Effect of Graded Hypothermia (27° to 34°C) on Behavioral Function, Histopathology, and Spinal Blood Flow After Spinal Ischemia in Rat
Martin Marsala, Ivo Vanicky, Tony L. Yaksh
Graded Spinal Hypothermia, 1994
Spinal cord temperatures in anesthetized rats were assessed by lowering temperatures in the paraspinal muscles to 34º, 31º, or 27º C. After ischemia, spinal cord temperature was raised to 37 degrees C for the next 30 minutes. Motor and sensory function were assessed after animals were maintained in this normothermic condition for 8 hours. In normothermic animals, 20 minutes of ischemia resulted in a loss of CO2 reactivity and hind limb paraplegia. Even mild hypothermia resulted in significant improvement of neurological function compared with the normothermic group. In moderate and deep hypothermic animal’s preservation of CO2 responsivity and complete recovery of neurological function were seen with no detectable histopathologic changes. These results show that a small decrease in temperature in the peri-ischemic period provides significant protection.