Sympathetic and hemodynamic response to volume removal during different forms of renal replacement therapy.

Sympathetic and hemodynamic response to a constant volume removal was investigated during pure ultrafiltration, hemofiltration, acetate hemodialysis, and bicarbonate hemodialysis in the same ESRD patients. Small solute removal rates were matched. The sympathetic response resulting in an increase of total peripheral vascular resistance was found to be qualitatively adequate in ultrafiltration and hemofiltration, but not in acetate and bicarbonate hemodialysis. This inadequate response to volume removal explains the clinically observed hemodynamic instability during hemodialysis. The purpose of the study was to substantiate the, compared to hemodialysis, improved tolerance to fluid withdrawal during ultrafiltration and hemofiltration with hemodynamic data and to correlate hemodynamic and sympathetic changes during the different treatment modalities of uremia.