Patent Publication Number: US-2020281775-A1

Title: Assembly and method for the preparation of a wound dressing

Description:
TECHNOLOGICAL FIELD 
     This disclosure is in the field of wound treatment and concerns a wound dressing assembly for the preparation of a blood clot and use of this blood clot in wound treatment. 
     BACKGROUND 
     Chronic wounds and skin ulcers are a serious medical condition and effective wound treatment approaches is a recognized medical need. 
     U.S. Pat. No. 9,180,142 discloses a wound treatment procedure by which blood is coagulated and the so-formed blood clot is applied onto a wound with a dressing material. 
     GENERAL DESCRIPTION 
     The present disclosure concerns wound treatment through the use of a blood clot. Specifically provided by this disclosure is a wound dressing assembly (e.g. in the form of a kit-of-parts for use in the currently disclosed wound treatment) for preparing such a blood clot, a method for preparing a wound dressing comprising such a blood clot, and a method for dressing the wound therewith. 
     The blood clot that is formed and used according to this disclosure is typically, but not exclusively, formed from blood of the same subject whose wound is to be dressed by the teaching of this disclosure. The blood is typically whole blood withdrawn from the subject in any manner acceptable in medical practice for blood withdrawal. In some other embodiments, the blood is whole blood from a blood bank. 
     By a first of its aspects, the present disclosure provides a wound dressing assembly comprising a blood-clotting mold device having an enclosure, defined between walls of a main body and a removable closure (e.g. in the form of a film) that seals an opening of the enclosure (to maintain sterility of the enclosure), the enclosure being configured for introduction of blood thereinto, typically without removal of the closure or portion thereof. This device serves, as will be further understood from the description below, as a mold for forming a blood clot that is intended for placing onto a wound. 
     By one embodiment, at least one of the walls or closure of the device is pierceable by a needle and through the pierce formed therewith, blood is introduced into the sealed enclosure. 
     By another embodiment, the enclosure has a port for blood introduction; or at times two ports, one for introducing blood and the other for venting (e.g. to permit egress of gas from the enclosure during blood introduction). The venting port may be a priori sealed, intended for removal of excess pressure during injection of the blood into the enclosure. Typically, prior to injection of the blood and in order to permit such venting, the vent is opened. 
     By one other embodiment, the enclosure (prior to introducing the volume of blood) is under vacuum. 
     In some embodiments, the enclosure comprises a coagulation initiator in an amount sufficient to facilitate coagulation of blood introduced into the enclosure. The coagulation initiator may also be held in an independent container for either mixing with the blood before it is introduced into the enclosure or for independent injection into the enclosure before or after introducing the blood thereinto. 
     Blood coagulation initiators are known in the art. In one embodiment of the present disclosure, the blood coagulation initiator comprises at least kaolin. The blood coagulation initiator (kaolin or any other coagulation initiator) may be provided in any form, such as, liquid, powder, granulate, etc. 
     Once the blood clot is formed within the enclosure, it is transferable onto a wound or onto a dressing material. 
     The assembly preferably comprises a scaffold matrix (blood clot supporting matrix) within the enclosure that is intended for being integrated or embedded with the formed blood clot. The scaffold matrix may, thus, have the purpose of (i) providing an overall support to the blood clot; (ii) assisting in maintaining structural integrity of the clot once formed, and/or (iii) enabling the transfer of the clot to the wound or onto a dressing and supporting the clot throughout such transfer. 
     This supporting scaffold matrix is typically in a form of a net, such as a plastic net, a cloth etc. in some embodiments, the matrix is of a material similar to that of a dressing material, e.g. gauze. 
     The blood injection is, typically, performed such that said matrix will be embedded within the blood and hence within the subsequently formed blood clot 
     The enclosure has a shape configured for extraction of the formed blood clot without compromising the integrity of the blood clot. For this, the opening of the enclosure that is initially sealed/closed by the closure, should be wide to permit such extraction, e.g. a shape of a relatively shallow cavity. 
     The mold device may have different shape and sizes to match different shapes and sizes of wounds. 
     In some embodiment, the enclosure has a shape and dimension that configures the eventual overall shape of the clotted blood mass formed within the enclosure and hence the shape and dimension of the blood clot subsequently applied onto the wound. The shape and dimension of the enclosure (and hence the shape and dimension of the eventual blood clot) may be designed according to the intended use and site of application. For a typical case of application onto a skin wound or ulcer, the enclosure is typically designed with an opening having a width sufficient to permit relatively easy extraction of the clot as whole without compromising its integrity. The clot is typically formed to have a horizontal dimension that is considerably larger than its height (thickness), e.g. in the form of a relatively shallow cavity as noted above. In some other embodiments, e.g. in the case of a tunneling wound, the relative dimension may be different and configured for such types of wounds. 
     In some embodiments, at least the walls of the main body are rounded (convex or U-shaped). Yet, in some other embodiments, the walls of the main body are polygonal, e.g. cubic shaped. 
     The enclosure may, by some embodiments, have the general form of a blister and the closure being a film that is removable from the rims of the main body. The enclosure may typically comprise a portion, e.g. all or parts of the main body, which is transparent. 
     Further, to facilitate transfer of the formed blood clot, without compromising the integrity of the clot, the enclosure is typically made of or is coated with a material of the kind to which a blood clot does not adhere or adheres to only weakly. 
     Also provided by this disclosure is a method for preparing a wound dressing making use of the blood-clotting mold device disclosed herein. Generally, the method comprises injecting a volume of blood into the enclosure of the of the currently disclosed blood-clotting mold device, permitting the volume of blood to clot to thereby obtain a blood clot within the device&#39;s enclosure, removing the closure and extracting the blood clot out of the enclosure. 
     to By some embodiments, contemplated within the method of this disclosure, is a procedure by which a wall of the enclosure or the closure is first pierced to form a vent, e.g. by a sharp object or by a needle (e.g. the same needle subsequently used for injection of the blood) and only then blood is injected into the enclosure. 
     In some embodiments, after extraction, the blood clot may be combined with a dressing material. Such combination may involve transfer of the blood clot onto the dressing material for subsequent placing of the combined blood-clot and dressing material onto a wound; or placing the blood clot directly onto the wound and covering it with the dressing material. The dressing material may be gauze or any other material suitable or commonly used for dressing wounds. 
     Also provided by this disclosure is a method for dressing a wound. This method comprises the preparation of a blood clot and its extraction, in the manner described above and then applying the extracted blood clot onto a wound. Prior to or after application of the blood clot onto the wound, the blood clot may be combined with a wound dressing material as described above. 
     The assembly of this disclosure, which may be in the form of a kit-of-parts (collection of discrete elements), can comprise, in addition to the blood-clotting mold device, other elements for use in the methods disclosed herein. 
     Without being limited thereto, such other elements may include means for transferring the blood clot that has been formed in said enclosure onto the wound. Accordingly, in some embodiments, the assembly comprises a blood clot removing tool, e.g. a spoon-like or spatula-like instrument. This tool can be made of plastic, metal, wood, cardboard, silicon, or be made from any other suitable material, and is configured for the removal of the clot from the enclosure preferably in a manner that preserves the clot&#39;s structural integrity. In some embodiments, the removing tool is configured also for separating the blood clot from the wall of the enclosure. 
     In some embodiments, the assembly comprises means for securing the formed blood clot to the wound. Such means may be a dressing material, e.g. gauze or any other material that is or may be used in medical practice for dressing wounds. 
     In addition, or alternatively, the assembly may include elements such as those used for blood withdrawal, a blood collection vial, a blood coagulant to prevent premature coagulation of the blood (e.g. before introducing into the enclosure), blood removal and transfer tool, etc. 
     Reference is also made to U.S. Pat. No. 9,180,142, the relevant portions thereof being incorporated herein by reference. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order to better understand the subject matter that is disclosed herein and to exemplify how it may be carried out in practice, embodiments will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which: 
         FIG. 1  is a picture providing a bottom perspective view of an enclosure, according to an embodiment of this disclosure, which is in the form of a blister. 
         FIGS. 2A and 2B  are side perspective views illustrating the injection of blood into the enclosure. 
         FIG. 3  shows the removal of the closure revealing the clot formed within the enclosure. 
         FIG. 4  is a schematic illustration of a wound dressing prepared according to an embodiment of this disclosure. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     The embodiments illustrated in the annexed drawings include an enclosure in the form of a blister, which is an exemplary embodiment of the broader context of the present disclosure. Thus, this description of specific embodiments is intended for illustration of the more general principle of this disclosure and is not intended to be limiting. 
     Referring first to  FIG. 1 , shown is a picture of an enclosure generally designated  100  and in the shape of a blister, having a main body  102  with a blister depression  104  and a flat rim  106 . Fitted onto the rim is a removable closure  108  in the form of a laminate/film. 
     Contained within the enclosure  100  is a coagulating initiator substance  110  which may be in the form of a liquid, powder, granulate, etc. The coagulation initiator may, for example, be kaolin. Also contained in the enclosure is a blood clot-supporting (scaffold) matrix  112  which may be made of gauze, of a polymeric mesh, etc., held at its peripheral portions between the rim and the closure and having a central portion within the enclosure. 
     Blood, typically whole blood, is withdrawn and then injected into the enclosure, as shown in  FIGS. 2A and 2B . Specifically, a needle  120  of a syringe  122  that contains the whole blood pierces the closure  108  and blood is injected until it fills a significant portion of the enclosure, sufficient to cover the blood clot-supporting scaffold matrix  112 , as seen in  FIG. 2B . It is possible, also, to initially pierce the closure so as to form a vent opening, e.g. by the blood injection needle, and inject the blood only subsequently. 
     The blood is then maintained in the enclosure for a time sufficient for the blood to coagulate and after clotting the film  108  is removed to reveal a blood clot complex  130  that includes a blood clot  132  embedded with the blood clot-supporting scaffold matrix  112 , as seen in  FIG. 3 . 
     This blood clot complex  130  that includes the blood clot  132  and blood clot-supporting matrix  112  can then be combined with a dressing material  134 , as seen in  FIG. 4 ; the dressing material being, for example, gauze, to form a dressing-clot complex. This dressing-clot complex combination can be transferred onto the wound; alternatively, after opening of the cover of the blister and revealing the blood clot complex, as seen in  FIG. 3 , the blood clot complex can be transferred onto a wound and the dressing material applied thereon while the former is on the wound.