VOL: 98, ISSUE: 12, PAGE NO: 39
Krzysztof Gebhardt, PhD, RGN, is clinical nurse specialist, pressure ulcer prevention, at St George’s Healthcare NHS Trust, London
The prevention of pressure ulcers should follow the same overall pattern as any other approach to health care: assessment (diagnosis), intervention where appropriate and evaluation of the outcomes. In the case of pressure ulcers, the process is influenced heavily by whether the patient is acutely or chronically susceptible.
According to the most recent guidelines (Rycroft-Malone, 2000), all patients admitted to a care setting should be assessed informally for risk of pressure ulceration. If there is any suspicion that the patient may be susceptible, a formal risk assessment should be undertaken by a professional who is educated in pressure-ulcer assessment and prevention. This should take place within six hours of admission and be documented in the patient’s casenotes.
In some instances, however, six hours would be too long to wait. An acute susceptibility to pressure ulcers is a medical emergency as severe pressure damage can develop within one to two hours (Kosiak, 1958; Reswick and Rogers, 1976). Also, the patient may have been experiencing tissue ischaemia for some time before admission (Versluysen, 1986).
For these reasons, preventive measures may have to be taken before any formal assessment and documentation. When a patient is assessed as not being at risk on admission, a reassessment should take place whenever his or her condition changes.
We know little about the physiology of the body’s defence mechanisms against pressure damage and the pathophysiology of pressure ulcer susceptibility. It is therefore not possible to identify with any certainty those patients who are and those who are not susceptible to pressure ulcers. In other words, susceptibility cannot be diagnosed directly in the way that diabetes, for example, can (from the symptoms and an analysis of the patient’s blood and urine).
However, there is a considerable amount of data on patients who develop pressure ulcers, some of which records patient outcomes (in terms of whether or not pressure ulcers developed) and compares the results with the patients’ initial conditions and other factors.
Taking all the available data and personal experience into account, certain trends can be identified which help the clinician to estimate a patient’s level of risk for pressure ulceration. It should be noted that in some cases certain parts of the body may be susceptible, rather than the patient as a whole. For example, a patient with sciatic nerve damage will be susceptible to pressure ulcers on the leg, while a patient with peripheral neuropathy may have susceptible feet.
It is clear that some patient groups are at high risk of developing pressure ulcers. These include patients with: traumatic, congenital or iatrogenic paralysis; a fractured neck of femur (Versluysen, 1986); and those in critical care units, especially if they are sedated, have multiorgan failure or are being given inotropes (Malone, 1992; Glavis and Barbour, 1990). With patients who fall into any of the above groups, preventive management should always be initiated.
In other patients, susceptibility is determined by the progress of their disease. This group includes patients with motor neurone disease, peripheral neuropathy (for example, patients with diabetes), multiple sclerosis, peripheral vascular disease and metastatic disease.
The key to ulcer prevention in these patients is regular reassessment and the initiation of preventive interventions at the right moment. The assessment should always include a consideration of general risk factors, but may also include more specific examinations of sensation such as those carried out on the feet of diabetic patients (Booth, 2000). Once the threshold of susceptibility has been reached, the degenerative nature of most of the conditions mentioned means the patient is likely to remain at high risk for the rest of his or her life.
In many patients, however, the level of risk is not so clear, and the clinician must make a decision on whether the risk is sufficiently high to justify preventive management. This decision should be based on an assessment of the presence or absence - and relative significance - of various factors, combined with clinical judgement and experience.
Several factors have been identified, although there is ongoing debate about the relevance of many of them (Bliss, 1993; Nixon, 2001). Box 1 lists the factors that RCN guidelines suggest are important (Rycroft and Malone, 2001).
Some factors can be considered direct causes such as loss of sensation or immobility (Gebhardt, 2002). Other factors indicate that a patient may be susceptible to ulceration. For example, incontinence is strongly associated with pressure ulcers in older patients (Norton et al, 1962), but not in babies. This is because it is normal for babies to be incontinent, while in adults incontinence may be the result of sensory loss/paralysis (spinal injury) or severe illness (older age). So incontinence is an indicator of the underlying conditions that may cause a patient to have a susceptibility to pressure ulcers.
Some factors, such as abnormally high/low body mass index or old age, are not relevant in the absence of other factors. However, if the patient is already susceptible for other reasons, pressure ulcers are likely to develop more quickly and be more severe than in an individual with comparable susceptibility but without these factors.
Risk assessment scales
Various scoring systems have been devised to help assess factors in a systematic way, including the Norton (1962), Waterlow (1988), Gosnell (1989) and Braden (Bergstrom et al, 1987) scores (see Table 1). These usually consist of subsections, each dedicated to a particular factor with different numerical weighting associated with the degree to which the factor is present.
The number (score) for each factor is filled in and then all the scores are added together to produce a total ‘risk score’. However, the validity of such risk scores as indicators of the risk of developing pressure ulcers is questionable. Current guidance suggests that the various risk-assessment tools should be used merely as an aide memoir and should not replace clinical judgement (Rycroft-Malone, 2000).
Assessing the skin
As well as assessing the risk factors, a patient’s skin should be examined carefully for any signs of pressure damage, persistent erythema or evidence of previous pressure ulcers. Not only does this yield important clues about the patient’s risk of ulceration, but it may also prove essential to a legal defence should a claim be made against the admitting clinician or employer for pressure ulcers that had developed elsewhere.
Signs of incipient pressure damage may include persistent erythema (reactive hyperaemia which persists longer than would be expected normally), non-blanching erythema (dull red patches which do not blanch on light pressure), discoloration, blisters, localised heat oedema or induration. In pigmented skin, discoloration may appear purplish/bluish rather than red and tends to be less noticeable. It is therefore important to examine people with darkly pigmented skin more carefully for the other signs described.
Assessing clinicians need to be aware that there are certain skin conditions which, although they appear similar to pressure ulcers, have a different aetiology. An example is friction damage, which is discussed in Part 1 (Gebhardt, 2002). Other mechanical damage can include chemical burns as a result of faecal continence problems and electrical burns due to the surgical use of electrocautery.
Allergic reactions to incontinence pads (Fig 1) may look like pressure ulcers at first glance, but closer examination will reveal that the most damaged areas are not where maximal pressure is applied (note the imprint of the pad), but in low-pressure areas where the pooling of fluid occurs.
Pyoderma gangrenosum is a ‘diagnosis not to be missed’ (Bull, 1997) as it is an aggressive, potentially fatal autoimmune disease. Lesions can appear in pressure areas making diagnosis difficult. However, unusually painful, progressively enlarging ulcers with a nodular initial appearance and undermined, violaceous edges (Fig 2), particularly in a patient with a history of autoimmune disease, should alert the clinician to the possibility of pyoderma. Medical opinion should be sought immediately.
Patients who are at chronic risk
For patients in this group, treatment needs to go beyond a simple assessment of risk to encompass the patient’s lifestyle, social situation, quality-of-life requirements and understanding of pressure ulceration and the associated risks. Without an understanding of these factors, it is unlikely that a plan for prevention will be successful.
Preventive management in patients who are at acute risk
When a patient is at acute risk of developing pressure ulcers, the most important consideration is to provide pressure relief. The main challenge is to provide this within two hours of admission to avoid pressure damage occurring.
Research evidence supports two interventions: the provision of pressure-relieving mattresses (Cullum et al, 2000; Rycroft-Malone, 2000) and reducing the time spent sitting in chairs to a maximum of two hours (Gebhardt and Bliss, 1994; Gebhardt, 2000).
There is little evidence to suggest that the physical repositioning of patients is an effective preventive strategy (Clark, 2001). However, repositioning is important to maintain joint mobility, comfort, and lung and bowel function.
For patients at risk of pressure ulcers, a mobility and repositioning schedule should therefore be part of the nursing care plan, with the frequency of repositioning determined by skin inspection and each patient’s needs. Rycroft-Malone (2000) states: ‘The positioning of patients should ensure that: prolonged pressure on bony prominences is minimised, that bony prominences are kept from direct contact with one another, and friction and shear is minimised.’
There appears to be a general consensus that patients who are at risk of pressure ulcers should be placed on pressure-relieving/reducing beds or mattresses (Fig 3) rather than on standard hospital mattresses (Rycroft-Malone, 2000; Cullum et al, 2000; Gebhardt, 2001). For such patients, pressure-relieving devices should also be used on operating tables.
The relative merits of the different types of pressure-relieving/reducing devices are, however, the subject of ongoing debate, which will be explored in Part 3 of this series.
The selection of equipment should depend on a holistic assessment of risk, comfort and the patient’s general state of health. It should be reviewed whenever the patient’s condition changes (Rycroft-Malone, 2000). Risk assessment scale scores should not be relied on for the selection of equipment (McGough, 1999).
Lengthy sitting in chairs, or ‘chair nursing’ as it is sometimes known, has been shown to be a high-risk activity for patients who are susceptible to pressure ulcers (Barbenel et al, 1977; Nyquist and Hawthorn, 1987; St Clair, 1992). The reasons for this are not difficult to identify. In the seated posture, exceptionally large compressive forces are generated on the ischial and sacral regions, even when specialised ‘pressure-reducing’ cushions are used (Medical Devices Agency, 1997). These compressive forces are coupled with shearing forces which are probably greater than in any other position (Goosens and Snijders, 1995).
Additionally, and possibly more importantly, as a result of complex physiological processes (Gebhardt, 2000), the blood does not perfuse the skin as readily during prolonged sitting. This is because circulating volume is withdrawn from the peripheral regions to compensate vital organs that have a lowered blood volume due to pooling in the lower limbs. This means that tissues that are already less vital as a result of reduced perfusion are subjected to exceptionally severe distortion for prolonged periods (Gebhardt, 2000).
It has been shown that reducing chair nursing to a maximum of two hours per session can significantly reduce the incidence of pressure ulcers in older orthopaedic patients (Gebhardt and Bliss, 1994; Gebhardt, 2000). There is little to support the practice of lengthy chair nursing, and until further research clarifies many of the factors involved in mobilisation it would be prudent to limit sitting time for patients who are at risk to no more than two hours per session until they are independently mobile.
Numerous ‘pressure-relieving’ and ‘pressure-reducing’ cushions are available, and some authors have stated that the chairs of all patients who are nursed on pressure-relieving or reducing mattresses should be provided with similar cushions. However, there is little or no reliable evidence of their benefit to patients in acute care.
Posture appears to have a more significant impact on the interface pressures experienced by the patient than cushions (Medical Devices Agency, 1997). To patients in acute care, therefore, providing chairs of an appropriate height and suitable dimension is likely to be more beneficial than the provision of cushions.
Optimal seating has been extensively reviewed by other authors (Collins, 1998; Letts, 1991) and a discussion is beyond the scope of this article. The general principles, however, include ensuring that the height of the chair allows a 90° angle at the knees, that the width of the chair is appropriate, that the patient’s elbows are well supported and that the chair provides adequate support for the lumbar spine, shoulders and head.
Preventive management in patients who are at chronic risk
The management of a patient who is at chronic risk presents more complex challenges, perhaps, than those encountered in the controlled environment of acute care. Not only does the patient have to be provided with adequate pressure relief on a long-term basis, but pressure area care must also dovetail with other aspects of the patient’s life if he or she is to comply. This often creates conflicts.
For patients in wheelchairs, for example, sitting is a high-risk activity yet the demands of mobility and of earning a living are likely to mean that long hours have to be spent in a wheelchair. Furthermore, the wheelchair must give adequate postural support and enable daily activities as well as providing optimal pressure reduction/relief.
For these reasons wheelchairs should be provided through wheelchair centres with specialist personnel who have the relevant skills and experience, and should not be modified (by changing cushions, for example) without reference to the providing centre. For example, a small change in the height of the cushion may seriously impair some patients’ ability to function, as that may depend on them being able to reach items arranged at a particular height.
Equally, it is important that preventive management involves educating the patient and/or carer in all aspects of pressure area management. However, clinicians must accept that patients and/or carers rapidly become expert in the care of their own pressure areas, and only a foolish clinician would ignore their views without proper consideration.
The frequency of re-evaluation will depend on the patient’s condition and, in the case of patients living at home, the confidence the health professional has in the patient’s ability to manage his or her own pressure areas. Like the assessment, evaluation should be carried out by a nurse who is educated in pressure ulcer assessment and prevention. This process should include patients and/or informal carers who are willing and able. Patients who are at chronic risk are usually trained to inspect their pressure areas daily.
To the clinician, particularly the tissue viability specialist, the most significant outcome of an assessment is likely to be the presence or absence of pressure ulcers. This should be determined by skin assessment as described earlier, and the results should be documented.
However, the patient may have different priorities. It is important, therefore, that at least part of the assessment is devoted to ensuring that the patient is willing to comply with the pressure prevention regimen and that it has the least possible negative impact on his or her comfort, mobility and quality of life, whether at home or in hospital.
When pressure ulcers develop
If evaluation reveals that a patient has developed pressure damage, the immediate step is to establish the direct cause, if at all possible. Next, the clinician needs to decide whether the precipitating event was a one-off or is likely to recur.
One-off events might include an episode of profound illness indicated by a trough in systolic blood pressure in a patient who is now making a good recovery, or a particular operative procedure. Recurrent events, such as regular trips to another hospital for medical procedures, will require that appropriate precautions are taken next time. This is likely to include liaison with the other departments involved.
Alternatively, the event may have marked a change in the patient’s susceptibility and aspects of the pressure ulcer prevention strategy may need to be reviewed to accommodate these changes in the patient’s status.
If no obvious cause can be identified, it is likely that a root-and-branch review of the entire management strategy will be required. Is the patient’s routine appropriate? Are pressure-relieving devices working correctly? Are they being correctly managed? Is the patient compliant with the pressure ulcer prevention plan?
If a patient is living at home, some sensitive and in-depth questioning may be necessary to get to the bottom of any problems and arrive at a workable compromise. There are many apocryphal stories about pressure-relieving mattresses being ‘popped’ on to the bed ‘to keep nurse happy’, then removed as soon as the nurse has left because patients find them uncomfortable or do not want to be separated from their partners while in bed. Once the problem is understood a solution can be found, such as a split mattress with appropriate surfaces for both the patient and his or her partner.
Health care professionals have to accept that the prevention of pressure ulcers is likely to be one of many competing priorities in a patient’s life, and not necessarily the highest. For example, a patient who is required to stay in bed to remain free of pressure ulcers may consider the price too high. The patient may prefer to live with a degree of pressure damage if this allows a degree of mobility in a wheelchair.
It is important that patients are given all information on the possible outcomes of non-compliance as accurately as possible, so that they can make an informed decision. The information given and the patient’s decision should be documented accurately.