Adequate fluid removal is one of the chief objectives in continuous renal replacement therapy, improving long-term patient survival. However, overly aggressive fluid reduction during dialysis is associated with an increased risk for sudden blood pressure drops, which can lead to organ damage. The treating personnel are therefore required to strike a balance between adequate fluid removal and the risk of hypotensive episodes. 

The volume chosen for removal is usually informed by patient weight dynamics, blood pressure, edema, and hydration markers, but perhaps most prominently by the intimate knowledge of the individual patient’s needs and limits, which can best be developed during long-term continuity of care. Even then, some patients experience blood pressure drops, cramps and headaches. This may lead to overly cautious fluid removal goals in such patients and chronic overhydration, potentially hurting the patient in the long run.

A research consortium between the HD & Co. research group of the Medical University of Vienna (MUV), the Austrian Institute of Technology (AIT) and the Research Institute for Molecular Pathology (IMP) was awarded a 2021 precision medicine grant by the Vienna Research and Technology Fund to resolve this issue with a personalized medicine approach. Integrating blood volume, hydration, and cardiovascular data from multiple non- to minimally invasive sources to derive novel prediction and intervention tools.

Overhydration estimation using bioimpedance spectroscopy, while designed to inform accurate fluid removal targets, adds another layer of complication to the care algorithm. It is at times impractical to use in fast-paced clinical routine and not uniformly trusted by dialysis professionals. The consortium aims to re-evaluate, further optimize and streamline the use of this widely available technology.

Calculation of absolute blood volume from information of a standardized fluid bolus infusion with blood dilution measurement, as integrated in many contemporary dialysis machines, makes possible the interpretation of intradialytic blood volume dynamics in the context of the patient’s absolute blood volume profile across dialysis sessions. The fluid bolus applied using this technique may also be useful in improving hemodynamic stability during sessions with ambitious fluid removal goals.

Brachial cuff pulse wave analysis using ARCsolver™ technology informs overall hemodynamic stability and cardiovascular status of patients. Continuous blood pressure surveillance, utilizing finger pulse oximetry and electrocardiography technology, may allow for early intervention in case of precursor signs of instability.

Proteomics of renin angiotensin system peptides in blood, urine and dialysate may inform the effect of different ultrafiltration goals on this hormonal axis, important for electrolyte and blood pressure regulation.

After integration of data, the consortium aims to develop novel theories on early detection and intervention algorithms to be applied and tested in a randomized controlled intervention trial with the goal of uncovering and reducing latent chronic overhydration, while minimizing the risk of hypotensive episodes.