Donation After Brain Death (DBD)

DBD — previously known as heart-beating donation — occurs when a patient has been confirmed as brain stem dead while being maintained on mechanical ventilation and organ perfusion support. The brain stem dead patient’s organs are continuously perfused with oxygenated blood until they are surgically retrieved in the operating theatre. This provides the optimal conditions for organ preservation — all major organs (heart, lungs, liver, kidneys, pancreas, small bowel) can potentially be retrieved, and the quality of organs from DBD donors is generally superior to DCD donors because the warm ischaemia time is minimal.

The sequence of events in DBD is: brain stem death confirmed → SNOD referred and family approached → authorisation confirmed (explicit or deemed) → donor optimisation initiated → donor management in ICU → retrieval operation in theatre → organs distributed to transplant centres.

Donation After Circulatory Death (DCD)

DCD occurs in patients who die following cardiac arrest rather than brain stem death. There are two main DCD pathways in UK practice. Controlled DCD (Maastricht category III) is the most common: following a decision to withdraw life-sustaining treatment in a patient who cannot survive without it, the retrieval team is on standby, and organ retrieval begins immediately after circulatory death is confirmed following withdrawal. The key variable in controlled DCD is the warm ischaemia time — the period between cessation of circulation and the start of cold preservation. Warm ischaemia causes a pattern of injury (ischaemia-reperfusion injury) in retrieved organs that is more pronounced than in DBD, and this limits both which organs can be retrieved and the acceptable warm ischaemia time.

Uncontrolled DCD (Maastricht categories I and II) — retrieval following unsuccessful CPR — is practised in a small number of specialist centres in the UK with advanced normothermic regional perfusion (NRP) programmes. NRP involves cannulating the patient and resuming extracorporeal circulation after circulatory death is confirmed, restoring perfusion to abdominal and (in some programmes) thoracic organs and allowing assessment of organ viability before retrieval. This pathway requires very rapid response and is not available in all centres.