Rethinking Seizure Care Blog

What Should the cEEG Monitoring Duration Be for Critically Ill Patients?

Posted by RSC Diagnostics on Apr 29, 2022

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Currently, the “standard” when it comes to continuous EEG monitoring is 24 hours for critically ill patients. However, recent research from a retrospective study from the Cleveland Clinic published in Epilepsia Open suggests that this is not enough time.

The researchers found that with critically ill patients who were undergoing cEEG monitoring, “Seizure detection increases linearly for the first 36 hours, with detection after that time more likely to occur in patients who are taking antiseizure medications or who have altered mental status, periodic epileptiform discharges or an acute brain insult.”

Stephen Hantus, MD, Director of Continuous EEG and Epilepsy Consult Service at Cleveland Clinic said, “Based on the linear trend to 36 hours that we found for seizure detection in critically ill patients, we recommend extending the current cEEG monitoring standard of 24 hours.” He went on to say, “And with this large study cohort, we were able to identify risk factors to justify longer—or shorter—monitoring durations.”

Why Are the Current cEEG Recommendations Potentially Incorrect?

During the first 24 hours of monitoring a patient, it’s possible to detect many of the seizures that occur. In around 20% of critically ill patients who are undergoing cEEG monitoring, it is possible to detect subclinical and nonconvulsive seizures. However, even though most of the seizures can be detected in those first 24 hours, other seizures are delayed. This means that they could be missed.

The current recommendations are that patients should be monitored for up to 24 hours, and for a minimum of 48 hours for those who have a history of seizures or who are comatose. The current guidance is based on risk factors found in other investigations. However, the fear is that there could be additional risk factors that could make longer monitoring a better option for the patients. The study was meant to “identify any additional risk factors for delayed seizure detection by cEEG in a large and more diverse patient population.”

What Did the Study Find?

The study cohort included adults who were hospitalized and who had cEEG at Cleveland Clinic in 2016. There were 2,402 patients, and 316 of them had at least one nonclinical seizure. The indication for monitoring that was used most often was observing a seizure-like episode in the patient.

The “timing of the first nonclinical seizure detection occurred at the following rates. 4% within 24 hours, 6% between 24 and 48 hours, and 0% after 48 hours.” The cumulative seizure detection increased linearly for the first 36 hours of monitoring, after which the odds of seizure detection increased by 46% for each additional day of monitoring.”

What were some of the main risk factors for delayed seizure identification? The researchers identified, stupor, lethargy, lateralized periodic discharges, generalized periodic discharges, acute brain insult, brain bleeds, altered mental status, and use of antiseizure medications as risks.


What Did the Researchers Conclude from the Study?

The researchers feel that the standard monitoring should be increased from 24 hours to 36 hours. They feel this is the best duration regardless of what risk factors are present. They also feel that it’s going to be helpful for patients who do not have much clinical history.

However, for some patients, 24 hours of monitoring would be enough. This would include patients who are aware and who do not have interictal epileptiform discharges.

Other patients might benefit from 48 hours of monitoring. This would include comatose patients, those who have acute brain insult, are using antiseizure medications, have altered mental status, and who have lateralized or generalized periodic discharges, as noted in the risk factors above.




Topics: Continuous EEG Monitoring