There seems to be a move to make that policy. If a patient on a ventilator has a poor prognosis for ever recovering, it's DNR and perhaps termination.
When the ER is on fire you have no choice. Battlefield decisions. Airway, breathing, circulation, eyes, ey, upper extremity, lower extremity. Succession of priorities as resources are available. Lastly, life. No body’s vision gets preserved until everybody is pink.
In battle it’s called “The Black Tag”.