Change in plasma glutamate concentration during cardiac surgery is a poor predictor of cognitive outcome.
OBJECTIVE
To develop a simple and reliable method for quantitating plasma glutamate concentration and apply this method to monitor systemic glutamate levels during coronary artery bypass graft (CABG) surgery, a procedure associated with neurologic deficits.


METHODS
Prospective serial investigation of cardiac surgery patients.


METHODS
Tertiary-care university teaching hospital.


METHODS
Patients undergoing CABG surgery (n = 33).


METHODS
Preoperative and postoperative neurologic and neurocognitive testing were done. Intraoperative blood samples for glutamate quantitation were obtained from jugular bulb and pulmonary artery catheters before, during, and after cardiopulmonary bypass.


RESULTS
Glutamate concentrations were determined using a reverse-phase high-pressure liquid chromatography method coupled to precolumn derivatization of the analyte with o-phthalaldehyde. The mean prebypass plasma glutamate concentration was 79.4 +/- 41.8 micromol/L. Plasma glutamate levels fluctuated during surgery with considerable degrees of temporal and quantitative interpatient variability. Neurologic and neurocognitive deficits were observed after CABG surgery. However, neither the occurrence nor the severity of cognitive decline could be predicted by the magnitude of increase in plasma glutamate concentration.


CONCLUSIONS
Fluctuations in intraoperative systemic glutamate levels do not predict post-CABG surgery neurologic outcome.
Reynolds
James D
JD
Department of Anesthesiology, Duke University Medical Center, Durham, NC 27710, USA. reyno010@mc.duke.edu
Amory
David W
DW
Grocott
Hilary P
HP
White
William D
WD
Newman
Mark F
MF
D000368:Aged; D015415:Biomarkers / Q000097:blood; D006348:Cardiac Surgical Procedures / Q000523:psychology; D002315:Cardiopulmonary Bypass; D003072:Cognition Disorders / Q000097:blood*; D001026:Coronary Artery Bypass; D005260:Female; D005971:Glutamates / Q000097:blood*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009657:North Carolina; D015588:Observer Variation; D011183:Postoperative Complications / Q000097:blood; D011237:Predictive Value of Tests; D011446:Prospective Studies; D016896:Treatment Outcome
D015415:Biomarkers; D005971:Glutamates