title: Moderate hypothermia after cardiac arrest of 17 minutes in dogs. Effect on cerebral and cardiac outcome.
abstract: Moderate hypothermia (30 degrees C) induced before circulatory arrest is known to improve neurologic 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 (N = 18), normothermic ventricular fibrillation cardiac arrest (no blood flow) of 17 minutes was reversed by cardiopulmonary bypass--normothermic in control group I (37.5 degrees C) and hypothermic to 3 hours in groups II (32 degrees C) and III (28 degrees C). Defibrillation was achieved in less than or equal to 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 group I--numerically higher overall and significantly higher in group III for the right ventricle alone (p = 0.02). Moderate hypothermia after prolonged cardiac arrest may or may not improve cerebral outcome slightly and can worsen myocardial damage.
authors.affiliation: International Resuscitation Research Center, University of Pittsburgh, PA 15260.
authors.forename: Y
authors.initials: Y
authors.lastname: Leonov
authors.forename: F
authors.initials: F
authors.lastname: Sterz
authors.forename: P
authors.initials: P
authors.lastname: Safar
authors.forename: A
authors.initials: A
authors.lastname: Radovsky
mesh_terms: D000818:Animals; D001794:Blood Pressure; D001831:Body Temperature; D001921:Brain / Q000473:pathology / Q000503:physiopathology; D002315:Cardiopulmonary Bypass; D004195:Disease Models, Animal; D004285:Dogs; D004569:Electroencephalography; D006323:Heart Arrest / Q000150:complications*; D006331:Heart Diseases / Q000209:etiology*; D007036:Hypothermia, Induced; D008297:Male; D009206:Myocardium / Q000473:pathology; D009422:Nervous System Diseases / Q000209:etiology*; D015424:Reperfusion; D013997:Time Factors