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Incontinence increase the risk of pressure ulcer development


Both incontinence and pressure ulcers are common and often co-exist. Patients with  incontinence are also more likely to be immobile and elderly, both of which have been demonstrated to be strongly associated with pressure ulcer development  (1,2). 

Chemical effects of incontinence on skin
Urine is composed of 95% normal water and 5% organic solutes, which are primarily urea (3). Normal skin has a pH of between 5.4 and 5.9; this acid environment has a bactericidal effect, limiting growth of pathogenic organisms. In the event of incontinence, urinary urea decomposes on the skin to form ammonium hydroxide, an alkaline substance that raises the skin pH and favours bacterial proliferation (3). Faecal incontinence also plays a major role in skin irritation and can contribute to breakdown. Faeces contain enzymes including; proteases and lipases that degrade the skin barrier function.

Once skin is compromised, the abundant levels of microrganisms (which comprise 50% of the solid component of faeces), enable prolific bacterial and fungal growth. The combination of both urinary and faecal incontinence causes significantly higher levels of skin irritation than urine or faeces alone (3). Use of soap based products to cleanse skin following incontinence have been shown to remove sebum from the skin. This lipid based substance provides a natural waterproofing layer and its removal accelerates epidermal water loss. A further effect is that soap based products raise the alkalinity and can cause skin irritation (3). 

Physical effects of incontinence on skin
The presence of excessive moisture on the skin causes a reduction in skin hardness and temperature. This increases the vulnerability to pressure induced blood flow reduction4. Frequent washing and drying causes frictional damage and adversely affects the barrier function of the skin. Gently patting is considered a better approach (3). Presence of excessive moisture on the skin can result in maceration (over hydration) and also dryness and cracking once the lesions begin to resolve.

Differences between incontinence lesions and pressure ulcers
Challenges exist, even for those with specialist knowledge of pressure ulceration, in identifying the differences between superficial pressure ulcers and incontinence lesions. Being able to distinguish between an incontinence lesion and a pressure ulcer is important as each has a different aetiology and thus different preventive measures (5). 

Characteristics of incontinence lesions
• Sacral and ischial locations
• Not necessarily on bony prominences
• Purple rather than red
• Surrounding tissue oedematous and swollen
• Skin is wet and incontinence or diarrhoea present (5)
• Appears symmetrical on both sides of the buttocks 

The magnitude of the problem
There is a particularly high prevalence of urinary incontinence for those within institutional care. More than 50% of nursing home residents in the UK and USA have urinary incontinence (6). A largestudy in a cohort of nursing and home residents identified that of those persons who were  immobile; more than 82% were also incontinent of urine (7).

Management of incontinence and pressure area care
Reduced mobility is a key prognostic factor for pressure ulcer development. Patients who are immobile and identified as being at risk of pressure ulcer development are likely to be  nursed using a specialist pressure redistributing mattress or overlay. A high proportion of these  patients may also be incontinent and this is most commonly managed using absorbent pads.  Recent research has identified that use of absorbent incontinence pads has an adverse  effect on the pressure redistributing qualities of specialist support surfaces. Peak pressure was  identified as being 20-25% higher beneath a buttock wearing a pad, compared with a naked  buttock (8). Ridges in the pads as a result of folding at the time of packing by the manufacturer,  contributes to the effect of pressure and smoothing of the pad by nursing staff prior to  usage was found to reduce peak pressures.

Recent technological developments have resulted in the incorporation of super-absorbent polymers into incontinence products, meaning that products can potentially be worn all night. Fader  2004 investigated the effects of less frequent pad changing on skin health, using 81 incontinent subjects in nursing and residential care homes. They identified that less frequent pad changing was associated with wetter skin, compared to the group that had more frequent pad changing. They also found that 5 subjects developed grade 2 pressure ulcers, which may have been attributable to either the fact that they were less frequently turned or that the skin was more vulnerable to friction and abrasion (9).

Implications for practice
Those caring for patients with incontinence and immobility, have little in the way of alternatives to absorbent pads as a method of managing the condition and maintaining moisture free skin (10). Use of indwelling urethral catheters are not recommended as bacteriuria is inevitable and urinary tract infection common11, except as a last resort management or for those who are terminally ill, for comfort reasons. ‘A faulty classification of a lesion leads to mistaken measures and negative results’ (5)  

If using incontinence pads, these should be smoothed prior to patient usage to minimise ridges and creases. A pad with the most appropriate absorbency and shape should be chosen for individual patients. Use of multiple pads for those with heavy incontinence is not recommended, as this is likely to decrease further the efficacy of the pressure redistributing device. 

If bed pads are being utilised (rather than body worn pads), they should not be stretched over the mattress or tucked in tightly, the risk here is that a hammock effect is produced and the patient rests on this, rather than being supported by the support surface underneath (12). 

Use of incontinence management barrier products such as non-soap skin cleansers and skin barrier products are recommended and have been demonstrated to result in reduced incidence of incontinence dermatitis (3).

Conclusion:
Urinary incontinence, immobility, impaired cognitive function and advanced age are all  associated with the development of pressure ulceration. It is important that practitioners are  aware of the differences between incontinence lesions and pressure ulcers, as each has a  different aetiology and management pathway. Incontinent and immobile patients identified as being ‘at risk’ of pressure ulcer development should have pads changed during the night and  regular positional changes undertaken. Use of specialist pressure redistributing support surfaces are recommended for patients at risk of pressure ulceration.

References
1) Lyder C (2003). Pressure ulcer prevention and management. Journal of the American Medical Association; 289(2): 223-226.
2) Nixon J and McGough A (2001). Principles of patient assessment: screening for pressure ulcers and potential risk. In M.Morison (ed) The prevention and treatment of
pressure ulcers. Edinburgh: Mosby.
3) Errsser SJ, Getliffe K,Voegeli D, Regan S (2005). A critical review of the inter-relationship between skin vulnerability and urinary incontinence and related nursing intervention. International Journal of Nursing Studies; 2: 823-835. 
4) Mayrovitz H, Sims N (2001). Biophysical effects of water and synthetic urine on skin. Advances in Skin and Wound Care; 14(6): 302-308.
5) Defloor T and Schoonhoven L (2004). Inter-rater reliability of the EPUAP pressure ulcer classification system using photographs. Journal of Clinical Nursing; 13: 952-959.
6) Durrant J, Snape J (2003). Urinary incontinence in nursing homes for older people. Age and Aging; 32: 12-18.
7) Aggazzotti G, Pesce F, Grassi D et al (2000). Prevalence of urinary incontinence among institutionalised patients: a cross sectional epidemiological study in a mid sized city in N.Italy. Urology; 56: 245-249.
8) Fader M, Bain D, Cottenden A (2004). Effects of absorbent incontinence pads on pressure management mattresses. Journal of Advanced Nursing; 48(6): 569-574.
9) Fader M, Clarke-O’Neill S, Cook D et al (2003). Management of night-time urinary incontinence in residential settings for older people: an investigation into the effects of different pad changing regimes on skin health. Journal of Clinical Nursing; 12: 374-386.
10) Clarke-O’Neill S (2004).The link between absorbent pads and pressure management products. Nursing Times; 100(20): 77.
11) Nicolle LE (2005). Catheter related urinary tract infection. Drugs Aging; 22(8): 627-639.
12) Hampton S (2005). Importance of the appropriate selection and use of continence pads. British Journal of Nursing; 14(5): 265-269.

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