Healing the Dying
When you are dying and receive healing, you regain hit points from the healing effect but you do not automatically go to 0 hit points. With this rule change, the example on p. 295 of the Player’s Handbook would read as follows:
Example: Anvil is at -15 hit points. His companion Terov, a cleric, uses Healing Word to help him. This assistance allows Anvil to spend a healing surge boosted by Terov’s extra healing from Healing Word and the Healer’s Lore class feature. The healing surge (13 hit points) plus Terov’s boost (6 hit points) restores Anvil to consciousness and increases his current hit point total to 4.