title: Influence of bispectral index monitoring on decision making during cardiac anesthesia.
abstract: OBJECTIVE
  To assess bispectral index (BIS) monitoring on decision making during cardiac surgery with cardiopulmonary bypass (CPB) by measuring the number of preset standardized comments with and without knowing the BIS value and by classifying the interventions following the BIS data.
  
  
  METHODS
  Prospective, randomized study.
  
  
  METHODS
  University Hospital.
  
  
  METHODS
  One hundred twenty-one patients scheduled for elective cardiac surgery (89 coronary patients, 24 valve replacement patients, and 8 valve replacement and coronary surgery).
  
  
  METHODS
  Patients were divided into 3 groups. An observing anesthesiologist recorded on a special form ("parallel" anesthesia record) data from the devices of the workstation and the BIS monitor. Conditions in which BIS monitoring was subjectively considered that might have been useful in anesthetic decision making were recorded as "events." In group A (36 patients), the responsible anesthesiologist had continuous access to BIS information. In group B (44 patients), intraoperative anesthetic management was "blinded" to BIS values, whereas in group C (41 patients), the anesthesiologist observing the BIS monitor was free to inform the attending anesthesiologist about the BIS score. The number of events was considered as negatively reflecting the quality of the clinical course of a patient. The reduction of events was considered as improvement in decision making. All patients received the same anesthetic regimen (propofol + remifentanil). Monitoring was equal in all cases. Mild hypothermic CPB was applied in 73 patients. Statistical analysis used 1-way analysis of variance, Student 2-tailed t test, and chi2 analysis.
  
  
  RESULTS
  Patient demographic data, underlying pathology, operation performed, hypothermia application, times of anesthesia, duration of operation, and CPB were similar in the 3 groups. In group B, the BIS value was considered by the observer as useful to know in 220 events (5.00 +/- 1.58 per patient). In group C, the BIS value was considered by the observer as useful to know in 143 events (3.49 +/- 1.31 per patient, P < 0.001) and, at the same time, the attending anesthesiologist was informed about BIS. In 112 (78.3%) cases, measures were taken. Titration of anesthetic drugs was done in 79 (70.5%) patients, whereas titration of vasoactive drugs was done in 9 (8.0%) patients, titration of both in 13 (11.6%) patients, and other diagnostic or corrective actions in 11 (9.8%) patients. Distributions of BIS values did not differ statistically (39.19 +/- 10.32, 37.38 +/- 10.21, and 38.29 +/- 10.01 in group A, group B, and group C, respectively). "Zenith" and "nadir" BIS values after induction also did not differ statistically. Awakening and extubation times were similar in both groups.
  
  
  CONCLUSIONS
  Subjectivity, although reduced as much as possible, can play a confining role in the value of our results. The usefulness of BIS monitoring is shown by the fact that BIS data resulted in corrective measures. Attending anesthesiologist's actions, based on BIS information, reduced the events in group C.
authors.affiliation: Department of Cardiac Anesthesia, University Hospital of Alexandroupolis, 68100 Alexandroupolis, Greece.
authors.forename: George
authors.initials: G
authors.lastname: Vretzakis
authors.forename: Eleni
authors.initials: E
authors.lastname: Ferdi
authors.forename: Helena
authors.initials: H
authors.lastname: Argiriadou
authors.forename: Basilios
authors.initials: B
authors.lastname: Papaziogas
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Mikroulis
authors.forename: Miltiadis
authors.initials: M
authors.lastname: Lazarides
authors.forename: George
authors.initials: G
authors.lastname: Bitzikas
authors.forename: George
authors.initials: G
authors.lastname: Bougioukas
mesh_terms: D000368:Aged; D000768:Anesthesia, General; D018686:Anesthetics, Intravenous / Q000008:administration & dosage; D001784:Blood Gas Analysis; D006348:Cardiac Surgical Procedures; D002315:Cardiopulmonary Bypass; D003331:Coronary Vessels / Q000601:surgery; D003657:Decision Making; D004311:Double-Blind Method; D004569:Electroencephalography; D005260:Female; D019918:Heart Valve Prosthesis Implantation; D006801:Humans; D007036:Hypothermia, Induced; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative; D015742:Propofol / Q000008:administration & dosage; D011446:Prospective Studies
chemical_list: D018686:Anesthetics, Intravenous; D015742:Propofol