Kinetic modelling and continuous on-line blood volume measurement during dialysis therapy.

Changes of relative blood volume during haemodialysis therapy have been investigated using kinetic modelling and on-line blood volume registration by continuous haemoglobinometry. An exponential relation has been found between blood volume reduction per litre of ultrafiltrate and the amount of fluid overload. Between the amount of refilling and ultrafiltration rate there was also an exponential dependence. There was a linear relation between the change in plasma sodium concentration and blood volume. An acceptable correspondence was found between calculated and measured data.