Can Bioimpedance Analysis Be Used to Estimate Absolute Blood Volume in Hemodialysis Patients?

Introduction: Under physiological conditions, blood volume and extracellular volume are in a ratio of 1-3, even in hemodialysis patients. The question therefore arises: can blood volume be inferred from the bioimpedance analysis data? The aim of the study was to compare the blood volumes calculated from extracellular volume determined by bioimpedance analysis data to the actually measured blood volumes.

Methods: Immediately before treatment, extracellular volume and volume overload were evaluated by bioimpedance spectroscopy.

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.