by Cathie Bree-Aslan, MSc RGN DipN Independent nurse expert advice on standards of care and breaches of duty in cases of potential clinical negligence.
In 2009, the NHS Institute for Innovation and Improvement published a list of 8 key High Impact Actions to improve quality and efficiency of care. One of these actions was promoting skin care and in particular, reducing the incidence of pressure injury1.
Historically, it has been considered that as many as 95% of pressure injuries are avoidable2 and yet between 20-30% of patients admitted to UK hospitals will develop a pressure injury3. This creates a huge cost burden on the health services and the potential for increased costly litigation. The Department of Health has defined avoidable and unavoidable pressure injury (figure 5)4 and this should underpin strategies for the prevention of pressure injuries.
A pressure injury can be described as
“localised injury to the skin and/or underlying tissue usually over a bony prominence, as a result of pressure or pressure in combination with shear. A number of contributory or compounding factors, such as friction and moisture may also be associated with pressure ulcers”5
There are numerous guidelines and Best Practice Statements available to health care professionals to aid in the prevention of pressure injury and yet despite this, the incidence of pressure injury does not appear to be falling.
The National Institute for Health and Clinical Excellence (NICE) recommends that every patient is risk assessed within 6 hours of being admitted for an episode of care (24 hours for community patients)6. Nurses generally undertake this role and most clinical areas will use one of the recognised Risk Assessment Tools such as the Waterlow, Braden or Norton Scores which take into account factors such as mobility, age, continence and co-morbidities. The Royal College of Nursing suggests however that these tools should not replace the nurses’ clinical judgement when assessing their patients for the risk of pressure ulcer development7. Evidence also suggests that despite their widespread use, risk assessment tools frequently fail to aid in the prevention of pressure injuries8.
This may be partly explained by the fact that pressure injuries are multifactorial in their aetiology. Alongside the extrinsic forces of pressure and shear, other factors, which may be intrinsic or external, may compound or contribute to the breakdown of the tissues (figures 1 & 2)
Clearly some of these factors cannot be avoided, but if they are identified early and their potential impact understood, interventions can be implemented to mitigate the risk of pressure injury. These risk factors should form part of the Risk Assessment and most of the common tools in use will incorporate some sort of calculation of risk set against these factors. Despite this, it is common to find cases where the risk assessment has failed to identify the ‘at risk’ patient; this suggests that nurses either do not assess their patient comprehensively or do not always understand how to use the tools.
When a patient is first admitted into an episode of care there may be may many reasons why a risk assessment is not fully completed for example, the patient may be critically ill and their medical condition will (and should) take precedent over a pressure ulcer risk assessment; the nurse does not know the patient and/or the patient may not be able to provide a full history – therefore making accurate assessment difficult; the patient may be unwilling/unable/difficult to move so that the skin can be accurately assessed etc. So the ‘6 hour’ recommendation from NICE may be as impractical as it is vital to the prevention of pressure injury. There should however be little excuse for a full and thorough risk assessment to have been carried out within 24 hours of a patient arriving for an episode of care. It must be considered though that by this time, the injury may already be developing.
It may be argued that the use of a tool just adds to the already burdensome paperwork that the nurse must complete. Should a nurse not be able to make a sound clinical judgement of likely risk without having to fill in a score card? This is a valid argument against the use of such tools but without them, the risk of pressure injury may not be well articulated and fully documented to form the basis of an appropriate care plan. The nursing care plan (in whatever form) is vital in supporting continuity of care and should be based on thorough patient assessment and consideration of the optimum care regimes.
Understanding Pressure Injury Aetiology and Prevention Methods:
When it comes to pressure injury, experience proves that frequently, little emphasis is placed on the importance of prevention and that more often than not, the risk assessment under-estimates the actual risk to the patient and hence, opportunities are missed to provide appropriate interventions.
In addition to the actual risk assessment is the requirement for the nurse to observe the patient’s skin and to monitor it closely throughout the patient’s episode of care. In reality, the risk assessment cannot be fully completed without the nurse observing the skin in the first instance. However, ongoing monitoring is required if the early signs of potential pressure injury are to be observed.
If the early signs of pressure injury are observed, interventions can be instigated to mitigate the risk of the injury developing
Pressure injuries occur when a person spends a prolonged period of time in one position. If the surface upon which the patient is being nursed (i.e. the mattress and/or chair) does not adequately reduce or alleviate the pressure, then injury can occur. The tissues becomes compressed by the firm surface and this deprives the skin of blood.
Once deprived of oxygen the skin turns pale in colour but when the pressure is alleviated the area flushes red as the blood vessels are released and blood can rush back into the tissues. This is referred to as a blanching or reactive hyperaemia. It is easily demonstrated when a person sits with their legs crossed – on uncrossing the legs there will be a red mark where the two surfaces were pressed together. At this point there is no damage caused in the tissues but if the pressure were to be repeated, the tissues would again be deprived of blood and eventually, if the pressure is not relieved, the tissues will become inflamed. In the patient, this will present as a reddened or discoloured patch of skin.
In the case of reactive hyperaemia, if gentle finger pressure is applied, the area turns pale (blanches), flushing red again when the finger pressure is released. Once the tissues become inflamed however, this finger pressure test will not produce a blanching of the skin and this is referred to as a non-blanching (non-blanchable) erythema or redness, and this is the first stage of pressure injury.
For nurses this means that they have a very quick and simple test that can be performed to ascertain if the patient’s skin is at risk of injury. If they recognise blanching hyperaemia they can take steps to alleviate the pressure and the patient should not then go on to develop a pressure injury. This blanching hyperaemia should dictate the frequency of repositioning required because it is a measure of how the patient’s skin is tolerating pressure.
Any reddening of skin should alert the nurse to the need to reposition the patient. Two hour periods are often quoted as the time that a pressure injury will occur. However, this is dependent on many factors with some people able to withstand long periods without damage, whereas others can develop an injury in less than an hour due to comorbidities, such as arterial disease. Therefore, the best method of prevention is to relieve pressure as often as the individual requires based on reddening of the skin. Any redness requires repositioning more often.
The simplest method of pressure injury prevention is the use of specialist equipment that either redistributes the pressure (such as soft foam, static air, low air loss mattress) or relieves the pressure over small areas on a regular basis (dynamic air mattresses). To alleviate the pressure over the heels, devices known as heel protectors can be used. The European Pressure Ulcer Advisory Panel (EPUAP) have categorised pressure injury into 4 stages (figure 3).
Pressure ulcers due to unrelieved pressure do not progress from category 1 to category 2 to category 3 and ultimately to category 4. Rather, they begin deep inside the tissues, close to the bone and finally erupt on the surface of the skin following a period of redness on the surface, turning to a bruised appearance or a blackened area (this category is unstageable or ungradable; figure 4). This process can take from 5 days to several weeks, dependent on the type of pressure and whether there are periods of relief. Those that occur due to totally unrelieved pressure will be black within 5 days and it then can take weeks for the tissues to breakdown and open.
Figure 4 previous page:
Additional descriptors for pressure injury
By the time the tissues have become blackened the breakdown is inevitable and cannot be prevented. In fact, the necrotic (black and dead) tissue breakdown is usually encouraged by either dressings (such as hydrogels to rehydrate the area and encourage autolysis (natural tissue breakdown) or through the use of sharp debridement (cutting out the dead tissue with scissors or scalpel).
There are other types of pressure injury such as a moisture lesion (caused by skin made damp from sweat or urine) and friction injury (often caused by poor moving and handling techniques). This is a very simplistic description of a very complex condition.
The wounds caused by unrelieved direct pressure are most often the shape of the bony prominence that is the cause of the damage with a round appearance (over the hip, heel or ischial tuberosities) or symmetrical shape over areas such as the sacrum.
Muscle requires more oxygen and being softer than skin would be damaged first and we know that pressure is five times greater at the level of the bone than it is at the surface. This is known as the ‘cone of pressure’ and means that any damage caused by unrelieved pressure will commence in the deeper tissues, closer to the bone and will work outwards to the less vulnerable skin surface while the skin remains red for days before this damage becomes apparent.
Repetitive tissue stress is an important contributor to ulceration in the more mobile patient and this can take weeks to manifest itself as the insult to the tissues is a constant pressure for long periods, with periods of relief which only partially recovers the tissues.
Coggrave and Rose9 studied 48 spinal cord injured patients and found it took nearly two minutes of pressure relief for reperfusion to take place. If the individual then repositions onto that area before the two minute recovery time, then there is not enough recovery to ensure irreversible damage is prevented. This constant pressure versus recovery will eventually lead to tissue injury. The appearance of this damage will not be symmetrical and often has a dark red and hardened appearance.
Ulcers due to friction and shearing have a different appearance. They often commence as a blister and may be multiple surface wounds. Friction and shear occur when the individual constantly moves or slides over a surface. For instance, someone may involuntarily slide in a chair and be constantly lifted back into position by thoughtful carers, only to slide again. This causes pinching of the tissues as the bone slides against the internal surface of the skin and the skin in that area will die. The shape of this wound is often irregular in appearance and can be superficial to the surface leaving the lower muscle intact.
The prevention of pressure injuries by frequent repositioning of patients is a widely accepted practice and nurses commonly reposition at risk patients every 2 hours. However, this is based on a myth that Florence Nightingale took 2 hours to reposition every injured soldier on her ward (Crimean War,1853-1856), thereby reducing the number of pressure injuries that occurred. Then, in 1961, a research study by Koziak, which examined a 2 hour turning schedule, also found this reduced pressure injuries10. This led to the belief that all at risk patients should be repositioned every two hours. Today we realise that every individual’s risk is different and each individual should be repositioned according to need11. The simplest method for this is to examine the tissues and view any reddening as a warning that pressure injury is inevitable if action is not taken to relieve the pressure12. This means that repositioning and equipment usage will be based on the individual’s personal requirements and pressure injury would be avoided in the majority of patients.
This method of prevention is supported by the NICE Guidelines and EPUAP Guidelines on prevention of pressure injuries. These guidelines are open to all and we can expect qualified nurses to have gained access to the recommendations or to have been informed of them by specialist nurses such as Tissue Viability Nurses, in order to prevent pressure injuries in their patients.
The aetiology of pressure injury development is well understood and all nurses are taught this as part of their basic nurse training. There are national guidelines and best practice statements upon which health care providers can base their own local policies and procedures for the nursing teams to follow and there is a huge variety of pressure relieving equipment available to meet all budgets. Furthermore, there is a vast bank of knowledge and expertise at health care providers’ disposal via specialised Tissue Viability Nurses. Utilising sound and timely risk assessment and ongoing monitoring of the patient’s skin in conjunction with these resources, pressure injuries can be identified before they develop and with the provision of appropriate interventions the majority of pressure injuries should be avoidable
The Department of Health has provided the health care profession with a definition as to what is deemed an ‘avoidable’ pressure injury: “Avoidable” means that the person receiving care developed a pressure ulcer and the provider of care did not do one of the following: evaluate the person’s clinical condition and pressure ulcer risk factors; plan and implement interventions that are consistent with the persons needs and goals, and recognised standards of practice; monitor and evaluate the impact of the interventions; or revise the interventions as appropriate.”
Unavoidable Pressure Ulcer: “Unavoidable” means that the person receiving care developed a pressure ulcer even though the provider of the care had evaluated the person’s clinical condition and pressure ulcer risk factors; planned and implemented interventions that are consistent with the persons needs and goals; and recognised standards of practice; monitored and evaluated the impact of the interventions; and revised the approaches as appropriate; or the individual person refused to adhere to prevention strategies in spite of education of the consequences of non-adherence”
The DH offers the following Guidance: “In determining whether the pressure ulcer is avoidable; commissioners, regulators or others could request to see evidence demonstrating the actions outlined in the “avoidable” definition are demonstrated”.
Figure 5 in box above: Department of Health Definition of Avoidable Pressure injury.
? References: 1 NHS III (2010)
2 Hibbs PJ (1998) Pressure Area Care for the City of Hackney Health Authority. City and Hackney Health Authority, London
3 Clark M
4 EPUAP 2009
6 NICE 2005
7 RCN 2001 PU prevention & Risk Ax
8 RCN 2005 management of PIs in primary & secondary care
9 Coggrave MJ, Rose LS. (2003) A specialist seating assessment clinic: changing pressure relief practice. Spinal Cord. ;41(12):692–5
10 Rosenberg, C. (2002). New checklist for pressure ulcer prevention. Journal of Gerontological Nursing, 28(8), 7-12
11 Hampton and Collins (2003) Tissue Viability. Whurr Publications. London
12 Hampton S & Bree-Aslan C (2009) Pressure Care (Part 2) The importance of Assessment. Nursing &