Patients may develop PI/PU in a variety of locations – Vanderwee et al. (2011) identified that the heels and sacrum account for more than 80% of all PI/PUs.2 Occurrence is common over bony prominences but in recent years PI/PU related to medical devices or other object have become more commonly reported.
Specific risk factors have been identified and should be
considered1,3 when planning patient care.
Mobility / activity
Perfusion including diabetes and previous PI/PU status
Nutrition and general health status
There are many risk assessment tools (RATs) available – estimates suggest there could be as many as 90 different versions,4 however there is no real consensus as to the optimal RAT to use.
RATs have been reported to be subjective and open to interpretation – additionally results are dependent on the expertise of the assessor.5 In a Cochrane systematic review, Moore & Patton (2019)6 found that neither the Braden nor the Waterlow risk assessment tools made any significant difference to PI/PU incidence rates, when compared to clinical judgement alone.
The 2019 International Clinical Practice Guidelines1 state that “skin and soft tissue assessment is a key component of PI/PU prevention, classification, diagnosis and treatment”. Routine skin assessment should include for example a visual assessment for erythema, palpation for differences in temperature and tissue consistence.1 The same Guidelines note the challenges in assessing darkly pigmented skin where areas of redness may be more diffcult to see.
EPUAP / NPUAP / PPPIA (2014) have developed a globally-adopted classification system that define six stages / categories characterise wounds with increased severity of tissue loss.
(National Pressure Ulcer Advisory Panel, European Pressure Ulcer Advisory Panel and Pan Pacific Pressure Injury Alliance. Prevention and Treatment of Pressure Ulcers: Quick Reference
Guide. Emily Haesler (Ed.). Cambridge Media: Osborne Park, Western Australia; 2014.)
Category / Stage 1
Intact darkly pigmented skin may not have visible blanching: its colour may differ from the surrounding area.
The area may be painful, firm, soft, warmer or cooler as compared to adjacent tissue.
Category I may be difficult to detect in individuals with dark skin tones. May indicate “at risk” persons.
Partial thickness loss of dermis presenting as a shallow open ulcer with a red pink wound bed, without slough.
May also present as an intact or open/ruptured serum-filled or sero-sanginous filled blister.
Full thickness tissue loss. Subcutaneous fat may be visible but bone, tendon and muscle are not exposed. Slough may be present but does not obscure the depth of tissue loss. May include undermining and tunneling.
Full thickness tissue loss with exposed bone, tendon or muscle. Slough or eschar may be present. Often includes undermining and tunneling. Exposed bone/muscle is visible or directly palpable.
Can extend into muscle and/or supporting structures (e.g. fascia, tendon or joint capsule).
Suspected Deep Tissue Injury
Purple or maroon localised area or discoloured intact skin or blood-filled blister due to damage of underlying soft tissue from pressure and/or shear. The area may be preceded by tissue that is painful, firm, mushy, boggy, warmer or cooler as compared to adjacent tissue.
Deep tissue injury may be difficult to detect in individuals with dark skin tones.
Full thickness tissue loss in which actual depth of the ulcer in completely obscured by slough (yellow, tan, grey,
green or brown) and/or eschar (tan, brown or black) in the wound bed. Until enough slough and/or eschar are removed to expose the base of the wound, the true depth cannot be determined.
Annual cost of PI/PUs to the US healthcare system
Patients in the US that develop
PI/PUs each year
Annual cost of PI/PUs to the UK healthcare system
European Pi/PU prevalence identified in Systematic Review
Most commonly reported
patient harm in the UK
The most common
sites for ulceration/injury
1. European Pressure Ulcer Advisory Panel, National Pressure Injury Advisory Panel and Pan Pacific Pressure Injury Alliance (2019). Prevention and Treatment of Pressure Ulcers/Injuries: Quick Reference Guide. Emily Hasler (Ed.). EPUAP/NPIAP/PPPIA
2. Vanderwee K., et al (2011). Assessing the adequacy of pressure ulcer prevention in hospitals: a nationwide prevalence survey. BMJ Qual Saf. 20(3):260-7
3. Guy, H. (2012). Pressure ulcer risk assessment. Nursing Times. http://www.nursingtimes.net/pressure-ulcer-risk-assessment/5040368.article
4. Moore Z., et al. (2018). Meeting Report: Enhancing efficiency of pressure ulcer/pressure injury care and patient outcomes with the SEM Scanner. Wounds UK; vol 14; no 1
5. Moore Z., et al (2014). Risk assessment tools for the prevention of pressure ulcers. Cochrane Database of Systematic Reviews, Issue 2, Art No.: CD006471. DOI: 10.1002/14651858.CD006471.pub3
6. Moore Z., et al. (2019). Risk assessment tools for the prevention of pressure ulcers. Cochrane Database of Systematic Reviews, Issue 1. Art. No.: CD006471. DOI: 10.1002/14651858.CD006471.pub4
7. Padula W., et al. (2019) The national cost of hospital-acquired pressure ulcers in the United States. International Wound Journal, 1-7
8. Berlowitz D., et al. (2012). Agency for Healthcare Research and Quality (AHRQ). Preventing Pressure Ulcers in Hospitals. A Toolkit for Improving Quality of Care. [online] Available at:
https://www.ahrq.gov/professionals/systems/hospital/pressureulcertoolkit/putool1.html (Accessed 7 April 2018)
9. Bennett G., et al. (2004). The cost of pressure ulcers in the UK. Age and Ageing. 33(3):230–235
10. Moore Z., et al. (2019). The prevalence of pressure ulcers in Europe, what does the
European data tell us: a systematic review. Journal of Wound Care. Vol 28:no 11: 710-719
11. NHS Safety Thermometer. https://www.safetythermometer.nhs.uk
12. AHRQ Agency for Healthcare Research and Quality (2014) Preventing Pressure Ulcers in Hospitals. Accessed January 2020
13. Oot-Giromini B., et al. (1989). Pressure ulcer prevention versus treatment, comparative product cost study. Decubitus, 2(3): 52–4
14. Schuurman JP., et al. (2009). Economic evaluation of pressure ulcer care: a cost minimization analysis of preventive strategies. Nurs Econ; 27(6): 390–400, 415
15. NHS Resolution. (2019). FOI 2913
16. Petrone K. (2017) Pressure Ulcer Litigation: What is the Wound Center’s Liability? Today’s Wound Clinic Vol 11 Issue 9
PI/PU reported to cause;
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