[Current concepts in diagnosing brain death in Germany].

Diagnosis of brain death requires definite evidence of an acute CNS catastrophe and exclusion of complicating medical conditions that may confound clinical assessment. Acute CNS catastrophe may be due to direct ("primary") brain damage (e.g., intracerebral hemorrhage, severe concussion, brain tumors), or indirect ("secondary") brain damage (e.g., cerebral hypoxia following cardio-pulmonary resuscitation). The cardinal findings in brain death are coma, absence of brainstem reflexes, and apnea. Persistence of these clinical signs determines brain death. In Germany, the intervals of a repeat clinical evaluation are at least 12 hours in patients with primary, and at least 72 hours in those with secondary brain damage. Electroencephalographically documented absence of electrical activity for at least 30 minutes or by means of transcranial Doppler ultrasonography or isotope angiography documented intracranial circulatory arrest also confirm brain death. Under such conditions, a repeat clinical evaluation is unnecessary in patients with clinical brain death signs. First of all, brain death is a clinical diagnosis. Confirmatory tests are not mandatory in most situations. In Germany, confirmatory tests are required in newborns, infants below the age of 2 years, and patients with infratentorial brain damage.