5 Pressure Ulcer Classification
Carol Dealey and Christina LindholmIntroduction
Pressure ulcer classification is a method of determining the severity of a pressure ulcer. A classification system describes a series of numbered stages or grades each determining a different degree of tissue damage. The deeper the ulcer and the more extensive the tissue damage the higher the grade number, as illustrated in Table 5.1. Pressure ulcer classification is a valuable tool for prevalence and incidence surveys as well as clinical practice and research.
The first author to publish a pressure ulcer classification system was Shea.1Since
then, numerous systems have been developed with varying numbers for grades ranging from a 0–5 grade classification to a 1–7 grade classification. The most complex system is the Stirling Grading System, which has 0–4 grades with up to four subscales within some of the grades; thus a deep necrotic infected ulcer would be labeled as 4.131.2 A review by Hitch3 identified ten different classification
systems and a later review by Haalboom et al.4found a further four systems.
Prob-ably the most widely used classification is that developed by the National Pressure Ulcer Advisory Panel (NPUAP)5and later adopted by the European Pressure Ulcer
Advisory Panel (EPUAP) with some minor textual changes (e.g. NPUAP refers to stages and EPUAP to grades; see Table 5.1).6 Figures 5.1–5.4 (see color section)
show examples of each of the EPUAP grades with line drawings to show diagram-matically the degree of tissue damage.
The major weakness of all classification systems is the lack of evidence to support their use, the most important factor being inter-rater reliability. Healey7
studied inter-rater reliability amongst 109 nurses when using three classification systems (Stirling,2Torrance,8and Surrey9) and found that although none of the
systems showed a high level of reliability, it was significantly lower in the most complex scoring system (Stirling). Healey also found that there was greater reliability in reporting the grades of severe ulcers compared with the less severe grades. Russell and Reynolds compared the reliability of the Stirling and EPUAP classification systems when used by 200 specialist and nonspecialist nurses and again found that the Stirling classification system was less reliable than the simpler EPUAP system.10 Russell and Reynolds conclude that classification of pressure
ulcers is not easy. Sharp concurs and suggests that such is the complexity of some classification systems that they require a level of expertise beyond the capability of general nurses.11Certainly, education is essential to ensure high levels of
inter-rater reliability.10
Defloor and Schoonhooven describe the validation process for an educational tool using the EPUAP classification to grade photographs of pressure ulcers.12In
the first stage of the process nine specialists were asked to review the clarity of 67 photographs and grade the ulcers. Eleven unclear photographs were eliminated. In the second phase 44 experts were asked to grade the pressure ulcers in the 56 remaining photographs and their findings were compared with the original nine experts. A high level of agreement was found between all the experts. However, the authors consider that it is likely that there would be less agreement amongst those with little experience.
Controversies in Pressure Ulcer Classification
There are a number of controversies relating to pressure ulcer classification that may well be linked to reliability. They are listed below and each will be discussed in turn.
• Grade 1 ulcers • Assessing dark skin • Reverse grading
• Identifying incontinence lesions
Grade 1 Ulcers
Russell has stressed the difficulties in defining early skin damage.13A reaction to
temporary closure of the dermal capillaries is called reactive hyperemia, clinically seen as a bright flush or reddened area that blanches under light pressure. It is thought to last from 30 minutes to 48 hours.14,15At this stage, damage to the
under-lying tissues has not yet occurred.
Shea provided the definition of a grade 1 ulcer as a persistent reddened area that does not blanch.1This definition was later supported by Versluysen and Yarkony
et al.14,15Dinsdale put forward an alternative definition of a grade 1 pressure ulcer
as persistent redness for more than a 24-hour period.16Lyder states that blanching
erythema indicates that tissue damage has not yet occurred.17Hence, this must
precede pressure ulcer development and thus nonblanching erythema should be taken as a true presentation of a grade 1 ulcer. Lyder also set up criteria for assess-ing a grade 1 pressure ulcer. Hitch considered that there is consensus on Lyder’s criteria for a grade 1 ulcer.3 Lyder’s criteria have subsequently been adapted by
Russell13and are shown in Table 5.2.
Table 5.1. EPUAP pressure ulcer classification system
Grade Definition
1 Nonblanchable erythema of intact skin.This may be difficult to identify in darkly pigmented skins
2 Partial thickness skin loss involving epidermis and/or dermis: the pressure ulcer is superficial and presents clinically as an abrasion, blister or shallow crater
3 Full-thickness skin loss involving damage or necrosis of subcutaneous tissue that may extend down to, but not through, underlying fascia: the pressure ulcer presents clinically as a deep crater with or without undermining of adjacent tissue 4 Extensive destruction tissue necrosis, or damage to muscle, bone or supporting structures with or without full-thickness skin
Assessing Dark Skin
Darkly pigmented skin creates problems because early skin changes are difficult to see.13 Meehan demonstrated that patients with dark skin had a larger
per-centage of high-grade ulcers and the least number of stage 1 ulcers.18 Since
nonblanchable erythema is difficult to detect in the darkly pigmented skin, palpation has been recommended.19Observation of localized heat has also been
suggested.13
The NPUAP convened a task force to review the definition of stage 1 pressure ulcer and determine the adequacy of this definition in assessing individuals with darkly pigmented skin. Following a comprehensive review of the literature and peer review by attendees at the Fifth NPUAP Conference in February 1997, the National Task Force on Darkly Pigmented Skin and Stage 1 Pressure Ulcers drafted the following new definition for stage 1 pressure ulcers, which was approved by the NPUAP Board of Directors in 1998:
A Stage I pressure ulcer is an observable pressure related alteration of intact skin whose indicators as compared to the adjacent or opposite area on the body may include changes in one or more of the following:
skin temperature (warmth or coolness), tissue consistency (firm or boggy feel) and/or sensation (pain, itching).
The ulcer appears as a defined area of persistent redness in lightly pigmented skin, whereas in darker skin tones, the ulcer may appear with persistent red, blue, or purple hues.20
Reverse Grading
As the use of pressure ulcer classification systems became established in clinical practice a number of misconceptions also crept in. One was the assumption that pressure ulcers will first present as a grade 1 and then naturally progress through to grade 4 without preventative measures, even though there is no evidence to support this belief. The other was the practice of reverse grading or describing a healing ulcer as progressing from a grade 4 to a grade 3 and so on back to grade 1. There is no logic in this practice as the tissues in a healing wound do not equate to the tissues as they were before pressure damage occurred. Thus a healing grade 4 pressure ulcer, which initially penetrated through to muscle, does not first replace
Table 5.2. Criteria for grade 1 pressure ulcers
Skin area that ranges from pale pink to bright red in color
Skin area that is nonblanching (blanchable erythema being a precursor to a grade 1 pressure ulcer)
Skin area that is warmer or cooler to touch
Skin area with erythema that does not resolve within 2 hours
Skin area that possibly has edema or induration that is ill defined when palpated Skin area with epidermis intact
the muscle tissue and then the dermis but gradually fills with granulation tissue. This topic was the subject of considerable debate in the USA21,22 and led to the
NPUAP making a position statement on the subject.23Within the position
state-ment the NPUAP state that:
Pressure ulcer staging is only appropriate for defining the maximum anatomical depth of tissue damage.
We support that viewpoint. If a pressure ulcer presents as a grade 3 it must always be described as such. However, it is also important to monitor healing and describe it clearly. Dealey described different ways in which wound healing could be evaluated.24
Incontinence Lesions
Persistent incontinence can cause erythema, maceration, and excoriation of the skin, which can be mistaken for a pressure ulcer, as can be seen in Figure 5.5 (see color section). Until recently there has been little discussion of this problem in the literature.25Schnelle et al. monitored the impact of incontinence on the skin and
found a high incidence of blanchable erythema, particularly in the perineal region.26They consider it to be a marker for increased risk of pressure ulcers and
other skin disorder, but it seems reasonable to postulate that an unskilled observer may consider such incontinence lesions to be grade 1 pressure ulcers. Incontinence lesions can be identified in the following ways:
• They are unlikely to occur over bony prominences. • They may be more purple than red in appearance. • The skin may be swollen or edematous.
• The skin may also be macerated and/or excoriated. • The patient is incontinent or suffers from diarrhea.
Education is essential to alert staff to the possibility of incontinence lesions and learn how to differentiate them from superficial pressure ulcers.
Conclusions and Recommendations
Pressure ulcer grading is a useful tool for defining the severity of pressure ulcers. However, it is obvious that education is essential in order to ensure that grades are correctly identified and that incontinence lesions are not mistaken for pres-sure ulcers. The EPUAP provides access to a very useful educational program via its website (www.epuap.org.uk). The PUCLAS program was developed at the Uni-versity of Ghent, Belgium. It provides both educational material and a self-assess-ment quiz. It is currently available in nine languages—English, Dutch, Finnish, French, German, Italian, Portuguese, Spanish, and Swedish—and may be freely used for personal or educational purposes. This is a great opportunity for individuals to improve their own assessment skills. Wide use of such educational tools could substantially improve the accuracy of pressure ulcer grading in the clinical area.
References
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