Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
Call emergency services now if someone is unresponsive and not breathing normally or is only gasping.
After discharge following cardiac arrest, seek emergency help for another collapse, severe trouble breathing, fainting, or new chest pressure.
Start CPR and use an AED as soon as possible.
Do not wait for routine medical advice.
Follow the discharge plan for any other symptoms that the treating team identified as urgent.
For routine follow-up, contact the healthcare team about persistent chest pain from CPR, medication questions, activity limits, driving, return to work, or emotional difficulties.
Attend planned heart, rehabilitation, and device appointments.
Every sign above is quoted from the sofidex article on CPR - adult and child after onset of puberty. If you are not sure, err upward — it is always reasonable to be checked.