Watching Doctor Oz on TV today about those life-saving portable AED machines installed in public places. He demonstrated how a person should go about administering electric shock to the heart of a victim using an AED machine as part of CPR Cardio-Pulmonary Resuscitation. But it occurred to me that the person administering this resuscitation might be sued by the the family of the revived victim if that victim had previously signed a (DNR) Do Not Resuscitate order as part of his (or her) living will.
I believe that it's a valid question.
(At least, it could be used as part of a plot for a fiction story.)