Soulguard

You cradle a glow of energy inside you and stash it away, keeping it safe, just in case the worst should happen.

Component Cost: 5,000 gp
Market Price: 20,000 gp
Key Skill: Heal (no check)
Level: 20
Category: Restoration
Time: 1 hour
Duration: 1 day

You sequester a portion of a creature’s life force for emergencies. The recipient of this ritual (which can be you) spends one healing surge. The next time the recipient is reduced to negative hit points equal to his bloodied value and would ordinarily die, he instead regains hit points equal to his healing surge value.

Published in Forgotten Realms Player's Guide, page(s) 146.