The effects of different rates of plasmanate infusions upon brain blood flow after asphyxia and hypotension in newborn piglets.

Brain blood flow was determined in 21 spontaneously breathing, awake, newborn piglets during control, asphyxia, superimposed hypotension, and subsequent volume expansion (15 ml/kg of plasmanate). The piglets were divided into three groups based upon the rate of volume expansion: rapid infusion group-piglets received plasmanate in three minutes; slow infusion group-piglets received plasmanate in 30 minutes: the noninfused group-piglets did not receive plasmanate. The results showed comparable increases in brain blood flow among each group during asphyxia, and similar reduction to preasphyxia values during superimposed hypotension. Although pressure-passive changes occurred, the rate of volume expansion did not influence the magnitude of change in brain blood flow. Significantly lower arterial blood pressure and brain blood flow were observed in those piglets who did not have a plasmanate infusion. Intracranial hemorrhages were not observed at autopsy in any of the study subjects. These data indicate that rapid or slow infusion of plasmanate for volume restoration did not influence the pattern of brain blood flow and that in these relatively mature brains, intracranial bleeding was not observed. Both plasmanate infused groups had higher brain blood flows at study completion (when compared to controls), reflecting compensation for anemia to maintain adequate oxygen delivery. Furthermore, regional differences in blood flow were found during asphyxia and superimposed hypotension (brain-stem greater than cerebellum greater than cerebrum), probably reflecting compensatory protection of vital portions of the central nervous system.