Measurement of cardiac output by thermodilution: theoretical considerations and practical aspects

Videodensitometry and thermodilution for measuring left ventricular function

In animal experiments contrast medium and physiologic saline were found to be equivalent as indicator substances in thermodilution. The ejection fraction is determined with approximately the same accuracy with thermodilution as with videodensitometry. The cardiac output, on the other hand, is smaller when determined with videodensitometry than with thermodilution. The results indicate that thermodilution gives too high values.