Left Ventricular Diastolic Dysfunction as a Predictor of Weaning Failure From Mechanical Ventilation

Trans-mitral flow velocities (peak early diastolic E and peak late diastolic A) will be recorded with pulsed-wave Doppler, placing the sample volume at the mitral valve tips from the apical 4-chamber view; deceleration time of the E wave (DTE) will be measured. Peak early diastolic velocity will be obtained with tissue Doppler imaging (TDI), in the apical 4-chamber view, positioning the pulsed-wave Doppler sample volume at or 1 cm within the septal insertion sites of the mitral leaflets, so as to cover the longitudinal excursion of the mitral annulus in both systole and diastole. Then, the E/A ratio and the trans-mitral inflow E wave to mitral annular e' (E/e) will be calculated.Diaphragmatic thickness will be assessed in the zone of apposition of the diaphragm to the rib cage between the 8th and 10th intercostal spaces using a 3-12 MHz linear array probe , we will record changes in diaphragm vertical excursion using M-mode ultrasound.