Movements in brain death: a systematic review

Brain death is the irreversible lost of function of the brain including the brainstem. The presence of spontaneous or reflex movements constitutes a challenge for the neurological determination of death. We reviewed historical aspects and practical implications of the presence of spontaneous or reflex movements in individuals with brain death and postulated pathophysiological mechanisms. We identified and reviewed 131 articles on movements in individuals with confirmed diagnosis of brain death using Medline from January 1960 until December 2007, using 'brain death' or 'cerebral death' and 'movements' or 'spinal reflex' as search terms. There was no previous systematic review of the literature on this topic. Plantar withdrawal responses, muscle stretch reflexes, abdominal contractions, Lazarus's sign, respiratory-like movements, among others were described. For the most part, these movements have been considered to be spinal reflexes. These movements are present in as many as 40-50% of heart-beating cadavers. Although limited information is available on the determinants and pathophysiological mechanisms of spinal reflexes, clinicians and health care providers should be aware of them and that they do not preclude the diagnosis of brain death or organ transplantation.