Summary: A randomized, controlled clinical trial in Japan found that using electroencephalography (EEG) to guide anesthesia in young children substantially reduced the amount of sevoflurane gas required while improving recovery after surgery. By monitoring brain-wave patterns to confirm unconsciousness, anesthesiologists maintained safe anesthesia with lower doses, producing faster wake-up times and fewer cases of post-anesthesia delirium.
Children whose anesthesia was adjusted using EEG emerged from anesthesia more than 20 minutes earlier on average and spent less time in post-anesthesia care. No cases of intraoperative awareness were recorded. The EEG-guided approach also reduced drug use, lowered per-case costs, and decreased emissions of a potent greenhouse gas.
Key facts
- Reduced anesthetic exposure: EEG monitoring cut sevoflurane doses by more than half for induction and maintenance compared with standard protocols.
- Faster recovery: EEG-guided patients woke about 21.4 minutes earlier and left post-anesthesia care 16.5 minutes sooner on average.
- Fewer delirium events: Pediatric anesthesia emergence delirium (PAED) occurred in 21% of EEG-guided cases versus 35% with standard dosing.
- Lower cost and emissions: Shorter recovery times translated into estimated savings of roughly $750 per case in US-equivalent post-acute care costs while reducing sevoflurane use and its environmental impact.
Source: Picower Institute at MIT
A team led by Yasuko Nagasaka at Tokyo Women’s Medical University designed this single-center, two-arm superiority trial, which enrolled more than 170 children aged 1 to 6 undergoing general anesthesia between October 2021 and March 2023. Lead author Kiyoyuki Miyasaka of St. Luke’s International Hospital performed anesthesia for all trial patients, using either standard dosing protocols (control group) or EEG readings to guide titration (experimental group). Emery N. Brown of MIT — an expert in EEG and anesthesia — trained and advised the team on interpreting brain-wave patterns and applying them to dosing decisions.
Brown and colleagues have demonstrated in prior work that different anesthetic drugs and depths of unconsciousness produce distinguishable EEG patterns. In this trial, every child had continuous EEG monitoring, but only the experimental group influenced dosing decisions. Using EEG guidance, clinicians induced unconsciousness with roughly 2% sevoflurane rather than the standard 5% and maintained anesthesia at about 0.9% instead of the typical 2.5%.
An independent observer, blinded to group assignment, assessed children for postoperative emergence delirium using the validated PAED scoring system. In the control group, 30 of 86 children (35%) met the threshold for PAED; in the EEG-guided group, 19 of 91 children (21%) met the threshold. This 14-percentage-point reduction reached statistical significance. No patient experienced intraoperative awareness.
Objective recovery measures also favored EEG-guided care. On average, EEG-guided patients had their breathing tubes removed 3.3 minutes earlier, regained consciousness 21.4 minutes sooner, and were discharged from post-anesthesia care 16.5 minutes earlier than those managed with standard dosing. The investigators emphasized that these differences were clinically meaningful and statistically significant.
Beyond clinical outcomes, the study highlights practical advantages for perioperative care. Shorter stays in recovery reduce staffing and facility costs and increase throughput. Using less sevoflurane also decreases the healthcare sector’s contribution to greenhouse gas emissions, since volatile anesthetics are potent atmospheric agents.
EEG spectrograms from the trial show distinct patterns between groups. Children in the EEG-guided arm exhibited well-defined power bands around 1–3 Hz and 10–12 Hz during anesthesia, whereas the control group showed elevated power across frequencies up to about 15 Hz. Children who developed PAED showed higher power at several frequencies up to 30 Hz compared with those who did not, suggesting EEG features that may help identify patients at greater risk for emergence delirium.
The authors conclude that routine monitoring of brain waves during pediatric anesthesia can give anesthesiologists actionable guidance to minimize excessive anesthetic exposure while preserving safety. Training clinicians to read EEG patterns and apply them to dosing decisions can be integrated into continuing medical education and hospital practice.
Study authors include Kiyoyuki Miyasaka, Emery N. Brown, Yasuko Nagasaka, and Yasuyuki Suzuki. Funding was provided by the MIT–Massachusetts General Brigham Brain Arousal State Control Innovation Center, the Freedom Together Foundation, and the Picower Institute for Learning and Memory.
About this research on consciousness and anesthesia
Author: David Orenstein
Source: Picower Institute at MIT
Contact: David Orenstein, Picower Institute at MIT
Image credit: Neuroscience News
Original Research: Closed access. “EEG-Guided Titration of Sevolfurane and Pediatric Anesthesia Emergence Delirium” by Emery N. Brown et al., JAMA Pediatrics.
Abstract
EEG-Guided Titration of Sevolfurane and Pediatric Anesthesia Emergence Delirium
Importance: Pediatric anesthesia emergence delirium (PAED) is a common and poorly understood complication after general anesthesia. Excess exposure to volatile anesthetics such as sevoflurane may contribute to PAED.
Objective: To test whether EEG monitoring can reduce PAED by minimizing sevoflurane exposure while maintaining safe unconsciousness.
Design, setting, and participants: A single-center, parallel-group randomized clinical trial conducted at an academic pediatric hospital in Japan from October 13, 2021, to March 18, 2023. The trial enrolled a convenience sample of children aged 1 to under 6 years undergoing procedures under general anesthesia. Primary outcome observers were blinded.
Intervention: EEG-guided titration to minimize sevoflurane exposure versus standard 1.0–MAC sevoflurane anesthesia.
Main outcome: Proportion of children developing PAED, defined by a maximum PAED score of 10 or higher.
Results: Of 177 children who completed follow-up (91 in the EEG-guided group, 86 in control), EEG-guided management reduced sevoflurane exposure by 1.4 MAC-hours on average. PAED occurred in 35% of control patients and 21% of EEG-guided patients (difference 14%; P = .04). EEG-guided children emerged a mean 21.4 minutes earlier and spent a mean 16.5 minutes less in the post-anesthesia care unit.
Conclusions and relevance: EEG-guided anesthesia reduced sevoflurane exposure and PAED incidence, producing faster emergence and shorter post-anesthesia recovery. These results suggest routine high-concentration induction and maintenance at 1.0 MAC may be excessive for some pediatric patients.
Trial registration: Japan Registry of Clinical Trials Identifier: jRCTs032210248