Sequential hemodynamic changes in end-stage renal disease and the anephric state during volume expansion.

The sequence of hemodynamic events during periods of salt- and water-loading was studied in anephric patients and those with end-stage kidney disease. The 10 patients studied showed four different sequential hemodynamic patterns: 1) no significant increase in blood pressure (BP) in two patients; 2) increase in BP associated with an increase in cardiac output and without change in total peripheral resistance in two patients; 3) increase in BP associated with an increase in total peripheral resistance from the beginning without an increase in cardiac output in five patients; and 4) increase in BP associated with an initial increase in cardiac output followed by an increase in total peripheral resistance in one patient. There was a significant positive correlation between BP and blood volume and between BP and total exchangeable sodium in the patients in whom salt- and water-loading increased the BP. It is concluded that during salt- and water-loading an initial rise in cardiac output is not necessary to increase BP and that a sustained rise in cardiac output does not always increase the total peripheral resistance. Mechanisms other than whole-body autoregulation play a role in increasing BP during salt- and water-loading in patients deprived of renal excretory function.