Acute autonomic neuropathy is a syndrome where the peripheral nervous system is damaged acutely, primarily, and diffusely. For refractory orthostatic hypotension, which persists in cases where the disorder has not been cured completely, hypertensors or mineralocorticoids are generally administered. We observed that patients who did not respond to such agents did, however, respond to Ryokei-jutsukan-to, although no one has reported previously on the use of this Kampo formulation for acute autonomic neuropathy. In order to define the mechanisms of action of this formulation, we conducted orthostatic tests and drug loading tests and also studied endocrinology and hemodynamics. Blood pressure rose with the treatment of Ryokei-jutsukan-to, and this proved to be due to an increase in peripheral vascular resistance. Furthermore, cardiac output was decreased, and the renin-angiotensin-aldosterone system, which had been slightly activated, was corrected. The increase in peripheral vascular resistance appears to be a result of direct action on the vascular wall, since the formulation inhibited the sympathetic activity and improved the denervation hypersensitivity of peripheral vascular receptors.

Frequently occurred sudden deaths in the bath have become to serious problem in Japan. Sudden death in the bath possibly concerned with neurally mediated syncope. During and after bathing, bather is possibly tended to occur orthostatic intolerance by thermal stress to the circulatory dynamics. The experiment was performed focused on changes in cerebral and cardiovascular hemodynamics by postural change in the bathing to discuss the safe way of bathing.
On 9 healthy young subjects, 41±1°C bathing was performed 15 minutes, change in oxidized hemoglobin (ΔOxyHb) on the forehead as an indicator of cerebral blood flow was monitored by near-infrared spectroscopy method at interval of 0.5s through the experiment. In sitting and upright position, blood pressure and heart rate were measured before bathing, at 5 minutes, 10 minutes and 15 minutes (upright with head down) after immersion and after bathing.
Some subjects felt dizziness at upright during and/or after bathing. It suggests that orthostatic stress under heat stress is implicative even for healthy young. ΔOxyHb for subjects with dizziness at upright during bathing is significant lower below the baseline than it for subject without dizziness.
Degrees of depression of systolic blood pressure, elevation of heart rate and depression of cerebral blood flow by standing at 10 minutes after starting immersion were significant larger than their values before bathing. Degree of elevation of heart rate and depression of cerebral blood flow by standing with head down were significant smaller than their value at standing without head down. It suggests that upright with head down reduce the orthostatic stress to the cerebral and cardiovascular hemodynamics.