Superfícies de suporte para prevenção de lesões por posicionamento cirúrgico: um estudo experimental

Abstract

The need for development of technologies related to patient safety has been widely discussed. Supporting surfaces (SSs) are specialized mechanisms whose purpose is to redistribute the pressure on bony prominences to prevent complications, such as pressure ulcers and compartment syndrome. This study aims to evaluate the SS viscoelastic polymer, satin vinyl foam, sealed foam D28, sealed foam D33, sealed foam D45, soft foam D18 and soft foam D28, used in operating tables due to their main mechanical properties and interface pressure on bony prominences. To this end, the research was divided into two stages called Mechanical Tests (Phase I) and Evaluation of Interface Pressure of Supporting Surfaces (Phase II). Phase I was characterized as a laboratory experimental research and Phase II as an almost experimental study, without randomization. In Phase I the SS were characterized with respect to density and hardness. The biomechanical tests carried out were permanent deformation compression, indentation force and dynamic fatigue. In Stage II, 20 healthy volunteers participated with different nutritional classifications: thin, eutrophic, overweight and obese, according to the World Health Organization classification (2006). Participants were evaluated on surgical supine position. Interface pressure was measured with the aid of sensor mesh on occiptal, subscapularis, sacral and calcaneous regions. To check if there was a significant difference between the SS evaluated in relation to the pressure exerted on bony prominences, test Anova was carried out for repeated measurements to a factor. The existence of statistical difference according to nutritional rating (leanness, eutrophic, overweight and obesity) in relation to numeric variables was verified through Anova for repeated measurements to more than one factor. The SS evaluated presented different biomechanical features, out of which the viscoelastic polymer was considered denser and harder compared to other foams. The viscoelastic polymer and sealed foam D45 showed lower deformation, greater resistance to the application of force and smaller loss of indentation force in the fatigue test, which indicates that these SS were more resistant to the use. The SS which showed greater durability were viscoelastic polymer and sealed foam. The use of viscoelastic polymer meant no reduction of interface pressure when compared to standard operating table. The foams presented lower interface pressure. The sacral region presented greater pressure, followed by the calcaneal region on the standard operating table and on viscoelastic polymer. In relation to foams, the calcaneal region presented greater interface pressure. There was no statistically significant difference between the groups of volunteers when considering the nutritional classification. It was concluded that the viscoelastic polymer presented better biomechanical12 behavior, however it did not reduce nor equalize the interface pressure levels when compared to other SS, the primary hypothesis of this research. Sealed foams D45 and D33 presented the best properties for reducing pressure on bony prominences. These findings point to the possibility of future interdisciplinary research focusing on the manufacture of new products for this area.