Neonatal lung ultrasound: From paradox to diagnosis … and beyond

Any medical student is taught that an ultrasound beam will not penetrate an air-filled organ. Therefore, the echographic exploration of the lungs is not possible. Yet, there has been an explosion of publications on lung ultrasound in the past ten years (Fig. 1) to create an objective paradox. The explanation, however, is quite simple. Combining images from anatomic structures and artifacts (i.e. reproducible images that have no anatomic equivalent), clinical researchers have created ultrasound profiles. These, in turn, have been validated as diagnostic markers of several important respiratory diseases both in adult and in the developing age [1]. One important assumption is that artifacts appear and change in a reproducible parallel with the air to fluid ratio, spanning from a normally aerated to a fully consolidated lung parenchyma (Fig. 2). The details of this approach applied to neonatal respiratory medicine are well described in recent reviews [2,3]. The present paper is a brief summary of the key points, an update of the most recent results and a speculation on promising research in neonatal lung ultrasound (LUS).