Wound dressing

Abstract

A wound dressing comprising an absorbent layer, the absorbent layer being gathered in a longitudinal direction by one or more resilient yarns.

Claims

1. A wound dressing comprising a nonwoven absorbent layer, the absorbent layer comprising two or more layers of fabric, wherein the two or more layers of fabric comprise gel-forming fibers, are layered together to substantially overlap and are gathered in a longitudinal direction by stitching through the two or more layers of fabric using one or more resilient threads or yarns and an inelastic thread or yarn, wherein the resilient and inelastic threads or yarns gather the two or more layers of fabric so that the two or more layers of fabric in use are configured to; (a) maintain close conformability with a wound during movement and (b) elongate by 35% to 85% and then recover.

2. The wound dressing as claimed in claim 1 further comprising an adhesive layer overlying the absorbent layer on a surface furthest from the wound in use and extending beyond the periphery of the absorbent layer so as to adhere the dressing to the skin surrounding the wound.

3. The wound dressing as claimed in claim 1 characterized in that the resilient thread or yarn is woven in between the inelastic thread or yarn stitches and between the two or more layer of fabric to gather the two or more layers of fabric.

4. A method of manufacturing a wound dressing for use on post-surgical wounds characterized in that the method comprises the steps of: (i) forming a nonwoven absorbent layer comprising two or more layers of fabric, wherein the two or more layers of fabric comprise gel forming fibers and are layered together to substantially overlap; (ii) gathering the two or more layers of fabric by stitching through the two or more layers of fabric with a resilient thread or yarn and an inelastic thread or yarn, wherein the resilient and inelastic threads or yarns gather the two or more layers of fabric so that the two or more layers of fabric in use are configured to: (a) maintain close conformability with a wound during movement, and (b) elongate by 35% to 85% and then recover; (iii) overlying the absorbent layer with an adhesive layer on a surface furthest from the wound in use and extending beyond the periphery of the absorbent layer so as to adhere the dressing to the skin.

5. The method as claimed in claim 4 characterized in that the two or more layers of fabric are formed from nonwoven fabrics.

6. The method as claimed in claim 5 characterized in that the method comprises the further step of simultaneously weaving the resilient thread or yarn about the stitches of inelastic thread or yarn.

7. The method as claimed in claim 6 characterized in that the resilient thread or yarn is woven about the stitches of inelastic thread or yarn and carried at the center of the two or more layers of fabric.

8. The method as claimed in claim 6 characterized in that the resilient thread or yarn is stitched about the stitches of inelastic thread or yarn.

Description

(1) Preferred embodiments of the invention will now be described with reference to the accompanying drawings in which:

(2) FIG. 1 is a view of a preferred embodiment of the dressing according to the invention in perspective view; and

(3) FIG. 2 is an exploded view of a further embodiment of the dressing according to the invention in perspective.

(4) In FIG. 1 the dressing comprises a layer of hydrocolloid adhesive 2 onto which is bonded an absorbent layer 4. A further layer 6 of hydrocolloid adhesive having a window 8 is applied over the absorbent layer so that the absorbent layer is sandwiched between the two adhesive layers with the window exposing the absorbent layer to the surgical site.

(5) The absorbent layer is made from a non woven roll made by forming a web of Lyocell which is then hydroentangled. The web is then carboxymethylated by sequential or simultaneous treatment of the cellulosic material with a strong alkali, monochloroacetic acid or a salt thereof. Two webs of the resulting fabric are then fed into a stitch bonding machine and stitched simultaneously with lines of longitudinal stitching in an inelastic yarn and a resilient yarn woven in between the stitches and so secured at the centre of the webs. The resilient yarn gathers the absorbent layer (not shown) and is carried by the inelastic stitch bonded yarn. The resulting layer has a basis weight of 350 gm.sup.2.

(6) In FIG. 2 the dressing comprises two layers of hydrocolloid adhesive 10, 12 reinforced by a polyurethane film 14 into which is cut a window 16. An absorbent layer 18 is positioned over the window and overlaps the adhesive layer around its margin. A further layer 20 of adhesive backed with a polyurethane film is applied over the absorbent layer so that the absorbent layer is sandwiched between the layers with the window 16 exposing the absorbent layer 18 to the surgical site.

(7) The absorbent layer is made from a tow of carboxymethyl cellulose filaments which has been needlefelted. Two webs of the needlefelted tow are fed into a stitch bonding machine and stitched simultaneously with lines of longitudinal stitching as shown in FIG. 2 in inelastic yarn and with a resilient yarn woven inbetween the stitches and so secured at the centre of the webs.

(8) In the context of the present invention the terms yarn and thread are used to interchangeably.

(9) Preferred embodiments of the invention will now be described with reference to the following examples:

EXAMPLE 1

(10) The absorbency of the dressing described in FIG. 1 was measured against the absorbency of a dressing used in the Jubilee method referenced above. The absorbencies of the dressings were measured using the method described in BS EN 13726-1:2002 Test Methods for Primary Wound DressingsPart 1: Aspects of absorbency.

(11) The results are shown below:

(12) TABLE-US-00001 Control, Jubilee method (4 layers of Aquacel and DuoDerm Extra Thin) Dressing of FIG. 1 Fluid absorbed by 6.3 (5.9-6.8) 6.9 (6.8-7.0) dressing (g/10 cm.sup.2) (24 hr) Fluid handling capacity 6.6 (6.2-7.2) 7.4 (7.3-7.5) (g/10 cm.sup.2) (24 hr)

(13) These results show that the dressing according to the invention with a gathered absorbent layer has an absorbency and fluid handling capacity equivalent to that of a dressing using four layers of the same absorbent material.

EXAMPLE 2

(14) The resilience of the dressing of FIG. 1 was measured by hydrating the dressing with 30 ml of solution A which was coloured using blue food dye. Masking tape was adhered to the short ends of the dressing and the dressing fixed in the grips of a Zwick Universal Testing Machine. The distance between the grips was extended by 20% and the Zwick was set to run a cyclic test with a pause at maximum extension of 15 seconds and a pause at recovery of 60 seconds. The number of cycles was 1000 with a speed of travel of 250 mm per minute. After testing no breakdown of the dressing was seen. The dressing remained integral and retained all of the solution A added at the beginning of the test. The force required to extend a 25 cm dressing length was 10.76 N. The stretch as a percentage of the original dressing length was 20%.

(15) These results suggest that the dressing may enable increased or easier limb movement during patient rehabilitation.