Effects of water immersion on plasma catecholamines in decompensated cirrhosis. Implications for deranged sodium and water homeostasis.

Although an impairment in renal sodium and water excretion is a commonly encountered clinical problem in cirrhotic patients, the mechanisms responsible for this abnormality are uncertain. Norepinephrine (NE) levels are elevated in some patients with decompensated cirrhosis, but a causal relationship between these levels and impaired sodium and water excretion has not been established. Since in normal man, water immersion to the neck (NI) results in a preferential central hypervolemia, and since theoretical considerations suggest that central hypervolemia might suppress NE, we designed the present study to determine if the natriuretic and diuretic responses of cirrhotic patients to NI are mediated by a decrease in NE. 16 cirrhotic patients with ascites were studied on two occasions: during a seated control study and during 4 h of NI: NE, determined by radioenzymatic assay, was measured hourly. 15 of the 16 patients manifested a marked diuresis, and 12 had a natriuresis that equalled or exceeded that documented in normal subjects during NI. NI did not alter mean NE, with 9 subjects manifesting an increase of NE as compared with the prestudy hour. Furthermore, peak urinary sodium excretion and flow rate varied independently of prestudy NE (r = 0.163 and -0.173, respectively), change in NE (r = 0.256 and 0.239), as well as nadir NE levels (r = 0.118 and -0.039). The demonstration of a natriuresis and a diuresis in a majority of the subjects, occurring without concomitant suppression of plasma NE, suggests that NE does not constitute the prepotent determinant in the impaired sodium and water excretion of many patients with advanced liver disease.