Impairment of baroreceptor reflex in patients with phaeochromocytoma.

We examined the baroreceptor reflex sensitivity (BRS) in two patients with adrenal phaeochromocytoma because of their wide BP fluctuations. These patients showed greatly reduced values for BRS, which returned to normal with marked improvements of BP fluctuations soon after the removal of phaeochromocytoma. In these patients, circulating blood volume was normal and episodic rises in BP occurred without detectable increases in plasma catecholamines. From these observations, a marked impairment of baroreceptor function is considered to be one of the determinants for the wide BP fluctuation in patients with phaeochromocytoma.