A healthcare agent is a person whom you are trusting to make medical decisions on your behalf if you can't make them for yourself. Choosing your agent is an important decision, and you should think carefully about who you want to assume this responsibility. This person may one day be deciding whether or not life support measures will be in your best interests or determining exactly how your personal and religious values would impact other treatments. A legal document that appoints a healthcare agent is sometimes called a "healthcare power of attorney."
If you can't make decisions on your own, a healthcare agent can make them for you even if you are not terminally ill or in an irreversible coma. This goes farther than a living will. A healthcare power of attorney also protects your interests if a hospital does not honor your living will completely.
In some cases, living will provisions are combined with a healthcare power of attorney. A LegalZoom Living Will lets you combine a living will with the appointment of a healthcare agent. You can also nominate an alternate healthcare agent, who will assume responsibility if your first choice can't do so.