Healing Surges

As an action, a character can use a healing surge and spend up to half his or her Hit Dice. For each Hit Die spent in this way, the player rolls the die and adds the character’s Constitution modifier. The character regains hit points equal to the total. The player can decide to spend an additional Hit Die after each roll.
A character who uses a healing surge can’t do so again until he or she finishes a short or long rest.
Under this optional rule, a character regains all spent Hit Dice at the end of a long rest. With a short rest, a character regains Hit Dice equal to his or her level divided by four (minimum of one die).