A method for measurement of total circulating blood volume using indocyanine green.

Abstract

A method of measuring total circulating blood volume (TBV) using indocyanine green (ICG) dye was investigated iii 7 dogs and 16 patients. Since concentration of injected ICG decreases exponentially from the circulating system after recirculation, concentration of the dye at the time of appearance (Cta) can be extrapolated by extending the slope of the dye dilution curve transcribed to a semi-logarithmic graph. TBV was calculated using the following formula : TBV=I/Cta, where I is the amount (mg) of ICG injected. Repeat measurements of TBV using ICG demonstrated good reproducibility (average coefficient of variation, 2.0%) and when compared to measurements made with Evans blue dye resulted in a correlation coefficient of 0.98 or more. We conclude that assessment of TBV using ICG is reliable and experimentally and clinically feasible. total circulating blood volume ; indocyanine green ; dye dilution method Total circulating blood volume (TBV) is one of the most important determinants in the understanding of circulatory physiology. At present, radio-isotopes such as 125I 131I, 51Cr, ssmTc and Evans blue dye (T-1824) are used for estimating blood volume. However, certain disadvantages are inherent to the use of these agents including: radiation contamination, long-term retention or temporary discoloration of the skin. Consequently, and although measurement of TBV is particularly important as a diagnostic tool, it is not routinely employed because of these methodological deficiencies. The development of a safe and reliable technique which could be easily performed is therefore needed.In 1968, Bradley and Barr reported a technique to measure TBV using indocyanine green (ICG), but its application has not been widely accepted. We modified Bradley's method and compared experimental and clinical TBV measurements made with ICG to results obtained usidg Evans blue (EB) dye.

Impact of the time window on plasma volume measurement with indocyanine green

“…The argument put forward for a need of biexponential regression of values beyond the 5th min is based on a supposed long mixing time (Haruna et al 1998, Sekimoto et al 1997. However, several other authors found, in agreement with us, complete mixing of the dye to be achieved at the latest after 3 min (Bradley and Barr 1968, Busse et al 1990, Haller et al 1993, Haneda and Horiuchi 1986, Iijima et al 1998.…”

Accuracy and repeatability of blood volume measurement by pulse dye densitometry compared to the conventional method using 51Cr-labeled red blood cells

“…The various substances investigated using the indicator dilution method in efforts to establish clinically applicable methods for blood volume measurement include ICG [14,15,16,17], carbon monoxide [18], hydroxyethyl starch [4], Evans blue [1], and radioactively labeled materials [19]. However, none of these has been accepted as clinically less invasive or capable of obtaining easy repeatability.…”

Technical and physiological background of plasma volume measurement with indocyanine green: a clarification of misunderstandings

“…The authors "saved" their mean in vivo results by entering a correction factor, namely, an assumed f cell ratio. In a comparison of ICG with Evans blue in 7 dogs and 16 patients, Haneda and Horiuchi (16) found a correlation coefficient of 0.98 between these two dyes. Although they erroneously assumed that they were measuring "total circulating blood volume," this misconception, inasmuch as the assumption was made for both markers, did not influence the information concerning validity of the ICG-DT.…”

“…In addition, several studies revealed a possible mutagenic potential for Evans blue (25,31). In 1968, indocyanine green (ICG) (3), a relatively unstable dye with an initial distribution volume comparable to that of Evans blue (16) and labeled albumin (28), was used for the first time to determine "blood volume." Further clinical applications are measurement of cardiac output (10) and liver function (6).…”