Effect of hypovolemic hypotension on the cerebral oxygen supply of rats with slightly raised or lowered body temperatures.

Combination effects of hypovolemia and body cooling or warming being important for laboratory animals, accident victims, hemorrhagic patients, etc. have been investigated in the anesthetized rat brain. Combined hypovolemic hypotension (MAP +/- SD = 36 +/- 7 mm Hg) and additional cooling (32 degrees) intensified the drop of cerebral cortex PO2 (rPO2) (initial rPO2 +/- SD = 28 +/- 16 mm Hg, hypovolemic rPO2 = 16 +/- 12 mm Hg, N = 15) while slight body warming (39 degrees) improved the cerebral hypoxia (initial rPO2 +/- SD = 41 +/- 20 mm Hg, hypovolemic rPO2 = 32 +/- 21 mm Hg, N = 11) despite arterial saturation of the oxyhemoglobin was normal (N = 11).