Utility of a blood volume monitor in the management of anemia in dialysis by computing the total hemoglobin mass.

Abstract

The degree of interdialytic weight gain and ultrafiltration may influence anemia results in dialysis. The purpose of this study is to evaluate the utility of a blood volume monitor (BVM) in the management of renal anemia and its ability to avoid the variability of hematocrit (Hct) and hemoglobin values (Hb) depending on plasma volume through a simple method of monitoring the total hemoglobin mass (MtHb ). Predialysis blood samples for measurement were drawn at both the midweek treatment and the beginning-of-the-dialysis-week treatment in 30 patients. The MtHb was calculated as MtHb = Vb × Hb, where Vb is the absolute blood volume determined by online dialysate dilution using an online hemodiafiltration machine incorporating a relative BVM. The MtHb and the total red cell volume (VRBC ) as measured with the bolus method at the starting of the treatment were 540 ± 148 grams and 1544 ± 339 mL, respectively. There were significant differences between the Hb levels and between the hematocrit levels according to the time of dialysis. However, the MtHb remained constant. There was also an excellent correlation between the Hb measurements by the BVM and the blood sampling method (R = 0.89, P value <0.001). Our study suggests that BVM could be very useful in the management of anemia in dialysis by computing the total Hb mass in clinical practice and may support better and more appropriate assessments of the factors influencing circulating Hb.