Withdrawal of life-sustaining low-burden care

A 90-year-old diabetic man with unreconstructable peripheral vascular disease, end-stage chronic obstructive pulmonary disease, relentless ischemic rest pain, and severe disability returns to your clinic asking you to deactivate his implanted pacemaker. To do so would likely precipitate his demise, and you ask him if he is aware of this. He tells you that he is and that he has been considering this request since he last saw you 3 months ago. Relief of his chronic pain would require bilateral hip-disarticulating amputations, procedures with a prohibitively high operative mortality rate, particularly with his age and comorbidities. He has been evaluated by a psychiatrist and found to be mentally competent. His treatment by a pain specialist, who used his full armamentarium of high-dose narcotics, electronic devices, nerve blocks, and psychological techniques, has been unsuccessful. You do not reside in Oregon. What is your most ethical course of action?