Unconsciousnes is a condition in DayZ Standalone (DZSA)
You may become unconscious/pass out due to various Status Effects and injuries
When you become unconscious, you can wait to see if you regain consciousness, or you can hope for another player to revive you using a Defibrillator or Epinephrine, or if you are not of the patient type, you can choose to respawn (in which case your character dies and you start out as a fresh spawn)