Effect of Fluosol-DA and hetastarch on local cerebral blood flow, cortical O2 availability and computerized EEG data during cerebral ischaemia*

Abstract

This study was designed to assess the effects of volume expansion with Fluosol-DA and hetastarch on local cerebral blood flow (CBF), cortical O2 availability (O2a) and computerized EEG power data during cerebral ischaemia in a primate stroke model. Focal cerebral ischaemia was produced in 20 anaesthetized Macaca monkeys by right unilateral middle cerebral artery (MCA) occlusion by the transorbital technique. Following occlusion of the right MCA, monkeys were randomized into one of the following treatment groups: Group A--Fluosol-DA 15 ml kg-1 i.v. + 40% O2; Group B--Fluosol-DA 15 ml kg-1 i.v. + 100% O2; Group C--hetastarch 30 ml kg-1 i.v. + 40% O2; Group D--hetastarch 30 ml kg-1 i.v. + 100% O2. In Group A, local CBF increased and EEG power data improved while O2a showed no change in the right MCA territory. In Group B, local CBF increased from 84% (P less than 0.001), O2a improved significantly, and EEG power data showed significant improvement in the right hemisphere. Cardiac output did not change during the Fluosol-DA infusions. In Groups C and D, local CBF increased significantly, O2a did not change, and EEG power data improved significantly in the right hemisphere. Cardiac output also increased significantly during the hetastarch infusions. These results show that Fluosol-DA and hetastarch improve local CBF and EEG power data in ischaemic brain. Only the Fluosol-DA + 100% O2 increased the O2a in the ischaemic brain. We conclude that the benefits with Fluosol-DA are due to its ability to increase O2 delivery to ischaemic brain.