Mark Rippon

Application of an in vitro model to evaluate bioadhesion of fibroblasts and epithelial cells to two different dressings

The cellular component of a healing wound consists of many cell types and the environment in which these cells grow is important to the rate and quality of healing which can be influenced by the type of dressing used. The most commonly used dressings are traditional gauze-type dressings. In many cases these dressings may adhere to the wound surface, and subsequent removal is often traumatic, causing pain and tissue reinjury. Some modern gelling dressings have been developed to overcome this adherence problem. In order to evaluate in more detail cell-dressing interactions, an in vitro model has been developed utilising wound fibroblasts and epithelial cells. Quantitative evaluation of adherence of cells cultured with a traditional gauze or a new gelling dressing has been undertaken using radiolabel and manual counting techniques. Scanning electron microscopy has been used to visualise the cells adherent to dressings allowing evaluation of their adhesion-morphology. The results show differential attachment of cells to viscose and gelling fibres of the dressings; considerably reduced cell adhesion to the gelling fibre was evident, and it was apparent that cells adhered predominantly to the viscose component of the dressing. This model can be used to investigate and compare the adhesion of cells to different dressings and their components.

Clinical correlation of a skin antisepsis model

The use of pigskin as a test substrate for evaluating topical antimicrobial activity has been developed. Simulated handwashing protocols with this in vitro model in parallel with in vivo studies have been evaluated, based on an ASTM method for the clinical evaluation of a healthcare personnel handwash. Using Serratia marcescens as the test organism, similar log reductions were observed using the in vitro model when compared to in vivo efficacy. Results suggest that this model can be used as a reliable indicator of antiseptic efficacy on the skin. The use of sterilized skin simplifies the use of this model for both efficacy and skin-pathogen interaction studies.

The effect of Ringer's solution within a dressing to elicit pain relief.

Clinical studies suggest that dressings containing Ringers solution, such as the TenderWet and HydroClean families, provide relief from wound pain. This report reviews the available evidence and possible mechanisms for the relief of wound pain by these dressings. The ability of dressings containing Ringers solution to provide pain relief is likely to be through providing a moist environment that is favourable for wound healing; furthermore, the dressing augments the protective barrier function by having additional fluid under the dressing, which covers exposed nerve endings and protects against friction damage. Ringers solution will have a dilution effect and an influence on the pH of exudate. Diluting cytokines within the exudate would be expected to decrease inflammation in chronic wounds and reduce the influence of caustic components such as matrix metalloproteases (MMPs). Altering the pH of the wound bed could inactivate proteins and glycoproteins implicated in the pain response such as MMPs and sodium and calcium channels. The moist environment may also be better at recruiting leukocytes that release natural painkillers at areas of injury. These mechanisms are likely to act in combination to explain why dressings containing Ringers solution can have analgesic effects.

A review of blisters caused by wound dressing components: Can they impede post-operative rehabilitation and discharge?

This review highlights that some wound dressings can be the cause of blistering. It also presents the mechanisms by which blisters may be caused by poor choice of dressings. The subsequent impact of the blisters on preventing patient mobility - and hence rehabilitation in terms of physiotherapy - is also identified. The possibility that the clinical sequelae (e.g. delayed wound healing, restricted joint range of motion (ROM), muscle atrophy and increased risk of deep vein thrombosis (DVT)) resulting from this might have a significant and deleterious impact upon patient-related outcomes is discussed. Strategies for the treatment and prevention of blisters are proposed, based upon current knowledge and expertise. The criticality of the wound care specialist and the physiotherapist working together to overcome these challenges and enhance patient care is underlined. This article is a review of the relevant literature combined with opinions based upon the experience and knowledge of the authors.

An in vitro assessment of bacterial transfer by products used in debridement

OBJECTIVE The aim of this in vitro study was to investigate the transfer of viable Pseudomonas aeruginosa biofilm microorganisms following treatment with debridement tools. METHOD The level of viable biofilm microorganisms transferred by debridement tools was compared following treatment that reflected the clinical practice of each product. RESULTS A significant level of microorganism transfer was seen in response to the mechanical debridement tool. Minimal transfer of microorganisms was seen when in vitro-established biofilms were treated with hydroresponsive wound dressing + polyhexamethylene biguanide (HRWD+PHMB, HydroClean plus). Less Pseudomonas aeruginosa was recovered from explants exposed to dressings compared with those exposed to debridement tools suggesting that there was less transfer of bacteria by dressings. CONCLUSION The reduced transfer of viable microorganisms by HRWD+PHMB may be the result of significant binding and retention of microbes by the superabsorbent polymer within the dressing, together with enhanced sequestered bacterial killing within the dressing by polymer-bound PHMB. The high levels of microbial transfer/transmission seen for debridement tools suggests that, in the clinical setting, a significant level of bacterial spread over the wound surface and/or surrounding skin by these cleansing tools is likely.

The potential benefits of using aloe vera in stoma patient skin care

Individuals living with an ostomy may suffer from a variety of peri-stomal skin complications related to the use of their stoma appliance or accessories. These conditions can be serious enough to significantly impact on a patients quality of life and may result in severe clinical complications (such as infection). This article is a review of the literature with the objective of investigating and presenting evidence for the well-documented use of aloe vera in the prevention of skin conditions similar to those seen in peri-stomal skin complications. An exploration for the potential use of aloe vera directly or indirectly (as an adjunct to medical devices such as wafers) in stoma patients is presented with the view that this use may be beneficial in the prevention of such peri-stomal skin complications.