Advance directives are those statements or documents that indicate the sort of health care people would want should they fall into incapacitated states. These statements may vary from general, offhand comments (�I wouldn't want to live if I had a lot of tubes sticking out of me.�) to written documents having a good amount of detail. Some advance directives take the form of �living wills,� in which patients offer specific details about what treatment is or is not acceptable to them. The central point of advance directives is that they are intended to medical decisions should a patient lose the capacity to express his or her wishes.
Advance directives come into play only when a patient is unable to communicate his or her wishes. It is also true � that at the same time � surrogate decision-makers must be involved in medical decisions. Surrogate decision-makers can use advance directives as guides when coming to decisions about medical care for a particular patient. In other words, while the advance directive is a guide for medical decisions it only comes into play through a surrogate decision-maker. In some cases, surrogate decision-makers may find that the patient's circumstances have changed and is not formally bound by ethics or the law to follow through on the advance directive as written. For example, some patients may not wish to undergo mechanical ventilation. However, that treatment can serve as a bridge to recovery in some medical conditions. A surrogate decision-maker might therefore choose to disregard an advance directive that absolutely ruled out all mechanical ventilation.
It should be remembered that most people in the United States have taken no steps to put in place a mechanism for guiding medical decisions should they become unable to make those decisions themselves. Even if patients do prepare some kind of advance directives, these are sometimes not available when needed, because it's not clear where the patient put them, for example. And it is also true that the advance directives may not be useful in all medical circumstances. For the vast majority of patients, therefore, the statutory approach to surrogate decision-making will prevail when patients are unable to make decisions for themselves.