Intraoperative physiologic variables and outcome in cardiac surgery: Part II. Neurologic outcome.
BACKGROUND
The impact of alterable physiologic variables on neurologic outcome after coronary artery bypass grafting procedures is unknown. The purpose of this study was to determine whether minimum intraoperative hematocrit, maximum glucose concentration, or mean arterial pressure during cardiopulmonary bypass influences risk-adjusted neurologic outcome after coronary artery bypass grafting.


METHODS
Outcome data from 2,862 patients undergoing coronary artery bypass grafting were merged with intraoperative physiologic data. A preoperative stroke risk index was calculated for each patient. Variables found significant by univariate logistic regression were tested in a multivariable model to determine association with outcome.


RESULTS
The incidence of stroke or coma in the study population was 1.3%. After controlling for stroke risk and bypass time, only an index of low mean arterial pressure during bypass retained a significant inverse association with outcome (p = 0.0304).


CONCLUSIONS
This study found no evidence that glucose concentration or minimum hematocrit are associated with major adverse neurologic outcome. The association between lower pressure during bypass and decreased incidence of stroke or coma persisted in all risk groups. This points to mechanisms other than hypoperfusion as the primary cause of neurologic injury associated with cardiac surgery.
van Wermeskerken
G K
GK
Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina 27710, USA.
Lardenoye
J W
JW
Hill
S E
SE
Grocott
H P
HP
Phillips-Bute
B
B
Smith
P K
PK
Reves
J G
JG
Newman
M F
MF
D000368:Aged; D001786:Blood Glucose / Q000032:analysis; D001794:Blood Pressure; D003128:Coma / Q000209:etiology; D001026:Coronary Artery Bypass / Q000009:adverse effects* / Q000401:mortality; D005260:Female; D006400:Hematocrit; D017052:Hospital Mortality; D006801:Humans; D007432:Intraoperative Period; D002546:Ischemic Attack, Transient / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D020521:Stroke / Q000209:etiology*
D001786:Blood Glucose