Which of these is true regarding advance directives?

If summoned, EMTs are legally obligated to provide emergency care to a patient, regardless of advance directive status, unless the directive is signed by a doctor. If the patient is brought to the hospital, physicians will evaluate the patient and implement the advance directive, if necessary. Two physicians, not one, are needed to determine if a patient is unable to make decisions for himself. Advance directives do not expire and remain in effect until they are changed. Some states do not honor advance directives created in other states, so if a patient moves, he/she should check with his/her new state policies on this topic.