Background: The primary aim of the international study DialysIS
(Dialysis therapy between Italy and Switzerland) is the increased
personalization of hemodialytic treatments through a modellistic
approach. Within the DialysIS study, we compare the accuracy of
a single-pool variable volume calcium kinetic model (SPVV-CaKM)
using two different dialysate calcium concentrations (CaD).
Methods: Pre- and post-treatment relevant variables of 34 patients
treated with nominal CaD of 1.5 mmol/l (Group 1) and 22 patients with
nominal CaD of 1.75 mmol/l (Group 2) were analyzed. The accuracy
was evaluated determining the difference between predicted
(Ca2+pwtP) and measured (Ca2+pwt) plasma water ionized calcium
concentrations at the end of the dialysis sessions. To account for the
changes in blood pH during dialysis session, which is known to affect
plasma water ionized calcium concentrations, Ca2+pwt values were
normalized at pH of 7.40.
Results: Fig. 1 indicate that the predicted values almost overlap t
he normalized values for Group 1, while it’s significantly higher for
Group 2.
Conclusion: The SPVV-CaKM is accurate in Group 1 while it
overestimates the Ca2+pwt Group 2. The Ca2+pwt of the two groups
doesn’t seem to account for the increased CaD. This suggests the
presence of an additional compartment. Our hypothesis is that the
administered calcium, predicted by our model, that doesn’t appear plasma could be deposited in bones and/or soft tissues. It is then
theoretically possible to estimate the total calcium deposition or
accumulation from the difference between predicted and measured
post-treatment values
