Effect of dialysate sodium concentration on interdialytic increase of potassium.
To evaluate the role of plasma tonicity in the postdialysis increment of plasma potassium (p[K(+)]), the outcome of two hemodiafiltration treatments that differed only in the Na(+) level in dialysate (Na(D))-143 mmol/L (high dialysate sodium concentration [H-Na(D)]) and 138 mmol/L (low dialysate sodium concentration [L-Na(D)])-were compared in the same group of uremic patients from the end of treatment (T0) to the subsequent 30 to 120 min and up to 68 h. Kt/V and intradialytic K(+) removal were comparable. At T0, plasma [Na(+)] was 145+/-1 and 137+/-1 mmol/L after H-Na(D) and L-Na(D), respectively (P<0.001). The difference in plasma tonicity persisted from T0 to T68 h. At T120, p[K(+)] was increased from the T0 value of 3.7+/-0.2 to 4.7+/-0.2 mmol/L (P<0.05) after H-Na(D), whereas it was unchanged after L-Na(D). The change of p[K(+)] was still different after 68 h (+76+/-10% and +50+/-7% in H-Na(D) and L-Na(D), respectively; P<0.05). Of note, in the first 2 h after the end of treatment, bioimpedance analysis revealed only in H-Na(D) a significant 11+/-3% decrement of phase angle that is compatible with a decrease of intracellular fluid volume at the expense of the extracellular volume. Similarly, within the same time frame, in H-Na(D), a significant reduction of mean corpuscular volume of red cells, associated with a 2 +/-1% decrease of the intracellular [K(+)], was observed. In contrast, mean corpuscular volume of red cells did not change and erythrocyte [K(+)] increased by 6+/-1% after L-Na(D) (P<0.005 versus H-Na(D)). Thus, hypertonicity significantly contributes to the increase of p[K(+)] throughout the whole interdialytic period by determining intracellular fluid volume/extracellular volume redistribution of water and K(+).
Nicola
Luca DE
L
Chair of Nephrology, School of Medicine, Second University of Naples, Italy.
Bellizzi
Vincenzo
V
Chair of Nephrology, School of Medicine, Lauria Hospital, Lauria, Italy.
Minutolo
Roberto
R
Chair of Nephrology, School of Medicine, Second University of Naples, Italy.
Cioffi
Mario
M
Chair of Nephrology, School of Medicine, Second University of Naples, Italy.
Giannattasio
Paolo
P
Chair of Nephrology, School of Medicine, Second University of Naples, Italy.
Terracciano
Vincenzo
V
Chair of Nephrology, School of Medicine, Lauria Hospital, Lauria, Italy.
Iodice
Carmela
C
Chair of Nephrology, School of Medicine, Second University of Naples, Italy.
Uccello
Francesco
F
Chair of Nephrology, School of Medicine, University Federico II, Naples, Italy.
Memoli
Bruno
B
Chair of Nephrology, School of Medicine, University Federico II, Naples, Italy.
Iorio
Biagio Raffaele DI
BRD
Chair of Nephrology, School of Medicine, Lauria Hospital, Lauria, Italy.
Conte
Giuseppe
G
Chair of Nephrology, School of Medicine, Second University of Naples, Italy.
D000328:Adult; D000368:Aged; D018592:Cross-Over Studies; D015314:Dialysis Solutions / Q000737:chemistry* / Q000627:therapeutic use*; D017097:Electric Impedance; D004909:Erythrocyte Indices; D004912:Erythrocytes / Q000378:metabolism; D005260:Female; D017583:Hemodiafiltration; D006801:Humans; D006982:Hypertonic Solutions / Q000627:therapeutic use; D007425:Intracellular Membranes / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009994:Osmolar Concentration; D011188:Potassium / Q000097:blood*; D016037:Single-Blind Method; D012964:Sodium / Q000032:analysis*; D014511:Uremia / Q000097:blood* / Q000628:therapy*
D015314:Dialysis Solutions; D006982:Hypertonic Solutions; D012964:Sodium; D011188:Potassium