Article Type

Original Study


Background Cardiogenic pulmonary edema has been recognized as a frequent cause of weaning failure. A spontaneous breathing trial (SBT) induced an elevation in the left ventricular filling pressure, which plays a key role in weaning failure. Transthoracic echocardiography (TTE) should be used to identify the cardiac origin of respiratory weaning failure. Tissue Doppler is a technique that directly measures myocardial velocities. The early diastolic mitral annulus velocity (Ea), pulsed Doppler mitral flow in early diastole E, and the resulting E/Earatio closely correlated with the measured invasive left ventricular filling pressure. Objective The aim of this study was to compare the success of weaning from mechanical ventilation (MV) and failure of weaning using TTE. Patients and methods The study included 30 patients who were divided into two groups: group I (the weaned group) (eight patients) included patients who fulfilled the criteria for weaning and the patients were not reintubated within 48 h following extubation, and group II (the weaning group) (22 patients) included patients with failed SBT or those who were reintubated within 48 h following extubation. The following parameters were recorded: demographic data (age, sex, and cause of MV), mean arterial blood and serum creatinine, the left ventricular ejection fraction, the E wave velocity by means of pulsed-wave Doppler analysis of mitral inflow, and the myocardial velocity recorded using the digital trunk interface technique. Eawas measured and E/Eawas calculated. The mean of three measurements was used for calculation. Results The success rate of weaning from MV was 26.7% and the mortality rate was 6.75%. The comorbidities associated with weaning failure were evident in the failure group. TTE parameters before SBT were as follows: left ventricular ejection fraction was comparable between the two groups, whereas E wave and E/Earatio were significantly decreased in the successful group. However, Eawave was significantly decreased in the failure group. Conclusion Measurement of the E/Earatio with TTE could predict weaning failure. Diastolic dysfunction with relaxation impairment is strongly associated with weaning failure.