Every year about 200,000 infants in the United States are given general anesthesia during their first year of life. We used a electroencephalography (EEG) to monitor brain activity in infants undergoing anesthesia, to see how their responses to anesthesia change as the brain develops. We detected slow waves of brain activity across the entire scalp of infants who were under 6 months old and under general anesthesia (see Figure below). Infants who were older than about 4 months displayed some faster brain waves called alpha (see Figure below).
Alpha brain-waves decreased in intensity as the infants began to wake up from general anesthesia. However, none of the infants had the same pattern seen in adults – where alpha waves appear at the front of the brain.
These findings reflect differences in brain development, and may help guide innovation of more reliable ways to monitor infants brain during anesthesia.
Who was eligible to participate?
- Infants aged 0 to 6 months who required sevoflurane general anesthesia for routine surgical procedures
- No known or suspected cardiovascular or neurological disorder
What did the study involve?
Infants were studied on the day of their scheduled surgery at Boston Children’s Hospital. We measured brain activity using EEG recordings- via electrodes placed over the scalp- when they were awake, during anesthesia, and as they emerged from anesthesia. We also measured body movement using video recordings.
Collaborating Research Groups
The study was a collaboration between members of Professor Berde’s laboratory in the Department of Anesthesiology, Preoperative & Pain Medicine at Boston Children’s Hospital, and our colleagues, Professor Brown and Dr Kim from Massachusetts Institute of Technology, and Dr Purdon from Massachusetts General Hospital.
Figure 2: Alpha (8-12Hz) activity decreases in power as end-tidal sevoflurane concentration decreases. Topographic maps of brain activity in infants (A) 0-3 months, (B) 4-6 months, and (C) corresponding percentage of infants who displayed gross body movement as they began to wake-up (Cornelissen et al, 2015, eLife).