Thermal dilution and ultrasound: alternative techniques for measuring cardiac output

We evaluated 5 TD CO units, 4 modules and 1 stand-alone, from 5 manufacturers. All units are rated Acceptable. Most of the test results met our accuracy and precision criteria; other results that demonstrated a small margin of error were still clinically useful. The utility of the TD method depends largely on proper technique, as well as the volume and temperature of the injection, number of injections, and the type of probe used. Purchasing decisions should be based primarily on the compatibility of the proposed TD units with existing physiologic monitors and whether a module or a stand-alone unit is more appropriate.