The thermodilution method for the clinical assessment of cardiac output

Conclusion The thermodilution technique has been shown to measure cardiac output accurately if flow is stationary. During mechanical ventilation the technique can be liable to gross errors. However, if certain precautions are followed mean cardiac output can be accurately estimated, even with a theoretical misuse of the Stewart-Hamilton equation. This can be done best by averaging three or four measurements equally spread over the ventilatory cycle. For this approach manufacturers of cardiac output computers have to be persuaded to include a phase selector and an automatic injector.