Spinal cord protection by papaverine and intrathecal cooling during aorticcrossclamping

Aim. To extend the safe period of aortic crossclamping in the porcine model by intrathecally dilating the spinal arteries, with cooling of the spinal cord, or using selfotel Methods. Experimental design and setting: prospective domestic laboratory p ig study. Interventions: fifteen animals were assigned to a control group ( C, N=5), intrathecal papaverine plus spinal cord cooling group (IP+C, N=5), or selfotel group (S, N=5). In the IP+C group, a lumbar laminectomy was pe rformed and an intrathecal catheter placed for intrathecal injection of pap averine and perfusion with cold Ringer's solution (4 degrees C) prior to ao rtic crossclamping. In the selfotel group, 20 mg/kg of selfotel was adminis tered 30 minutes before aortic crossclamping. In all 15 animals, the aorta was cross-clamped for 60 minutes at normothermia. Measures: immediately aft er the operation and 24 hours later, lower limb function was evaluated. Results. All five control animals were paralyzed; all 5 IP+C animals could stand or walk (p=0.004 versus control); and in the selfotel group, one had paraparesis, three had paraplegia and one died before evaluation (p=n.s.) Conclusions. The combination of intrathecal papaverine to dilate spinal art eries and prevent spasm from the cold solution plus intrathecally cooling t he spinal cord appears to extend the period of safe aortic cross-clamping. Selfotel, in this model of extended, severe, spinal cord ischemia, was inef fective.