Xenon-enhanced computed tomography in brain death
J. M. Darby, H. Yonas, D. Gur and R. E. Latchaw
The absence of cerebral blood flow is a valuable adjunct confirming
clinical criteria of brain death. However, current methods to confirm
absent cerebral blood flow have problems that limit their clinical use. We
reviewed cerebral blood flow data obtained with xenon-enhanced computed
tomography in nine patients who were being evaluated for brain death. In
eight patients who met clinical criteria for brain death, mean cerebral
blood flow was 1.6 +/- 2.0 mL X 100 g X min. This value was within the
range of error inherent in the method, and therefore represented absent
flow. In a patient with persistent respiratory efforts, flow values
compatible with absent flow were obtained in the supratentorial
compartment, while mean flows as high as 24 mL X 100 g X min were measured
in selected regions of interest in the infratentorial compartment,
correlating with the clinical evidence of residual function of the brain
stem. Xenon-enhanced computed tomography may be a useful test to confirm
the absence of cerebral blood flow in patients being evaluated for brain
death.
