Portal de Periódicos da CAPES

What Do Prevalence Studies of Pressure Ulcers in Nursing Homes Really Tell Us?

2002; Wiley; Volume: 50; Issue: 4 Linguagem: Inglês

10.1046/j.1532-5415.2002.50178.x

1532-5415

George Taler,

Diagnosis and Treatment of Venous Diseases

Pressure ulcers (PUs) have long been considered emblematic of poor nursing care and, as such, have drawn the attention of many quality improvement initiatives, state and federal surveyors, and trial lawyers. The findings of Coleman et al.1 reported in this issue of the Journal of the American Geriatrics Society, show that the prevalence of PUs has not changed since the implementation of Omnibus Budget Reconciliation Act of 1987. This is a disappointment and justifies the continued vigilance. Our challenge for the future is not only to develop and implement more-effective prevention strategies, but also to better educate those who use PU prevalence as the yardstick for quality. I would like to address the problems in designing and interpreting prevalence studies of PU, as exemplified by this study, then discuss the policy implications. There are serious problems in extrapolating from our current methods of defining wounds to an understanding of their etiology, let alone to the quality of care implications. The current system for staging PUs was initially designed by Shea solely as a “shorthand” for wound description.2 Subsequent work by the National Pressure Ulcer Advisory Panel has clarified and firmly established this construct3 and promulgated its use throughout the healthcare system. However, staging tells us neither about the causes of the wound nor about its natural history and evolution towards healing. From an etiological perspective, PUs can be construed as superficial or deep. Superficial injuries, such as “true” stage 1 and 2 PUs, have in common: (1) “what you see is what you get” immediately after the trauma, which is related to friction and shear more than pressure and likely exacerbated by skin maceration, (2) have minimal to no systemic sequelae, and (3) heal by regeneration of native tissue with simple local care, usually within 30 days. Although these wounds are often considered trivial in respect to the overall clinical course, they provide instant feedback on the care exhibited by the nursing staff. I used the term “true” above because deep wounds may pass through these stages in the course of their natural history. In the development of deep injuries, such as stage 3 and 4 PUs, the pressure/shear is usually sustained and repetitive. This creates a pressure wave that induces ischemic injury in a cone-like distribution initially in the adipose layer adjacent to the fascial plane between the fat and muscle (stage 3) or in the muscle just above the bone (stage 4).4 A necrotic abscess is formed in these deep tissues, which, if not absorbed through the normal phagocytotic process, tracks toward the surface. The leading edge of the abscess provokes changes in the overlying skin that suggest superficial injury, before breaking through and fully manifesting the extent of the damage. These wounds are different in nearly every respect from their superficial counterparts. (1) The extent of injury will become evident well after the trauma (from experimental data, no sooner than 1 week).5 (2) The injury will have significant systemic implications dependent on the volume of necrosis and the vigor of the inflammatory response. (3) Healing is by secondary intent, which requires a coordinated interdisciplinary effort and is prolonged over months to years. Although these wounds raise great consternation in the management of the individual patient, as they should, they are less useful as an indicator for quality improvement efforts targeting the prevention of PUs in long-term care settings. Studies have shown that up to 66% of nursing home patients with PUs were brought into the institution from acute care facilities or home.6 Therefore, given the less-than-100-day exclusion, the authors greatly reduced the likelihood of “imported” stage 2 ulcers, but had little affect on the prevalence of “imported” stage 3 and 4 ulcers. Unfortunately, despite the apparent differences between the changes in prevalence by stage, the improvement in stage 2 prevalence shows a trend, but does not reach statistical significance. This line of argument also undermines the precept that improvement in care can be measured through a “stage shift.” First, “true” stage 2 ulcers (the vast majority of stage 2 wounds) do not become stage 3 or 4—they are of very dissimilar etiologies. Given the differences in healing mechanisms and their clinical course, I would also hope that the authors did not intend that stage 3 and 4 PUs would be “down-staged” as they heal. Although this is consistent with the descriptive intent of the staging system (and complies with misguided Medicare policies), it treats two very distinct processes of healing as equivalent, with deleterious consequences for the more-compromised patients. There are very important policy implications depending on one's interpretation of the prevalence rates among the different PU stages. In conducting a survey, there is an implicit assumption that there is some direct association between the prevalence rates and the incidence rates. However, among PUs, the vast differences in healing rates can easily lead to erroneous assumptions. For example, because two-thirds of stage 3 PUs and three-quarters of stage 4 PUs take longer than 6 months to hea1,7 a single PU on a prevalence survey represents the potential for no more than two such ulcers over the course of the year. However, more than half of all stage 2 ulcers heal within 1 month,7 so that finding a single PU could represent a potential for many more ulcers over the course of the year. Let us now assume that state and federal surveyors focus on the more dramatic wounds, but give some leeway on injuries felt to be less serious—a commonly held belief. This would be bad for two reasons. The nursing home, which is likely not to have been responsible for the deeper wounds, could well feel unjustly criticized and refrain from accepting patients with deep PUs in the future. Alternatively, glossing over wounds considered clinically insignificant jeopardizes the use of a powerful tool for quality improvement. Everyone would prefer to see fewer wounds overall, but contrary to the implications of the “stage shift,” improvement in care could be consistent with a greater percentage of stage 3 and 4 PUs! The conclusion that regulatory interventions may not be sufficient to stimulate improvements in the care of nursing home patients is an important caveat. The survey process has become a dominant “customer” of the long-term care enterprise, and the Center for Medicare and Medicaid Services needs to recognize their effect on the provision of long-term care. Just as schools can be accused of teaching toward qualifying examinations, and missing the essence of an education, nursing homes can be too easily diverted from their mission by too greatly focusing their attention on satisfying the survey and certification processes. The Law of Unintended Consequences is always operant in complex systems such as long-term care, and policy makers need to be more intent on joining together regulatory compliance and good clinical care. The authors and I agree on one final point. Quality improvement initiatives are difficult to implement and sustain. Certainly, this study shows that we have a long way to go in the quality improvement process. The development of clinical practice guidelines is only a beginning on which to build. There is reason to believe that the level of nursing assessment has improved (Coleman et al., unpublished data), but the next challenge is to consistently tie preventive interventions to the clinical evaluations. Then perhaps we will all be pleasantly surprised by the results.