title: Rewarming Rate During Cardiopulmonary Bypass Is Associated With Release of Glial Fibrillary Acidic Protein.
abstract: BACKGROUND
  Rewarming from hypothermia during cardiopulmonary bypass (CPB) may compromise cerebral oxygen balance, potentially resulting in cerebral ischemia. The purpose of this study was to evaluate whether CPB rewarming rate is associated with cerebral ischemia assessed by the release of the brain injury biomarker glial fibrillary acidic protein (GFAP).
  
  
  METHODS
  Blood samples were collected from 152 patients after anesthesia induction and after CPB for the measurement of plasma GFAP levels. Nasal temperatures were recorded every 15 min. A multivariate estimation model for postoperative plasma GFAP level was determined that included the baseline GFAP levels, rewarming rate, CPB duration, and patient age.
  
  
  RESULTS
  The mean rewarming rate during CPB was 0.21° ± 0.11°C/min; the maximal temperature was 36.5° ± 1.0°C (range, 33.1°C to 38.0°C). Plasma GFAP levels increased after compared with before CPB (median, 0.022 ng/mL versus 0.035 ng/mL; p < 0.001). Rewarming rate (p = 0.001), but not maximal temperature (p = 0.77), was associated with higher plasma GFAP levels after CPB. In the adjusted estimation model, rewarming rate was positively associated with postoperative plasma log GFAP levels (coefficient, 0.261; 95% confidence intervals, 0.132 to 0.390; p < 0.001). Six patients (3.9%) experienced a postoperative stroke. Rewarming rate was higher (0.3° ± 0.09°C/min versus 0.2° ± 0.11°C/min; p = 0.049) in the patients with stroke compared with those without a stroke.
  
  
  CONCLUSIONS
  Rewarming rate during CPB was correlated with evidence of brain cellular injury documented with plasma GFAP levels. Modifying current practices of patient rewarming might provide a strategy to reduce the frequency of neurologic complications after cardiac surgery.
authors.affiliation: Division of Cardiac Surgery, Department of Surgery, The Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Daijiro
authors.initials: D
authors.lastname: Hori
authors.affiliation: Department of Pediatrics, The Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Allen D
authors.initials: AD
authors.lastname: Everett
authors.affiliation: Department of Anesthesiology and Critical Care Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Jennifer K
authors.initials: JK
authors.lastname: Lee
authors.affiliation: Division of Cardiac Surgery, Department of Surgery, The Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Ono
authors.affiliation: Department of Anesthesiology and Critical Care Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Charles H
authors.initials: CH
authors.lastname: Brown
authors.affiliation: Division of Cardiac Surgery, Department of Surgery, The Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Ashish S
authors.initials: AS
authors.lastname: Shah
authors.affiliation: Division of Cardiac Surgery, Department of Surgery, The Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Kaushik
authors.initials: K
authors.lastname: Mandal
authors.affiliation: Division of Cardiac Surgery, Department of Surgery, The Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Joel E
authors.initials: JE
authors.lastname: Price
authors.affiliation: Department of Anesthesiology and Critical Care Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Laeben C
authors.initials: LC
authors.lastname: Lester
authors.affiliation: Department of Anesthesiology and Critical Care Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland. Electronic address: chogue2@jhmi.edu.
authors.forename: Charles W
authors.initials: CW
authors.lastname: Hogue
mesh_terms: D000368:Aged; D002545:Brain Ischemia / Q000097:blood / Q000209:etiology; D002315:Cardiopulmonary Bypass / Q000009:adverse effects / Q000379:methods*; D005260:Female; D005904:Glial Fibrillary Acidic Protein / Q000097:blood*; D006801:Humans; D008297:Male; D011446:Prospective Studies; D017694:Rewarming / Q000379:methods*; D013997:Time Factors
chemical_list: D005904:Glial Fibrillary Acidic Protein