Correction of acidosis by hemodialysis: proposal of a correlation with urea kinetics.

Background/aims: We examined the effect of hemodialysis (HD) on acid-base status and its relation to urea kinetics in clinically stable renal HD patients. The purpose of this study was to design a practical approach to monitoring the correction of acidosis, as it can be assisted by routine parameters of adequacy.

Methods: Blood samples were drawn immediately before and after HD from 46 chronic renal patients to determine electrolytes, blood gases, serum albumin and blood urea nitrogen (BUN). Additional measurements of pH and serum bicarbonate were done in 35 patients in the periods before, immediately after and 4 h after HD. The normalized protein catabolic rate (nPCR) was calculated and correlated with the serum albumin and bicarbonate values before HD. Equilibrated KT/V (eKT/V) and urea reduction ratio (URR) were calculated and correlated with the degree of bicarbonate correction, defined as DeltaHCO(3)(-).

Results: There was no correlation between nPCR and pre-HD HCO(3)(-), while there was a significant correlation between URR and eKT/V and DeltaHCO(3)(-) (p < 0.003).

Conclusions: The Deltabicarbonate was well correlated with URR and eKT/V, and the study suggests that in standard HD the correction of acidosis may be related to target URR and eKT/V levels.