[Kinetics of potassium transfer during hemodialysis].
BACKGROUND
In order to study whether the removal of potassium in haemodialysis patients could be increased, we analyzed the kinetics of potassium transfer in the dialyzer.


METHODS
40 patients were included in the study. We studied: a) in vitro potassium exchanges between erythrocytes and plasma; b) plasma and erythrocyte potassium concentrations at dialyzer input and output; c) potassium transfers into the dialysate, using plasma clearance and direct measurement in the collected dialysate and d) erythrocyte potassium concentrations at the beginning and the end of dialysis.


RESULTS
In vitro, there is virtually no potassium transfer between erythrocytes and plasma. In vivo, erythrocyte potassium concentration is not affected by the dialyzer (98.7 +/- 6.4 mmol/l to 97.7 +/- 7.5 mmol/l, p = NS). Potassium transfer levels determined by calculated plasma clearance were similar to values obtained by measuring potassium in dialysate (0.71 +/- 0.10 mmol/min vs 0.68 +/- 0.10 mmol/min, p = NS). These results suggest that erythrocytes do not participate in potassium exchange in the dialyzer. This was confirmed by measured erythrocyte potassium concentrations, which were the same at the beginning and the end of dialysis (104.0 +/- 5.6 mmol/l vs 104.2 +/- 5.0 mmol/l, p = NS).
Division d'endocrinologie, diabétologie et métabolisme, Département de médecine interne, CHUV, Lausanne.
C
C
Bulliard
J P
JP
Guignard
J
J
Ruiz
H
H
Moret
G
G
Fellay
D000328:Adult; D000368:Aged; D004912:Erythrocytes / Q000378:metabolism; D005260:Female; D006801:Humans; D007700:Kinetics; D008297:Male; D008657:Metabolic Clearance Rate; D008875:Middle Aged; D010949:Plasma / Q000378:metabolism; D011188:Potassium / Q000097:blood* / Q000378:metabolism; D006435:Renal Dialysis; D013696:Temperature
D011188:Potassium