One option is the Battle Standard of Healing.
If one PC drops unconscious and is dying, they can be brought back to 1 hit point if someone else spends a healing surge in the zone. Note that all they need to do is spend a healing surge. This could be a second wind, Healing Potion, or any other number of powers/items that let you spend one.
For rules clarity, from Healing the Dying:
When you are dying, any healing restores you to at least 1 hit point.
Become Conscious: As soon as you have a current hit point total that’s higher than 0, you become conscious and are no longer dying.