A 55-year-old male collapses in front of you and is unresponsive. He is not breathing and you can't feel a pulse. What should you do?
The patient appears to be in cardiac arrest. Immediately call for emergency medical help and start CPR. Give chest compressions at a rate of about 100-120 per minute and, if available, use an automated external defibrillator (AED) as soon as possible. Continue providing CPR until emergency medical services arrive.