Final answer:
After ensuring safety, check for breathing on an unconscious person and start CPR if necessary. For drowning, remove from water first; for choking, attempt back slaps or the Heimlich. Seek emergency help if needed.
Step-by-step explanation:
When you come upon an unconscious person, after ensuring it is safe to approach, the first thing to do is check for breathing and determine if CPR (cardiopulmonary resuscitation) is necessary. If the person is not breathing, you should begin CPR immediately. Remember to follow the current guidelines which emphasize performing high-quality chest compressions at a depth of at least 5 cm and a rate of 100 compressions per minute, which aligns with the beat of the song 'Staying Alive' by the Bee Gees. If there's a suspicion of drowning, the person must be removed from the water before CPR can be effective. In cases of choking, if an individual is unable to speak, cough, or they're showing signs of severe distress, you may need to take measures such as back slaps or the Heimlich maneuver, and seek emergency medical help if initial efforts don't resolve the choking.