There's an old joke that although you may want to be sure to complete your own end-of-life health care planning with some form of advance directive what you may really need to do is ask to see your doctor's advance directive. The knowing laugh that follows the joke is based on the observation that your own advance directive is only as good as anyone's willingness to implement it. And, it turns out, that your doctors may have some say in that.
For what it is worth, I know of not one reported case involving a determination of liability against a health care provider (individual or institutional) for refusal to implement an AD. There are reported cases involving questions of under-treatment, so I can understand where the liability-sensitive feel the push to err on the side of invasive treatment.
Today, someone sent me a link to a recent study that indicates asking to see your provider's AD might not be enough. You might, in fact, want to ask what that provider's standard procedures are in certain circumstances because there is some evidence that your provider may not give you what they would ask for themselves, but end-of-life care that is more invasive.
What an odd situation: the one receiving care not wanting that level of intensity and the one providing care not wanting that level of intensity for themselves but wanting it for you. It is as if the doctor-patient relationship has no meaning except in the context of larger concerns about liability, reimbursement, and fear of failure.
Doctors are not alone as potential thwarters of ADs. Divisive families are often noted as potential derailers. I often tell people that completing the AD is not nearly as important — or difficult — as the conversations that must follow with family, friends, and providers because this is where the rubber meets the road.