Similarity of blood flows using indocyanine prepared in saline or distilled water

Directly measured blood flow pumped through a mixer circuit was compared to estimates of flow from indicator dilution curves derived from bolus injections of indocyanine green dye prepared in 0.9% saline (saline dye) and in triple-distilled water (3 D dye). At flows whose mean appearance time was 1.6 s, the mean error of estimate +/-SD of 2.3 +/- 5.1% using 3 D dye was significantly different (P less than 0.05) from that of 5.6 +/- 7.0% using saline dye. Essentially, there was no difference in estimates of blood flow with each dye solution when mean appearance time was increased to 3.8 s. Thus, the error, which was perhaps due to electrolyte in the concentrated indocyanine green dye (saline dye) and subsequent slowed rate of optical stabilization after dilution in plasma, is small and does not explain the overestimation by indocyanine dilution curves of blood flow in intact dogs.