EEG monitoring helps reduce anesthesia usage and improves pediatric recovery

EEG monitoring helps reduce anesthesia usage and improves pediatric recovery

Newly published results from a randomized, controlled clinical trial in Japan of more than 170 children aged 1 to 6 years who had undergone surgery show that anesthesia monitoring by using EEG readings of brain waves to monitor unconsciousness can significantly reduce anesthesiologist's anesthesiology risk. On average, the young patients had significant improvements in several postoperative outcomes, including faster recovery and a reduced incidence of delirium.

I think the main takeaway is that with children, with the EEG, we can reduce the amount of anesthesia we give them and maintain the same level of consciousness. “

Emery N. Brown, Edward Hood Taplin Professor of Medical Engineering and Computational Neuroscience at MIT and anesthesiologist at Massachusetts General Hospital, study co-author

The study was published on April 21stJama - Pediatrics.

Yasuko Nagasaka, chair of anesthesiology at Tokyo Women's Medical University, a former colleague of Brown's in the US, designed the study. She asked Brown to train and advise senior lead author Kiyoyuki Miyasaka of St. Luke's International Hospital in Tokyo on how to use EEG to monitor unconsciousness and adjust anesthesia dosage in children. Miyasaka then served as an anesthesiologist for all patients in the study. Participating anesthesiologists not involved in the study were always there for supervision.

Brown's research has shown that a person's level of consciousness under a particular anesthetic drug can be detected from patterns of their brain waves. Each child's brain waves were measured using EEG, but in the control group Miyasaka adhered to standard anesthesia dosing protocols while in the experimental group he used the EEG measures as a guide for dosing. The results show that when he used EEG, he was able to induce the desired consciousness with a concentration of 2 percent sevoflurane gas instead of the standard 5 percent. Maintaining unconsciousness, meanwhile, required only a 0.9 percent concentration, rather than the standard 2.5 percent.

Meanwhile, a separate researcher, blinded to whether EEG or standard protocols were used, assessed the children for "pediatric anesthesia emergence delirium" (PAED), in which children sometimes wake up from anesthesia with a range of side effects, including lack of eye contact, inseparability, unawareness of surroundings, restlessness and undisputed movements. Children who received standard anesthesia met the threshold for PAED 35 percent of the time (30 of 86), while children who received EEG-guided dosing met the threshold 21 percent of the time (19 of 91). The difference of 14 percentage points was statistically significant.

Meanwhile, the authors reported that, on average, EEG-guided patients had breathing tubes removed 3.3 minutes earlier, emerged from anesthesia 21.4 minutes earlier, and were discharged 16.5 minutes after acute care than patients who received anesthesia using the standard protocol. All of these differences were statistically significant. In the study, no child became alert during the operation.

The authors found that faster recovery in patients who received EEG-guided anesthesia not only improved medically but also reduced health care costs. Post-acute time in the US costs about $46 per minute, so the average reduction of 16.5 minutes would save about $750 per case. Sevoflurane is also a powerful greenhouse gas, Brown said, so reducing its use is better for the environment.

In the study, the authors also present comparisons of the EEG recordings of children in the control and experimental groups. There are notable differences in the "spectrograms" that show the power of individual brainwave frequencies both as children operated and as they approached anesthesia, Brown said.

For example, in children who received EEG-guided dosing, there are well-defined bands of high power at approximately 1-3 Hertz and 10-12 Hz. In children who received standard protocol dosing, the entire frequency range is up to 15 Hz at high power. In another example, children who experienced PAED showed higher performance at several frequencies up to 30 Hz than children who did not experience PAED.

The results further validate the idea that monitoring brain waves during surgery can provide anesthesiologists with actionable guidance to improve patient care, Brown said. Training to read EEGs and guide dosages can be easily integrated into hospitals' ongoing medical education practices, he added.

Yasuyuki Suzuki is co-author alongside Miyasuka, Brown and Nagasaka.

Funding sources for the study include the MIT-Massachusetts General Brigham Brain Pathogen State Innovation Innovation Center, the Freedom Together Foundation and the Picower Institute for Learning and Memory.

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