INVESTIGATIONS FOR ORTHOSTATIC HYPOTENSION

Orthostatic hypotension, which is common mainly in the eldery, is in many cases related to hypovolemia and/or vasodilators intake. However, when an impairment of the autonomic nervous system is suspected, orthostatic hypotension severity and mecanism may be investigated. The most common tests are the head upright tilt-test and the Valsalva manoeuvre. Both of them examine the baroreflex system as a whole, and become non invasive tests with the development of finger arterial blood pressure continuous measurement. Each part of the baroreflex system may be investigated separately. So, cardiac vagal responses to ocular compression, to carotid sinus massage, to respiratory change or to atropine infusion, may be tested. On the other hand, sympathetic efferent pathways may be stimulated in a variety of ways, such as isometric exercise, cutaneous cold, mental arythmetic, norepinephrine infusion, or tilt-test. None of these tests should be applied systematically, but according to the clinical features.