Hepatic blood flow measurement. A comparison of the indocyanine green and electromagnetic techniques normal and abnormal flow states in the dog.

Very few studies have compared the total hepatic blood flow using the Indocyanine green (ICG) method with the instantaneous electromagnetic flow method under unsteady circulatory conditions. In this study, a hypotensive circulatory state was produced by rapid hemorrhage in 14 dogs. Total hepatic blood flow was measured using the ICG single injection method, comparing it with the electromagnetic flow method. After confirming the validity of the ICG single injection method in measuring total hepatic blood flow in the steady state, the experiment was then carried out using 23 normal healthy dogs. The close correlation between the ICG clearance technique and the electromagnetic values under normal steady state was confirmed. However, after hemorrhage the indirect ICG method estimated only 71% of the simultaneous electromagnetic flow value. It is reasonable to assume that while the electromagnetic method continues to measure the actual total hepatic blood flow in both the steady and unsteady states, the ICG clearance method measures only the functional hepatic blood flow which is reduced due to shunting or impaired hepatocellular function in the unsteady and hypotensive circulatory state.