An advance directive typically does not get reviewed by emergency personnel prior to your treatment as they are not medical orders that can be acted upon. Do Not Resuscitate (DNR) orders and Physician Orders for Life-Sustaining Treatment (POLST) are medical orders signed by a doctor that can be followed by first responders. Your doctor should discuss these documents with you if you are seriously ill or very frail to see if they are appropriate for you.
Your advance directive will be reviewed at the hospital or other healthcare facility and turned into medical orders based upon the contents of your advance directive and your health condition. For example, if in your living will you state that you do not want CPR if you are in a persistent vegetative state for more than a month, that wish will be expressed as a medical order by your treating physician and placed within your medical record.