Stable

The best way to save a creature with 0 hit points is to heal it. If healing is unavailable, the creature can at least be stabilized so that it isn't killed by a failed death saving throw.
You can use your action to administer first aid to an Unconscious creature within reach and attempt to stabilize it, which requires a successful DC 10 Wisdom (Medicine) ability check. Doing so requires at least one free hand.
A stable creature doesn't make death saving throws, even though it has 0 hit points, but it does remain Unconscious for as long as it has less than one hit point. Unconsciousness lasts for 1 minute if the creature has 1 or more hit points. The creature stops being stable, and must start making death saving throws again, if it takes any damage.
Whenever a creature with at least 1 hit point is reduced to 0 hit points, that creature gains a level of Exhaustion.