Special support surfaces are indispensable measures for essure ulcer prevention in high risk patients. Since merous products and systems are on the market, it may metimes be difficult to find out which ones work best. stematic reviews evaluating and summarizing the levant clinical data in the literature provide excellent pport for practitioners who are expected to make idence-based decisions, such as in regard to purchase protective equipment for a patient population or escription of a support surface for an individual. With eir high-quality systematic review and meta-analysis, cInnes et al. (2012) made a valuable contribution to our idence-based knowledge in pressure ulcer prevention. sults from over 50 different studies were collected, refully evaluated and analyzed using state-of-the-art ethodological standards. However, a typical limitation of ch meta-analyses is that information which is inherent the individual studies, is somehow lost when ‘‘avering’’ the many trials together. It is this loss of sometimes portant information which may later on cause problems our general understanding of whether and how the vestigated interventions might have worked. One major and still not fully resolved problem in essure ulcer research is the definition of what pressure cers really are. Conceptual difficulties persist around aetiology, pathogenesis and clinical appearance (e.g. Beeckman et al., 2009; Campbell and Parish, 2010; Kottner et al., 2009). These difficulties are very well reflected in the constantly changing pressure ulcer classifications. In 1975, Shea proposed, what soon became one of the first formal pressure ulcer classification systems, five pressure ulcer categories including so called ‘‘Closed Pressure Sores’’ under intact skin. Among others, Shea described category 1 pressure ulcers as ‘‘. . . a thickening and distortion of all tissue layers between the surface and the underlying bone’’ (p. 91). This definition of category 1 pressure ulcers and the ‘‘Closed Pressure Sore’’ category indicate that Shea regarded the origin of pressure-related tissue breakdown somewhere in all the tissue layers that could potentially be affected by the mechanical loading, including the dermis, subcutaneous fat and muscles. These ideas correspond to very early experimental results (e.g. Groth, 1942) but they are also very well accepted today (e.g. Bouten et al., 2003; Gefen, 2007). The development of pressure ulcers under intact skin is sometimes called bottom-up or inside-out process, in which damage first appears in skeletal muscle tissue directly under a weight-bearing bony prominence or in adipose tissue in vicinity of such a bony prominence (Fig. 1). There is a ‘‘middle-model’’ as well (Sharp and McLaws, 2005), which describes the onset of cell death and tissue damage anywhere in the skin or deeper tissues (Fig. 2). Importantly, both theories share the concept that sustained mechanical loads, which are manifested by compressive, tensile and shear deformations in all the soft tissue layers around a weight-bearing bony prominence, are primarily being responsible for the clinical outcome of a deep tissue injury (Bouten et al., 2003). On the other hand, nearly all the subsequently proposed pressure ulcer classification systems seemed to be based on a kind of top-down or outside-in mechanism. The (implicit) assumption of these models is that tissue R T I C L E I N F O
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Feb 23, 2019
Willeke A Traa + 5
Open Access
