© 2009 The Medical-Legal News
By Frances W. Sills, RN, MSN, ARNP
Objectives: At the completion of this CE offering you will be able to: 1) define deep tissue injury, 2) explain the importance of including it in the NPUAP (National Pressure Ulcer Advisory Panel) pressure ulcer staging system and 3) differentiate the characteristics among the levels of the staging system.
Deep tissue injury is a term that has been proposed by the National Pressure Ulcer Advisory Panel (NPUAP) to describe a unique form of pressure ulcers.
While these ulcers have been described by clinicians for several years with terms such as “purple heel,” “ulcers likely to deteriorate” and “bruises noted on bony prominences,” there has been no standardized term assigned to them.
Why is it important to have another label for pressure ulcers? The simple answer is that this particular deep tissue injury represents a dangerous skin lesion — due to its potential for rapid deterioration. The proposed definition by NPUAP is, “a pres-sure-related injury to the subcutaneous tissue under intact skin. Initially, these lesions have the appearance of a deep bruise. These lesions may herald the subsequent development of a Stage 111-1V pressure ulcer even with the optimal treatment.” (NPUAP, 2002).
Because no break in the skin exists the lesion would be classified as a Stage 1 and interventions to prevent further breakdown would be targeted to a Stage 1. Proper labeling will provide the clinician a more accurate diagnosis, and lay a foundation for the development of effective interventions in a timelier manner.
Since 1989, the NPUAP staging system has been one of the most widely used pressure ulcer classification systems. The system was originally developed to guide clinical description of the depth of tissue destruction that occurs with pressure ulcers.
Over the years, the staging system has continued to evolve.
We have gained greater understanding of the mulifactorial pathogenesis of pressure ulcer development because of clinical, ultrasonography and computer-assisted tomography-based research. An example is a 1997 change to the definition of a Stage 1 pressure ulcer to include identifying descriptors for those with darkly pigmented skin.
Now after five years of research, discussion and consensus building, the NPUAP pressure staging system was updated in 2007.
A pressure ulcer is “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” (NPUAP, 1989).
Since early history, pressure ulcers have been afflictions. The earliest documentation is believed to be from Hippocrates in 400 B.C. Paget, in his clinical lectures on bedsores in 1873, said that pressure ulcers at times were observed to erupt from under intact skin. Even today, pressure ulcers remain a significant clinical, quality of life, economic, regulatory and legal problem for providers and patients.
Staging system problems
Inherent to the accuracy of pressure ulcer staging is:
1) Knowledge of the integumentary anatomy and deeper tissue layers including the ability to identify and differentiate between these layers.
2) Assessment and differential diagnostic skills.
3) Validity (accuracy) and reliability (consistency of results) of the staging system.
Staff nurses frequently exhibit uncertainty in accurately differentiating between Stage 11 and Stage 111, and lesions secondary to moisture or friction. Given the ulcers’ anatomical location, herpetic, fungal and moisture lesions are often misclassified as pressure ulcerations (Defloor et al, 2005)
Neuropathic foot ulcers, epidermal stripping from adhesive removal, reactive hyperemia, bruises, radionecrosis, surgical wounds and ulcers secondary to venous and arterial insufficiency have also been staged incorrectly using the NPUAP system.
Diagnostic inaccuracies result in inappropriate prevention and treatment interventions, and misappropriated healthcare expenditures with the potential for punitive regulatory, litigious and quality implications.
Etiology of DTIs
In 2001, the concept of another etiology for pressure ulcers was discussed by the NPUAP.
These pressure ulcers were known to begin as “purple-” or “bruised-” looking tissue and many progressed rapidly to a large Stage 1V. The term “deep tissue injury” was selected because it was likely that the etiology of these pressure ulcers was high levels of pressure at the bone-muscle interface.
Deep tissue injury (DTI) was initially defined as “a pressure-related injury to subcutaneous tissues under intact skin. Initially, these lesions have the appearance of a deep bruise and they may herald the development of subsequent development of a Stage 111-1V pressure ulcer even with optimal treatment.” (NPUAP, 1997).
The reasons for the rapid deterioration seen with DTI may be a combination of direct ischemic injury and reperfusion injury from oxygen free radicals, cytokines and neutrophilic adhesion to the microvascular endothelium.
When a long duration of ischemia exists, the direct damage resulting from hypoxia alone is the predominant mechanism. With shorter periods of ischemia, the indirect or reperfusion-mediated damage becomes increasingly more important. Research studies by Parks and Granger (1988) showed that injury produced by reperfusion can be more severe than the injury induced by ischemia per se. Reperfusion is the restoration of blood flow to a part of the body previously deprived of it.
A task force was formed and a thorough review of the literature was conducted to determine previous documentation on the phenomenon of DTI.
To much surprise, some documentation existed. In 1873, Paget wrote that ulcers could erupt from intact skin and that tissue may be purple or yellow from extravasation of blood. He further stated that the deeper tissues die, including muscles and bones, where sloughing follows in the skin and fat and the place under the skin ulcer is empty.
In 1943 Groth, a German scientist, created ulcers in an animal model by applying external pressure and describing these ulcers that started in the muscle as “malignant.”
Shea in 1975, in addition to defining the stages of pressure ulcers, included a “closed pressure ulcer.” As you can see from these significant pieces of literature it was apparent that the idea of a DTI pressure ulcer was not new, but had been overlooked in the existing staging system.
Updating the NPUAP staging system
When the NPUAP pressure staging system was first developed, knowledge of pathology leading to pressure ulcers was more limited, suspected DTIs were not considered and differential diagnoses of lesions secondary to incontinence and friction were not addressed.
In using the 1997 NPUAP staging system, suspected DTIs were often misclassified as Stage 1 pressure ulcers or just a bad bruise.
In sampling the national pulse on the issue of deep tissue injury, a series of international, national, regional and local presentations to wound care providers clinically validated that DTI pressure ulcers remained a significant, yet poorly understood clinical problem. Through many venues, DTI was validated as an etiology of pressure ulcers. While little formal study has been done on these pressure ulcers, it was agreed by clinical experts that they do exist.
How to describe them using the staging system remained unclear. DTI could be called a variant of Stage 1 or unstageable using the current terms. Stage 1 pressure ulcers have classically been accepted as ulcers that can heal on their own without regeneration of significant tissues or production of scar. The placement of DTI may not always fit well in the Stage 1 category, except to indicate that it is in a closed presentation and it heralds the development of more severe ulcers. DTI can also be staged in the unstageable category particularly in those health systems where placement is mandatory (such as MDS, computerized documentation) because the true extent of the wound is not known. When narrative documentation is used, objective description was recommended along with the label of suspected deep tissue injury or deep tissue injury. The concern with collapsing the DTI into an unstageable category may prolong the ability to fully understand the phenomena. If classified as a Stage 1V pressure ulcer because of its presumed depth and severity of tissue damage, one must remember that not all DTIs evolve into full-thickness ulcers. If identified early, ischemic and injured tissue may be salvageable with offloading and reperfusion, although basic science and clinical research is needed in this area.
Definitions were drafted with the goal of achieving accuracy, clarity, succinctness, clinical utility and discrimination between and among other definitions for both stages of pressure ulcers and other types of wounds. A key determinant of accuracy was available scientific evidence. Brevity was emphasized in drafting definitions. Each definition includes a “further description” to support educational efforts and refine clinical utility and clarity.
Following a lengthy validation and refinement process, the stage was set for the 2007 NPUAP Consensus Conference.
During the 2007 Consensus Conference, attendees were asked to use the updated definitions of pressure ulcers to classify 30 photographs of pressure ulcers and other dermal lesions. Percent of agreement was computed with an average of 60% for all photos. Most inaccuracies were due to classification of pressure ulcers on the foot or heel in patients with diabetes or arterial inflow diseases as diabetic foot ulcers or arterial ulcers, rather than as pressure ulcers.
Updated staging system
The goal of the revision was to clarify each stage and reduce the number of incorrectly staged ulcers or other types of wounds and skin lesions. Integrated into the staging system is an assumption that the ulcer is due to pressure, hence the etiologies of wounds will not be inaccurately classified as pressure ulcers, but the understanding of their etiology is imperative for the prescription and choice of interventions or treatments.
The NPUAP has updated the staging system to improve clinical accuracy, clinical usability and discrimination from other dermal wounds. The use of a staging system is to provide a method of communication that is consistent and describes the amount of anatomical tissue loss in a pressure ulcer.
Accurate staging is critical for care planning, communication and reimbursement.
One must remember that staging only represents what can be seen, it cannot describe history or healing. There is a continuing need to communicate the history of the wound, including the past stages, to ensure quality care in all settings.
Ongoing basic science and clinical research is needed in order to validate the NPUAP pressure staging system and evaluate the effectiveness of educational programs aimed at enhancing inter-rater and intra-rater reliability of the staging system. This will provide the necessary data for evidenced-based-practice in relation to the prevention and treatment of pressure ulcers. •
• Black, Joyce, et al, “National Pressure Ulcer Advisor Panel’s Updated Pressure Ulcer Staging System,” Urol Nurs. 2007:27(2) 144-150.
• Ankrom, M., et,al, (2005). “Pressure-related deep tissue injury under intact skin and the current pressure ulcer staging systems.” Advances in Skin and Wound Care 18(1), 35-42.
Frances W. (Billie) Sills, RN, MSN, ARNP, is an assistant professor at ETSU College of Nursing in Tennessee;firstname.lastname@example.org.