You can control your future healthcare even when you are in a coma or incompetent by creating advance directives while you are competent. A living will is a type of advance directive in which you write down your choices for end-of-life care. Generally, medical facilities must honor your directive, although "reason-of-conscience" exceptions can apply.
You can create a living will by obtaining an advance directive form from state courts, your attorney or an online legal document service. In the document, you may specify the type of medical care and treatment you want and do not want, such as life-sustaining or life-prolonging measures, should you become incompetent. Healthcare providers generally are legally bound to honor the terms of your living will, but certain exceptions can apply.
Exceptions for Reasons of Conscience
Some states do not require hospitals to honor a living will if they have policies, based on reasons of conscience, against carrying out the medical treatment requested. If a Catholic hospital has a conscience-based policy that prevents it from following some part of your advance directive, its duties depend on the law of the state in which it is located. In some states, the hospital must arrange to transfer you to a medical facility that will honor your healthcare instructions. You can avoid such issues by asking about hospital policy at institutions near you before the need for hospitalization arises.