Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
These symptoms need medical assessment but are not always emergencies.
Seek emergency help for blue or gray coloring, severe breathing effort, long pauses in breathing, inability to stay awake, collapse, or heavy bleeding.
Contact the care team promptly if the child develops increasing nasal blockage, worsening noisy breathing, difficulty feeding, poor weight gain, persistent foul-smelling discharge, fever after a procedure, or bleeding that does not quickly stop.
A baby who cannot breathe well enough to feed also needs urgent assessment.
Regular follow-up with the ear, nose, and throat team is important after surgery.
The clinician checks that the opening remains clear, removes crusting when necessary, and monitors breathing, feeding, sleep, and growth.
Long-term follow-up may involve audiology, cardiology, genetics, speech and feeding specialists, or developmental services when related conditions are present.
Children with isolated, successfully treated choanal atresia may need less intensive follow-up once the airway has healed and remained open.
The article also says
Families may be given a specific plan for nasal saline, suctioning, feeding, and activity.
The plan can change as healing progresses.
Keep scheduled appointments even if breathing appears normal, because early narrowing may be easier to manage before symptoms become severe.
Every sign above is quoted from the sofidex article on Choanal atresia. If you are not sure, err upward — it is always reasonable to be checked.