EEG Can Be Used to Predict Successful Weaning from Anesthetics in Refractory Status Epilepticus
Key findings
- In a retrospective cohort of 34 patients, successful weaning from intravenous anesthetics and recovery from refractory status epilepticus were heralded by certain changes in functional connectivity parameters on EEG
- The changes occurred both six hours before and 30 minutes before a successful anesthetic wean
- An automated classifier tool based on the results predicted wean success
For the treatment of refractory status epilepticus (RSE), few data are available to guide decisions about the duration of anesthetics and the timing of anesthetic weaning. A common practice is to administer a continuous infusion of anesthetics for 24 hours or more before attempting to wean, but this duration is arbitrary. Many patients may be able to wean sooner, which would reduce the risk of adverse effects.
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Daniel B. Rubin, MD, PhD, neurologist, and Eric S. Rosenthal, MD, director of the Neurosciences Intensive Care Unit of the Department of Neurology at Massachusetts General Hospital, and colleagues have found that certain quantitative measures on EEG predict success in weaning from anesthetics in RSE. In Brain, they also report progress toward creating a predictive tool that could be used in real time at the bedside.
Study Details
Using prospectively collected continuous EEG data, the researchers identified 34 consecutive patients diagnosed with RSE between 2016 and 2019 who were treated with at least one intravenous third-line anesthetic. Any cause of status epilepticus was acceptable for inclusion except cardiac arrest.
The team reviewed patient medical records to confirm that each attempted wean was for the purpose of liberating the patient from anesthetic therapy, not a temporary pause for a neurological exam. Once confirmed, weans were classified as:
- Successful — cessation of IV anesthetics without the development of recurrent status epilepticus for at least 48 hours
- Unsuccessful wean — either recurrent status epilepticus or resumption of intravenous anesthetics to treat an EEG pattern concerning for incipient status epilepticus
47 anesthetic weans (23 successful, 24 unsuccessful) were further analyzed.
Primary Outcome
During the 30-minute period prior to anesthesia cessation, six of eight functional connectivity parameters of the EEGs (specified in the article) were significantly different between successful and unsuccessful weans. Findings were largely similar when the researchers examined EEGs up to six hours before anesthesia discontinuation.
None of the four spectral EEG parameters were significantly different between successful and unsuccessful weans.
There was no significant difference in EEG features between anesthetic weans that did or did not follow a period of burst suppression pattern on EEG.
Predictive Model
The researchers used the results to create an automated classifier to predict wean outcomes. They trained it on data from a random group made up of 80% of the patients, then tested on the remaining 20%.
The final model was 76% accurate in predicting the outcome of weaning in the training set and 75.5% accurate in the testing set. When applied to a validation cohort of 15 weans (data provided by a different institution), it was 75% accurate.
Hope for the Future
For this study, it took about 2.5 hours on a multicore processor to analyze 24 hours of EEG data. The researchers believe that an automated classifier could run in real-time at the bedside on an adequately powered system. Neurophysiological signatures predicting successful withdrawal of anesthetics in RSE could result in earlier liberation from a coma and mechanical ventilation.
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