Idiopathic orthostatic hypotension in adults

Abstract

Only a few experiments have been done investigating the hemodynamics of idiopathic orthostatic hypotension (I.O.H), but no report has yet been known made on the hemodynamics of the brain, heart and kidney in I.O.H. especially. In this report, the influences of autonomic dysfunction on hemodynamics of I.O.H. are examined in 122 patients and in experimental animals. Methods The function of the autonomic nervous system was observed by the pharmacodynamic methods (mecholyl, noradrenaline, atropine, adrenaline and pilocarpine test), intracuti-reaction of acetylcholine/adrenaline and Ashner's phenomenon. The circulating blood and the plasma volume were measured by the Evans Blue method, and the time for circulation from arm to tongue or from vena dorsalis pedis to tongue was measured by the Decholin method. The circulating and the output quotient were calculated as follows. Circulating quotient = (circulating blood volume (1))/total circulation time × 60 Output quotient = circulating quotient / pulse rate The concentration of carbonic acid in the serum was measured by CONWAY'S method and the blood pressure of arteria centralis retinae by an ophthalmodynamometer (SCHlOTZ). The character test was performed by C.M.I. and Y. G., and renal function was measured by the renal plasma flow (RPF) and glomerular filtration rate (GFR). In animal experiments rabbits weighing 2.5-3kg were used. For the blocking of the sympathetic nerve, bilateral cervical sympathectomy was done or a ganglion blocking agent (tetraethylammonium bromide) was injected intravenously. The output volume of the heart was measured before and after hypothalamic lesion. In order to produce lesion experimentally, a stainless steel bipolar electrode was inserted stereotaxically in the sympathetic area of the hypothalamus and 0.5 mA D.C. was electrified for 60-120sec. with the object of coagulating brain structures.