Mild hypothermia after cardiac arrest in dogs does not affect postarrest multifocal cerebral hypoperfusion.

Although mild resuscitative hypothermia (34 degrees C) immediately after cardiac arrest improves neurological outcome in dogs, its effects on cerebral blood flow and metabolism are unknown.We used stable xenon-enhanced computed tomography to study local, regional, and global cerebral blood flow patterns up to 4 hours after cardiac arrest in dogs. We compared a normothermic (37.5 degrees C) control group (group I, n = 5) with a postarrest mild hypothermic group (group II, n = 5). After ventricular fibrillation of 12.5 minutes and reperfusion with brief cardiopulmonary bypass, the ventilation, normotension, normoxia, and mild hypocapnia were controlled to 4 hours after cardiac arrest. Group II received (minimal) head cooling during cardiac arrest, followed by systemic bypass cooling (to 34 degrees C) during the first hour of reperfusion after cardiac arrest.The postarrest homogeneous transient hyperemia was followed by global hypoperfusion from 1 to 4 hours after arrest, with increased "no-flow" and "trickl...