There's been a lot of press lately about an 80 year old woman who had "do not resuscitate" tattooed on her chest. This is a good idea, but it's too vague, since DNR only applies if a person's heart stops or they stop breathing. To eliminate any ambiguity, the following additional tattoos should also be considered:
"no artificial hydration or nutrition"
"no cardioversion for rapid atrial fibrillation"
"no intubation and mechanical ventilation for potentially reversible conditions"
"no pressors if hypotensive"
"no painful, high risk surgical procedures with a very low likelihood of success"
"...and no dialysis under any circumstances"