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Table C-1Stages of pressure ulcer equivalency

NPUAP StageDescriptionYarkony-KirkDescriptionSheaDescriptionDeLisa, MikulicDescriptionTorranceDescription
IIntact 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.IRed area:
  1. Present longer that 30 minutes, but less than 24 hours
  2. Present longer than 24 hours
NANo EquivalentIPressure sore is an acute inflammatory response involving the epidermis An irregular, ill-defined area if soft-tissue erythema accompanies by in duration and heat persists for more than 24 hours. The epidermis remains intact, and the ulcer is reversible.IPersistent erythema of the skin
IIPartial 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 blisterIIEpidermis and/or dermis ulcerated with no subcutaneous fat observedILimited to epidermis exposing dermisIIPressure sore is a break in or blistering of the epidermis surrounded by erythema and in duration. Potentially, it also is reversible.IIBlister formation or superficial subcutaneous ulcer
IIIFull thickness tissue loss. Subcutaneous fat may be visible but bone, tendon or muscles are not exposed. Slough may be present but does not obscure the depth of tissue loss. May include undermining and tunneling.IIISubcutaneous fat observed, no muscle observedII, IIIFull-thickness of dermis to junction of subcutaneous fat

Fat obliterated, limited by deep fascia undermining of skin
IIIPressure ulcer is an inflammatory fibroblastic response extending through the dermis to the junction with subcutaneous fat. Clinically presents as an irregular, shallow ulcer that has subcutaneous fat at its base and is surrounded by erythema, induration, and heat.IIIDeep subcutaneous ulcer-ulceration progress through the dermis
IVFull 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.IV–VMuscle/fascia observed, but no bone observed
Bone observed, but no involvement of joint space
IVBone at the base of ulcerationIV – musclePressure ulcer extents through the full thickness of skin into the deep fascia and/or muscle. Its draining, necrotic base is often foul-smelling, and under-mining of the surface tissues may be excessive.IV
V – exposed bonePressure ulcer penetrates the underlying bone, causing osteomyelitis. It has no anatomic limit and is surrounded by erythema and induration. Clinically, it presents as an extensive ulcer with exposed bone, joint, muscle, and/or fascia at its base.
VIInvolvement of joint spaceVClosed large cavity through a small sinusV
Suspected Deep Tissue InjuryPurple 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 found to be painful, firm, mushy, boggy, warmer or cooler as compared to adjacent tissue.
UnstageableFull 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.

From: Appendix C, Stages of Pressure Ulcers

Cover of Pressure Ulcer Treatment Strategies: Comparative Effectiveness
Pressure Ulcer Treatment Strategies: Comparative Effectiveness [Internet].
Comparative Effectiveness Reviews, No. 90.
Saha S, Smith MEB, Totten A, et al.

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