Alterations in brain and muscle oxygenation during hypovolemia and replacement with plasma substitutes in rats.

A study was conducted on the effects of mild hemorrhage-induced hypovolemia and subsequent replacement with lactated Ringer's dextran or hemoglobin solution in 52 pentobarbital-anesthesized rats. Blood loss of 1.25% of body weight had no significant effect on the blood flow or relative tissue PO2 of the white matter of the cerebral cortex. Blood flow and relative tissue PO2 of the biceps brachii muscle were lowered during hypovolemia. Volume replacement with any of the three plasma substitutes had no effect on blood flow or relative tissue PO2 of cortical white matter. They all caused partial restoration of blood flow and relative tissue PO2 in the biceps brachii muscle. Full return in the muscle was not achieved, nor were there any significant differences between the treatment groups.