Civil law challenged by personal beliefs

Were a doctor or surgeon to believe that, in the light of his knowledge and skills, his patient should receive the treatment or surgery he considers appropriate, could the patient’s wishes be ignored, especially if the latter is unconscious?

In the event that the patient had previously provided the hospital with an Advanced Health Care Directive (AHCD), a legally-binding document signed in sound mind, and had also reminded the relevant medicos of the existence of such a document (as I have each time I was listed for surgery), could the surgeon ignore my right to decide how I am to be treated?

My AHCD says that any procedure requires my consent; and that I am not to be resuscitated if unconscious. That is, to allow nature to take its course.

The issues raised here are:
Who owns the body and mind of the patient?
What of his human rights, since his legal rights may be abrogated?
• What consideration should be given by the medicos to the patient’s quality of life post-treatment?
• What logic underwrites this medico stance to god-like status?
• Should life be prolonged at any cost? Why?

How, in an officially-secular democratic nation, could a medico’s beliefs over-ride the legal rights of a fellow-human? We do need the protection of the law from arbitrary decisions by others.