Neurological damage in a cardiopulmonary arrest model in the rat

In view of the interest in cerebral protection in the framework of cardiopulmonary arrest (CPA), we assessed the neurological damage in a CPA model in the rat. CPA was induced in anesthetized Wistar rats by discontinuation of the jet ventilation and intracardiac injection of KCl. The animals were resuscitated after a CPA of either 7 min, 10.5 min, or 14 min. Six rats were used as nonischemic controls. All nonischemic rats survived, whereas in the resuscitated rats the 7-day survival rate decreased with increasing CPA duration. In the resuscitated rats, the neurological score was worse than in the control rats, and the score after 10.5-min CPA was worse than after 7-min CPA. Seizures were observed in 68% of resuscitated rats. Histopathological evaluation revealed moderate but selective neuronal necrosis in the hippocampus of all ischemic rats, and no cortical necrosis. However, neither the occurrence of seizures nor the extent of neuronal necrosis was related to the CPA duration. We conclude that in this model survival rate, neurological score, occurrence of seizures, and histopathological assessment can be used to evaluate neurological damage, although the contribution of other organ failure to these effects cannot be excluded.