Affiliation:
1. Department of Medicine III, Division of Nephrology & Dialysis Medical University of Vienna Vienna Austria
2. Center for Public Health, Department of Epidemiology Medical University of Vienna Vienna Austria
3. AIT Austrian Institute of Technology Center for Health & Bioresources, Medical Signal Analysis Vienna Austria
4. Department of Nephrology Klinik Favoriten Vienna Vienna Austria
5. Rosbach Germany
6. Otto Loewi Research Center, Division of Physiology Medical University of Graz Graz Austria
Abstract
AbstractIntroductionPrescribing the ultrafiltration in hemodialysis patients remains challenging and might benefit from the information on absolute blood volume, estimated by intradialytic dialysate bolus administration. Here, we aimed at determining the relationship between absolute blood volume, normalized for body mass (specific blood volume, Vs), and ultrafiltration‐induced decrease in relative blood volume (∆RBV) as well as clinical parameters including body mass index (BMI).MethodsThis retrospective analysis comprised 77 patients who had their dialysate bolus‐based absolute blood volume extracted routinely with an automated method. Patient‐specific characteristics and ∆RBV were analyzed as a function of Vs, dichotomizing the data above or below a previously proposed threshold of 65 ml/kg for Vs. Statistical methodology comprised descriptive analyses, two‐group comparisons, and correlation analyses.FindingsMedian Vs was 68.6 ml/kg (54.9 ml/kg [Quartile 1], 83.4 ml/kg [Quartile 3]). Relative blood volume decreased by 6.3% (2.6%, 12.2%) over the entire hemodialysis session. Vs correlated inversely with BMI (rs = −0.688, p < 0.001). ∆RBV was 9.8% in the group of patients with Vs <65 ml/kg versus 6.0% in the group of patients with Vs ≥65 ml/kg (p = 0.024). The two groups did not differ significantly regarding their specific ultrafiltration volume, normalized for body mass, which amounted to 34.1 ml/kg and 36.0 ml/kg in both groups, respectively (p = 0.630). ∆RBV correlated inversely with Vs (rs = −0.299, p = 0.008).DiscussionThe present study suggests that patients with higher BMI and lower Vs experience larger blood volume changes, despite similar ultrafiltration requirements. These results underline the clinical plausibility and importance of dialysate bolus‐based absolute blood volume determination in the assessment of target weight, especially in view of a previous study where intradialytic morbid events could be decreased when the target weight was adjusted, based on Vs.
Funder
Vienna Science and Technology Fund