Blood volume monitoring and control

Fluid volume control during and between dialysis treatments is an important factor in determining the adequacy of the dialysis delivered to the uraemic patients. Besides controlling fluid intake between treatments, curbing the blood volume decrease during dialysis may result in a reduced frequency as well as severity of dialysis hypotension. During haemodialysis the fluid is removed by ultrafiltration from the intravascular compartment, but it naturally derived from both the intravascular and interstitial volume. This implies a continuous refilling of fluid from the extravascular to the plasma compartments. The plasma refilling rate is the difference between the total fluid loss and plasma volume loss per time unit. In order to minimize the impact of the blood volume decrease on the patient's haemodynamic stability during the treatment, and to reduce the incidence of hypovolaemia in the genesis of haemodialysis hypotension, the following points ought to be dealt with: