To begin with this is a bad scenario, you have this patient that is 97 years old that more than likely has CAD and other coronary disease in a dangerous rhythm. My personal approach would be to contact medical control, depending on your service area and the meds that you carry, and request an alternate treatment plan that may include a calcium channel blocker ( Diltiazem, or Verapamil) , benzodiazepine (Lorazepam) , or beta-blocker (Metoprolol), at least with a CCB you have calcium chloride / gluconate to reverse the effects and it is a slow push that you can stop pushing if you notice undesired effects. I am not sure I am comfortable pushing adenosine as a first line drug in someone over the age of 85 or so. This is only my take on avoiding the cardiac arrest situation, now to the question of the DNR, it is what it is. Say you are called to the scene of an auto accident, the patient is a 20 year old male that is a terminal cancer patient that is unresponsive, has a pulse, with a respiratory rate of 6, do we intubate even though the DNR is second to the CA, the answer is no, it does not matter the situation of the arrest the DNR is a legal document and the family has the right to seek legal help and sue if the DNR is violated. I hope this helps and would like to get the opinion of other EMS professionals on the use of CCB, benzos, and beta blockers prior to adenosine in the high risk patient.