Chest Ultrasound in Predication of Weaning Failure

Failure of weaning from mechanical ventilation (MV) is a common problem that faces the intensivist despite having some prediction indices. Application of chest ultrasonography (US) may help in weaning and prediction of its outcome.

100 patients on invasive MV fulfilling criteria of weaning shifted to spontaneous breathing trial (SBT) (using PSV 8 cm H₂O) for 1 hour. Weaning failure was defined as; Failed SBT, reintubation and/or ventilation or death within 48 hours. Echocardiography was used to get Ejection fraction, E/A ratio, Doppler tissue imaging (DTI) &, lung ultrasound (LUS) was used to assess LUS score, diaphragm ultrasound was used to assess diaphragmatic thickening fraction (DTF).

Mean age 57.1 ± 14.5, 62% were males. Weaning was successful in 80% of patients. LUS score was significantly higher in the failed weaning group: (10.8 ± 4.2) vs (16.5 ± 4.2 cm), (p: 0.001). (DTF) Was significantly higher in the successful weaning group: (43.0 ± 10.7) vs (28.9 ± 2.8 cm), (p: 0.001). DTF can predict successful weaning using Receiver operating characteristic (ROC) curves with the cutoff value: ≥ 29.5 with sensitivity 88.0% and specificity 80.0% with a p-value < 0.001.LUS score can predict weaning failure by using a ROC curve with cutoff value: ≥ 15.5 with sensitivity 70.0% and specificity 82.5 % with a p-value < 0.001.).

The use of bedside chest US (to assess lung and diaphragm) of great benefit throughout the weaning process.