Determinants of deranged sodium and water homeostasis in decompensated cirrhosis.

: Previous studies from this laboratory have demonstrated that the redistribution of blood volume and concomitant central hypervolemia induced by water immersion to the neck (NI) results in a significant natriuresis, kaliuresis, and diuresis. The NI model was utilized to assess the role of "effective volume" and hyperaldosteronism in the impairment of sodium and water handling in cirrhosis. Eleven cirrhotic patients were studied twice while in balance on a 10 mEq. Na, 100 mEq. K diet: control and NI. The conditions of seated posture and time of day were identical. UNaV was constant throughout C, ranging from 1 to 2 muEq per minute. During NI, UNaV increased progressively from 1 +/- 1 (S.E.M.) during the prestudy hour to 89 +/- 32 muEq per minute during hour 5 of NI (p less than 0.02), greatly exceeding the comparable value found in normal subjects on an identical diet. (See article).