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Monitoring Pressure Ulcer Healing in Persons with Disabilities
Pressure ulcers are a high-risk, high-volume, and high-cost problem for persons with disabilities. This article describes four tools published in the literature and reports the validity, reliability, strengths, and limitations of each. These tools include the Pressure Ulcer Scale for Healing (PUSH), the Pressure Sore Status Tool (PSST), the Sussman Wound Healing Tool (SWHT), and the Sessing Scale. Rehabilitation nurses should use a consistent framework with accurate quantification to assess, document, and monitor changes in pressure ulcers over time. Such a measurement tool must prove valid for the disabled population in which the tool is used. This will enable healthcare providers to communicate more effectively and evaluate the therapeutic plan of care.
The purpose of this article is to explore existing tools for measuring pressure ulcer healing, discuss the strengths and weaknesses of these tools, and recommend future direction for rehabilitation nurses who monitor pressure ulcer healing in persons with disabilities. Rehabilitation nurses who understand the importance of assessment and the trajectory of wound healing will appreciate the applicability of these measurement tools in the rehabilitation setting. A good measurement tool is necessary to assess the healing trajectory and recommend continued or modified treatment.
Pressure ulcers are a significant source of morbidity that seriously affect quality of life in persons with disabilities. Inpatient treatment is required for most patients in this vulnerable population with Stage III or Stage IV pressure ulcers, resulting in long hospital stays at a significant cost. Despite the availability of multiple published clinical practice guidelines (CPG) (Bergstrom et al., 1994; Consortium for Spinal Cord Medicine [CSCM], 2001), there is significant variation in practice among rehabilitation nurses regarding the measurement and monitoring of pressure ulcer healing.
The reported prevalence of pressure ulcers in persons with disabilities differs in the rehabilitation literature. This variation is due to unclear ulcer staging, the use of different formulas to calculate prevalence, differing case mix, dissimilar data sources, and others issues. Databases indicate that between 1990 and 2000, pressure ulcer prevalence for Stages I–IV in patients postrehabilitation was 12%–27%, and ranged from 15.2%–30% among spinal cord injury (SCI) patients (Cuddigan, Berlowitz, & Ayello, 2001).
The National Pressure Ulcer Advisory Panel (NPUAP) recommended that the following elements be considered when calculating pressure ulcer costs: physician fees, care-related devices, equipment, supplies, laboratory, drugs, room and board associated with extended lengths of stay, nursing, and nutrition (1989). In a quasi-experimental longitudinal study with retrospective and prospective measurement in a 77-bed long-term care facility, the total cost of prevention and treatment was $12,618/ulcer in 1997 when direct and indirect nursing care and supplies were calculated (Xakellis, Frantz, Lewis, & Harvey, 2001).
Given the high prevalence of pressure ulcers in persons with disabilities, the cost to the healthcare industry is enormous. In addition, these costs do not reflect the days the patient is absent from work; the necessity of obtaining a caregiver in the community setting because of the patient’s inability to perform his or her activities of daily living, ulcer care, meal preparation, and other limitations resulting from avoiding putting pressure on an ulcer; a compromised quality of life because therapeutic confinement to bed (for ulcers on the trunk) limits community participation; the onset of secondary complications related to relative immobility, such as deconditioning and pneumonia; and other factors affecting functional status, relationships, and vocational and avocational activities.
The cumulative effect of these factors contributes to significant compounding of the patient’s original disability with a secondary disability (i.e., a pressure ulcer). Pressure ulcer healing is of paramount importance so patients can return to their pre-ulcer physical and psychosocial status.
Pressure Ulcer Assessment
The Agency for Health Care Policy and Research (AHCPR) provided recommendations in their evidence-based CPGs for pressure ulcer assessment (Bergstrom et al., 1994). These guidelines recommended the following:
Related recommendations include:
As the ulcer progresses to the ultimate outcome of healing (i.e., trajectory), these assessment elements will provide the “window” to a delicate biological process. Several factors including nutritional status, offloading of pressure, specialty support surface, hemoglobin, hematocrit, and chronic diseases (e.g., pulmonary, renal) may affect the would healing trajectory, and, consequently, the assessment elements.
Wound Healing Trajectory
Pressure ulcers are chronic wounds, not acute wounds. Acute wounds, such as surgical incisions, progress through a systematic and predictable schedule of events to promote healing. Chronic wounds such as pressure ulcers, however, do not proceed in such an orderly manner (Lazarus, et al., 1994). Frequently, damage to underlying tissues is largely unknown (Kramer & Kearney, 2000), and multiple factors are associated with pressure ulcer healing (e.g., size, stage, exudate).
A retrospective analysis of 10 patients with Stage IV ulcers in a Veterans Healthcare Administration facility documented the following days to full healing: small ulcers (initial wound area 18–24 cm2) = 82–119 days; medium wounds (initial wound area 36–51 cm2) = 91–176 days; large ulcers (initial wound area 80.5–117 cm2) = 102–233 days (Brown, 2000).
Reliable and valid measurement tools enhance communication among clinicians by defining a common language in the tool’s instructions. Using this language, a care team commonly comprising a physician, nurse, and other disciplines (e.g., therapist) can identify characteristics of the wound and describe its healing trajectory. Serial pressure ulcer assessment is imperative to detect pressure ulcer deterioration, a healing plateau, or the degree and quality of healing. Instructions with clear definitions of terms are provided with all of the measurement tools. Based on the description of the pressure ulcer’s characteristics, continuity of care can be provided by maintaining or modifying the ulcer management plan.
Table 1 indicates reliability and validity data and strengths and limitations of four instruments that measure pressure ulcer healing: the Pressure Ulcer Scale for Healing (PUSH), the Pressure Sore Status Tool (PSST), the Sussman Wound Healing Tool (SWHT), and the Sessing Scale.
Pressure Ulcer Scale for Healing (PUSH)
The PUSH tool is a data collection form developed by a task force of the NPUAP (NPUAP, 2003). The tool originally was presented to the Centers for Medicare and Medicaid Services (CMS) in March 1998. CMS conducted a clinical test of the tool for usability in long-term care. The revisions seen in Version 3.0 are a result of that pilot test and a second retrospective study. Incorporation of the PUSH tool into future versions of the Minimum Data Set for subacute and long-term care facilities currently is under consideration. If accepted, CMS would base its reimbursement on data collected using the PUSH tool.
The PUSH tool was designed to assess the progression of an ulcer over time. The tool has three subscores (length by width, exudate amount, tissue type) and a total score (sum of the three subscores). It is not a “scale” in the usual sense of psychometric scaling. Scoring instructions and two useful graphing formats to display repeated measurements of the ulcer over time are available (NPUAP, 2003, Thomas, 1997). A graph of a patient’s accumulated PUSH scores reflects the trajectory of change of the ulcer over time (Cuddigan, 1997; NPUAP, 2003).
Content validity was explored with data from 103 patients from multiple sites whose ulcers were tracked for 10 weeks. Among the eight variables for which data were available for the patients over time, a combination of the three PUSH subscores was reported to provide the best-fit model of healing, with the PUSH scores accounting for 58%–74% of the variation across the 10 weeks (Thomas et al., 1997).
In another study of 269 nursing home residents from multiple sites, a modified PUSH instrument was examined for interrater reliability (Stotts et al., 2001). Agreement among personnel was reported as 95%, although it was not indicated whether this was for items or total score. For these nursing home patients, the modified PUSH (three subscores) again provided the best-fit model of healing and accounted for 39%–57% of the variation over time for the entire group.
Pressure Sore Status Tool (PSST)
The PSST is a data collection form designed to describe the status of a pressure ulcer over time for clinical and research needs (Bates-Jensen, Vredevoe, & Brecht, 1992). Thirteen items are scored on a Likert response format (1 = best, 5 = worst): size, depth, edges, undermining, necrotic tissue type, necrotic tissue amount, exudate type, exudate amount, skin color surrounding wound, peripheral tissue edema, peripheral tissue induration, granulation tissue, and epithelialization. The sum of the 13 item scores provides a numerical indicator of wound status at the time of observation.
To establish PSST content validity, development began with a panel of 20 experts. Items were refined by an expert panel of nine judges. Concurrent validity was explored using the Shea Staging System (Thomas, 1997). Beginning PSST scores for each ulcer were compared with beginning Shea staging scores (1–4). PSST scores could differentiate between Shea Stages 1 and 2 and Shea Stages 3 and 4, but scorces could not differentiate between Shea Stages 1 and 2, nor between Shea Stages 3 and 4 (Thomas, 1997). Two enterostomal therapy (ET) nurses determine PSST scores for 20 patients twice within 90 minutes. Interrater reliability for the total score was 0.91 for rater 1 and 0.92 for rater 2. Intrarater reliability was 0.99 for rater 1, and 0.96 for rater 2 (p < .001). With rater training, excellent interrater reliability was achieved for all items with percentage of agreement of 86% or higher and Kappa coefficients above 0.75 (excellent agreement beyond chance; Bates-Jensen, Vredevoe, & Brecht, 1992). Bates-Jensen performed additional reliability tests and concluded that with training, acceptable reliability can be reached even when healthcare workers who are not specialists in wound care complete the scoring (Bates-Jensen, 1997). One subscale related to wound bed tissue health showed preliminary promise as a possible subscore to predict time to 50% healing (B. Bates-Jensen, personal communication, 8/03.
Sussman Wound Healing Tool (SWHT)
The SWHT is based upon a model used to assess acute wounds (Sussman & Swanson, 1997). The tool consists of 10 categorical variables that are assessed as “present/not present”: necrosis, undermining, maceration, erythema, hemorrhage, fibroplasias, appearance of contraction, sustained contraction, adherence of wound edge, and epithelialization. Five factors are favorable and five factors are unfavorable to wound healing. The SWHT also comprises 11 variables related to size, location, and measures of wound healing phase (e.g., depth, undermining/tunneling, location, and healing phase; Sussman & Swanson, 1997). Physical therapists tested this tool in a long-term care setting in 112 patients (Sussman & Swanson). Concerns have been raised regarding the SWHT’s sensitivity to change in ulcers over time because the end scores reflect factors scored as unfavorable (0) from favorable (5) (Thomas, 1997). Little has been published describing the performance of this tool.
The Sessing Scale (Ferrell, Artinian, & Sessing, 1995; Ferrell, 1997) is graded from 0 (normal skin, but at risk for skin breakdown) to 6 (breaks in skin around primary ulcer, purulent drainage, foul odor, necrotic tissue and/or eschar; may have septic symptoms), and offers no individual evaluation of healing factors. Developed to measure the progression of pressure ulcers with a goal of standardizing care, it was tested with 84 nursing home residents with pressure ulcers. Validity was examined in relation to Shea staging scores and the size of the wound. Interrater reliability was acceptable. Test-retest agreement was adequate. No reports using the Sessing Scale in a disabled population have been found.
Discussion and Implications
The validity of a healing instrument is established only if assessment parameters are associated with wound healing and if assessment reflects ulcer status. An instrument to assess and track healing is reliable if multiple measurements of the same pressure ulcer by different clinicians produce the same results. By using measurement tools that minimize assessment variation, rehabilitation nurses can identify increments of real change over time. Thus, a tool must be sensitive to changes in pressure ulcer status. Validity, reliability, and sensitivity are important for wound healing assessment to be clinically useful (Thomas, 1997). Although one end point or goal in pressure ulcer management is ulcer healing with resurfacing (the other is preventing a recurrence), the healing trajectory helps rehabilitation nurses make appropriate treatment decisions along the path of healing.
Although providers strongly believe pressure ulcer management (assessment, prevention, and treatment) differs significantly in persons with disabilities compared with frail, elderly patient populations, little research has documented these differences. This lack may be because reliable and valid tools describing pressure ulcer healing and the trajectory of healing have received attention relatively recently.
The PUSH tool has been described as a valid and reliable instrument for specialists and nonspecialist care providers to track pressure ulcers over time. It is easy to score and to understand, but healthcare providers who manage pressure ulcers have expressed concern regarding this tool. For example, the greatest clearly delineated surface area (lenght x width) value in the PUSH is “24.0 cm2;” this makes serial comparisons difficult in larger wounds. Makelbust (1997) reported discussions with providers from acute care, home care/outpatient care, and long-term care settings. The results of these discussions indicate that clinicians believe the PUSH does not include information they consider necessary for their regular clinical work. Stotts and Rodeheaver (1997) called this “clinical practicality.”
Although the PSST provides a more comprehensive assessment for tracking pressure ulcers over time than the PUSH tool (reporting 13 items rather than 3), it is more time-consuming to use in the clinical setting than the PUSH. In addition, the relationships among the 13 items of the PSST have not been explored (e.g., interitem correlations or factor analysis), nor is there any published analysis of the PSST score responsiveness to change.
The SWHT and the Sessing Scale have sensitivity, reliability, and validity limitations. The SWHT is quite lengthy (21 items), and the Sessing Scale has no individual evaluation of pressure ulcer healing factors.
A review of the literature regarding pressure ulcer healing in persons with disabilities reveals three significant limitations:
Observational studies are needed to develop and test tools to monitor pressure ulcer healing in persons with disabilities, describe the temporal aspects of pressure ulcer healing in this population, and describe the cost burden of care associated with pressure ulcers. Findings from such a study would be useful to (a) establish the validity, reliability, and sensitivity of a tool to monitor pressure ulcer healing, applicable to select disabled populations, (b) explain the trajectory of pressure ulcer healing in relation to treatment decisions and discharge planning, and (c) provide a population-based quality indicator for comparison and benchmarking.
Although clinicians value existing measurement tools for quality improvement initiatives, many believe that by adding a few carefully chosen clinical indicators, a modification to one of these tools (e.g., the PUSH tool) can improve pressure ulcer assessment and guide treatment decisions and discharge plans at the individual patient level. For example, several wound experts agree that deep tissue injury (DIT) with intact skin is a potentially serious presentation that may herald an impeding deep pressure ulcer evolving beneath the skin surface (9th National MPUAP Consensus Conference, Feb., 25–26, 2005); well-defined assessment parameters for DTI should be incorporated into a wound healing tool.
Rehabilitation nurses would benefit from a valid and reliable evidence-based outcome tool that would provide a population-based quality indicator for comparison and benchmarking pressure ulcer healing in persons with disabilities. This tool must achieve clinical practicality for rehabilitation nurses while also serving as a rigorous research tool.
About the Authors
Maria Mullins, MD MBA is a research scientist with Patient Safety Center of Inquiry, VISN 8, Tampa, FL, and the University of South Florida, College of Medicine.
Susan S. Thomason, MN RN APRN-BC CWRN, is a clinical nurse specialist and enterostomal therapy nurse, spinal cord injury service, James A. Haley Veterans Hospital, Tampa, FL.
Marcia Legro, PhD EdM, is the implementation research coordinator for the Veterans Health Administration Spinal Cord Injury Quality Enhancement Research Initiative (QUERI), Seattle, WA.
Address correspondence to Susan Thomason at James A. Haley Veterans Hospital, 13000 Bruce B. Downs Boulevard, Tampa, FL 33612 or via e-mail at firstname.lastname@example.org.
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