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 now if someone:
Is not breathing or is only gasping
Cannot be woken or is becoming less responsive
Has blue, grey, or very pale lips or skin
Has stopped breathing after choking, injury, or possible overdose
Has severe facial or throat swelling with breathing difficulty
Collapses or has a seizure followed by abnormal breathing
Place the person on a firm surface and follow the emergency dispatcher’s instructions.
Start CPR if they are not breathing normally.
Use an automated external defibrillator, or AED, if one is available.
If opioid overdose is possible, give naloxone if available, but do not delay CPR or the emergency call.
Repeated sleep pauses without emergency signs usually need a routine appointment.
And for anyone, someone who:
is struggling to breathe, gasping, choking, or cannot get words out
has lips or skin that look pale, blue, grey or blotchy
Other emergency signs, for anyone
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 you believe has taken an overdose or swallowed something poisonous
2
Is any of this happening?
Be seen today
Seek same-day medical advice for newly slow or shallow breathing while awake, especially after starting or changing a medicine.
And for anyone, someone who:
is getting rapidly more short of breath, or has gained several pounds in a few days with swelling
3
Does any of this apply?
Book an appointment
Book one if there is loud snoring, witnessed choking during sleep, morning headaches, or ongoing daytime sleepiness.
And for anyone, someone who:
is more tired or breathless than usual doing things they used to manage
The article also says
If an unconscious person is breathing normally, place them on their side unless an injury makes movement unsafe.
Stay with them and keep checking their breathing.
Do not give food, drink, or medicine by mouth.
Every sign above is quoted from the sofidex article on Breathing - slowed or stopped. If you are not sure, err upward — it is always reasonable to be checked.