Measurement of ejection fraction by thermal dilution techniques.

The reproducibility, accuracy, and clinical applicability of ventricular ejection fraction derived by a thermal dilution technique were assessed in 22 dogs and 18 patients. Results obtained by the thermal technique were compared to simultaneous results obtained by radionuclide angiography. Right ventricular ejection fraction, measured in 9 dogs (1014 determinations) and 8 patients (744 determinations) was reproducible +/- 5%. Left ventricular ejection fraction, measured in 10 patients, was reproducible +/- 5%. Correlation between thermal and radionuclear measurements varied from 0.86 to 0.93 (all P less than 0.02). We conclude that, because of its low cost, ease of use, and accuracy, thermally derived ejection fraction determinations can be helpful in hemodynamic monitoring of critically ill patients.