Neuropsychologic impairment after coronary bypass surgery: effect of gaseous microemboli during perfusionist interventions.
OBJECTIVE
Neuropsychologic impairment is a common complication of coronary bypass surgery. Cerebral microemboli during cardiopulmonary bypass are the principal cause of cognitive deficits after coronary bypass grafting. We have previously demonstrated that the majority of cerebral emboli occur during perfusionist interventions (ie, during the injection of air into the venous side of the cardiopulmonary bypass circuit). The purpose of this study was to determine whether an increase in perfusionist interventions is associated with an increased risk of postoperative cognitive impairment.


METHODS
Patients undergoing elective coronary artery bypass grafting (n = 83) underwent a battery of neuropsychologic tests preoperatively and 3 months postoperatively. Patients were divided into 2 groups according to the median value of perfusionist interventions during cardiopulmonary bypass. Group 1 patients (n = 42) had fewer than 10 perfusionist interventions, and group 2 patients (n = 41) had 10 or more interventions.


RESULTS
The 2 groups of patients were similar for all preoperative, intraoperative, and postoperative variables, with the exception of longer cardiopulmonary bypass times in group 2 patients (P <.001). Group 2 patients had lower mean scores on 9 of 10 neuropsychologic tests, with 3 (Rey Auditory Verbal Learning, Digit Span, and Visual Span) being statistically significant. Group 2 patients had worse cognitive test scores, even when controlling for increased bypass times. Group 2 patients had a nonsignificant trend toward an increased prevalence of neuropsychologic impairment 3 months postoperatively.


CONCLUSIONS
Introduction of air into the cardiopulmonary bypass circuit by perfusionists, resulting in cerebral microembolization, may contribute to postoperative cognitive impairment.
Division of Cardiovascular Surgery, Toronto General Hospital, University Health Network, University of Toronto, Toronto, Ontario, Canada.
M A
MA
Borger
C M
CM
Peniston
R D
RD
Weisel
M
M
Vasiliou
R E
RE
Green
C M
CM
Feindel
D002315:Cardiopulmonary Bypass / Q000009:adverse effects* / Q000523:psychology; D003072:Cognition Disorders / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000209:etiology* / Q000523:psychology; D001026:Coronary Artery Bypass / Q000009:adverse effects / Q000523:psychology*; D003327:Coronary Disease / Q000601:surgery; D005260:Female; D006801:Humans; D020766:Intracranial Embolism / Q000150:complications / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000523:psychology*; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D015995:Prevalence; D011446:Prospective Studies; D017585:Ultrasonography, Doppler, Transcranial