Background: Criteria for determining brain death (BD) vary between countries. We report the results of an investigation designed to compare procedures to determine BD in different European countries.
Methods: We developed a web-based questionnaire that was sent to representatives of 33 European countries. Responses were reviewed, and individual respondents were contacted if clarification was required.
Results: Responses were received from 28 (85 %) of the 33 countries to which the questionnaire was sent. Each country has either a law (93 %) or national guidance (89 %) for defining BD. Clinical examination is sufficient to determine BD in 50 % of countries; coma, apnea, absence of corneal, and cough reflexes are mandatory criteria in all. Confirmation of apnea is required in all countries but not defined in 4 (14 %). In the 24 (86 %) of countries with a formal definition of the apnea test, a target pCO2 level (23/24, 96 %) is the pre-specified end point in most. The (median, range) number of clinical examinations (2, 1-3) and minimum observation time between tests (3 h, 0-12 h) vary greatly between countries. Additional (confirmatory) tests are required in 50 % of countries. Hypothermia (4 %), anoxic injury (7 %), inability to complete clinical examination (61 %), toxic drug levels (57 %), and inconclusive apnea test (54 %) are among the most common indications for confirmatory tests. Cerebral blood flow (CBF) investigation is mandatory in 18 % of countries, but optional or indicated only in selected cases in 82 %. Conventional angiography is the preferred method of determining absent CBF (50 %), followed by transcranial Doppler sonography (43 %), computerized tomography (CT) angiography (39 %), CT perfusion, and magnetic resonance imaging (MRI) angiography (11 %). Electroencephalography is always (21 %) or optionally (14 %) recorded.
Conclusions: Although legislation or professional guidance is available to standardize nationally the BD diagnosis process in all European countries, there are still disparities between countries. The current variation in practice makes an international consensus for the definition of BD imperative.