Week 3 | Pressure Ulcer Scope Etiology and Staging (16180-SP)

Photo of older woman in hospital bed.

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Pressure Ulcer Scope Overview

  • Significance
  • Scope of the problem
  • Prevalence: Number of patients with at least one pressure ulcer who exist in a given population at a given point in time.
  • Incidence: Number of patients who were initially ulcer free who develop a pressure ulcer within a particular time period in a defined population.

Pressure Ulcer Etiology

  • Pressure Ulcer: A localized injury to the skin and/or underlying tissue usually over a bony prominence, as a result of pressure, or pressure in combination with shear and/or friction. A number of contributing or confounding factors are also associated with pressure ulcers; then significance of these factors is yet to be elucidated.
  • Pressure from devices.
  • Mucosal pressure ulcers: pressure ulcers found on the mucous membrane with a history of a medical device in use at the location of the ulcer.
  • Causative factor is pressure which is dependent upon:
    • Intensity of pressure.
    • Duration of pressure.
    • Tissue tolerance: the condition or integrity of the skin and supporting structures that influences the skin’s ability to redistribute pressure.
  • Factors affecting tissue tolerance
    • Intrinsic
      • nutritional debilitation
      • advanced age
      • low blood pressure
      • stress
      • smoking
      • elevated body temperature
    • Extrinsic
      • Friction
      • Shear
      • Moisture
  • Pathophysiologic theories of pressure ulcer development
    • Ischemia caused by occlusion of capillaries.
    • Reperfusion injury.
    • Impaired lymphatic function.
    • Mechanical deformation of tissue cells.
  • Common pressure ulcer locations
  • Heel pressure ulcers

National Pressure Ulcer Advisory Panel Staging System: used only classify pressure ulcers based on the depth of tissue destruction.

  • Suspected Deep Tissue Injury (DTI)
  • Stage I
  • Stage II
  • Stage III
  • Stage IV
  • Unstagable

Practice classifying tissue damage

Pressure Ulcer Stages

Suspected Deep Tissue Injury: Purple or maroon localized area of discolored 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.

Further description: Deep tissue injury may be difficult to detect in individuals with dark skin tones. Evolution may include a thin blister over a dark wound bed. The wound may further evolve and become covered by thin eschar. Evolution may be rapid exposing additional layers of tissue even with optimal treatment. 

Stage I: Intact skin with non-blanchable redness of a localized area usually over a bony prominence. Darkly pigmented skin may not have visible blanching; its color may differ from the surrounding area.

Further description: The area may be painful, firm, soft, warmer or cooler as compared to adjacent tissue. Stage I may be difficult to detect in individuals with dark skin tones. May indicate "at risk" persons (a heralding sign of risk).

Stage II: 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 blister.

Further description: Presents as a shiny or dry shallow ulcer without slough or bruising.* This stage should not be used to describe skin tears, tape burns, perineal dermatitis, maceration or excoriation.
*Bruising indicates suspected deep tissue injury

Stage III: Full thickness tissue loss. Subcutaneous fat may be visible but bone, tendon or muscle are not exposed. Slough may be present but does not obscure the depth of tissue loss. May include undermining and tunneling.

Further description: The depth of a stage III pressure ulcer varies by anatomical location. The bridge of the nose, ear, occiput and malleolus do not have subcutaneous tissue and stage III ulcers can be shallow. In contrast, areas of significant adiposity can develop extremely deep stage III pressure ulcers. Bone/tendon is not visible or directly palpable.

Stage IV: Full thickness tissue loss with exposed bone, tendon or muscle. Slough or eschar may be present on some parts of the wound bed. Often include undermining and tunneling.

Further description: The depth of a stage IV pressure ulcer varies by anatomical location. The bridge of the nose, ear, occiput and malleolus do not have subcutaneous tissue and these ulcers can be shallow. Stage IV ulcers can extend into muscle and/or supporting structures (e.g., fascia, tendon or joint capsule) making osteomyelitis possible. Exposed bone/tendon is visible or directly palpable.

Unstageable: Full thickness tissue loss in which the base of the ulcer is covered by slough (yellow, tan, gray, green or brown) and/or eschar (tan, brown or black) in the wound bed.

Further description: Until enough slough and/or eschar is removed to expose the base of the wound, the true depth, and therefore stage, cannot be determined. Stable (dry, adherent, intact without erythema or fluctuance) eschar on the heels serves as "the body's natural (biological) cover" and should not be removed.

For more information, contact npuap.org or 202-521-6789
Copyright: NPUAP 2007

Objectives for Learning Outcomes

After completing this session, you will be able to:

  1. Discuss the significance of pressure ulcers as a health care problem. 
  2. Differentiate between prevalence and incidence of pressure ulcers. 
  3. Describe the etiology of a pressure ulcer. 
  4. Define the NPUAP classification system for staging pressure ulcers.
Course summary

Renee Anderson, MSN, RN, CWON
Certified Wound Ostomy Nurse; Co-Director, Wound Management Education Program (WMEP) and Wound Management Fundamentals Course (WMFC), Continuing Nursing Education, University of Washington School of Nursing, Seattle; President, Rainier Clinical Consultants, Inc, Seattle, WA

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