Indocyanine Green (ICG) and Evans Blue: Comparative Study of Plasma Volume Measurement
Abstract
Plasma volumes (PV) were measured in two groups of rats by injection of ICG (n = 213) or Evans Blue (n = 100) via indwelling jugular cannulae. Both groups had similar (p > 0.05) body weights, core temperatures, plasma protein concentrations, and corrected venous hematocrits. Serial blood samples were obtained over 10 min (8 samples, ICG) or 60 min (6 samples, Evans Blue). PV's were determined directly by dye dilution, and blood (BV2) and cell volumes (CV were calculated. The coefficients of determination (r squared, X + or - SD) of ICG and Evans Blue plasma dye disappearance curves were 0.995 + or - 0.008 (p < 0.01) and 0.677 + or - 0.215 (p < 0.01), respectively. The half-lives (t sub 1/ 2) were 3.1 + or - 0.5 and 256 + or - 139 min (p < 0.01) for the ICG and Evans Blue groups, respectively, and corresponding disappearance constants (K, fraction of dye disappearing/min) were 0.23 + or - 0.04 and 0.0034 + or - 0. 0017/min (p < 0.01). The PV, BV, and CV values (ml, X + or - SD) for ICG were 21.7 + or - 4.3, 36.0 + or - 5.2, and 14.3 + or - 2.0 and were not significantly different (p > 0.05) from corresponding values for Evans Blue. In additional experiments (n = 12), PV was quantitated (21.9 + or - 3.2 ml) by ICG followed by injection of known volumes of 0.9% saline (6.1 + or - 0.5 ml). One h later, the predicted volume (28.0 + or - 3.6 ml) was not significantly different (p > 0.05) from the measured volume (28.2 + or - 4.1 ml), and the correlation (r = 0.858) was significant (p < 0.01). The data indicate that ICG can be used to measure PV in rats and simultaneously assess changes in liver function (i.e. clearance rate). Because of its short t sub 1/2, PV can be reestimated within an h.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 16, 1982
- Accession Number
- ADA124055
Entities
People
- Denise Schehl-geiger
- Roger W. Hubbard
- William R. Sandel
Organizations
- United States Army Research Institute of Environmental Medicine