Sonographic measurement of lung aeration versus rapid shallow breathing index as a predictor of successful weaning from mechanical ventilation

Abstract

Background Lung ultrasonography is a beneficial tool for evaluation of the extent of lung aeration through measurement of the amount of extravascular lung water. Lung ultrasonography offers some advantages over other methods of assessment of lung aeration including the lack of ionizing radiation and the possibility of use at patient's bedside. It facilitates dynamic assessment of the lung during mechanical ventilation and during weaning. Aim To assess lung aeration by lung ultrasonography in patients ready for weaning and to validate the significance of its use as a predictor of weaning outcome in comparison with rapid shallow breathing index. Patients and methods A prospective observational study was conducted on 30 critically ill mechanically ventilated patients for 48 h or more, and ready to undergo spontaneous breathing trial (SBT), according to the readiness criteria. It was conducted in Beni-Suef University Hospital from October 2017 to May 2018. Rapid shallow breathing index was measured before initiation of SBT, and lung ultrasound was done, before, during, and after SBT [lung ultrasound score (LUS) 1, 2, and 3] and were used as predictors for SBT outcome. Patients were divided, according to outcome, into successful weaning group (group A) and failed weaning group (group B). Results In the failed weaning group, LUS1, LUS2, and LUS3 were significantly higher than those of the successful weaning group. At cutoff value of 8.5, LUS3 could be used for prediction of weaning failure with sensitivity 85% and specificity 100%. Moreover, there was a statistically significant relation between LUS and the other variables including hospital stay, mechanical ventilation duration, and mortality. Conclusion Lung ultrasound is useful as a bedside tool that can help physicians in their weaning decisions.