[Haemodilution and cerebral blood flow (author's transl)]

Cerebral blood flow has been estimated in 10 patients during acute haemodilution and during the consecutive operation. Cerebral blood flow showed a lasting increase during the time of haemodilution, but this increase did not parallel the decrease of haematocrit value. The increase of cerebral blood flow became pronounced only, when the haematocrit become lower than 30%. Assumably the elevation of cerebral flow is mainly due to autoregulative mechanisms of cerebral blood flow to sustain oxygenation. It is concluded, that haemodilution below values of 30% hc might be dangerous in patients suffering from cerebral sclerosis.