Abstract
Continuous positive airway pressure masks for breathing assistance are used widely during the coronavirus pandemic. Nonetheless, these masks endanger the viability of facial tissues even after a few hours because of the sustained tissue deformations and extreme microclimate conditions. The risk of developing such device-related pressure ulcers/injuries can be reduced through suitable cushioning materials at the mask-skin interface, to alleviate localised contact forces. Here, we determined the facial tissue loading state under an oral-nasal mask while using hydrogel-based dressing cuts (Paul Hartmann AG, Heidenheim, Germany) for prophylaxis, which is a new concept in prevention of device-related injuries. For this purpose, we measured the compressive mask-skin contact forces at the nasal bridge, cheeks, and chin with vs without these dressing cuts and fed these data to a finite element, adult head model. Model variants were developed to compare strain energy densities and effective stresses in skin and through the facial tissue depth, with vs without the dressing cuts. We found that the dry (new) dressing cuts reduced tissue exposures to loads (above the median loading level) by at least 30% at the nasal bridge and by up to 99% at the cheeks, across the tissue depth. These dressing cuts were further able to maintain at least 65% and 89% of their protective capacity under moisture at the nasal bridge and cheeks, respectively. The hydrogel-based dressings demonstrated protective efficacy at all the tested facial sites but performed the best at the nasal bridge and cheeks, which are at the greatest injury risk.