FUNCTIONAL TESTS IN CUTANEOUS MICROCIRCUL ATION - EVALUATION OF PHYSIOLOGICAL AND PATHOPHYSIOLOGICAL PATTERNS

Functional tests simulating local stresses are especially suitable for the evaluation of physiological and pathophysiological patterns in th e cutaneous microcirculation, particularly if combined with non-invasi ve methods such as laser-Doppler fluxmetry and oxygen tension measurem ents. Arterial occlusion (3 min) and local heating (up to 42 degrees C ) are appropriate as stimuli to simulate specific local demands on the cutaneous perfusion similar to those produced by pressure, myokinesis , heat, and inflammation. When the current microcirculatory status is described the initial values (LDF and pO(2)) and their time-courses du ring each functional test can be used to determine the so-called posts timulatory parameters. These - corresponding to physiological equivale nts - allow statements on the vascular reactivity towards hypoxia and ischaemia. Furthermore, dynamic performance parameters can easily be d erived from the poststimulatory values. They describe the capacity of cutaneous microcirculation with regard to perfusion reserves and ischa emic tolerance in local stress situations in an appropriate manner. As an example of the usefulness of functional tests for cutaneous microc irculation, the physiological and pathophysiological patterns found in systemic sclerosis are described.