Letter to the Editor: Partial-thickness pressure injuries and epidermal blisters: concerning definitions

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Laura Bolton, PhD Adjunct Associate Professor, Surgery, Rutgers University Medical School (New Brunswick, NJ); and Co-chair, International Consolidated Guideline Task Force

Regarding Bohn G. Pressure injury replaces pressure ulcer: provider thoughts on changes to pressure ulcer staging. Ostomy Wound Manage. 2016;62(5):47–48: Laura Edsberg, PhD provided an eloquent explanation of the decision-making process and resultant revisions to the National Pressure Ulcer Advisory Panel’s (NPUAP) staging recommendations in her presentation at the Wound Ostomy Continence Nurses Society/Canadian Association for Enterostomal Therapy meeting in Montreal June 4–8, 2016. However, the NPUAP consensus conference results that state no granulation tissue is formed when healing partial-thickness wounds (see Sidebar) and the wording regarding epidermal blisters seem out-of-step with evidence on partial-thickness wound healing and slough/eschar. 

All of the consensus in the world cannot change the biology of healing. First, dermal healing requires proliferation, migration, and differentiation of fibroblasts, endothelial cells, and associated smooth muscle cells, forming granulation tissue. Second, epidermal healing (actually regeneration) occurs by proliferation, migration, and differentiation of keratinocytes. Partial-thickness wounds extend into the dermis but not through the underlying fascia. Any damage to the dermis of a partial-thickness wound results in clearly visible granulation tissue, documented histologically and histochemically. Dermatologic and surgical textbooks are quite clear on this. Sadly, the new definition misleads persons unfamiliar with the histopathology of wound healing and misguides research, further clouding pressure ulcer (PU)/injury diagnosis and staging and creating legal issues as folks observing granulation tissue in a healing PU assume it is a full-thickness Stage 3 or Stage 4 injury. The revised verbiage is not in sync with biological, histopathological, dermatological, and surgical definitions of wound healing, leading confusion rather than clarification for professionals and health care management, as well as reimbursement and regulatory authorities.

Another issue is that an epidermal blister, left in place, can present as “slough” if kept moist or “eschar” if not kept moist. During her presentation at the WOCN/CAET meeting, Sunniva Zaratkiewicz, PhD, RN, CWCN ran into this issue when trying to accommodate the old/new definitions in her research showing that many “unstageable” PUs healed as though they were a “Stage 2 pressure injury.” Researchers and caregivers deserve clearer, more reliable definitions, with better face and concurrent validity across specialties, to inform all members of the wound care team. It would seem more accurate to say unknown depth if a wound is covered with slough or eschar until nature makes the observation clear.  

As such, it may be best to stick with the NPUAP/European Pressure Ulcer Advisory Panel/Pan Pacific Pressure Injury Alliance staging definitions we have for now. 


This article was not subject to the Ostomy Wound Management peer-review process.