Blood volume determination with sodium fluorescein and radioactive chromium--a clinical comparison of methods

OBJECTIVE: There exists no method so far for the determination of circulating blood volume as an important parameter of circulatory function widely usable under clinical conditions. Therefore, the present study was designed to investigate whether identical distribution spaces could be measured by two methods for blood volume determination using sodium fluorescein (SoF) and radioactively labelled red blood cells (51Cr*). DESIGN: Comparative study. SETTING: Operating theatre, recovery room, or intensive care unit of a university hospital. PATIENTS: 35 patients undergoing abdominal, urological or vascular surgery. INTERVENTIONS: Simultaneous determinations of blood volume using SoF and 51Cr* in the intra- and postoperative period. RESULTS: There were no significant differences between the calculated means of blood volume (4,445 vs. 4,407 ml), red cell volume (1,554 vs. 1,540 ml), and plasma volume (2,891 vs. 2,807 ml) for 51Cr*-vs. SoF-stained red blood cells. The coefficient of correlation between the two methods was r = 0.95. The mean percentage error was -0.6% between the two methods, the precision 5.6%. CONCLUSIONS: SoF-stained erythrocytes allow a determination of the same distribution space as the well-established radioactive method using 51Cr*. Therefore, SoF-staining may replace 51Cr* labelling of red blood cells for the determination of blood volume in patients.