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Updated: Aug 1, 2026
Infant Auditory Processing and Event-related Brain Oscillations
Published on: July 1, 2015
The differences in the bispectral index between infants and children during emergence from anesthesia after
A J Davidson1, M E McCann, P Devavaram
1Department of Anesthesia, Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, USA.
Insights
The bispectral index (BIS) monitoring showed a significant increase with decreasing sevoflurane levels in children but not infants during anesthesia emergence. BIS values increased significantly from pre- to postarousal in both age groups.
Area of Science:
- Anesthesiology
- Pediatric Anesthesia
- Neurophysiology
Background:
- The bispectral index (BIS) is a validated measure of consciousness during adult anesthesia.
- Understanding BIS behavior during emergence from anesthesia in pediatric patients is crucial for safe anesthetic practice.
Purpose of the Study:
- To evaluate the correlation between the bispectral index (BIS) and consciousness levels during emergence from sevoflurane anesthesia in infants and children undergoing circumcision.
- To compare BIS changes in response to decreasing sevoflurane concentrations and auditory stimulation between pediatric age groups.
Main Methods:
- Prospective, blinded study involving 24 children and 25 infants undergoing elective circumcision.
- Anesthesia maintained with sevoflurane; stepwise reduction of sevoflurane concentration with auditory stimulus for arousal testing.
- Bispectral index (BIS) and end-tidal sevoflurane concentrations were recorded throughout the emergence period.
Main Results:
- BIS significantly increased as sevoflurane decreased in children (P < 0.001), but this relationship was not observed in infants.
- BIS values at lower sevoflurane concentrations were significantly higher in children than in infants (P < 0.02 and P < 0.002).
- BIS increased significantly from pre- to postarousal in both children (P = 0.01) and infants (P < 0.001).
Conclusions:
- The relationship between BIS and decreasing sevoflurane concentration differs between children and infants during emergence from anesthesia.
- BIS monitoring effectively tracks arousal responses to stimuli in both pediatric age groups.
- Further research is needed to understand maturational effects on EEG and BIS during anesthetic emergence.
Unlabelled:
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).
Implications:
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.
