BLOOD-VOLUME CHANGES DURING 3 DIFFERENT PROFILES OF DIALYSATE SODIUM VARIATION WITH SIMILAR INTRADIALYTIC SODIUM BALANCES IN CHRONIC HEMODIALYZED PATIENTS

The aim of this study was to evaluate the effects on blood volume (BV) preservation of three different profiles of dialysate sodium variatio n with similar intradialytic sodium balances. Ten uremic patients aged 50 +/- 11 years receiving regular bicarbonate hemodialysis for 49 +/- 57 months were studied. Each patient underwent three hemodialysis tre atments with different modalities of dialysate sodium profiles: consta nt sodium hemodialysis (CHD), high-low sodium hemodialysis (H-LHD), an d low-high sodium hemodialysis (L-HHD). In CHD, the dialysate sodium c oncentration was 141 mEq/L and did not change during treatment. In H-L HD and L-HHD, the dialysate sodium concentration at the start of dialy sis was 160 mEq/L and 133 mEq/L, respectively, and remained constant f or 60 minutes. At this time, a single-step break point of variation of dialysate sodium concentration occurred. The dialysate sodium concent ration changed according to a model aimed to keep identical the amount of dialysate sodium exchanged in the three different dialysis procedu res. The duration of hemodialysis, the blood flow rate, the dialysate flow rate, and the dialysis membrane were the same for all three diffe rent hemodialysis modalities. The ultrafiltration rate was kept consta nt during treatment. Total dialysate collection and intradialytic sodi um balance were calculated for each hemodialysis session. Blood pressu re and heart rate were monitored at 10-minute intervals; percent reduc tions of BV (%R-BV) were continuously monitored by an online optical r eflection method (Hemoscan; Hospal-Dasco, Medolla, Italy). The results have shown a lower intradialytic %R-BV with H-LHD compared with L-HHD and CHD. No differences in total ultrafiltration rate, systolic and d iastolic blood pressures, and heart rate were observed among the three different dialysis procedures. The total dialysate sodium collected a nd the intradialytic sodium balances were very similar among the three different dialysis procedures, confirming the accuracy of the precisi on of the sodium model used. The H-LHD sodium profile may be a useful tool in the prevention of excessive %R-BV and of dialysis intolerance episodes. (C) 1997 by the National Kidney Foundation, Inc.