This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Nathan, H. J. Articles by Wozny, D. Search for Related Content PubMed PubMed Citation Articles by Nathan, H. J. Articles by Wozny, D. Pubmed/NCBI databases Medline Plus Health Information Heart Surgery Related Collections Behavioral/psychosocial - CV surgery Behavioral/psychosocial - stroke CV surgery: coronary artery disease Embolic stroke Neuroprotectors

(Circulation. 2001;104:I-85.)
© 2001 American Heart Association, Inc.

Surgery for Coronary Artery Disease

Neuroprotective Effect of Mild Hypothermia in Patients Undergoing Coronary Artery Surgery With Cardiopulmonary Bypass

A Randomized Trial

Howard J. Nathan, MD; George A. Wells, PhD; Janet L. Munson, PhD; Denise Wozny

From the Division of Cardiac Anaesthesia, University of Ottawa Heart Institute (H.J.N., D.W.), Clinical Epidemiology Unit, Ottawa Civic Hospital (G.A.W.), and Department of Family Medicine, University of Ottawa (J.L.M.), Ottawa, Ontario, Canada.

Reprint requests to Dr Nathan, University of Ottawa Heart Institute, H341 HIRC, 40 Ruskin St, Ottawa, Ontario K1Y 4W7, Canada. E-mail hnathan{at}ottawaheart.ca

Background— Neuropsychological deficits occur in 30% to 80% of patients undergoing heart surgery and are due in part to ischemic cerebral injury during cardiopulmonary bypass. We tested whether mild hypothermia, the most efficacious neuroprotective strategy found in laboratory studies, improved cognitive outcome in patients undergoing coronary artery surgery.

Methods and Results— Patients 60 years or older scheduled for coronary artery surgery were enrolled. During cardiopulmonary bypass, patients were initially cooled to 32°C then randomly assigned to rewarming to 37°C (control) or 34°C (hypothermic), with no further intraoperative warming. Testing was scheduled preoperatively and 1 week and 3 months postoperatively. Eleven tests were combined into 3 cognitive domains: memory, attention, and psychomotor speed and dexterity. A patient was classified as having a cognitive deficit if a decrease of 0.50 SD was realized in 1 or more domains. The incidence of cognitive deficits 1 week after surgery, which was the primary outcome, was 62% () in the control group and 48% () in the hypothermic group (relative risk 0.77, P=0.048). In the hypothermic group, the magnitude of deterioration in attention and in speed and dexterity was reduced by 55.6% (P=0.038) and 41.3% (P=0.042), respectively. At 3 months, the hypothermic group still performed better on one test of speed and dexterity (grooved pegboard). There was no difference in morbidity or mortality.

Conclusions— Our findings support a neuroprotective effect of mild hypothermia in patients undergoing coronary artery surgery and should encourage physicians and perfusionists to pay careful attention to brain temperature during cardiopulmonary bypass.

Key Words: cerebral ischemia • cardiopulmonary bypass • trials • brain • nervous system