An Experimental Evaluation of the Thermodilution Method for Determination of Cardiac Output and of Intracardiac Right-to-Left Shunts

The thermodilution method for cardiac output was tested on cats. Cold saline was injected in the left atrium and temperature recorded in the aorta. A close correlation was obtained to electromagnetically measured flows. Injections in the right atrium underestimated cardiac output. An artificial right-to-left shunt was inserted. Thermodilution curves after saline injections in the right atrium were analyzed according to the forward triangle method. A significant relation between calculated and measured shunt fractions was obtained with the thermodilution method as well as with the blood gas equation.