Prospective, observational multicentric study which aims at identifying lung POCUS (Point of Care UltraSound) findings associated with failure of noninvasive ICU-LRS (Intensive Care Unit Level Respiratory Support) (defined as escalation of settings or need for intubation and invasive mechanical ventilation) in infants requiring noninvasive ICU-LRS in the ICU for bronchiolitis and other LRTI (Low Respiratory Tract Infection) and at identifying lung, pleural, and diaphragm POCUS findings that are associated with a clinical improvement after escalation of ICU-LRS support by comparing POCUS findings from the first 24 hours of ICU stay to a subsequent study 1 day later.