Sodium concentration in dialysate – an important but neglected parameter in haemodialysis of patients with chronic renal failure

Czech version

Authors: F. Lopot ^1,2; F. Švára ^1,3; V. Polakovič ^1,3
Authors‘ workplace: Interní oddělení Strahov VFN Praha, přednosta prim. MUDr. Vladimír Polakovič, MBA ¹; Ústav biofyziky a informatiky 1. lékařské fakulty UK Praha, přednosta prof. MUDr. RNDr. Jiří Beneš, CSc. ²; Klinika nefrologie 1. lékařské fakulty UK a VFN Praha, přednosta prof. MUDr. Vladimír Tesař, DrSc., MBA ³
Published in: Vnitř Lék 2012; 58(7 a 8): 60-65
Category: 80th Birthday MUDr. Miroslav Mydlík, DrSc.

Overview

Sodium ion with its accompanying anions plays the major role in osmolality of body fluids changes of which determine overall fluid balance in health given on one side by water intake and on the other side by its excretion via kidneys. In renal failure, control of the excess fluid removal is taken over by dialysis but control of water intake via thirst induced by changes in osmolality remains functional. Sodium balance is thus of utmost importance. It consists of two components – dietary salt intake and sodium balance during haemodialysis (HD). Choice of sodium concentration in dialysis solution (CD_Na) and its difference from plasma sodium (CP_Na) may thus significantly influence water intake during the interdialytic period. And despite of rather wide interindividual scatter in CP_Na, majority of dialysis centres still uses the same CD_Na value for all patients and their dietary counselling stresses the need of restriction in fluid intake only. The article analyzes possible impact (benefits) of the two principal approaches to CD_Na manipulation – its individualisation with the value being kept constant during the whole HD session and use of sodium profiling (changing CD_Na during the course of HD). Based on literary data and on own measurements, CD_Na individualisation appears far more beneficial in the long-term perspective. Contemporary off-line sodium profiling, regardless of how sophisticated control algorithm is used brings in the risk of positive sodium balance with all negative effects associated with it. Restriction of salt intake should be stressed in dietary counselling instead of mere fluid restriction.

Key words:
haemodialysis – sodium concentration – sodium balance – weight gains – individualization – sodium profiling

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