Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
1
Is any of this happening now?
Call 911
Call emergency services if a baby:
Is not breathing or does not quickly start breathing again
Turns blue or gray around the face, lips, or tongue
Becomes limp, unresponsive, or unusually difficult to wake
Has severe chest pulling, choking, or obvious trouble getting air
Follow the emergency dispatcher's instructions.
These signs are not always emergencies, but they should not be ignored.
Other emergency signs, for anyone
Someone who is struggling to breathe, gasping, choking, or cannot get words out
Someone who has chest pain, tightness or pressure lasting more than a few minutes
Someone who has sudden weakness or drooping on one side of the face or body, slurred speech, or sudden confusion
Someone who is unconscious, or cannot be woken
Someone who is bleeding heavily and it will not stop with firm pressure
Someone who has had a seizure that will not stop, or does not wake up afterwards
Someone who has lips or skin that look pale, blue, grey or blotchy
Someone who you believe has taken an overdose or swallowed something poisonous
2
Is any of this happening?
Be seen today
Seek prompt medical assessment for a first unexplained breathing pause, repeated pauses, color changes, feeding difficulty, or increased work of breathing.
A baby younger than 3 months with a fever of 38°C or 100.4°F or higher also needs prompt medical assessment.
3
Does any of this apply?
Book an appointment
Arrange routine follow-up for ongoing snoring, restless sleep, sweating, poor weight gain, feeding fatigue, or increasing monitor alarms when the baby otherwise appears comfortable.
The article also says
Begin infant CPR if the baby is unresponsive and not breathing normally, if you have been trained to do so.
Every sign above is quoted from the sofidex article on Infantile sleep apnea. If you are not sure, err upward — it is always reasonable to be checked.