Advancing wound care naturally...8th April 2014
The ideal wound dressing should manage and prevent infection, maintain a moist wound bed, protect the peri-wound skin and newly-formed tissue, and promote healing (European Wound Management Association [EWMA], 2004; Dai et al, 2011). To meet these goals, the dressing therefore should:
- Form an effective bacterial barrier
- Maintain hydration of the wound and peri-wound skin, while offering protection from potentially irritant wound exudate and excess moisture
- Require minimal disturbance or replacement
- Produce minimal pain during application or removal as a result of adherence to the wound surface
- Possesses antimicrobial activity capable of containing localised infection
- Be able to remove or inactivate proteolytic enzymes in chronic wound fluid
- Possess haemostatic activity (World Union of Wound Healing Societies [WUWHS], 2007).
Furthermore, the dressing should not release particles/non-biodegradable fibres into the wound during use, and be free of toxins and irritants (WUWHS, 2007).
KytoCel® (Aspen Medical) is a new gelling fibre dressing with all of these properties that makes it a ‘natural’ choice for wound management, whatever the stage of wound healing. The dressing uses chitosan, an abundant natural resource with proven efficacy in biomedicine, combined with advanced dressing technology, to provide a unique dressing that is protease-modulating, antimicrobial, haemostatic and highly absorptive, while also being biodegradable, biocompatible and non-toxic (Struszczyk, 1995).
The unique properties of Chitosan
Chitosan is widely recognised as an under-utilised resource and a versatile biomaterial that has a number of applications (Dutta et al, 2004). It is a natural polysaccharide derived from chitin, the second most abundant polysaccharide in the world (Dai et al, 2011). Chitin is widely found in nature, particularly in the exoskeletons of crustaceans (such as crabs, lobsters, shellfish and shrimps) (Lee et al, 2009; Dai et al, 2011). The processing of chitin into chitosan results in a positively charged molecule that allows it to interact with many negatively charged molecules such as gram-positive bacteria, blood cells, proteins, metals and lipids (Lee et al, 2009). Chitosan’s unique characteristics give it a variety of applications in medicine, such as orthopaedics, tissue engineering, drug delivery, surgical adhesion and wound management (Khor and Lim, 2003; Senel and McClure, 2004; Foda et al, 2007; Raafat et al, 2008; Dai et al, 2011).
Chitosan in wound management
Within the field of wound care, Chitosan has been shown to:
- Accelerate wound healing (Li et al, 1992; Khor and Lim, 2003; Foda et al, 2007; Lee et al, 2009)
- Stimulate the immune response (Lee et al, 2009)
- Have antimicrobial (bacteriostatic and fungistatic) action (Li et al, 1992; Khor and Lim, 2003; Niekrasewicz, 2005; Foda et al, 2007)
- Be haemostatic (Li et al, 1992; Khor and Lim, 2003; Niekrasewicz, 2005; Foda et al, 2007)
- Be biocompatible, bio-degradable and non toxic (Li et al, 1992; Khor and Lim, 2003; Niekrasewicz, 2005; Foda et al, 2007; Jayakumar et al, 2011).
Chitosan accelerates healing
Chitosan has an accelerating effect on wound healing (Dutta et al, 2008; Lee et al, 2009; Jayakumar et al, 2011). It enhances the function of polymorphonuclear neutrophils, macrophages and fibroblasts to promote granulation and organisation (Dai et al, 2011). Chitosan has also been shown to activate immune cells, cytokine production and giant cell migration, as well as stimulating type IV collagen synthesis (Mezzana, 2008). These healing properties make chitosan useful at every stage of tissue repair (Dai et al, 2011).
Chitosan stimulates the immune response
Chitosan has been shown to enhance the function of inflammatory cells, such as macrophages, that emerge during the inflammatory response, while also accelerating migration of these cells to the wounded site (Ueno et al, 2001). Once activated, these cells kill microorganisms, remove dead cells and stimulate other immune cells, thereby improving overall healing by reducing the opportunity for infection (Lee et al, 2009).
Chitosan has antimicrobial (bacteriostatic and fungistatic) efficacy
Chitosan has antibacterial efficacy against both gram-positive and gram-negative bacteria, and is fungicidal. It is effective against common wound pathogens such as Eschericia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Candida Albicans (Balicka-Ramisz et al, 2005). The exact mechanism of action of Chitosan’s antibacterial efficacy is not completely understood, but it is thought to be the result of several events, that may occur simultaneously or in sequence (Raafat et al, 2008). These include destabilisation of the outer membrane of gram-negative bacteria, and permeabilisation of the microbial plasma membrane (Goy et al, 2009; Dai et al, 2011).
Positively charged chitosan fibres bind rapidly to negatively charged red blood cells, resulting in fast coagulation. By polymerising with blood to form a net-like structure, the chitosan fibres further capture red blood cells leading to clotting (Li et al, 1992; Khor and Lim, 2003; Foda et al, 2007; Niekraszewicz, 2005). In the US, Chitosan has gained regulatory approval for inclusion in bandaging and other haemostatic agents (Dai et al, 2011).
Biocompatible, bio-degradable and non-toxic
As a natural polymer, Chitosan is biodegradable to normal body constituents, and when broken down, is safe and non-toxic. Its biodegradability and biocompatibility make it an attractive material for medical applications, including wound management products (Ueno et al, 2001; Dutta et al, 2004; Senel and McClure, 2004; Niekraszewicz, 2005; Raafat et al, 2008).
KytoCel® Gelling fibre dressing and wound care
KytoCel utilises natural, biodegradable acylated chitosan fibres to bring all the benefits of chitosan to a gelling fibre dressing for use in wound management.
High absorbency and long wear times
The unique chitosan fibres of Kytocel bond with wound exudate on contact to form a clear gel that locks-in fluid. KytoCel can retain a large volume of wound exudate (Aspen Medical, data on file, b) leading to longer wear times and associated cost-savings. Tests have shown that Kytocel has a greater, or comparable absorbency to other available gelling fibre dressings (Aspen Medical, data on file, a)
Protection of peri-wound skin and the wound bed
The minimal lateral wicking demonstrated by KytoCel (Aspen Medical, data on file, b) prevents the spread of wound exudate to the edges of the dressing, protecting the peri-wound skin from the risk of maceration. Kytocel is conformable to the wound bed, thereby supporting wound healing by causing no damage to the newly-formed tissues and providing a gentle contact surface with the wound bed.
Bacterial sequestration to lock away wound pathogens
Commonly encountered wound pathogens, e.g. E.coli and S. aureus, are sequestered by Kytocel and are effectively locked away within the dressing. KytoCel has been shown to be more effective at reducing organism numbers within and under the dressing than the leading alginate and hydrofiber® (Aspen medical, data on file)
Percentage reduction in bacteria*
* after 18 hours incubation at room temperature
KytoCel’s antimicrobial action offers protection to wounds at risk of infection. It is effective against commonly encountered wound pathogens including Candida albicans, E. coli, S. aureus, and meticillin-resistant Staphylococcus aureus (MRSA) (Aspen Medical, data on file, c). Its antimicrobial mode of action is not confined to a single target molecule but results from a sequence of untargeted molecular events that take place simultaneously or successively (Raafat et al, 2008). As a result, the development of bacterial resistance to chitosan is unlikely, meaning it has strong future potential in the management and prevention of wound infection (Dai et al, 2011).
High wet strength
The dressing’s high wet strength also means that it can be removed in one-piece, remaining intact even when fully saturated (Aspen Medical, data on file, a, b), without leaving behind dressing fibres or residue (Aspen Medical, data on file, a, b). This, in turn, makes dressing changes easier and promotes patient comfort.
Natural haemostatic ability stops wound bleeding
The unique positive charge of chitosan fibres enable them to stop bleeding by binding to negatively charged red blood cells, resulting in blood coagulation (Li et al, 1992; Khor and Lim, 2003; Niekrasewicz, 2005; Foda et al, 2007)
Chitosan also polymerises with blood to form a net-like structure, which further captures red blood cells, leading to clotting (Li et al, 1992; Khor and Lim, 2003; Niekrasewicz, 2005; Foda et al, 2007)
KytoCel gelling fibre dressing is available in a variety of shapes and sizes. For more information go to: http://www.aspenmedicaleurope.com/specialist-woundcare/search-product/kytocel/
KytoCel is indicated for the management of moderate to heavily exuding chronic and acute wounds, including:
- Pressure ulcers
- Venous leg ulcers
- Diabetic foot ulcers
- Cavity wounds (ribbon dressing)
- Donor sites and graft sites
- Surgical wounds (e.g. postoperative wounds left to heal by secondary intention)
- Skin abrasions and lacerations
- Superficial and partial-thickness burns
- Exudate absorption in oncology wounds (e.g. fungating cutaneous tumours, cutaneous metastases and Kaposiís sarcomas)
- Control of minor bleeding in superficial wounds.
The dressing can remain in situ for up to seven days, depending on the patient’s situation, the condition of the periwound skin and the volume of exudate being produced.
KytoCel is not indicated for use for surgical implantation, third-degree burns, or to control heavy bleeding. It should not be used on patients with known sensitivities to any of the components of chitosan, or who have had an allergic reaction to the dressing.
This 60-year-old turkey farmer sustained a trauma injury to his third finger while culling turkeys for the Christmas market on 19 December 2013. The sharp injury caused damage to the distal phalanx, incorporating the nail bed and distal phalanx joint. Initial first-aid treatment consisted of adhesive plasters, but he was unable to stop the bleeding so attended his local surgery for medical advice, and was referred to the tissue viability team.
At presentation, the tissue viability team decided to apply KytoCel to the wound bed as a primary dressing to aid haemostasis, manage exudate, reduce the risk of infection and maintain dexterity. A polymeric membrane finger dressing (PolyMem® Finger/Toe, Aspen Medical) was applied and secured with Micropore Surgical tape (3M Healthcare) to maintain functional hand movement while providing protection, to enable the patient to continue working.
The patient was advised to keep the wound as clean as possible and his wife was shown how to change his dressing and encouraged to do so as required. He was informed that he would probably lose the nail and arrangements were made for a follow-up appointment in the outpatient clinic one week later. However by this stage, the wound had healed and the nail did not require evulsion.
Chitosan is a versatile, abundant naturally occurring polysaccharide that has numerous applications as a result of its unique characteristics. Within wound management, these include the ability to reduce bioburden, accelerate healing, stimulate the immune response, and stem bleeding. Furthermore chitosan is non-toxic, degradable and bio-compatible. Kytocel dressing combines all these benefits of chitosan with advanced dressing technology to produce a product with high wet tensile strength, absorption, and low lateral wicking, and which is gentle enough to protect peri-wound skin and new tissue. It is a unique, natural dressing that meets many of the criteria for an ideal wound management dressing.
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