How can a hyperoxia test be useful in determining etiology in a neonate?

The hyperoxia test is particularly useful in differentiating between respiratory and cardiac issues in neonates. This test involves administering supplemental oxygen and measuring the resultant changes in blood oxygen levels, which can help discern whether a neonate's hypoxemia is due to a respiratory problem, such as respiratory distress syndrome or pneumonia, or a cardiac issue, like congenital heart disease.

In instances where the hypoxemia improves significantly with the administration of oxygen, it typically indicates a primary respiratory problem because the lungs can effectively oxygenate the blood under increased oxygen concentrations. Conversely, if there is little to no improvement, this suggests a potential cardiac issue, as the defect may hinder effective oxygenation despite high levels of oxygen being provided. Therefore, the hyperoxia test becomes a valuable tool for clinicians, enabling targeted diagnostics and management based on the underlying cause of the neonate's condition.