Retrograde Cerebral Perfusion with Hypothermic Blood Provides Efficient Protection of the Brain: A Neuropathological Study

Abstract

Retrograde cerebral perfusion is a method that is recently being used for protection of the brain during operations on the aortic arch. This method is useful but is said to provide a limited time for protecting the brain. We designed an experiment in dogs to investigate neuropathologically the effect of protecting the brain for 120 minutes under: (1) circulatory arrest (CA); (2) retrograde cerebral perfusion with moderately cooled blood (RCPMC); and (3) retrograde cerebral perfusion with deeply cooled blood (RCPDC). We calculated the number of the abnormal cells of 400 hippocampal neurons per dog light microscopically. The number was 199 +/- 23 (mean +/- 1 SD) in the CA group, 149 +/- 50 in the RCPMC group, and 72 +/- 33 in the RCPDC group. The difference between the CA group and the RCPMC group was not statistically significant (p < 0.05), but there was a significant difference between the RCPMC and RCPDC groups (p < 0.05). The degree of cerebral protection provided by retrograde cerebral perfusion for 120 minutes is not sufficient when using moderately cooled blood. If we use deeply cooled blood at a temperature of about 10 degrees C, we should obtain a sufficient degree of protection of the brain.

Failure of retrograde cerebral perfusion to attenuate metabolic changes associated with hypothermic circulatory arrest

“…The evidence for cerebral metabolic support by RCP is species dependent. Although RCP is capable of contributing to cerebral metabolism in dogs, 19 no significant cerebral blood flow or metabolic benefit has been demonstrated in baboons. 20 Evidence of true cerebral perfusion in human subjects is also limited.…”

Neuropsychometric outcome following aortic arch surgery: a prospective randomized trial of retrograde cerebral perfusion

“…Although a metabolic effect has been seen in some species, this has not been demonstrated in man or other primates. 5,6 Other potential benefits of RCP include flushing out atheromatous or gaseous emboli and toxic metabolites, 7 and the potential maintenance of cerebral hypothermia. 8 However, RCP may also increase the risk of cerebral edema due to raised venous and intracranial pressure.…”

Hypothermic retrograde jugular perfusion reduces brain damage in rats with heatstroke

“…Animal experiments also confirmed that RCP provided better cerebral protection compared with HCA alone (38,39). In addition, Imamaki et al (41) used deeply cooled blood during RCP to provide better protection of the brain. This finding suggests that enhanced cranial hypothermia, rather than brain perfusion, may be the major beneficial factor of retrograde cerebral perfusion.…”