A living will—also known as an Advance Health Care Directive—is a document in which the declarant or principal (person making the living will) specifies what kind of medical treatment the declarant does and does not want if the declarant has a medical emergency and is unable to communicate those wishes. A living will may direct health care providers to administer, withhold, or withdraw life-sustaining treatments if the declarant is in a terminal or irreversible condition.

Laws and terminology for documents related to living wills, Advance Health Care Directives, Do Not Resuscitate orders (DNRs), and other health care documents vary from state to state. These laws are generally located in a state’s statutes—often in the probate code or estates code.

In Hawaii, an Advance Health Care Directive (AHCD) serves as a living will, allowing individuals to outline their preferences for medical treatment in the event they are unable to communicate their wishes due to a medical emergency. The AHCD can include instructions on administering, withholding, or withdrawing life-sustaining treatments if the individual is in a terminal condition or an irreversible coma. Hawaii Revised Statutes §327E-3 defines the AHCD and provides the framework for its execution, including the requirement for it to be witnessed by two individuals or notarized. The statute also allows for the appointment of a health care power of attorney within the same document, enabling the designation of an agent to make health care decisions on the individual's behalf. Additionally, Hawaii recognizes Do Not Resuscitate (DNR) orders, which are separate from AHCDs and instruct medical personnel not to perform cardiopulmonary resuscitation (CPR) if the patient's breathing or heart stops.