There are two ways to be dead in this country: dead according to neurological criteria ("brain death" -- an increasingly controversial concept) and dead according to cardio-pulmonary criteria. According to the latter, death occurs when there is an irreversible cessation of all cardiac and pulmonary function. This is the standard adopted in the Uniform Determination of Death Act and adopted by statute, regulation, or judicial decision in all 50 states and the District of Columbia. Pulselessness and lack of spontaneous respiration: They have signalled death for eons.
The development of CPR sharpened the concept of cardiopulmonary death. If CPR (or, in a clinical setting, Advanced Cardiac Life Support) fails to reëstablish a pulse, irreversibility is established and death can be declared.
A procedure known as circulatory determination of death ("DCD") allows this sequence of events to occur in an operating room. It begins when ventilator support is withdrawn from a prospective organ donor. The surgical team waits for up to 90 minutes (times may vary by institution) for the cessation of cardiac and pulmonary function. If that occurs, the clock starts clicking (typically for 5 minutes, longer at some institutions) to see if the patient experiences autoresuscitation. If not, irreversibility is deemed to be established, the patient can be declared dead, and the organ retrieval may begin.
DCD organ donations were originally controversial -- including a Cleveland prosecutor's 1997 assertion that DCD may be tantamount to killing patients for their organs (NY Times; may be behind paywall) -- and are still opposed by a minority of experts. On the other hand, DCD is actively promoted by UNOS and is supported by a majority of ethics commentators.
NRP takes DCD one step further and arguably pushes beyond the outer limits of irreversibility. There are various forms of NRP, but most appear to involve cutting off any possible blood flow to the brain and reestablishing circulation by connecting the donor to ECMO (Extra-Corporeal Membrane Oxygenation). At least one version of this process may result in restarting the donor's heart. You can see the possible conflict with the requirement of irreversibility.
The NPR story is a good introduction to the controversy. For a deeper dive, the American Journal of Bioethics ("AJOB") devoted an entire issue to NRP. (This, too, may be behind a paywall.) If AJOB is unavailable, run this search in NIH's PubMed service. Today it pulled up 69 articles, including some that are available for free.
