： This study aimed to determine which parameters by transthoracic echocardiography (TTE) are more likely to be affected in a critical care setting.
： Ninety mechanically ventilated ICU patients were enrolled into the study group. The control group consisted of 90 patients who underwent interventional therapy. All patients had bedside TTE for. Parametric measurement included the right ventricular size, septal kinetics and left ventricular ejection fraction (LVEF) by eyeballing (visual assessment) , the tricuspid annular plane systolic excursion (TAPSE), mitral annular plane systolic excursion (MAPSE) by M-mode sonography, the right ventricular outflow tract velocity-time integral (RVOT VTI) and left ventricular outflow tract velocity-time integral (LVOT VTI) by pulse-Doppler, and the right ventricular fraction of area change (FAC) and left ventricular ejection fraction (LVEF Simpson) by endocardium tracing. We compared the differences in the frequency of optimal image acquisition in assessment of these parameters between the two groups, as well as the difference in acquisition rates of parameter measurement in ventilated ICU patients.
：There were significantly fewer patients in the study group who had optimal images acquisitions for parameter assessments from M-mode method, pulse Doppler method and endocardium-tracing method than in the control group (p＜0.05); The two groups showed no significant difference in the number of patients with optimal images for RV eyeballing and LVEF eyeballing. In the study group, there were significantly fewer patients with optimal images for FAC than for TAPSE(22.2% vs 72.2%, X2=45.139, P <0.001) and RVOT VTI (22.2% vs 71.1%, X2=43.214, P <0.001) ;there were also fewer patients with optimal images for LVEF Simpson than for MAPSE (37.8% vs 84.4%, X2=41.236, P<0.001) and LVOT VTI (37.8% vs 85.6%, X2=43.455, P＜0.001) .
：Images acquisition of optimal TTE images tend to be difficult in mechanically ventilated ICU patients, but eyeballing method for function evaluation could be an alternative method. For quantitative parameters measurements, M-mode based longitudinal function evaluation, and pulse Doppler-based VTI were superior to the endocardium-tracing based parameter assessment.