200 Mild Protective and Resuscitative Cerebral Hypothermia Improves Outcome after Asphyxial Cardiac Arrest in a New Rat Model
Prehospital and Disaster Medicine
Objective: To summarize the results of a logical sequence of four cardiac-arrest outcome studies. Methods: The standardized ventricular fibrillations (VF) 10 or 12.5 min (no-flow) outcome models in dogs were used. In studies #1, #3 and #4, reperfusion was with brief cardiopulmonary bypass (CPB). In study #2, reperfusion was with external CPR. The use of intermittent positive pressure breathing (IPPV) was to 20 h and intensive care with outcome evaluation to 72 or 96 h. Outcome was determined as
... e was determined as overall performance, neurologic deficit, and brain histologic damage scores. Mild hypothermia (34°C) was induced from reperfusion to 1-2 h; in study #2, a combination of external cooling methods was started after restoration of spontaneous normotension. Results: In all four studies, cerebral functional and morphologic outcomes were significantly better in the mild hypothermia groups compared with normothermic concurrent controls. Mild hypothermia was more beneficial than was post-arrest moderate (30°C) or deep hypothermia (15°C), which worsened cardio-vascular variables. When start of cooling was delayed by 15 min after reperfusion, histologic but not functional improvement occurred. Conclusions: These dog data and others' rat data justify clinical development and evaluation of rapid mild brain cooling methods for use in EMS and hospitals.