[Comparison of propofol concentration in the spinal cord between intra-aortic and intravenous infusion]

To investigate the effect of propofol intra-aortic and intravenous infusion on the concentration of propofol for an ischemia-reperfusion spinal cord injury in rabbits.

Forty-six healthy adult New Zealand white rabbits were randomly divided into 3 groups: saline infusion group (group N, n = 10), propofol intra-aortic infusion group (group A, n = 16) and propofol intravenous infusion group (group V, n = 16). The infrarenal abdominal aorta was occluded for 30 min during which propofol 50 mg/kg was infused continuously intra-aortic or intravenous with a pump in group A and V. In group N, the same volume of normal saline was infused in the same way and at the same rate as in group A. Upon reperfusion, propofol concentration of the spinal segments of L4-6 and T6-8 was examined in group A and V. At 48 hours after reperfusion, the neurological outcomes were recorded in each group.

Mean blood pressure in group V from the time of 5 minutes after occlusion decreased more than in group N (P < 0.05) and than in group A from the time of 10 minutes after occlusion (P < 0.05). The mean blood pressure in group N increased more than in group A from 15 minutes after occlusion (P < 0.05). The heart rate increased more in group V from 10 minutes after occlusion than in group N and A (P < 0.05) in which no difference was observed. The propofol concentration in L4-6 of group A (26,950.5 +/- 30,242.3) ng/g was higher than that in T6-8 of group A (3,587.4 +/- 2,479.3) ng/g and both L4-6 (3,045.9 +/- 2,252.9) ng/g and T6-8 (3,181.1 +/- 1,720.9) ng/g of group V (P < 0.05). The paraplegia incidence was lower (30%) and the median of normal neurons was higher (8.4) in group A than in group N (80%, 2.2) and group V(100%, 1.9), (P < 0.05). There was no significant difference in group N and V in paraplegia incidence and the median of normal neurons (P > 0.05).

Intra-aortic infusion shows a better neurological outcome than intravenous infusion and could contribute to higher concentration of propofol in the ischemia spinal cord.