Abstract
The authors evaluate the usefulness of transcranial Doppler (TCD) examination in Intracranial hypertension and brain death, on the basis of an experiment using a feline intracranial hypertension model and, on clinical studies.
The vanishing end-diastolic pattern of TCD is believed to show the critical point of intracranial hypertension. Experimentally, the vanishing end-diastolic pattern was observed at a cerebral perfusion pressure of approximately 50mmHg, accompanied by severe suppression in electroencephalography. In severe head injury patients, the absence of end-diastolic flow in TCD gives a forewarning of a potential fatal prognosis.
In eleven brain death cases, which satisfied the criteria of Japanese Health and Welfare Ministry's committee, TCD examination demonstrated one of the classical patterns of virtual cessation of cerebral blood flow (zero, systolic spike, or to and fro) with a sensitivity response of 91%. Doppler signals from the superficial temporal artery and internal maxillary artery, which resemble signals of the middle cerebral artery, must be differentiated, in order to avoid the danger of misinterpretation.
