International Urology and Nephrology (2018) 50:1143–1149
NEPHROLOGY - ORIGINAL PAPER
Treatment dose and the elimination rates of electrolytes, vitamins,
and trace elements during continuous veno‑venous hemodialysis
· Karl Träger
· Bernd Schröppel
· Helmut Reinelt
· Philipp von Freyberg
Received: 20 January 2018 / Accepted: 26 March 2018 / Published online: 2 April 2018
© Springer Science+Business Media B.V., part of Springer Nature 2018
Introduction During continuous renal replacement therapy, achievement of recommended treatment dose is important.
However, relevant substrate loss may occur and recommended nutrition during critical illness could not be suﬃcient for
higher dialysis doses. We investigated the correlation of dialysis dose and substrate loss for a broad range of dialysis doses.
Methods Forty critically ill patients with acute kidney injury undergoing citrate CVVHD were included in this prospec-
tive study. Three diﬀerent corresponding blood ﬂow (BF) and dialysate ﬂow (DF) rates were applied (BF/DF: 100 ml/min,
2000 ml/h; 80 ml/min, 1500 ml/h; 120 ml/min, 2500 ml/h). Delivered eﬄuent ﬂow rate (DEFR) was calculated and correlated
with losses of vitamins, electrolytes, and trace elements during recommended nutritional supplementation.
Results For folic acid, vitamin B12, zinc, inorganic phosphate, and magnesium, no correlation of losses and DEFR was
detected. For ionized calcium, a correlation was observed and additional substitution was required.
Conclusion Clinically relevant loss of folic acid, vitamin B12, zinc, inorganic phosphate, and magnesium was not observed
for diﬀerently used dialysis doses of CVVHD, and the loss was covered suﬃciently by daily recommended nutritional sup-
plementation. Increased loss of ionized calcium for higher dialysis doses occurred during citrate CVVHD. Therefore, a strict
protocol must maintain calcium homeostasis to avoid calcium depletion.
Keywords Acute kidney injury · Continuous renal replacement therapy · Citrate anticoagulation · Critical illness · Trace
Acute kidney injury (AKI) is a critical organ dysfunction
and therefore associated with relevant morbidity and mor-
tality . Continuous renal replacement therapy (CRRT)
is used to treat high-grade AKI . Anticoagulation dur-
ing CRRT is recommended in most cases to prevent ﬁlter
clotting. Regional citrate anticoagulation is increasingly
used due to prolonged circuit life span, diminished risk of
bleeding and to avoid heparin-induced thrombocytopenia
[2–4]. Body weight-adapted treatment doses are recom-
mended for CRRT, but rarely performed in clinical practice
. Limited data are available concerning CRRT induced
losses of electrolytes, vitamins, and trace elements [6–8].
Trace elements are small in size and thus dialyze readily .
We investigated diﬀerent dialysis doses and hypothesized
that these losses could be strongly clinically dependent on
the dialysis dose.
Materials and methods
This prospective study was performed in a mixed surgical
intensive care unit at a university hospital with approval
of local ethics committee according to the Helsinki Dec-
laration, and patients gave written informed consent.
Patients with AKI as deﬁned by the KDIGO criteria 
and an indication for CRRT were included, independent
* Thomas Datzmann
Department of Cardiac Anesthesiology, University Hospital
Ulm, Albert-Einstein-Allee 23, 89081 Ulm, Germany
Department of Nephrology, University Hospital Ulm, Ulm,
Department of Anesthesiology, Klinikum Heidenheim,
Heidenheim an der Brenz, Germany