Hemo/thermodynamic model for analysis of thermodilution

A model of the cardiovascular system that combines hemodynamic and thermodynamic effects was developed to study the errors involved with thermodilution measurements of cardiac output and ejection fraction. The model considered heat transfer between the catheter and its surroundings and allowed control of hemodynamic variables as well as injection parameters. The model was used to assess the accuracy of the algorithms presently used for calculating cardiac output and ejection fraction. The results indicated that the simplifying assumptions that were made in the development of these algorithms are not justified. The model was found to be a good tool for development and testing of new algorithms and thermal methods.