Point-of care lung ultrasound in the NICU: uses and limitations of a new tool

Pulmonary imaging in the neonatal intensive care unit (NICU) relies traditionally on the conventional chest radiogram. Translating evidences from adult emergency medicine, pediatricians and neonatologists have recently started to apply lung ultrasonography to the critical infant and child with respiratory problems [1]. Because of the high impedance of a normally aerated lung, an ultrasound scan does not render an anatomical image of the organ. However, ultrasounds clearly define the pleural surface with the normal sliding movement. Pleural effusions and lung consolidations can also be reliably diagnosed with ultrasonography. However, ultrasounds penetrating the lung will also generate artifacts (i.e. structures not naturally present in the living that appear as authentic images). These imagery anomalies come from the machine acquisition of the ultrasound beam path through means with markedly different acoustic impedance in close proximity. The horizontal reverberations of the pleural line (aka the A lines see Figure 1A) and the vertical hyperecoic image departing from the pleura (aka the B linessee Figure 1B) are commonly seen artifacts. Real and artefactual images have been combined in disease specific ultrasound profiles. Using these profiles, adult emergency physicians have shown that lung ultrasound outperforms conventional radiology in relevant diagnoses such as pleural effusion, pneumonia or pneumothorax. Pediatricians have started to use lung ultrasound with success to their patients affected by pneumonia but also by bronchiolitis [2]. In the NICU, lung ultrasound has