Measurement of cerebral blood flow in the fetal lamb with a note on the flow-distribution.

The cerebral blood flow was measured in the acutely exteriorized fetal lamb by 133Xenon washout and microsphere distribution techniques. The measurements were performed at different blood gas levels. Regional cerebral blood flow was calculated from the microsphere distribution for five different parts of the brain. This gave estimates for blood flow in both the grey and white matter of the hemispheres, which were in close agreement with the cerebral blood flow estimated by the 133Xe washout technique. The microsphere distribution shows that the fetal cerebral hemisphere has a low blood flow compared to the basel parts of the brain and that this difference is increased during hypoxia and hypercarbia.