Objectives: a) To examine the clinical utility of transcranial Doppler and continuous-wave Doppler in monitoring nonsurgical patients with severe intracranial disease until intracranial circulatory arrest and brain death; and b) to investigate if hemodynamic phenomena that occur under such conditions are correlated to specific transcranial Doppler and continuous-wave Doppler waveforms.
Design: Prospective, observational study.
Setting: Medical intensive care unit (ICU) in a city hospital.
Patients: Thirty-seven consecutive patients with Glasgow Coma Scores of < 7.
Measurements and main results: Transcranial Doppler examination was conducted transtemporally on the left- and right-middle cerebral artery four times daily. In all patients, transcranial Doppler waveforms exhibited high resistance profiles with low, zero, and then reversed diastolic flow velocity. Only three waveform patterns, consisting of diastolic reverse flow without diastolic forward flow, brief systolic forward flow, and undetectable flow in the middle cerebral artery were registered in the 22 brain-dead patients, but in none of the other comatose patients.
Conclusion: Transcranial Doppler offers a noninvasive method to document deterioration of cerebral perfusion pressure and in the future could be included in protocols for brain death diagnosis.