All states require a power of attorney to be evidenced by a written instrument signed by the principal. The text of this document must outline the agent's authority with enough specificity to provide reasonable guidance to a third party as to the extent of the agent's authority. Any mentally competent adult (at least 18 years old) may act as agent, except that many states forbid the principal's health care provider from acting as agent. A temporary medical power of attorney must state that the agent's authority is triggered when the patient becomes incompetent -- unconscious, mentally incapacitated or unable to communicate -- and automatically lapses when the patient regains competence. The principal may authorize the agent to select among available medical treatments, to authorize treatment or to withhold treatment altogether in case of terminal illness.
All states require a power of attorney document to include some type of authentication of the principal's signature -- the signature must be either notarized or witnessed by two or three witnesses. If witnesses are required, they must sign the document. The witnesses' signatures attest that to the best of their knowledge, the principal was mentally competent when he signed the document and understood its contents.
The principal may revoke a power of attorney at any time, as long as he is competent. In some states, revocation becomes effective as soon as the principal informs his health care provider, even if this notification is oral. In other states, revocation does not become effective until the agent learns of the revocation.
Third Party Rights and Liabilities
A third party, such as an attending physician, cannot be held civilly or criminally liable for honoring an apparently valid power of attorney, as long as he acts competently and in good faith. The third party is insulated from liability even if the power of attorney has already been revoked, as long as he had no reason to know of the revocation. A third party may also refuse to honor a valid power of attorney as long as the refusal is reasonable under the circumstances. Some states require a physician who refuses to honor a power of attorney to cooperate with the transfer of the principal to a new facility, if the agent so desires, and to arrange for the prompt and orderly transfer of medical records.
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