The infant who needs supplemental oxygen requires a thorough initial assessment to determine the diagnosis (and sometimes the prognosis), to assess the efficacy of the therapy, and to provide a baseline for future evaluations. This includes an inspection for congenital defects, growth parameters, and gestational age and an evaluation of neurologic and cardiac function. The most revealing part of this assessment is performed without a stethoscope, as the nurse assesses the infant’s level of distress. Indicators of concern on visual inspection include rapid respiratory rate, grunting, nasal flaring, the presence of retractions, asynchrony of abdominal and chest excursion, and diminished perfusion. The infant’s chest should then be auscultated for symmetry and quality of breath sounds, including the presence of crackles, wheezes, or other sounds.