Cumbrous Fortitude( Savage Species, p. 31)
You have a greater chance than normal to resist attacks against your vitality, but at a cost.
Great Fortitude (PH) ,
Before rolling a Fortitude save, you can decide to activate this feat, which gives you a +6 bonus on your saving throw. After the saving throw is resolved, regardless of the result, you are staggered until the end of the encounter. A staggered character can take only a partial action when he or she would normally be able to take a standard action.