Plasma volume measurement in septic patients using an albumin dilution technique: comparison with the standard radio-labelled albumin method

• Published in: Intensive care medicine 2005-02, Vol.31 (2), p.289-295
• Main Authors: MARGARSON, Michael P, SONI, Neil C
• Format: Article
• Language: English
• Subjects: Albumins; Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Biological and medical sciences; Blood Volume Determination - methods; Cardiovascular system; Case studies; Critical Illness; Critically ill; Emergency and intensive respiratory care; Female; Health aspects; Humans; Indicator Dilution Techniques; Intensive care medicine; Investigative techniques of hemodynamics; Investigative techniques, diagnostic techniques (general aspects); Male; Medical sciences; Middle Aged; Plasma diagnostics; Plasma Volume; Septic shock; Serum Albumin, Radio-Iodinated; Shock, Septic - blood; Statistics
• ISSN: 0342-4642; 1432-1238
• DOI: 10.1007/s00134-004-2481-4

To investigate a technique using 20% albumin for measurement of plasma volume in critically ill patients. Laboratory and clinical investigation in the adult intensive care unit and anaesthetic laboratories of a university hospital. 12 patients fulfilling ACCP/SCCM criteria for septic shock. Each patient received (125)I-labelled albumin, and the volume of distribution was measured at 1 and 10 min. The accepted standard plasma volume measurement (98% of the 10-min volume of distribution) was calculated. Immediately thereafter 200 ml 20% human albumin was given. Albumin concentrations were measured before and 1 min after this 40-g bolus, and the volume of distribution calculated using a formula that corrected for the 200 ml fluid in which the albumin was dissolved. Plasma volumes measured using the albumin dilution technique at 1 min were smaller than the standard technique by 110+/-280 ml; limits of agreement were from -660 to +440 ml (-16% to +11%). Plasma volumes measured by (125)I-albumin at 1 min were smaller than the standard by 120+/-110 ml; limits of agreement were from -330 to +100 ml (-8 to +2%). Non-labelled albumin can be used easily and quickly to measure a plasma volume in ICU patients and gives a moderately accurate estimate when compared with the (125)I-labelled albumin methods. The normal isotope method over-estimates plasma volumes in septic patients because excessive transcapillary escape of albumin is inadequately compensated for by the standard correction factor.