When is someone dead? (dead enough to donate organs?)

 Transplantation of deceased-donor organs has made us rethink the notion of death itself.  What does it mean that a person is dead, while organs are still sufficiently alive to be transplanted?  In particular, if death is declared due to cessation of heartbeat, what does it mean if the heart can be transplanted and re-started in another patient's body?  Does it mean the donor wasn't really dead?  

These questions were very front of mind when heart transplants first began in the late 1960's. Those debates were resolved by the legal recognition of brain death, so that a patient could be recognized as dead while still having a heartbeat.   And for years, most deceased donation occurred after brain death.  But these issues are once again controversial, as transplants of all organs are growing not just after brain death, but increasingly from Donation after Circulatory Death (DCD).  

Vox has the (long but very clearly written) story:

The breakthrough changing how Americans donate organs
A growing form of donation is expanding the organ supply in the US — and testing how medicine protects dying patients. by Pratik  Pawar

"In the last decade, DCD has gone from a rare practice to something that now accounts for nearly half of all organ donors who have died in the United States. In 2000, DCD donors supplied just 219 organs (kidneys, livers, lungs, hearts, and pancreas combined) to the transplantation system in the US. In 2025, DCD brought in close to 17,000 organs. (Most transplanted organs, about 85 percent, come from dead donors, though some organs, most often kidneys, can also come from living donors.) 
 

"That growth has saved lives, but it has also pushed transplant medicine into an unusually sensitive moment: the time after a family has decided to let their loved one die but before death has actually occurred.
 

"In brain-death donation, a patient has already been declared dead before the possibility of donation is raised with the family. Because most brain-dead donors are on ventilators, with machines supplying oxygenated blood to their organs, transplant teams can take their time with the donation process.
 

"DCD doesn’t offer that same cushion. Because organs deteriorate so quickly after circulation ceases, the work of donation — the testing, matching, surgical teams flying in — has to be set in motion once the family has decided to withdraw life support but before the patient has died.
 

"This is where the tension in DCD begins. The process pushes transplantation into the narrow interval between that decision to let someone die and the moment death occurs. It creates a situation with almost no parallel in medicine: one set of hands caring for the dying, even as another prepares to recover and transplant their organs."