Abstract
Lung ultrasonic B-lines have high accuracy in diagnosing extravascular lung water (ELW) but have not been systematically subcategorized to differentiate the varied etiologies of ELW. This brief communication describes subcategories of B-lines into "inflammatory" and "transudative" patterns, based on their location, pleural morphology and associated subpleural pathologies. This subcategorization was derived using information from trainees undergoing lung ultrasound training in the Learning Ultrasound in Critical Care program, pathophysiological principles and their corresponding ultrasound correlates. This subcategorization helped trainees differentiate inflammatory pathologies of ELW (e.g. pneumonia, acute respiratory distress syndrome) from transudative (congestive) pathologies (e.g. fluid overload, cardiac failure).