title: Impact of deep hypothermic circulatory arrest on the BIS index.
abstract: OBJECTIVE
  To investigate the influence of duration of deep hypothermic circulatory arrest (DHCA) on recovery of the bispectral index (BIS).
  
  
  METHODS
  Prospective cohort study.
  
  
  METHODS
  Operating room of university teaching hospital.
  
  
  METHODS
  30 adult, ASA physical status III and IV patients scheduled for cardiac surgery with extracorporeal circulation (ECC) and DHCA.
  
  
  METHODS
  There were no study-specific interventions undertaken with the study patients.
  
  
  METHODS
  After induction of anesthesia, propofol and sufentanil were used for maintenance. Duration until BIS values reached indices of 10, 20, and 30 after DHCA was measured. DeltaBIS was defined as the difference between BIS before the start of ECC and after DHCA at the same nasopharyngeal body temperature. Data are means + or - SD (ranges).
  
  
  RESULTS
  Duration of DHCA was 24 + or - 15 min (8-71 min). The deepest nasopharyngeal temperature was 20.1 + or - 2.7 degrees C at the end of DHCA. BIS reduction was 1.8/ degrees C. At the end of DHCA, BIS was 2 + or - 6 and at the end of ECC, BIS was 33 + or - 11. Duration until BIS reached a value of 10 (BIS10) was 23 + or - 21 min (0-83 min); until BIS reached 20 (BIS20): 36 + or - 36 min (0-140 min); and until BIS reached 30 (BIS30): 43 + or - 29 min (1-130 min). Regression analysis between duration of DHCA and BIS10 was R = 0.76; BIS20: R = 0.67; and BIS30: R = 0.54.
  
  
  CONCLUSIONS
  Deep hypothermia influences BIS linearly. In addition, there appears to be a reasonable correlation between recovery of BIS values and duration of DHCA.
authors.affiliation: Department of Anesthesiology, Intensive Care Medicine and Pain Therapy, University of Saarland, 66421 Homburg/Saar, Germany. sziegeler@hotmail.com
authors.forename: Stephan
authors.initials: S
authors.lastname: Ziegeler
authors.forename: Heiko
authors.initials: H
authors.lastname: Buchinger
authors.forename: Wolfram
authors.initials: W
authors.lastname: Wilhelm
authors.forename: Reinhard
authors.initials: R
authors.lastname: Larsen
authors.forename: Sascha
authors.initials: S
authors.lastname: Kreuer
mesh_terms: D000368:Aged; D001831:Body Temperature; D006348:Cardiac Surgical Procedures / Q000379:methods*; D050792:Circulatory Arrest, Deep Hypothermia Induced / Q000379:methods*; D015331:Cohort Studies; D056805:Consciousness Monitors; D005112:Extracorporeal Circulation / Q000379:methods*; D005260:Female; D006785:Hospitals, University; D006801:Humans; D008297:Male; D008875:Middle Aged; D009305:Nasopharynx; D011446:Prospective Studies; D012044:Regression Analysis; D013997:Time Factors