Absolute blood volume and long-term survival in chronic hemodialysis patients.

Current online hemodiafiltration devices can be used to determine the absolute blood volume in clinical practice using the dialysate bolus method. Most of publications on this method have focused on preventing intradialytic complications. The influence of absolute blood volume on long-term prognosis has not been reported yet.

Vascular refilling in hemodialysis using feedback-controlled ultrafiltration profile.

Background: The rate and the duration of ultrafiltration (UF) are considered the most important factors to affect vascular refilling. The aim of the study was to investigate whether a UF profile could improve the vascular refilling.

Methods: Dialysis was delivered by a machine providing feedback control of ultrafiltration rates.

Vascular refilling depends on the ratio of blood volume to extracellular volume in hemodialysis patients.

The ratio of blood volume to extracellular volume is approximately one to three under physiological conditions and also in stable chronic hemodialysis patients. Recently, it was found that this ratio remains unchanged during hemodialysis despite ultrafiltration. This would signify that the higher the ratio, the lower the refilling and vice versa.

Dynamics of vascular refilling in extended nocturnal hemodialysis.

Introduction: Long dialysis treatments are generally assumed to mitigate the ultrafiltration (UF) induced volume perturbation and to improve vascular refilling because of reduced UF rates and sufficient time for volume re-equilibration. The time course of vascular refilling was therefore examined during extended nocturnal dialysis.

Methods: For each hour of dialysis, vascular refilling volume was calculated from the absolute blood volume changes and UF volume removed.

An improved method to estimate absolute blood volume based on dialysate dilution.

Online hemodiafiltration machines equipped with a blood volume monitor and the possibility to rapidly infuse exact amounts of ultrapure dialysate into the extracorporeal circulation can be used to determine absolute blood volume in clinical practice. The aim of the present study was to evaluate the reproducibility of such measurements. Intra-individual reproducibility was evaluated in four measurements taken in hourly intervals within the same dialysis treatment.