Blood volume-monitored regulation of ultrafiltration in fluid-overloaded hemodialysis patients: study protocol for a randomized controlled trial.
BACKGROUND
Data generated with the body composition monitor (BCM, Fresenius) show, based on bioimpedance technology, that chronic fluid overload in hemodialysis patients is associated with poor survival. However, removing excess fluid by lowering dry weight can be accompanied by intradialytic and postdialytic complications. Here, we aim at testing the hypothesis that, in comparison to conventional hemodialysis, blood volume-monitored regulation of ultrafiltration and dialysate conductivity (UCR) and/or regulation of ultrafiltration and temperature (UTR) will decrease complications when ultrafiltration volumes are systematically increased in fluid-overloaded hemodialysis patients.


METHODS
BCM measurements yield results on fluid overload (in liters), relative to extracellular water (ECW). In this prospective, multicenter, triple-arm, parallel-group, crossover, randomized, controlled clinical trial, we use BCM measurements, routinely introduced in our three maintenance hemodialysis centers shortly prior to the start of the study, to recruit sixty hemodialysis patients with fluid overload (defined as ≥15% ECW). Patients are randomized 1:1:1 into UCR, UTR and conventional hemodialysis groups. BCM-determined, 'final' dry weight is set to normohydration weight -7% of ECW postdialysis, and reached by reducing the previous dry weight, in steps of 0.1 kg per 10 kg body weight, during 12 hemodialysis sessions (one study phase). In case of intradialytic complications, dry weight reduction is decreased, according to a prespecified algorithm. A comparison of intra- and post-dialytic complications among study groups constitutes the primary endpoint. In addition, we will assess relative weight reduction, changes in residual renal function, quality of life measures, and predialysis levels of various laboratory parameters including C-reactive protein, troponin T, and N-terminal pro-B-type natriuretic peptide, before and after the first study phase (secondary outcome parameters).


CONCLUSIONS
Patients are not requested to revert to their initial degree of fluid overload after each study phase. Therefore, the crossover design of the present study merely serves the purpose of secondary endpoint evaluation, for example to determine patient choice of treatment modality. Previous studies on blood volume monitoring have yielded inconsistent results. Since we include only patients with BCM-determined fluid overload, we expect a benefit for all study participants, due to strict fluid management, which decreases the mortality risk of hemodialysis patients.


BACKGROUND
ClinicalTrials.gov, NCT01416753.
Department of Internal Medicine III, Nephrology and Dialysis, Medical University of Vienna, Währinger Gürtel 18-20, Vienna 1090, Austria.
Manfred
M
Hecking
Marlies
M
Antlanger
Wolfgang
W
Winnicki
Thomas
T
Reiter
Johannes
J
Werzowa
Michael
M
Haidinger
Thomas
T
Weichhart
Hans-Dietrich
HD
Polaschegg
Peter
P
Josten
Isabella
I
Exner
Katharina
K
Lorenz-Turnheim
Manfred
M
Eigner
Gernot
G
Paul
Renate
R
Klauser-Braun
Walter H
WH
Hörl
Gere
G
Sunder-Plassmann
Marcus D
MD
Säemann
D001317:Austria; D001810:Blood Volume; D001811:Blood Volume Determination; D001823:Body Composition; D018592:Cross-Over Studies; D004553:Electric Conductivity; D017583:Hemodiafiltration / Q000009:adverse effects / Q000401:mortality; D006801:Humans; D007674:Kidney Diseases / Q000175:diagnosis / Q000401:mortality / Q000503:physiopathology / Q000628:therapy*; D008991:Monitoring, Physiologic / Q000379:methods*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012107:Research Design; D013696:Temperature; D013997:Time Factors; D014882:Water-Electrolyte Balance; D014883:Water-Electrolyte Imbalance / Q000175:diagnosis* / Q000401:mortality / Q000503:physiopathology / Q000628:therapy; D015430:Weight Gain; D015431:Weight Loss