Fig. 4

The measurements of E/Ea and DE before and after SBT in a patient of respiratory failure within 48 h. a, b, c, d, e represented the results before SBT, and f, g, h, i, j represented the results after SBT. a DE (right) was 7 mm. b DE (left) was 10 mm. c E was 68 cm/s. d Ea (septal) was 5 cm/s. e Ea (lateral) was 7 cm/s. f DE (right) was 9 mm. g DE (left) was 17 mm. h E was 94 cm/s. i Ea (septal) was 5 cm/s. j Ea (lateral) was 7 cm/s. Before SBT, DE (average) was 8.5 mm, and E/Ea (average) was 11.3. After SBT, DE (average) was 13 mm, and E/Ea (average) was 15.7. After extubation, respiratory failure occurred within 48 h and then NIV was used. The patient was not re-intubated within 1 week and free of NIV in the end. DE diaphragmatic excursion, E/Ea the ratio of mitral Doppler inflow velocity (E) to annular tissue Doppler wave velocity (Ea), NIV noninvasive ventilation, SBT spontaneous breathing trial