A doctor claims most organ donors are not dead when their organs are removed.

In an article in the Journal of Law and Medicine, Melbourne physician and associate professor James Tibballs argues it is "impossible to be certain" that the brain and circulation have ceased "irreversibly" before organs are taken.

"It may be better to concede that, although organ donation is presently conducted under the guise of total brain death, it is in reality conducted under a point of `neurological no return' or `as good as dead'," he said.

Tibballs, from the Royal Children's Hospital, argues discrepancies between legal definitions of death and actual clinical practice lead to ethical and legal problems.

"What perhaps is needed is acknowledgement by the medical and legal professions, and acceptance by the public, that organ donation is presently commonly carried out on persons not actually dead but rather in the process of dying or `not completely dead but dead enough'," he said.

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