Objectives: 1. To analyze the changes in peripheral tissue oxygenation in tissues subjected to different pressure regimes in healthy humans. 2. To analyze changes in microvascular flow in peripheral tissues subjected to different pressure regimes in healthy humans. 3. To determine thresholds of tissue perfusion flow and transcutaneous oxygen depending on exposure levels and angling pressure in healthy volunteers. 4. To evaluate the distribution of tissue perfusion flow and transcutaneous oxygenation in real clinical situations in residential care and acute hospital care in patients at risk for impaired skin integrity.