What document is signed when an individual, while still healthy, indicates their care preferences during terminal illness?

The document referred to in the question describes a legal instrument that allows individuals to express their wishes regarding medical treatment and healthcare decisions in the event that they become unable to communicate their preferences due to a terminal illness or other medical condition. This is known as an advance directive.

Advance directives are designed to ensure that a person's healthcare preferences are honored when they are no longer capable of making those decisions themselves. It encompasses various forms of communication, including living wills and sometimes healthcare proxies.

While a living will is specifically a type of advance directive that outlines the individual's wishes regarding treatment options, advance directives also include other documents that may assign a healthcare agent to make decisions on the person's behalf. This broader definition captures all forms of advance planning concerning potential future healthcare needs, thereby making it the most accurate answer to the question posed.

It is important to note that both consent forms and power of attorney documents serve different purposes: consent forms typically pertain to agreeing to specific treatments, while a power of attorney gives legal authority to someone to make decisions on another's behalf, which may or may not address healthcare specifically. Thus, advance directives is the term that best encompasses the idea of planned healthcare preferences during a terminal illness.