Dynamic function tests for detection of physiologic and pathophysiologic reactions in cutaneous microcirculation

Functional tests simulating local stresses are especially suitable for the evaluation of physiological and pathophysiological patterns in the cutaneous microcirculation, particularly if combined with non-invasive methods such as laser-Doppler fluxmetry and oxygen tension measurements. Arterial occlusion (3 min) and local heating (up to 42° 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 during each functional test can be used to determine the so-called post-stimulatory parameters. These-corresponding to physiological equivalents - allow statements on the vascular reactivity towards hypoxia and ischaemia. Furthermore, dynamic performance parameters can easily be derived from the poststimulatory values. They describe the capacity of cutaneous microcirculation with regard to perfusion reserves and ischaemic tolerance in local stress situations in an appropriate manner. As an example of the usefulness of functional tests for cutaneous microcirculation, the physiological and pathophysiological patterns found in systemic sclerosis are described.