Effect of temperature on optical density of rabbit blood in dye dilution studies

The optical desity of rabbit blood increased on cooling. This increase was additive to the deflection produced by indocyanine green at all concentrations measured. If calibration curves were not corrected for any increase in optical density produced by cooling the blood, and error (minimum 11%) was introduced in the estimation of cardiac output. The effect of temperature was investigated with three different densitometers. Its wave-length dependence did not follow the absorption spectrum of oxyhemoglobin.