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Phosphorus dynamics during hemodialysis
Author(s) -
KJELLSTRAND Carl M.,
ING Todd S.,
KJELLSTRAND Per T.,
ODARCEDERLOF Ingegerd,
LAGG Chris R. B
Publication year - 2011
Publication title -
hemodialysis international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.658
H-Index - 47
eISSN - 1542-4758
pISSN - 1492-7535
DOI - 10.1111/j.1542-4758.2011.00538.x
Subject(s) - dialysis , hemodialysis , urea , phosphorus , medicine , zoology , kt/v , endocrinology , surgery , chemistry , biochemistry , biology , organic chemistry
We studied phosphorus (P) dynamics and its relation to urea dynamics in a wide range of dialyses by measuring predialysis and postdialysis serum P levels and all removed P and urea in dialysate during 455 hemodialyses. Dialyses were performed at different frequencies (range 3–6 treatments/wk); duration of dialysis (t) (range 80–560 minutes), varied blood and dialysate flow, and with high‐flux and low‐flux membranes. Kt/V‐P, Kt/V‐urea, weekly removal of P—and urea and removal volumes (Vr) and their relationships to varying dialyses, and predialysis concentrations, and protein catabolic rates were studied in linear and multiple regression analyses. A weekly dialysis time of >30 hours was needed to maintain serum P concentration normal without the use of phosphate binders. Vr‐P as a percentage of body weight was dependent on predialysis serum P and increased steeply as predialysis serum P decreased and dialysis time was prolonged. There was no relationship between Vr‐urea and Vr‐P. Phosphorus removal per week was mainly dependent on weekly frequency, and time on dialysis and >38 h/wk were necessary to remove the recommended P intake. Phosphorus shows highly variable dynamics during dialysis. The body maintains extracellular P concentration by releasing P from large compartments when the dialysis time is prolonged and the serum concentration of P decreases during dialysis. Vr‐P shows huge variation between patients and in an individual patient, depending on predialysis serum P. Kt/V is inaccurate in describing P removal. To remove P efficiently, it is most important to perform long and more frequent hemodialysis.