Oscillating transcranial Doppler patterns of brain death associated with therapeutic maneuvers

Abstract

Transcranial Doppler (TCD) is a specific test for brain death diagnosis. Several Doppler patterns could change slightly during an increase of intracranial pressure related to mass effect. We present two patients with a clinical diagnosis of brain death after massive brain hemorrhage. A Doppler pattern of reverse flow with small diastolic positive flow in both middle cerebral arteries and basilar arteries was observed in both cases. TCD was repeated 6 h later, showing an increase of systolic and diastolic flow associated with high intracranial pressure (ICP) in the first patient and a decrease of ICP in the second patient associated with polyuria. Transient improvements of blood cerebral flow could be related to the use of adrenergic drugs or the use of osmotic drugs to decrease ICP. Finally the patients showed a pattern of low spikes that led to the diagnosis of cerebrovascular arrest and brain death. Therapeutics drugs to decrease ICP and several physiological processes can change several patterns of TCD associated with progression of brain death.