Introduction Ultrasound is a non-invasive and bedside accessible method of cardiac function monitoring. Cardiac echocardiography has several limitations due to difficulties to obtain an acceptable acoustic window in critical care settings. Left ventricular outflow tract (LVOT) velocity time integral (VTI) can be measured in most critical care patient and is an useful tool for this purpose. Calculations of cardiac output needing aortic valve area are strongly dependent on skills and observers . We hypothesize that twofold LVOT-VTI is an accurate calculation of stroke volume index (SVI).