Heart beating donors
Most donors providing organs for transplant are described as heart-beating donors, who have been declared as having brain stem death but the organs, including the heart, lungs, kidneys etc are being supported with a ventilator and other therapies.
Non heart beating donors
An alternative type of donor is a non-heart beating donor (NHBD). A NHBD is an individual for whom the attending doctors (after discussion with the next of kin) withdraw medial treatment after identifying the prognosis as hopeless. They are individuals who have sustained damage to the brain that is non recoverable but does not affect the brain stem. Once medical treatment is withdrawn the transplant team will wait for the heart to stop beating (asystole) prior to commencing the retrieval process. If the period of time from withdrawal of treatment to asystole is greater than one hour the transplant team will usually not proceed with donation due to concerns of reduced oxygen levels in the tissues.