If a person shows up in the ER truly brain dead and not breathing on their own then their organs will not be usable. If they are put on life support before they are truly brain dead we are back to the original question.
We humans are not as smart as we think we are. Here is a link proving why we shouldn't jump to conclusions, even educated ones: http://www.nytimes.com/2011/12/04/magazine/can-ambien-wake-minimally-conscious.html?pagewanted=all
with great expense to my estate, and to my living heirs and for no good purpose.
I guess it depends on who decides what a good purpose is.
My daughter showed up to the ER “not brain dead”.
Why?
Her pupils were still reactive to light.
Her urine output was normal.
Certain reflexes were still there.
She had been receiving CPR from a good samaritan at our accident scene.
Emergency responders continued artificial respiration for her during her ambulance trip.
Upon arrival at the ER she was placed on the ventilator.
She was transferred to another hospital where a team of doctors evaluated her brain function everyday.
After five days her brain began to lose more function.
Her pupils stopped reacting.
Her urine output increased.
More tests were conducted concerning blood flow and brainwave function.
Her internal organs began to shut down.
The ventilator was shut off to check for the gasp reflex.
They did an inner ear test to check for reflex.
Three doctors went through the brain death protocol checklist and confirmed she met all the criteria (you can google the protocol)
From the moment of our accident until the moment her heart was harvested to save the life of a 2 yr. old girl, my daughter was not “still breathing”. She was not drawing her own breath.
Thirteen years later her heart still beats.