Brain death in children: characteristic common carotid arterial velocity patterns measured with pulsed Doppler ultrasound.

The clinical criteria for brain death in children remain controversial. An accepted confirmatory test for brain death is the documented absence of intracranial blood flow, the most common methods being arteriography and radionuclide cerebral angiography. We correlated the common carotid arterial blood velocity patterns measured by pulsed Doppler ultrasound in 32 brain-dead infants and children with results of their clinical examinations and, whenever possible, with radionuclide cerebral angiography. A distinct, characteristic carotid arterial blood velocity waveform indicating absent cerebral blood flow appeared in 19 of the 23 brain-dead patients 4 months of age or older. The velocity patterns of the other four older children were similar, but not identical, to the characteristic waveform. The remaining nine brain-dead patients were infants 4 months of age or younger. These infants had velocity waveforms different from those of healthy infants, but also were totally different from the characteristic brain death pattern of older children. No patient had the characteristic brain death waveform without being clinically brain dead. Measurement of carotid arterial blood velocity with pulsed Doppler ultrasound is a repeatable, noninvasive, portable test useful for confirmation of brain death in children.