An elderly man with end-stage emphysema presents to the emergency room awake and alert and complaining of shortness of breath. An evaluation reveals that he has pneumonia. His condition deteriorates in the emergency room and he has impending respiratory failure, though he remains awake and alert. A copy of a signed and witnessed living will is in his chart stipulates that he wants no "invasive" medical procedures that would "serve only to prolong my death." No surrogate decision maker is available. Should mechanical ventilation be instituted?

If the patient has remained awake and alert, his living will is irrelevant to medical decision making. The potential risks and benefits of mechanical ventilation need to be presented to the patient. If he refuses this therapy with an understanding of the consequences, his wishes should be honored. If he opts for mechanical ventilation, it should be instituted when it becomes medically necessary. The presence of a living will or other advance directive does not obviate the responsibility to involve a competent patient in medical decision making.