This month's continuing medical education activity (page 571) by Sibbald, Krasner, Woo, and the Original Paradigm Expert Panel (SOPE Panel) develops a set of new lenses and frames by which we can see the reasons to reconceptualize the venerable grade 1 pressure ulcer (PrU). The long-held clinical beliefs about grade 1 PrUs have been the source of review, criticism, and discourse for more than a generation. For many of us who have been taught that PrUs follow a certain trajectory, which can be visualized and furthermore be graded, the article by Sibbald et al gives us a powerful reason to think about how we formulate our clinical beliefs.
Sensitivity and Specificity
Our ability to make an accurate diagnosis for a grade 1 PrU is currently elusive given the lack of technology available to measure sensitivity and specificity or the combined sensitivity or specificity of the target tissues. If the "nonblanching erythema" is considered our visual inspection test (VIT) for an impending PrU, then we must apply rigor to the value of the test. In general, the more sensitive a test is for a disease, the higher its false-positive rate, thus lowering its specificity. Typically, a highly sensitive test is ideal for a screening examination (in our case, the VIT), whereas highly specific tests are best in a confirmatory role. The mnemonics SnOut (Sensitive tests rule Out the condition when they are negative) and SpIn (Specific tests rule In the condition when they are positive) provide some guidelines on how to interpret sensitivity and specificity for an individual patient.1,2
Applying this concept to our ability to accurately diagnose blanching erythema utilizing our VIT is best described as neither diagnostically sensitive nor specific. Of all the ordinal grades describing PrUs, the term grade 1 is more nominal. In addition to the lack of specificity in confirmatory testing issues related to describing PrUs is our language. There are more questions than answers-not only about the meaning of a grade 1 PrU, but also about the words we use to communicate among ourselves about wound care. I refer to this as the taxonomy of discourse.
Taxonomy of Discourse
In the scientific sense, taxonomy is a method of classification. It is the agreed-upon nomenclature we use to categorize, catalog, arrange, and organize a given biologic or clinical model. In some instances, there is international consensus about the nomenclature of specific problems. An example of this is the World Health Organization's International Classification of Diseases. Taxonomy (classification) gives us the ability to engage in discourse (communication) in a common language. With this common language, advances can occur. This is an important concept for wound care practitioners to debate and incorporate. For example, being able to use appropriate descriptors for the types of wounds we evaluate and treat will help us communicate more effectively among ourselves and with policy makers, researchers, and patients. It will also facilitate communication with wound care practitioners throughout the world, solidifying the "one world" concept of our increasingly global economy.3
Taxonomy of Discourse in Action
We do not have to look far to examine the changing language of wound care; the metamorphosis of our journal's name is a perfect example. From Decubitus, the journal focused on PrUs; by 1994 the readership's interests had reached far beyond PrUs, and the name of the journal was changed to Advances in Wound Care. And in 2000, we changed the name again, to Advances in Skin & Wound Care. The inclusion of skin-the largest organ in the body-in the title more appropriately reflects that this total organ system is at risk for wounds. Wound care professionals from other countries, who use a slightly different taxonomy of discourse, provide us the ability to "cross-walk" our wound care languages, exemplified by the current manuscript by the SOPE panel that is advancing our discourse.
A scientific axiom that exemplifies how we crystallize our clinical acumen is attributed to "Indeed, we can only see what we know-what we have been taught to see."
"We only see what we know."-Johann Wolfgang von
Goethe (1749-1832).4
Richard "Sal" Salcido, MD
References