Lung ultrasound in infants with bronchiolitis

Lung ultrasound (LUS) is nowadays a fast-growing field of study since the technique has been widely acknowledged as a cost-effective, radiation free, and ready available alternative to standard X-ray imaging. However, despite extensive acoustic characterization studies and documented medical evidences, a lot is still unknown about how ultrasounds interact with lung tissue. One of the most discussed lung artifacts are the B-lines [in all ages] and the subpleural consolidations (in young infants). Recently, LUS has been claimed to be able to detect pneumonia in infants with bronchiolitis, although this can be an overestimation due to the peculiar physiology of small peripheral airways of the pediatric lung (particularly in neonate/infants). Distinguishing consolidations from atelectasis in young infants with bronchiolitis can be challenging and those criteria well defined for adults and older children (size and bronchogram) cannot easily translated in this specific subset. Therefore, if decades of studies clearly defined the low risk of SBI in bronchiolitis, we need to be careful before stating that LUS may confirm pneumonia in such a high number of cases and, importantly, new and promising techniques such as LUS should give us new insights bringing us to improvements and not back to overuse of antibiotics. More studies are surely need on this topic.