Assessment of left ventricular ejection fraction in critically ill patients at the time of speckle tracking echocardiography: intensivists in training for echocardiography versus experienced operators

BACKGROUND: The biplane Simpson's method is considered the gold standard to assess and monitor left ventricular (LV) ejection fraction (EF) in critically ill patients. Recently, a new semi-automatic technique based on speckle tracking echocardiography called "Auto-EF" has been introduced. We compared LVEF values obtained with biplane Simpson's method and Auto-EF by two groups of operators: trainee echocardiography intensivists and experienced echocardiographers. METHODS: A standard transthoracic echocardiography was performed on 37 patients. According to image quality 29 patients were selected. Each inexperienced and experienced operator executed an off-line analysis using both Simpson's method and Auto-EF. LVEF obtained by the two groups of operators were then compared. RESULTS: EF values assessed with Simpson's method showed a moderate correlation (r=0.70, P<0.01) between inexperienced and experienced operators. The Bland-Altman analysis showed a mean bias of 0.3% with limits of agreement (LoA) from -24.4 to +25.1%. Values obtained with Auto-EF showed a good correlation (r=0.94, P<0.01) with a mean bias of 0.2% and LoA from -10.1 to +10.4%. CONCLUSIONS: Due to its semiautomatic nature, for inexpert operators Auto-EF seems more reproducible than the traditional Simpson's method for monitoring left ventricular function in critically ill patients.