at least one end portion of the base strip. For convenience of tensioning and securing such multiple draw members they are preferably connected at their free, outer ends. Another means of developing a tensioning force generally in the plane of the base strip is by means of an overcentre toggle arrangement, for example one comprising a member overlying a medial portion of the base strip and having one end secured to the strip and the other connected to a lever member pivotally mounted on the base strip such that it may be pulled -back to tension the overlying member, and then secured to the base strip and/or skin. With this arrangement a pad affixed to the under surface of the base strip will be caused to assume a generally S-shaped configuration after operation of the lever member, with the lower bend of the S being formed by the folding of the pad around the lower edge of the lever member and exerting a pressure over the puncture site. It will be readily appreciated that some forms of pressure-generating means may be positioned on- the under- face of the base strip, particularly those relying on stored energy; however in some cases a pivotable, rotatable or deformable member may also be positioned on underface. For example, a rotatable member of elliptical cross-section and having a handle extending over the outer surface of the strip may be pivoted, after appli¬ cation of the base strip, from a position in which its major axis is generally parallel with the base strip to one in which the major axis is generally normal to the base strip. The medial portion of the base strip may be non-adhesive to allow rotary movement of the rotatable member or be adhered to the rotatable member. in another form of pressure-generating means, such means may comprise a base plate located on the adhesive side of the base strip, a stem extending through the strip, and securing means located on the outer, non-adhesive, side of the base strip. In use the base strip, having a non-adhesive medial area is applied to the puncture site with the base plate immediately thereover. The area of base strip surrounding the stem is then raised and secured to the stem thus causing the base plate to exert a pressure on the puncture site. Preferably projections are provided on the base strip to enable it to be gripped for lifting and such projections may also form part of the securing means. In an embodiment of a dressing according to the present invention incorporating this form of pressure- generating means, the means comprise a member generally resembling an enlarged collar stud and having a basal disc or rectangular plate, an upstanding central stem extending through the base strip, and an upper plate which has means co-operating with the hoops or clips mounted on the base strip to maintain it in a raised position. All the above-described embodiments rely on a pressure generated by mechanical movement of the pressure means by the operator. In the other basic type of pressure means the pressure is stored as potential energy: preferably the pressure means may comprise a compressible substance or a leaf or spiral spring which is stored under compression, and which expands on removal of a constraint. For example a compressed sponge may be stored within an envelope and be releasable by a ripcord tear strip or the spiral spring provided with a removable end cap. Again, the expansive energy may be stored in chemical form, for example in the form of a body of material which swells on wetting, e.g. a hydratable cellulose derivative. ' The overall length of the dressing is conveniently about 10 to 12 cm so that the end portions may be stuck to the skin at the sides of the hand in a direction generally normal to the central portion. However, the dressing should not be so long that there is normally any risk of the hand being completely encircled with the consequent danger of total vascular restriction. Such a length will also afford effective anchorage at other puncture sites and allow the dressing to be suitably scaled down for paediatric use. The adhesive area may be protected by conventional protective panels which are peeled off before use. Any of the haemostatic dressings described in this specification for use in techniques of haemostatis after vascular puncture may be used, on a larger scale, to compress wounds whether traumatic or surgical, especially where such a wound is likely to produce haemotoma, and with great effect where the wound overlies a bone, for example after hip arthroplasty. Elongate, enlarged and multiple versions of my dressings may be used. Although the present invention may be carried out in a great variety of ways some particular embodiments thereof will now be described, by way of example, with reference to the accompanying drawings in which Figure 1 is a perspective view of a haemostatic dressing according to a first embodiment of the invention, partially prepared for-use; Figure 2 is a side elevation of the dressing of Fig. 1 after application; Figure 3 is a perspective view of a haemostatic dressing according to a second embodiment; and Figure 4 is a side elevation of the dressing of Fig. 3 after application. In the drawings and ensuing description the same reference numerals are used to indicate the same or similar parts. As shown in Figs. 1 and 2, a dressing 10 comprises a base strip 12 of knitted or woven and at least longi¬ tudinally non-stretchable material coated on its undersurface with a layer of pressure-sensitive adhesive protected by two removable panels 14, 16; at its inner end each panel is folded to provide an integral tab 14a_, 16a respectively to facilitate removal. Secured to the underside of the pad in a central position by the pressure-sensitive adhesive is a pad 18 formed of quite hard foam of which at least the surface is absorbent. Secured to one end of the base strip 12 is a draw strip 20 formed of non-stretchable material. One wider terminal portion 20a_ is adhered to the base strip 12 and the other wider terminal portion 20b bears a layer of pressure-sensitive adhesive 22 which is protected by a removable panel 24 having a projecting portion 24a_ to facilitate its removal. The narrower shank 2θ£ which connects the terminal portions 20a_, 20b_ passes through an elongate stainless steel wire eye 26 constituted by a staple stapled through a reinforcing panel 28 adhered to the upper surface of the strip 12, and through the base strip 12 itself . Conveniently the strip 20 may be formed of two identical T-shaped pieces secured together to form a double thickness shank. To use the dressing 10 to effect haemostasis, the protective panels 14,16 are removed and the strip 12 applied across the back of the hand 34 with one end of the pad 18 over the point of emergence of the needle (or cannula) and the length of the pad 18 over the path of the needle in the vein 32. When the needle is to be withdrawn the removable protective panel 24 is peeled off and the terminal portion 20b_ of the strip 20 pulled hard through the eye 26 in a direction past its secured end and secured to the upper surface of the wider portion 20a_ and the skin 36 beyond the end thereof. By this action the end portion of the base strip and the underlying skin 36 adhered thereto are approximated, thus rucking and compressing the skin as at 38 and exerting considerable pressure on the puncture site in the vein 32 under the pad 18 to effect haemostasis. The needle is then withdrawn. When haemostasis has been achieved, the base strip 12 is removed together with the end of the draw strip 20 is stuck to the patient's skin 36. Correct choice of the lengths of the non-adhesive shank and terminal adhesive portion 20b of the strip 20 is important, as is the distance between the eye 26 and the pad 18. In the second embodiment, shown in Figs. 3 and 4, which is an opposed draw member dressing 40, the base strip 12, panels 14,16, and pad 18 correspond to those of the first embodiment. A first draw member 42 is formed from a strip of non-stretchable material coated with a layer 43 of pressure-sensitive adhesive. By folding back a medial lateral portion along the centre line and sticking it to the other portion there is produced an offset, non-adhesive, double-thickness shank 44 which connects a root portion 42a., which is adhered to the upper surface of one end of the base strip 12, to a free end portion 42b, the terminal margin of which is folded and stuck back to provide an integral, non-adhesive tab 46. The second draw member 48 is identical to the first but mounted on the base strip 12 in the reverse direction. In the unused condition of the dressing 40 the adhesive layer 43 on each free end portion 42b,48b is protected by being stuck on to the upper surface of the root portion 42a.,48a. of the other draw member. For use the base strip 12 is applied over the puncture site as described for the dressing 10. The 'free end portions 42b,48b of the draw members 42,48 are then detached from the base strip 12 and the members pulled outwardly in opposite directions as shown by the arrows, thus approximating the end portions of the base strip 12 to which their respective root portions 42a_,48a_ are attached and tightly bunching the skin 36 lying between each root portion and the pad 18 as shown at 50,52 and exerting sufficient pressure over the puncture site to achieve haemostasis. The draw members 42,48 are. secured in their tensioned condition by sticking the end portions 42b_,48b down onto the upper surface of the base strip 12 and possibly also to the skin 36. In an unillustrated modification one draw member may have a full width shank and the other pass through an aperture therein; in such a case the other draw member may be non-adhesive and very narrow, eg be a string or tape.

Claims: Claims: 1. A haemostatic dressing (10,40) for applying local pressure to the site of a vascular puncture com¬ prising a base piece (12) of flexible sheet material at least partly coated on one face with adhesive for adhering the material to the skin of a patient in the area of said site and means for maintaining against said site a pressure previously applied by an operator, characterised in that the pressure means (20,26) are operable to generate pressure against said site by deformation of the base piece (12) after the application thereof to a patient's skin. 2. A dressing as claimed in Claim 1 , in which the pressure generating means are draw means arranged to approximate the end portions of the base strip (12) generally in the plane thereof. 3. A dressing as claimed in Claim 2, in which the draw means (20,26) are operable by drawing in one direction. 4. A dressing as claimed in Claim 3, in which the draw means comprise a draw member attached to one end portion of the base strip (12) and an eye (26) attached to the other end portion of the base strip (12) and through which the draw member (20) passes, the member (20) being provided with attachment means (22) for - maintaining it in the drawn condition 5. A dressing as claimed in Claim 3, in which the draw means are operable by drawing in opposed directions, 6. A dressing as claimed in Claim 5, in which the draw means comprise two draw members (42,48) each attached at one end (42, 48a) to a respective end of the base piece ( 2) and each having at the other, free end (42b,48b) attachment means (43) for attaching it to the base strip (12) and/or skin to maintain it in the drawn condition. 7. A dressing as claimed in Claim 5, in which the draw members are arranged such that the end portions remain in alignment- after approximation. 8. A dressing as claimed in Claim 1, in which the pressure-generating means are arranged to develop a pressure generally normal to the plane of the base piece. 9. A dressing as claimed in Claims 1 or 2, in which the pressure-generating means comprise a tension¬ able member which, in use, bridges the end portions of the base piece and a spacing member which is, in . use, positioned between the tensionable member and base piece. 10. A dressing as claimed in Claim 1 or 2 and 8, in which the pressure generating means comprise a lever member hinged at one edge to the base strip and arranged as an over-centre toggle which, when operated, approx- imates the end portions of the base piece and causes the hinged edge of the lever member to exert a pressure in a direction out of the plane of the base piece. 11. A dressing as claimed in any preceding Claim and additionally comprising a pad (18) mounted on the under¬ side of the base piece (12) and having sufficient thick¬ ness and stiffness to cause the skin to ruck preferen- tially on one side (38) or both sides (50,52) thereof when the end portions of the base piece (12) are approx¬ imated.

Inventors: MOORE PATRICIA, MOORE, PATRICIA
Applicants: MOORE PATRICIA, MOORE, PATRICIA
Application year: 1986
Main classification: A61F13
IPC codes: A61F13