A health care proxy let you names someone who can make decisions about your medical care if you can’t make them yourself. Therefore, such a document may spare you and your family from expensive disputes if you are stricken by a serious illness or injury. (This document might be known as a power of attorney for health care in some states.)

Ideally, the agent you name as your health care proxy will be someone who has some knowledge of medical care. In addition, this person must be able to make reasoned decisions under stress.

Ask your chosen candidate if he or she is willing to serve, before naming anyone in a document. Similarly, locate a willing replacement if your first choice is not available.

Your health care proxy should authorize the release of your medical history to the people you’ve named. They might need this information to make reasoned decisions and federal law may prohibit the release of your records, without explicit authorization.

Your state probably offers a free copy of its health care proxy form, on its Web site.