COMPARATIVE EXPERIMENTAL-STUDY OF CEREBRAL PROTECTION DURING AORTIC-ARCH RECONSTRUCTION

Background. The optimal adjunctive method for cerebral protection duri ng aortic arch repair remains controversial. Methods. Retrograde cereb ral perfusion, selective cerebral perfusion, and hypothermic circulato ry arrest were compared in terms of their effect on cerebral function of mongrel dogs using somatosensory evoked potentials. Brain temperatu res were held at 20 degrees C for 90 minutes during cerebral perfusion or circulatory arrest and then rewarmed gradually to normal temperatu re. Results. Somatosensory evoked potentials completely disappeared as soon as retrograde cerebral perfusion or hypothermic circulatory arre st started and did not recover completely. In the selective cerebral p erfusion group, it recovered in all cases. Only 2% of cerebral blood n ow and about 3% of the cerebral metabolic rate for oxygen were obtaine d during retrograde cerebral perfusion compared with the preoperative value. The analysis of adenosine triphosphate and water content of the brain supported these results. Conclusions. Retrograde cerebral perfu sion had some advantage for cerebral protection compared with hypother mic circulatory arrest, but could not supply sufficient cerebral blood flow to maintain brain function. Selective cerebral perfusion was the safest method for arch reconstruction that requires cerebral protecti on for 90 minutes.