title: Change in plasma glutamate concentration during cardiac surgery is a poor predictor of cognitive outcome.
abstract: 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.
authors.affiliation: Department of Anesthesiology, Duke University Medical Center, Durham, NC 27710, USA. reyno010@mc.duke.edu
authors.forename: James D
authors.initials: JD
authors.lastname: Reynolds
authors.forename: David W
authors.initials: DW
authors.lastname: Amory
authors.forename: Hilary P
authors.initials: HP
authors.lastname: Grocott
authors.forename: William D
authors.initials: WD
authors.lastname: White
authors.forename: Mark F
authors.initials: MF
authors.lastname: Newman
mesh_terms: 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
chemical_list: D015415:Biomarkers; D005971:Glutamates