ObjectiveTo investigate the clinical significance of cardiac function index (CFI) and global ejection fraction (GEF), derived from single-indicator transpulmonary thermodilution technique, in assessment of cardiac function in critically ill patients. MethodsA prospective clinical observational study was conducted in the Intensive Care Unit of the First Affiliated Hospital of Guangzhou Medical University. Between January 2012 and December 2012, 39 patients who underwent PiCCO monitoring were recruited, including 18 cases with left ventricular systolic dysfunction and 21 cases without left ventricular systolic dysfunction. Both groups underwent transpulmonary thermodilution measurements and transthoracic cardiac ultrasonography. Pearson correlation analysis was conduced to assess the correlation between left ventricular ejection fraction (LVEF) and CFI and GEF. ROC curve was established to calculate the predicted threshold of CFI and GEF for diagnosing cardiac insufficiency. ResultsLVEF was significantly correlated with CFI and GEF (r=0.553, P < 0.005; r=0.468, P < 0.005). The area under ROC curve of CFI, GEF and LVEF for diagnosing cardiac insufficiency was 0.885, 0.862 and 0.903, respectively (P > 0.05 for comparison). The cut-off value of CFI for predicting cardiac insufficiency was 4.25/min, with a sensitivity of 77.8% and a specificity of 88.9%. The cut-off value of GEF for predicting cardiac dysfunction was 19.5/min, with a sensitivity of 88.9% and a specificity of 66.7%. ConclusionCFI and GEF measured by transpulmonary thermodilution correlate well with LVEF assessed by transthoracic echocardiography, both can be used for assessment of left ventricular systolic function.