Washington law allows residents to sign a document called a "Health Care Directive" that declares whether they want to have artificially hydration and nutrition if they are diagnosed in a terminal condition or permanent unconscious condition. The document is intended to give guidance to doctors and family members if you're ever in a life-threatening coma and unable to communicate your intentions yourself. It's sometimes called a Living Will.
The Health Care Directive is a somewhat unwieldy document that doctors say doesn't always apply to every situation. One of the best uses of the Health Care Directive is to reassure your family members if they have to make a life-or-death decision about you. You can also leave clear instructions by having a good conversation with your closest family members, particularly those you've designated on a Power of Attorney Document.