Related Experiment Video
Updated: Jun 28, 2026

Determination of Cardiac Output in a Porcine Model for Ex Vivo Pulmonary Perfusion
Published on: June 28, 2024
Is the cardiac output obtained from a Swan-Ganz catheter always zero?
1Division of General Anesthesia and Intensive Care, Medical University of Vienna, Waehringer Guertel 18-20/9 i, 1090, Vienna, Austria. wolfgang.schramm@meduniwien.ac.at
Objective:
By means of a Swan-Ganz catheter cardiac output is calculated using the Stewart-Hamilton thermodilution equation. Assuming the body as a thermally isolated inert system, this equation theoretically always results in zero cardiac output.
Methods:
Using the first and second law of thermodynamics together with a few lines simple analysis this statement is proven.
Conclusion:
It is at least a necessary condition for the application of the Stewart-Hamilton equation, that core body temperature is kept constant in a thermo- regulatory steady state.
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