Intra-aortic injection of propofol prevents spinal cord injury during aortic surgery.
OBJECTIVE
We investigated whether propofol, a widely used anesthetic, injected into clamped aortic segments quickly attenuated transcranial spinal motor-evoked potential (MEP) amplitudes and protected against spinal cord injury during thoracoabdominal aortic surgery.


METHODS
Eighteen beagle dogs were divided into three groups (n=6, each group): group 1 (20 ml of saline, intra-aortic injection), group 2 (1.5 mg/kg of propofol, intravenous injection), and group 3 (1.5 mg/kg of propofol, intra-aortic injection). Aortic cross-clamping was performed for 30 min. In each group, MEP amplitudes were recorded before, during, and after aortic cross-clamping. Tarlov score and histopathological examination were used to evaluate the protective effects of intra-aortic propofol injections.


RESULTS
MEP amplitudes in group 3 attenuated to a value that was 60% of the control in just a minute after aortic cross-clamping, but maintained 40% of the control value during aortic cross-clamping. However, MEP amplitudes in groups 1 and 2 gradually attenuated and almost disappeared. Groups 1 and 2 amplitudes were lower than those in group 3, 30 min after aortic cross-clamping (p<0.001). Twenty-four hours after ischemia, the Tarlov score in group 3 was 3.5+/-0.5 and was higher than scores from groups 1 and 2, which were 0.5+/-0.5 and 1.3+/-1.2 (mean+/-SD, p<0.001, and p<0.001), respectively. Histopathologically, normal spinal cord motor neurons in group 3 were preserved to a significantly greater extent than in groups 1 and 2 (p=0.0031, and p=0.0282, respectively). There was a strong correlation between Tarlov scores at 24h and the number of normal motor neurons in the anterior horns of spinal cords (r=0.897; p<0.001).


CONCLUSIONS
Intra-aortic propofol injections produce the quick suppression of MEP amplitudes and protect spinal cords from ischemia during aortic cross-clamping.
Kumagai
Hajime
H
Department of Surgery, Division of Clinical Medical Science, Graduate School of Biomedical Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan. hajimek@hiroshima-u.ac.jp
Isaka
Mitsuhiro
M
Sugawara
Yuji
Y
Okada
Kenji
K
Imai
Katsuhiko
K
Orihashi
Kazumasa
K
Sueda
Taijiro
T
D000818:Animals; D001011:Aorta / Q000601:surgery*; D001014:Aortic Aneurysm / Q000601:surgery; D003250:Constriction; D004285:Dogs; D004353:Drug Evaluation, Preclinical; D019054:Evoked Potentials, Motor / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects; D007269:Injections, Intra-Arterial; D007430:Intraoperative Care / Q000379:methods*; D016343:Monitoring, Intraoperative / Q000379:methods; D018696:Neuroprotective Agents / Q000627:therapeutic use*; D015742:Propofol / Q000627:therapeutic use*; D020760:Spinal Cord Ischemia / Q000473:pathology / Q000503:physiopathology / Q000517:prevention & control*
D018696:Neuroprotective Agents; D015742:Propofol