Radovsky A. Moderate hypothermia after cardiac arrest of 17 minutes in dogs: effect on cerebral and cardiac outcome. Stroke

Moderate hypothermia (30 ° C) induced before circulatory arrest is known to improve neuro-logic outcome. We explored, for the first time in a reproducible dog outcome model, moderate hypothermia induced during reperfusion after cardiac arrest (resuscitation). In three groups of six dogs each (iV=18), normothermic ventricular fibrillation cardiac arrest (no blood flow) of 17 minutes was reversed by cardiopulmonary bypass — normothermic in control group I (37.5 ° C) and hypothermic to 3 hours in groups II (32 ° C) and III (28 ° C). Defibrillation was achieved in <5 minutes and partial bypass was continued to 4 hours, controlled ventilation to 20 hours, and intensive care to 96 hours. All 18 dogs survived. Electroencephalographic activity returned significantly earlier in groups II and III. Mean±SD best neurologic deficit between 48 and 96 hours was 44 ±8 % in group I, 38 ±12 % in group II, and 35 ±7 % in group III (differences not significant). Best overall performance category 2 (good outcome) between 48 and 96 hours was achieved in none of the six dogs in group I and in four of the 12 dogs in the combined hypothermic groups II and III (difference not significant). Mean±SD brain total histologic damage score was 130±22 in group I, 93±28 in group II (p=0.05), and 80±26 in group III (p=0.03). Gross myocardial damage was greater in groups II and III than in grou