How does lateral tilting effect internal strains in the sacral region bed ridden patients? – A contribution to pressure ulcer prevention

• Published in: Clinical biomechanics (Bristol)
• Main Authors: Oomens, C.W.J, Broek, M, Hemmes, B, Bader, D.L
• Format: Journal Article
• Language: English
• Published: 2016
• Subjects: Physical Medicine and Rehabilitation; lateral tilt; pressure ulcers; repositioning; finite element analysis
• DOI: 10.1016/j.clinbiomech.2016.03.009
• ISSN: 0268-0033

Abstract Background Repositioning of individuals with reduced mobility and at risk of pressure ulcers is an essential preventive step. Manual or automatic lateral tilting is a way of doing this and the international guidelines propose a 30o to 40o degree side lying position. The goal of the present study was to determine the internal strains in individuals lying in supine position and during tilting Methods Based on MRI images of the sacral area of human volunteers, subject specific finite element models were developed. By comparing calculated contours of skin, fat and muscle with MRI measurements on a flat surface the models were validated. A parameter study was performed to assess the sensitivity of the model for changes in material properties. Simulations were performed at tilting angles of volunteers between 0o and 45o. Findings Subjects in a supine position or tilted have the highest strains in the muscle and fat. Tilting does effect the strain distribution, taking away the highest peak strains. There seems to exist an optimal tilting angle between 20o and 30o , which may vary depending on factors such as BMI of the subject and is in the current paper investigated only for the sacrum. Interpretation The study shows that tilting indeed has a significant, positive influence on internal strains, which is important for the prevention of deep tissue injury. Additional studies are needed to draw conclusions about the greater trochanter area and the tissues around the shoulder.