Extracerebral postresuscitation disease after cardiac arrest (CA) in dogs. A preliminary report

Introduction: After prolonged CA, ischemic injury to the brain is most debilitating, but no blood flow >10min also causes changes in extracerebral organs. We hypothesized that the degree of changes in viscera correlates with the duration of arrest, and with cerebral functional and morphologic outcome. Methods: 9 dogs were exsanguinated over 5 min to CA no-flow of 15 min (groups 1 and 2) or 30 min (group 3). Resuscitation was with closed-chest cardiopulmonary bypass. Control group 1 (n=3) remained normothermic. Groups 2 and 3 had aortic arch flush via a balloon catheter with saline at 4°C, which lowered "brain temperature" to about 34°C at 5 min of CA. Intensive care was to 72h. Complete macroscopic necropsies were performed and samples of heart, lung, liver, kidneys, stomach, and small and large intestine were taken for light microscopic (HE) examinations and semiquantitative scoring of lesions as mild=0-25%, moderate=25-50%, severe=50-75%, or extensive 75-100%. Results: Overall, severe microscopic changes were noted in heart, liver, kidneys and small intestine in group 3, moderate in group 1 and minimal in group 2. The heart had severe multifocal myocardial necroses in group 3; mild in groups 1 and 2. The lung was normal except for occasional thromboemboli. The liver in group 3 had moderate, confluent hepatocytic necroses predominantly in zone 3. The kidneys had mild to moderate acute tubular necrosis (ATN) and moderate to severe vacuolization in the proximal convoluted tubules in group 3, mild in group 2, and moderate ATN and mild vacuolization in group 1. The small intestine had moderate to severe ischemic changes in the mucosa, most prominent in crypt epithelium in group 3. Histologic damage scores (HDS) correlated with neurologic deficit scores (NDS 0%=normal, 100%=brain death), and brain HDS. Conclusions: Morphologic changes in extracerebral organs correlate with brain HDS. Even when exsanguination CA is survivable, these changes may cause disability.