Spinal cord ischemia: an evaluation of pharmacologic agents in minimizing paraplegia after aortic occlusion

Superoxide dismutase (SOD), barbiturates, and hypothermic crystalloid were evaluated for their effectiveness in minimizing ischemic damage to the spinal cord at 40 minutes of aortic occlusion. Forty-two dogs underwent proximal and distal thoracic aortic occlusion for 40 minutes with infusion of test agents into the occluded segment. The dogs were divided into six groups. Group 1 (n = 6) served as control. Group 2 (n = 6) received hypothermic crystalloid. Group 3 (n = 6) animals received thiopental. Group 4 (n = 7) received SOD. Group 5 (n = 9) received hypothermic crystalloid and thiopental. Group 6 (n = 8) received hypothermic crystalloid, thiopental and SOD. The animals were observed for neurologic deficit for 72 hours. In group 1, six of six dogs showed complete paralysis. Five of six dogs from group 2, five of six dogs from group 3, and five of seven dogs from group 4 showed complete paraplegia. The remaining dogs in these groups showed varying degrees of recovery. Four of nine dogs in group 5 had complete paraplegia, three dogs showed varying degrees of recovery, and two dogs had no neurologic deficit. In group 6, one dog had complete paraplegia, three had partial recovery, and four had no neurologic deficit. Group 6 was the only group that showed significantly less late neurologic impairment than the control group. We concluded that although cold perfusion, barbiturates, and SOD are not protective when used alone, they are effective when all are used in combination. The combination of cold perfusion, barbiturates, and SOD significantly decreases neurologic deficit after 40 minutes of aortic occlusion.