Assessment of Biophysical Skin Properties at Different Body Sites in Hospitalized Old Patients: Results of a Pilot Study

<b><i>Background:</i></b> Skin aging is a risk factor for a decubitus and biophysical skin properties could help to identify persons at risk. Whether such biophysical properties of aged human skin differ between areas is undetermined. <b><i>Objective:</i></b> To investigate whether viscoelasticity, hydration or friction differ between important areas for decubitus risk. <b><i>Methods:</i></b> Pilot study in 32 (18 female, 14 male) acute and subacute old patients aged 81.9 ± 5.9 years (±SD), without active skin disease after an average of 10 days of stay. Assessment of skin resilience/viscoelasticity (E) and hydration (H) at the volar forearm (VF), trochanter (TR) and the sacrum (SA), nutrition by a Mini Nutritional Assessment (MNA), total body water (TBW), lean body mass (LBM), % body fat (%F) by bioimpedance and routine laboratory parameters (hemoglobin, hematocrit, leukocytes, C-reactive protein, serum proteins and creatinine). <b><i>Results:</i></b> Mean body mass index (27 ± 4.2), MNA (22.5 ± 2.9), Braden score (20 ± 2.5), E (68.5 ± 6.0%) and H (38.3 ± 6.7) at any site and laboratory parameters did not differ by sex. Men had more TBW (+12 ± 1.5 liters), LBM (+9 ± 2 kg), less %F (–8.8 ± 2.1%), increased H-TR (+7.11 ± 2.8) and H-SA (+5.68 ± 2.5). Overall E-VF correlated significantly with E-TR (r² = 0.40, p < 0.0001) and E-SA (r² = 0.40, p < 0.0001). In contrast, skin hydration was not correlated. <b><i>Conclusion:</i></b> Results of forearm elasticity experiments can be used as a model for other body sites at risk for the development of pressure ulcers.