Recent work has questioned the accuracy of the indocyanine green (Cardio-Green) dye dilution techniques of measuring blood flow in high flow states and established the accuracy of the electromagnetic flowmeter. Using eight dogs simultaneous dye dilution and electromagnetic flowmeter measurements were made beginning at the normal state, progressing through staged hemorrhage, and after infusion of fluids and blood. The dye dilution technique gave values much too high: 39% before hemorrhage, up to 66% during hemorrhage, and 26% after infusion of fluids and blood. A catheter-tip electromagnetic flow probe is now available to allow clinical use of this technique.
Jacobs RR, Williams BT, Schenk WG. Cardiac Output in HypovolemiaAn Evaluation of the Dye Dilution Method Using the Electromagnetic Flowmeter As a Standard. Arch Surg. 1971;102(3):199-202. doi:10.1001/archsurg.1971.01350030037010