title: Early bispectral index and sedation requirements during therapeutic hypothermia predict neurologic recovery following cardiac arrest.
abstract: OBJECTIVE
  To test the hypothesis that low bispectral index scores and low sedative requirements during therapeutic hypothermia predict poor neurologic outcome.
  
  
  METHODS
  Observational study of a prospectively collected cohort.
  
  
  METHODS
  Cardiovascular ICU.
  
  
  METHODS
  One hundred sixty consecutive cardiac arrest patients treated with therapeutic hypothermia.
  
  
  METHODS
  None.
  
  
  RESULTS
  Eighty-four of the 141 subjects (60%) who survived hypothermia induction were discharged from the ICU with poor neurologic outcome, defined as a cerebral performance category score of 3, 4, or 5. These subjects had lower bispectral index (p < 0.001) and sedative requirements (p < 0.001) during hypothermia compared with the 57 subjects discharged with good outcome. Early prediction of neurologic recovery was best 7 hours after ICU admission, and median bispectral index scores at that time were 31 points lower in subjects discharged with poor outcome (11 [interquartile range, 4-29] vs 42 [37-49], p < 0.001). Median sedation requirements decreased by 17% (interquartile range, -50 to 0%) 7 hours after ICU admission in subjects with poor outcome but increased by 50% (interquartile range, 0-142%) in subjects with good outcome (p < 0.001). Each 10-point decrease in bispectral index was independently associated with a 59% increase in the odds of poor outcome (95% CI, 32-76%; p < 0.001). The model including bispectral index and sedative requirement correctly reclassified 15% of subjects from good to poor outcome and 1% of subjects from poor to good outcome. The model incorrectly reclassified 1% of subjects from poor to good outcome but did not incorrectly reclassify any from good to poor outcome.
  
  
  CONCLUSIONS
  Bispectral index scores and sedative requirements early in the course of therapeutic hypothermia improve the identification of patients who will not recover from brain anoxia. The ability to accurately predict nonrecovery after cardiac arrest could facilitate discussions with families, reduce patient suffering, and limit use of ICU resources in futile cases.
authors.affiliation: Division of Critical Care Medicine, Department of Anesthesiology (NB, CW, FB); Division of Cardiology, Department of Medicine (RH, JM); and the Department of Biostatistics (LW, CY); Vanderbilt University School of Medicine, Nashville, TN, USA.
authors.forename: Nicholas E
authors.initials: NE
authors.lastname: Burjek
authors.affiliation: Division of Critical Care Medicine, Department of Anesthesiology (NB, CW, FB); Division of Cardiology, Department of Medicine (RH, JM); and the Department of Biostatistics (LW, CY); Vanderbilt University School of Medicine, Nashville, TN, USA.
authors.forename: Chad E
authors.initials: CE
authors.lastname: Wagner
authors.affiliation: Division of Critical Care Medicine, Department of Anesthesiology (NB, CW, FB); Division of Cardiology, Department of Medicine (RH, JM); and the Department of Biostatistics (LW, CY); Vanderbilt University School of Medicine, Nashville, TN, USA.
authors.forename: Ryan D
authors.initials: RD
authors.lastname: Hollenbeck
authors.affiliation: Division of Critical Care Medicine, Department of Anesthesiology (NB, CW, FB); Division of Cardiology, Department of Medicine (RH, JM); and the Department of Biostatistics (LW, CY); Vanderbilt University School of Medicine, Nashville, TN, USA.
authors.forename: Li
authors.initials: L
authors.lastname: Wang
authors.affiliation: Division of Critical Care Medicine, Department of Anesthesiology (NB, CW, FB); Division of Cardiology, Department of Medicine (RH, JM); and the Department of Biostatistics (LW, CY); Vanderbilt University School of Medicine, Nashville, TN, USA.
authors.forename: Chang
authors.initials: C
authors.lastname: Yu
authors.affiliation: Division of Critical Care Medicine, Department of Anesthesiology (NB, CW, FB); Division of Cardiology, Department of Medicine (RH, JM); and the Department of Biostatistics (LW, CY); Vanderbilt University School of Medicine, Nashville, TN, USA.
authors.forename: John A
authors.initials: JA
authors.lastname: McPherson
authors.affiliation: Division of Critical Care Medicine, Department of Anesthesiology (NB, CW, FB); Division of Cardiology, Department of Medicine (RH, JM); and the Department of Biostatistics (LW, CY); Vanderbilt University School of Medicine, Nashville, TN, USA.
authors.forename: Frederic T
authors.initials: FT
authors.lastname: Billings
mesh_terms: D000328:Adult; D000368:Aged; D002490:Central Nervous System / Q000503:physiopathology*; D015331:Cohort Studies; D056805:Consciousness Monitors; D005260:Female; D005283:Fentanyl / Q000008:administration & dosage*; D006323:Heart Arrest / Q000628:therapy*; D006801:Humans; D006993:Hypnotics and Sedatives / Q000008:administration & dosage*; D007036:Hypothermia, Induced; D007362:Intensive Care Units; D008297:Male; D008874:Midazolam / Q000008:administration & dosage*; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012372:ROC Curve; D012680:Sensitivity and Specificity; D016896:Treatment Outcome
chemical_list: D006993:Hypnotics and Sedatives; D008874:Midazolam; D005283:Fentanyl