A Computer Modeling Study to Assess the Durability of Prophylactic Dressings Subjected to Moisture in Biomechanical Pressure Injury Prevention

The sacral area is the most common site for pressure injuries (PIs) associated with prolonged supine bedrest. In previous studies, an anisotropic multilayer prophylactic dressing was found to reduce the incidence of PIs and redistribute pressure. The purpose of the current study was to further investigate relationships between design features and biomechanical efficacy of sacral prophylactic dressings. Using computer modeling, the anisotropic multilayer dressing and a hypothetical dressing with different mechanical properties were tested under dry and 3 levels of moist/wet conditions. Sixteen (16) finite element model variants representing the buttocks were developed. The model variants utilized slices of the weight-bearing buttocks of a 28-year-old healthy woman for segmentation of the pelvic bones and soft tissues. Effective stresses and maximal shear stresses in a volume of interest of soft tissues surrounding the sacrum were calculated from the simulations, and a protective endurance (PE) index was further calculated. Resistance to deformations along the direction of the spine when wet was determined by rating simulation outcomes (volumetric exposures to effective stress) for the different dressing conditions. Based on this analysis, the anisotropic multilayer prophylactic dressing exhibited superior PE (80%), which was approximately 4 times that of the hypothetical dressing (22%). This study provides additional important insights regarding the optimal design of prophylactic dressings, especially when exposed to moisture. A next step in research would be to optimize the extent of the anisotropy, particularly the property ratio of stiffnesses (elastic moduli).