Talisman of Fortune, Level 15 item (AV, p178)
Power (Daily): Lose 1 healing surge, or take damage equal to one quarter of your maximum hit point total if you have no
healing surges remaining. Gain one extra daily use of a
magic item in your possession (your choice, not including
the talisman of fortune) until the end of the encounter.
You also renew the power of the talisman.
There's a bit more to this item, but that's the relevant bit. Precedent for burning 1/4 max HP when out of healing surges to power a magic item.