Biomaterial Database

Hypothermia to reduce neurological damage following coronary artery bypass surgery. 2001

K Rees, and M Beranek-Stanley, and M Burke, and S Ebrahim

Department of Social Medicine, University of Bristol, Canynge Hall, Whiteladies Road, Bristol, BS8 2PR. Karen.Rees@bristol.ac.uk

BACKGROUND Coronary artery bypass surgery (CABG) may be life saving, but known side effects include neurological damage and cognitive impairment. The temperature used during cardiopulmonary bypass (CPB) may be important with regard to these adverse outcomes, where hypothermia is used as a means of neuroprotection. OBJECTIVE To assess the effectiveness of hypothermia during CABG in reducing neurological damage and subsequent cognitive deficits. METHODS The Cochrane Controlled Trials Register was searched for randomised controlled trials (RCT) and this was updated by searching MEDLINE and EMBASE to December 1999 using database specific RCT filters. Reference lists of retrieved articles were searched and experts in the field were contacted. METHODS Only RCTs were considered. All patients undergoing CABG, either first time or revisions, elective or emergency procedures, were included. Any hypothermia protocol was considered. Only trials reporting neurological outcomes were included. METHODS Studies were selected independently and data were extracted from the source papers independently by two reviewers. Authors were contacted for further information. Studies were combined with meta-analysis where appropriate, and meta-regression was used to explore heterogeneity. RESULTS There was a trend towards a reduction in the incidence of non fatal strokes in the hypothermic group (OR 0.68 (0.43, 1.05)). Conversely, there was a trend for the number of non stroke related perioperative deaths to be higher in the hypothermic group (OR 1.46 (0.9, 2.37)). Hypothermia had no effect on the incidence of non fatal myocardial infarction (OR 1.05 (0.81, 1.37)), but the incidence of another marker of myocardial damage, low output syndrome, was higher in the hypothermic group (OR 1.21 (0.99, 1.48). When pooling all "bad" outcomes (stroke, perioperative death, myocardial infarction, low output syndrome, intra aortic balloon pump use) there was no significant advantage of either hypothermia or normothermia (OR 1.07 (0.92, 1.24)). Only 4 of 17 trials reported neuropsychological function as an outcome. CONCLUSIONS This review could find no definite advantage of hypothermia over normothermia in the incidence of clinical events. Hypothermia was associated with a reduced stroke rate, but this is off set by a trend towards an increase in non stroke related perioperative mortality and myocardial damage. There is insufficient data to date to draw any conclusions about the use of mild hypothermia. Similarly, there is insufficient data to date to comment on the effect of temperature during CPB on subtle neurological deficits, and further trials are needed in these areas.

UI	MeSH Term	Description	Entries
D007036	Hypothermia, Induced	Abnormally low BODY TEMPERATURE that is intentionally induced in warm-blooded animals by artificial means. In humans, mild or moderate hypothermia has been used to reduce tissue damages, particularly after cardiac or spinal cord injuries and during subsequent surgeries.	Induced Hypothermia,Mild Hypothermia, Induced,Moderate Hypothermia, Induced,Targeted Temperature Management,Therapeutic Hypothermia,Hypothermia, Therapeutic,Induced Mild Hypothermia,Induced Mild Hypothermias,Induced Moderate Hypothermia,Induced Moderate Hypothermias,Mild Hypothermias, Induced,Moderate Hypothermias, Induced,Targeted Temperature Managements
D009203	Myocardial Infarction	NECROSIS of the MYOCARDIUM caused by an obstruction of the blood supply to the heart (CORONARY CIRCULATION).	Cardiovascular Stroke,Heart Attack,Myocardial Infarct,Cardiovascular Strokes,Heart Attacks,Infarct, Myocardial,Infarction, Myocardial,Infarctions, Myocardial,Infarcts, Myocardial,Myocardial Infarctions,Myocardial Infarcts,Stroke, Cardiovascular,Strokes, Cardiovascular
D002303	Cardiac Output, Low	A state of subnormal or depressed cardiac output at rest or during stress. It is a characteristic of CARDIOVASCULAR DISEASES, including congenital, valvular, rheumatic, hypertensive, coronary, and cardiomyopathic. The serious form of low cardiac output is characterized by marked reduction in STROKE VOLUME, and systemic vasoconstriction resulting in cold, pale, and sometimes cyanotic extremities.	Low Cardiac Output,Low Cardiac Output Syndrome,Output, Low Cardiac
D003072	Cognition Disorders	Disorders characterized by disturbances in mental processes related to learning, thinking, reasoning, and judgment.	Overinclusion,Disorder, Cognition,Disorders, Cognition
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D001026	Coronary Artery Bypass	Surgical therapy of ischemic coronary artery disease achieved by grafting a section of saphenous vein, internal mammary artery, or other substitute between the aorta and the obstructed coronary artery distal to the obstructive lesion.	Aortocoronary Bypass,Bypass, Coronary Artery,Bypass Surgery, Coronary Artery,Coronary Artery Bypass Grafting,Coronary Artery Bypass Surgery,Aortocoronary Bypasses,Artery Bypass, Coronary,Artery Bypasses, Coronary,Bypass, Aortocoronary,Bypasses, Aortocoronary,Bypasses, Coronary Artery,Coronary Artery Bypasses
D015201	Meta-Analysis as Topic	A quantitative method of combining the results of independent studies (usually drawn from the published literature) and synthesizing summaries and conclusions which may be used to evaluate therapeutic effectiveness, plan new studies, etc., with application chiefly in the areas of research and medicine.	Clinical Trial Overviews,Data Pooling,Overviews, Clinical Trial,Clinical Trial Overview,Data Poolings,Meta Analysis as Topic,Overview, Clinical Trial
D016032	Randomized Controlled Trials as Topic	Works about clinical trials that involve at least one test treatment and one control treatment, concurrent enrollment and follow-up of the test- and control-treated groups, and in which the treatments to be administered are selected by a random process, such as the use of a random-numbers table.	Clinical Trials, Randomized,Controlled Clinical Trials, Randomized,Trials, Randomized Clinical
D020521	Stroke	A group of pathological conditions characterized by sudden, non-convulsive loss of neurological function due to BRAIN ISCHEMIA or INTRACRANIAL HEMORRHAGES. Stroke is classified by the type of tissue NECROSIS, such as the anatomic location, vasculature involved, etiology, age of the affected individual, and hemorrhagic vs. non-hemorrhagic nature. (From Adams et al., Principles of Neurology, 6th ed, pp777-810)	Apoplexy,Cerebral Stroke,Cerebrovascular Accident,Cerebrovascular Apoplexy,Vascular Accident, Brain,CVA (Cerebrovascular Accident),Cerebrovascular Accident, Acute,Cerebrovascular Stroke,Stroke, Acute,Acute Cerebrovascular Accident,Acute Cerebrovascular Accidents,Acute Stroke,Acute Strokes,Apoplexy, Cerebrovascular,Brain Vascular Accident,Brain Vascular Accidents,CVAs (Cerebrovascular Accident),Cerebral Strokes,Cerebrovascular Accidents,Cerebrovascular Accidents, Acute,Cerebrovascular Strokes,Stroke, Cerebral,Stroke, Cerebrovascular,Strokes,Strokes, Acute,Strokes, Cerebral,Strokes, Cerebrovascular,Vascular Accidents, Brain