“…Transthoracic lung ultrasound has several advantages over conventional radiological means for assessing lung aeration: it is reliable and accurate (17,18,23), highly reproducible (34), noninvasive, and easily repeatable at the bedside. Several studies have demonstrated that lung ultrasound is accurate for assessing positive end-expiratory pressure and prone position-induced lung recruitment (17,(35)(36)(37), lung reaeration following antimicrobial therapy in ventilator-associated and communityacquired pneumonia (18), and lung reaeration associated with resolution of various forms of pulmonary edema (38)(39)(40)(41)(42)(43)(44). Although the ultrasound detection of SBT-induced lung derecruitment does not give any indication about the cause of aeration loss, upper airway obstruction, persisting pneumonia, congestive heart failure, aspiration of secretions, cough inefficient to remove excessive bronchial secretions, and muscle weakness as observed in critically ill patients with polyneuropathy, it can be used as a predictor of extubation failure.…”