European Pressure Ulcer Advisory Panel

Incontinence-Related Skin Health

Alan Cottenden

Continence & Skin Technology Group, University College London, England

Wearers of incontinence pads often experience soreness and discomfort in the diaper area. When skin is occluded by pad materials - especially if they are wet - it becomes over-hydrated and susceptible to abrasion damage by friction. Furthermore, pressure ulcers are associated with incontinence, and abrasion damage over boney prominences may be a factor in pressure sore initiation. This lecture will describe a program of work which involves developing and validating methods for characterizing over-hydrated skin and using them to study the interaction of incontinence pads with the skin of their wearers.

The presentation will begin by reviewing the prevalence of incontinence-related skin problems among incontinence pads wearers and the nature of the skin problems they suffer. Initial work on the development of a new tool for categorizing incontinence-related skin problems (based on photography and descriptive terms) will be reported.

A new method will be described for measuring friction between skin and incontinence pad materials. Example results will be shown for different materials on normal and on over-hydrated skin. Results from the method will be shown to agree well with a mathematical analysis of the test configuration.

Methodologies will be described for estimating the mass of excess water in over-hydrated skin from drying curves (water vapour flux versus time) logged using evaporimetry. Results from five different devices for measuring water vapour flux density will be compared and their strengths and limitations highlighted. Correlations will be shown with the hydration level of the stratum corneum at the skin surface (measured using Opto-Thermal Transient Emission Radiometry - OTTER). The application of the drying curve method to testing the efficacy of skin barrier creams will be described

Nursing issues and skin care

Sue Bale

Trust Headquarters, Grange House, Llanfrechta Grange, Cwmbran, South Wales, NP64 8YN, UK

With an increasingly elderly population in the Western world, ensuring patients’ skin integrity is an important element of maintaining health and well being in this group of people. Incontinence is a common clinical problem that is under diagnosed, under reported and under treated. In continence becomes increasingly prevalent as people get older and less independent. It affects between 10 and 35% of adults and at least 70% of people living in Care Homes. When incontinence is not adequately controlled incontinence dermatitis can occur, causing skin lesions and skin breakdown. Here, urinary incontinence combined with faecal incontinence causes the most severe skin damage. Protecting the skin continence promotion and/or skin protection are key factors in maintaining skin integrity.

Strategies for achieving skin integrity include:

• comprehensive skin assessment
• structured, appropriate education and training of staff
• the use of protocols and pathways
• skin cleansing regimes that are skin-friendly
• the use of skin care barrier creams and films that are designed to protect adult skin

Current issues that will be explored include:

• a limited understanding of the pathophysiology of incontinence
• challenges associated with differentiating between moisture/incontinence lesions and superficial pressure ulcers
• cultural challenges for nursing practices surrounding skin care.

Maintaining skin integrity is one of the many challenges for nurses caring for vulnerable, older people. Adopting a structured approach across different healthcare settings is key to the promotion of skin integrity and the prevention of skin breakdown.

Can we influence the environment at the Patient Support Interface?

Dan Bader DSc

School of Engineering and Materials Science, Queen Mary University of London, Mile End Road, London E1 4NS, UK and Department of Biomedical Engineering, Eindhoven University of Technology, the Netherlands.

From a bioengineering viewpoint, there are a range of external parameters which might be monitored at the interface between the patient and a support surface. Indeed there are often associations between these parameters when assessing the propensity of a soft tissue site to breakdown. For example the presence of interface shear has been shown to reduce the equivalent levels of normal pressures on its required to result in tissue breakdown (Dinsdale 1974). The presence of moisture at the interface can increase the interface friction and affect the barrier properties of the outermost skin layers. In addition, both temperature and humidity are associated with an increased metabolic rate and/or change in tissue integrity, both factors of which can lead to increased susceptibility to tissue breakdown. These effects may be important during loading and subsequent reperfusion phases, both of which are relevant for the initiation of pressure ulcers (Bouten et al. 2003; Peirce et al, 2000).

Current support systems offer the potential of altering the temporal profile of various interface parameters. In a stimulated model of a ‘sweating body’, similar to that previously reported (Figiola 2003), our study involved monitoring the temperature and humidity levels on a range of air support systems. Results suggested that in certain conditions the humidity levels could be controlled, which would provide benefit to prolonged loading on support surfaces.

How dangerous is shear?

Cees Oomens

Eindhoven University of Technology, Eindhoven, The Netherlands

Ever since Reichel (1958) raised the point that shear forces are a dangerous risk factor for pressure ulcers, supported by evidence from Dinsdale (1974) and Bennet (1979), shear has become a big issue in pressure ulcer prevention. It was the incentive for a lot of work on shear sensor technology and for the analyses of sitting posture in the eighties and nineties (Goossens, 1995). The discussion has become rather technical over the years and probably hard to follow for people that do not have a training in mechanics. This was one of the reasons for starting a working group on ‘Shear Force’, by members of the American, European, and Japanese pressure ulcer advisory panels.

The current presentation is aimed at an understanding of the difference between shear forces, normal forces and friction at an interface between body and supporting surface. It will be explained why these forces are considered boundary conditions and that it is important to know what the effect of these boundary conditions is on the internal mechanical state of the skin, fat, muscle and other tissues. A few different mechanisms will be discussed, that may lead to tissue damage and eventually a pressure ulcer.

Can we find a relationship between external pressure and shear and internal deformation?

Karlien Ceelen, A.~Stekelenburg, J.L.J.~Mulders, C.W.J.~Oomens, F.P.T.~Baaijens

Eindhoven University of Technology, Department of Biomedical Engineering, Eindhoven, The Netherlands

Introduction

A major issue in pressure ulcer research is to find a damage threshold. From an increasing number of publications, it has become clear that external pressure measurements alone do not supply sufficient information to determine such a threshold. It is indispensable to know the internal deformation of tissue, resulting from external pressure and shear at the interface between tissue and supporting surface. If this internal deformation can be related to damage development, it will be possible to define an objective damage threshold for tissues. This is especially relevant for the problem of deep tissue injury.

Currently, internal deformation can be measured by means of Magnetic Resonance Imaging (MRI) techniques. It is also possible to calculate internal deformation with theoretical models, based on the Finite Element Method (FEM). However, such theoretical models have to be validated. The objective of the current study is to compare results from deformation measurements using a technique called Magnetic Resonance Tagging, with FEM calculations.

Methods

The tibialis anterior region of a rat hindlimb was deformed using an MR compatible loading device.¹ Tissue displacement was tracked in two dimensions. The experiment was simulated with an FE model on a 2D mesh based on the geometry of the specific rat hindlimb. To compare tagging and model results, displacements from both methods were interpolated on an identical grid, and strains were subsequently calculated. Location and magnitude of the maximum shear strains and strain energy densities from tagging and model were compared.

Results and conclusions

The agreement between the two methods is quite good. This means that the model can be used to estimate regions of high internal strains, and compare these with damage locations obtained from T2-weighted MRI experiments.²