I am not really sure what your question is. Generally an advanced directive (as you set forth above) is directions to a health care provider to allow someone else to make medical decisions for you when you are unable to do so. In this case, you would be incapacitated, and therefore would not be able to enforce anything. The surrogate decision maker could ask the court for an injunction; however, if the hospital has already acted, you would have to consider how the action would be undone... Would it be worth the effort to get a restraining order?
I am licensed in California, therefore, my answers are based on general prinicpals of law or California law, which may not be applicable in your jurisdiction. Answers posted to Avvo are for general information only. Do not conclusively rely on any information posted online when deciding what to do about your case. Every case depends is fact dependent, and responses are limited to and is based on the information you posted. No attorney-client relationship shall be created through the use reading of this response on Avvo. You should never delay seeking legal advice, disregard legal advice, or commence or discontinue any legal action because of information in this response.
You are asking the question- does this make it purely hypothetical or is this an actual case as to which you need advice. If so, the facts are inadequately set forth
If you and your domestic partner are a same-sex couple, you may want to contact the legal helpline at the National Center for Lesbian Rights in San Francisco. (They represent both male and female same-sex couples, as well as couples in which one or both partners is transgender or genderqueer.) NCLR's Relationship Recognition Project addresses the issues faced by couples whose family relationship is not recognized by hospitals, schools, employers, or other institutions. As with Avvo, they cannot give you legal advice, but they can give you information about the law that may help you decide how to proceed.
NCLR's Legal Information Helpline information: http://www.nclrights.org/site/PageServer?pagename=legal_getHelp
More information on the Relationship Recognition Project: http://www.nclrights.org/site/PageServer?pagename=issue_relationshipRecognition_overview
Best of luck to you.
I am licensed to practice in California, and all answers presume California law unless I expressly state otherwise. This answer is not legal advice, and does not establish an attorney-client relationship or a confidential relationship between myself and the asker.