Weaning patients from mechanical ventilation is considered one of the critical decisions in intensive care unit as earlier patient weaning from mechanical ventilation is recommended to avoid complications of prolonged mechanical ventilation (Boles et al. 2007). Weaning failure is the inability of spontaneous breathing trial (SBT) to work or the need for re-ventilation within 48 hours of weaning is typically accompanied by cardiovascular disease or an inability of the respiratory pump to sustain breathing demand (Heunks and Hoeven 2010). Various measures had been previously reported for evaluation of volume status such as fluid balance and echocardiography before the SBT aiming to identify patients who would benefit from diuretic therapy to achieve successful weaning from mechanical ventilation. Although these measures could give us a good idea about weaning of patients from mechanical ventilation, thoracic fluid content measurement may also be beneficial and more accurate in this aspect (Caille et al. 2010). Thoracic fluid content represents the whole (extravascular, intravascular, and intra pleural) fluid component in the thorax; thus, TFC was considered to provide an estimation of the extravascular lung water in absence of significant pleural or pericardial effusion (Hammad et al. 2019). Echocardiography is now widely used to evaluate cardiac function during the ventilator weaning process. Using echo we can measure both inferior vena cava (IVC) size and collapsibility which can give us an idea about hypovolemic patients for estimation of right atrial pressure and trans-mitral to mitral annular early diastolic velocity ratio (E/Ea ratio) which is an echo Doppler non invasive estimation of left ventricular filling pressures (Rudski et al. 2010).