title: The differences in the bispectral index between infants and children during emergence from anesthesia after circumcision surgery.
abstract: The bispectral index (BIS) correlates with consciousness during adult anesthesia. In this prospective, blinded study of children (n = 24) and infants (n = 25) undergoing elective circumcision, we evaluated BIS and consciousness level during emergence from anesthesia. Anesthesia was maintained with sevoflurane, and a penile nerve block was performed in each patient before surgical stimulation. At the completion of surgery, the sevoflurane was decreased stepwise from 0.9% in increments of 0.2%, and arousal was tested with a uniform auditory stimulus given after a steady state of end-tidal sevoflurane concentration was achieved at each step. The BIS increased significantly as the sevoflurane concentrations decreased in children (0.9%, 62.5 +/- 8.1; 0.7%, 70.8 +/- 7.4; and 0.5%, 74.1 +/- 7.1; P < 0.001 for 0.7% and 0.5% compared with 0.9%), but a similar relationship was not demonstrated in infants. The BIS values at 0.7% and 0.5% sevoflurane were significantly higher in children than infants (P < 0.02 and P < 0.002, respectively). In both children and infants, the BIS increased significantly from pre- to postarousal (children, 73.5 +/- 7 to 83.1 +/- 12, P = 0.01; infants, 67.8 +/- 10 to 85.6 +/- 13.6, P < 0.001). The BIS at which arousal was possible with the stimulus tended to be higher in children than in infants (P = 0.06).
  
  
  
  In this study comparing the Bispectral index (BIS) in infants and children undergoing circumcision surgery by use of a standardized surgical and anesthetic technique, a significant decrease in BIS was detected in children during a stepwise decrease in end-tidal sevoflurane concentration. A similar relationship was not demonstrated in infants less than 1 yr old. In both children and infants, BIS increased significantly from pre- to postarousal. Additional studies are necessary to determine changes in BIS with maturational changes in the electroencephalogram.
authors.affiliation: Department of Anesthesia, Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, USA.
authors.forename: A J
authors.initials: AJ
authors.lastname: Davidson
authors.forename: M E
authors.initials: ME
authors.lastname: McCann
authors.forename: P
authors.initials: P
authors.lastname: Devavaram
authors.forename: S A
authors.initials: SA
authors.lastname: Auble
authors.forename: L J
authors.initials: LJ
authors.lastname: Sullivan
authors.forename: J M
authors.initials: JM
authors.lastname: Gillis
authors.forename: P C
authors.initials: PC
authors.lastname: Laussen
mesh_terms: D000293:Adolescent; D000758:Anesthesia; D002648:Child; D002675:Child, Preschool; D002944:Circumcision, Male; D004569:Electroencephalography; D006801:Humans; D007223:Infant; D008297:Male; D011446:Prospective Studies