Pressure Ulcers/Pressure Injuries/Bedsores
Pressure Ulcers are localized injuries to the skin and/or underlying tissue, usually over a bony prominence, resulting from sustained pressure.
Pressure Ulcers or Pressure Injuries?
Since the injury was first described, there has been ongoing debate about its terminology. The earliest term used was decubitus, meaning ‘dead tissue due to lying down,’ referring to wounds that developed in patients confined to bed.
After the publication of Bedsore Biomechanics1, the term bedsore became more widely used. Although this term reinforced the association with bed rest, it was already known at the time that pressure ulcers could develop whenever soft tissue is in prolonged contact with any supporting surface. Shear forces and deformation were recognized as key contributors. The word ‘sore’ also implies pain, which may not be present in all cases.
By the early 1990s, the term pressure ulcers became more common. This term moved away from bed-specific associations and referred instead to open ulcers on the skin surface that are difficult or fails to heal. However, this term fails to capture both deep tissue injuries (internal wounds beneath intact skin) and Category/Stage I pressure ulcers, in which the skin remains intact2.
All of these terms are still in use today. Generally, ‘pressure injury‘ is the preferred term in North America, Asia, Australia, and New Zealand, while ‘pressure ulcer’ is more commonly used in Europe. While none of the terms completely reflect the full etiology of the injury, they all describe the same phenomenon.
As a European organization, EPUAP continues to use the term pressure ulcers.
What Causes a Pressure Ulcer?
When someone stays in one position for too long (such as lying in bed or sitting in a wheelchair), the pressure from their body weight can squeeze the skin and tissue, cutting off blood and fluid flow. Without enough oxygen and nutrients, the cells start to die. In some cases, the pressure can also directly damage the cells by physically deforming them. Pressure ulcer can be also formed by a medical device. These are called device-related pressure ulcers and often match the shape of the device, such as masks, tubes, or casts.
Early studies3,4 showed that the amount of pressure and how long it’s applied both matter. Higher pressure for a short time or lower pressure over a longer time can both lead to damage. This relationship is now better understood as a curve that helps explain how pressure and time interact with the body’s ability to tolerate it5. However, not everyone’s body responds the same way. Things like age, poor nutrition, past wounds, or medical conditions (such as diabetes) can lower a person’s ability to withstand pressure6.
The areas most at risk are where skin and tissue are pressed between a hard surface (like a bed or chair) and the bones or tendons underneath. This pressure can also be made worse by shear forces (e.g. like when a patient slides down in bed) stretching and twisting the tissue.
Modern research over the last 20 years has greatly improved our understanding of how these injuries form. Although we still don’t know every detail, scientists believe there are four main reasons why pressure ulcers develop7,8,9:
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- Lack of blood flow (localized ischemia)
- Tissue damage when blood flow returns (reperfusion injury)
- Blocked lymph drainage, which leads to fluid build-up
- Direct cell damage caused by pressure and distortion of tissues
Understanding these causes helps us better prevent and treat pressure injuries, especially in people who are at higher risk.
Want to Learn More?
References
1. Kenedi JM, editor. Bedsore Biomechanics: University Park Press; 1976
2. European Pressure Ulcer Advisory Panel, National Pressure Injury Advisory Panel and Pan Pacific Pressure Injury Alliance. Prevention and Treatment of Pressure Ulcers/Injuries: Clinical Practice Guideline. The International Guideline. Emily Haesler (Ed.). EPUAP/NPIAP/PPPIA: 2019.
3. Kosiak M. Etiology and pathology of ischemic ulcers. Archives of physical medicine and rehabilitation. 1959;40(2):62-9.
4. Reswick JB, Rogers JE. Experience at Rancho Los Amigos Hospital with devices and techniques to prevent pressure sores. In: Kenedi RM CJ, editor. Bed Sore Biomechanics. London: Strathclyde Bioengineering Seminars. Palgrave; 1976.
5. Gefen A. Reswick and Rogers pressure-time curve for pressure ulcer risk. Part 1. Nurs Stand. 2009;23(45):64, 6, 8 passim.
6. Coleman S, Nixon J, Keen J, Wilson L, McGinnis E, Dealey C, et al. A new pressure ulcer conceptual framework. J Adv Nurs. 2014;70(10):2222-34.
7. Bouten CV, Oomens CW, Baaijens FP, Bader DL. The etiology of pressure ulcers: skin deep or muscle bound? Arch Phys Med Rehabil. 2003;84(4):616-9.
8. Oomens CW, Bader DL, Loerakker S, Baaijens F. Pressure induced deep tissue injury explained. Ann Biomed Eng. 2015;43(2):297-305.
9. Gefen A, Brienza DM, Cuddigan J, Haesler E, Kottner J. Our contemporary understanding of the aetiology of pressure ulcers/pressure injuries. Int Wound J. 2022;19(3):692-704.
