Sloane Atkinson is awaiting a donor heart. Doctors dismissed a newborn’s “grunting” as normal sounds — but six weeks later, the baby was intubated in the PICU, and is now awaiting a heart transplant.

When these airways become constricted, the chest may feel tight or congested, and a wheeze can often be heard. Other sounds to look out for, discussed below.

Doctors urge parents to watch for rapid breathing, chest retractions, cyanosis, and feeding issues in babies for early ...