PROTECTION OF THE BRAIN BY RETROGRADE CEREBRAL PERFUSION DURING CIRCULATORY ARREST

Hypothermic circulatory arrest is commonly used to facilitate repair o f complex congenital heart defects and aortic lesions and for complex neurosurgical procedures. However, extended periods of circulatory arr est may impair cerebral metabolism and cause ischemic injury. Retrogra de cerebral perfusion has been applied recently in aortic surgery to p rotect the brain. From January 1991 to December 1993, 29 patients unde rwent emergency operations to repair acute type A aortic dissection wi th the aid of hypothermic circulatory arrest. Six patients received hy pothermic circulatory arrest without retrograde cerebral perfusion wit h a rectal temperature of 16.4 degrees +/- 0.9 degrees C (mean a stand ard error of the mean, group 1). Retrograde cerebral perfusion during hypothermic circulatory arrest was performed in 15 patients with a rec tal temperature of 15.9 degrees +/- 0.5 degrees C (group 2) and in eig ht patients with a rectal temperature of 21.7 degrees +/- 0.8 degrees C (group 3). The hypothermic circulatory arrest times were 25 +/- 4, 4 2 +/- 4, and 63 +/- 6 minutes, respectively (p < 0.05). The cardiopulm onary bypass times were 173 +/- 5, 184 +/- 7, and 143 +/- 6 minutes, r espectively (p < 0.05). All patients survived the operation and regain ed consciousness with no neurologic defects. Follow-up (mean 23.2, 14. 5, and 5.1 months, respectively) was complete in all patients except o ne. This patient, from group 2, was killed in a road traffic accident 12 months after the operation. Our experience suggests that retrograde cerebral perfusion can effectively protect the brain from ischemic in jury and extend the safe period of hypothermic circulatory arrest. Wit h the aid of retrograde cerebral perfusion, prolonged circulatory arre st can probably be performed safely with moderate hypothermia.