What term best describes the condition of an infant struggling to breathe despite receiving supplemental oxygen?

The term that best describes an infant who is struggling to breathe despite receiving supplemental oxygen is "severe respiratory distress." This condition indicates that the breathing difficulties are significant enough that the infant requires additional oxygen support but is still unable to maintain adequate respiratory function on their own.

In the context of respiratory health, severe respiratory distress is characterized by marked tachypnea, retractions, nasal flaring, and possibly wheezing or grunting. The reliance on supplemental oxygen while still facing difficulties highlights the severity of the respiratory compromise. This may be due to underlying conditions such as pneumonia, respiratory infections, or other pathophysiological issues affecting the infant's ability to oxygenate adequately.

The other choices represent varying levels of respiratory distress or stability. Mild and moderate respiratory distress would typically imply a less critical state and would not usually require supplemental oxygen to the same extent as seen in severe cases. Additionally, "stable" indicates a condition where the infant is not showing any signs of distress, which does not apply here since the infant is actively struggling to breathe despite receiving oxygen. Thus, "severe respiratory distress" accurately captures the gravity of the situation.