1st level characters get maximum hit points. For each additional level gained, characters receive 1 plus 1/2 maximum for the type of hit die their class would give them. In all cases, add bonuses such as con bonus and toughness.
While monsters and unnamed NPCs are dead when they take their maximum hit points in damage, player characters have Vitality equal to their Constitution plus Fort save bonus. A PC is dead when their negative hit point total is greater than their Vitality.
At zero HP, a player must make a Vitality check DC 10 to stay conscious. Bonuses to the die include Fort save bonus plus levels of the Toughness feat. Failure means the character is unconscious. If conscious the character may take one standard or move action. A strenuous action, like combat, spell-casting, moving more than 10 feet, or other physical exertion will require another Vitality check. Failure of this second check will cause the PC to take 1 HP damage (going negative) and lose consciousness, ending the PCs round.
At negativeHP, an unstabilized PC must make a Vitality check DC 10 (bonuses as above, but penalties on the roll equal to negative HP) or or lose an additional HP ending the PCs round.
A stabilized PC can choose to make a Vitality check to become conscious and unstable. Win or lose, the PC takes a point of damage and ends their round.
A conscious but unstable PC can take one action, standard or move, as above at zero HP. Taking any action other than an attempt to stabilize will cause 1 HP damage and unconsciousness unless the action results in gaining enough HP to go positive.
A conscious, stable PC with negative hit points can take one action, but a strenuous action will cause 1 HP damage and the loss of stability and consciousness.
Healing and First Aid
Healing, magical and otherwise, works as in Pathfinder with the addition of First Aid.
After combat rounds are over, within ten minutes, each wounded PC may be tended for First Aid by someone rolling a Heal skill check. Anyone may attempt First Aid but only one F.A. attempt per victim may be made per encounter. Assistance may be given on first aid checks up to a maximum of +2. Also, anyone doing FA who has actual ranks in Heal gets a +2 on FA heal checks. A successful F.A. Heal check cures 1d4 HP.