Pre-HD dilution aciciosis, without post-HD contraction alkalosis in uremic patients

The aim of this study was to verify if the degree of pre-HD acidosis and its correction post-HD is related to body fluid expansion during the interdialytic period. Twelve uremic patients without major problems, with stable hematocrit, with regular and similar HD-session characteristics, but widely varying amounts of body fluid expansion in the interdialytic period were included. Blood samples were collected from arterial line pre-and post-HD, anaerobicalty in heparinized syringes, for determination of HCO3, pH and PaCO2 (radiometer Copenhagen ABL 300 Acid-Base Laboratory), in two similar HD-sessions for each patient (12 patients, 24 HD-sessions). The percentage (%) of body weight gain in the interdialytic period was also estimated, For each patient, the mean value of parameters studied in the two HD-sessions was used for the evaluation of findings. According to mean values ( plus or minus SD) of HCO3, pH and PaCO2 Pre-HD (18.26 plus or minus 1.99 mmol/L, 7.31 plus or minus 0.03, 36.27 plus or minus 2.5 mmHg respectively) and post-HD (26.37 plus or minus 1.7, 7.43 plus or minus 0.03, 38.43 plus or minus 2.10 respectively) patients are acidotic pre-HD and slightly alkalemic post-HD. Correlation between the percentage (%) of interdialytic body weight gain (I8WG) and the values of HCO3, pH and PaCO2, Pre-HD (r=-0.814, p