With 94,000 Americans on an ever-lengthening list of candidates for organ donation, transplant surgeons are eager to expand the pool of potential donors. An op-ed in the New York Times contends that one way is donation after cardiac death.

"The propriety of donation after cardiac death is so well established and its potential to ease organ shortages is so great that the Health Resources and Services Administration has deemed it an important goal for the nation," writes Dr Francis L. Delmonico, the medical director of the New England Organ Bank.

Since it is a fundamental ethical rule that patients must be dead before their organs are transplanted, the problem is defining when they actually die. The normal criterion is strict: brain death, even in the brain stem. In other words, no brain function at all. This is less common than cardiac death which occurs when a person's heart stops beating. Lungs, livers and kidneys remain viable after cardiac death.

Normally brain-dead patients have been on a ventilator, with their hearts still beating, until the moment of transplant. This gives the organs a better chance of survival. But many patients die without being on a ventilator. When their heart stops, their organs begin to deteriorate immediately. The contentious issue is how long doctors should wait before removing organs. The standard interval is five minutes. Apparently there has never been a documented case of heart resuming after two minutes.

In the US, the Joint Commission on Accreditation of Healthcare Organizations will require hospitals to enable the practice from next year. However, some doctors are uneasy about removing organs too soon after the heart stops and many hospitals will take advantage of an opt-out clause. Dr Delmonico worries that their scruples could cause lives to be lost unnecessarily.