Peripheral Perfusion and Oxygenation in Areas of Risk of Skin Integrity Impairment Exposed to Pressure Patterns. A Phase I Trial (POTER-DIC)

Sample: the preclinical phase will be conducted in 20 healthy volunteers enrolled in the Faculty of Health Sciences of the University of Malaga. Clinical phase will take place in 12 subjects admitted to acute hospitalization in 'Costa del Sol' Health Agency and 12 subjects admitted to nursing homes in the District of Primary Knowing this information will identify different thresholds start in peripheral microcirculation disorders associated with various systems of body position and consequent pressure levels. This particular seems a reasonable need from baseline parameters allow to further explore specific situations of tissue injury and isolate direct and indirect causal factors. It is also necessary to conduct the study in subjects from different environments (home, hospital) to determine under real clinical practice how these parameters behave and how it can affect common procedures performed in clinical practice, such as repositioning or using pressure surfaces. This sample of 24 subjects was calculated taking into account a change in the capillary flow of 30% between baseline and the first hour of exposure to pressure, according to data of Kallman et al. (15) with an 80% output and statistical confidence level of 95%. In total, each subject will provide a total of 28 hours of measurement.

Phase 1: Inclusion criteria:Healthy volunteers, between 20 and 65 years old, with no cardiovascular, neurological, digestive, endocrine, renal, gynecological, respiratory, hematologic, infectious, dermatological, autoimmune or diagnosed musculoskeletal disease or functional limitations, with tissue integrity and BMI between 18.5 to 25.9 kg/cm2 without scars in the sacred, back-lumbar, trochanteric, heels, elbows and shoulder blades areas.

Exclusion criteria: The usual consumption for any reason of alpha-beta-blocking agents, or alpha-beta agonists, or directly or indirectly vasodilator-vasoconstrictor action drugs of any kind, anticoagulants, topical or systemic steroids, presence of pacemakers or implantable defibrillator, smoking, high consumption of alcohol (>20g/week), presence of tattoos in the areas of measurement, and lower limb amputation

Phase 2: Inclusion criteria: Patients admitted to acute hospitalization, with risk of skin integrity deterioration assessed by Braden scale (punctuation lower than 16) without pressure ulcers, who agree to participate in the study. Exclusion criteria: presence infusion of vasoactive drugs at the time of the study (dopamine, epinephrine, norepinephrine, dobutamine, nitroprusside, nitroglycerin, calcium channel blockers, ACE inhibitors). Regular oral treatment of alpha and beta-blockers and/or agonists or calcium channel blockers, nitrates, ACE inhibitors, angiotensin, renin inhibitors, diuretics, SSRIs, NSAIDs, will be accepted. Also patients with pacemakers and/or implanted defibrillator, fever, anemia with Hb <10g/dl, hypotension with systolic blood pressure <80 mmHg, presence of transfusions in the past 4 weeks, consumption and derivatives of erythropoietin, iron supplements, oral or parenteral anticoagulants will be excluded.

Interventions: Different positions will be applied to subjects in order to measure preipheral tissue oxygenation, pressure, and changes in microvascular flow.