The biomechanical protective effects of a treatment dressing on the soft tissues surrounding a non‐offloaded sacral pressure ulcer

Abstract

Patients who are immobile endure prolonged bodyweight‐related compressive, tensional and shear loads at their body‐support contact areas that over time may lead to the onset of pressure ulcers (PUs). Approximately, one‐third of the common sacral PUs are severe and classified as category 3 or 4. If a PU has occurred, off‐loading is the basic, commonly accepted clinical intervention; however, in many situations, complete off‐loading of sacral PUs is not possible. Minimising the exposure of wounds and their surroundings to elevated mechanical loads is crucial for healing. Accordingly, in the present study, we aimed to investigate the biomechanical effects of the structural and mechanical properties of different treatment dressings on stresses in soft tissues surrounding a non‐offloaded sacral PU in a supine patient. Using a novel three‐dimensional anatomically realistic finite element modelling framework, we have compared performances of three dressing designs: (a) The Mepilex Border Sacrum (MBS) multilayer anisotropic silicone foam dressing (Mölnlycke Health Care), (b) an isotropic stiff dressing, and (c) an isotropic flexible dressing. Using our newly developed protective efficacy index (PEI) and aggravation index (AI) for assessing prophylactic and treatment dressings, we identified the anisotropic stiffness feature of the MBS dressing as a key design element.

Protecting prone positioned patients from facial pressure ulcers using prophylactic dressings: A timely biomechanical analysis in the context of the COVID‐19 pandemic

“…Following the same computational methodology reported in our previous published work concerning FE simulations of the use of sacrum and heel prophylactic dressings, 45,46,[53][54][55][56][57][58][59] the layers of the dressings applied here ( Figure 1B) were all considered elastic materials. The tensile elastic moduli associated with stretching of the dressing materials during weight-bearing of the head in the prone position (E x , E y ), the compressive elastic moduli of the dressing layers (E z ) and the Poisson's ratios were calculated.…”

Modelling an adult human head on a donut‐shaped gel head support for pressure ulcer prevention

“…The TSCE has been defined here as the area bounded between the corresponding stress curve in Figure and the horizontal (stress) axis, for the highest quartile of the calculated stress range (to focus on exposures to elevated or focal tissue stresses). The aforementioned TSCE has been calculated separately for the effective stress curves (TSCE effective) and for the shear stress curves (TSCE shear) …”

“…All elements were of the tetrahedral type; the numbers of elements in each model component are specified in Table . The FE simulations were set up using Preview (version 1.19, University of Utah, Salt Lake City, Utah), solved using the Pardiso FE solver (version 2.5) and post‐processed using PostView (version 1.9.1), which are all modules of the FEBio software package (University of Utah, Salt Lake City, Utah) . The runtime of each simulation was approximately 17 hours using a 64‐bit Windows 10 Pro‐based workstation with a CPU comprising Intel Xeon E5‐2620 2 GHz (two processors) and 64 GB RAM.…”

Which endotracheal tube location minimises the device‐related pressure ulcer risk: The centre or a corner of the mouth?

“…In each model variant, the effective and maximal shear stresses in the lips, mucosal tissues, and facial skin were calculated and compared, separately for each tissue type. Additionally, volumetric exposures of these parameters were plotted and compared across the two model variants, as per our published methodology to quantify device‐tissue interactions in the context of PUs and MDRPUs in particular . In order to allow systematic comparison between the model variants, all data analyses were performed for the soft tissues elements near the ETT segment with effective stress values greater than 3 kPa, which has been set as the threshold for defining the size of the volume of interest (VOI) (Figure ).…”