Blood flow and electrolytes in spinal cord ischemia.

The contribution of reoxygenation-reperfusion injury to ischemic brain damage has been clearly demonstrated but not in the spinal cord. To evaluate this phenomenon in spinal cord ischemia, we measured spinal cord blood flow (SCBF) by [14C]iodoantipyrine and electrolytes in rabbits after 10 or 40 min ischemia followed by 30 min or 4 days recirculation. Ischemia for 10 or 40 min reduced blood flow in the lower lumbar segments L5-L7 (30 ml/100 g/min) to 5 and 10% of control. After 30 min of recirculation moderate hyperemia (25-40% above control) was observed in segments L5-L7 which was not related to the degree of functional impairment. Na+, water, and Ca2+ increased and K+ decreased after 40 min ischemia, but were unchanged after 10 min ischemia. Recirculation for 30 min after 40 min of ischemia resulted in a progressive rise in Ca2+ which correlated with irreversible spinal cord injury.