Continuous EEG Monitoring Helps Detect Unusual Brain Patterns in Real Time for Neurocritical ICU Care

Innovations in Neurology & Neurosurgery | Summer 2019

In an intensive care unit (ICU), physicians monitor blood pressure, heartbeat and oxygen levels, among other stats. Monitoring brain activity as well can provide valuable information for diagnosing and treating these patients.  

For stroke, head trauma and other critically ill patients who are in a coma, either with or without a recent seizure, continuous electroencephalogram (EEG) monitoring helps detect seizures, swelling and ischemia in real time. Early detection allows doctors to treat seizures and other unusual symptoms early, as well as detect patterns that may have gone undiagnosed otherwise.

MIchael DeGeorgia, MD

University Hospitals is one of the few health systems in the country to offer continuous EEG in an ICU setting. At the Reinberger Neuroscience Intensive Care Unit (NSU), neurology, neurosurgery and interventional neuroradiology patients receive complete critical care from a multidisciplinary team. The NSU complements the Department of Neurology at University Hospitals Cleveland Medical Center, which includes the Epilepsy Center, a Tier 4 program, as well as a top neurology and neurosurgery program.

Continuous EEG monitoring allows NSU specialists to gain immediate insight into certain brain abnormalities. “There was data emerging that if you monitor intensely, you can detect things you couldn't detect clinically,” says Michael DeGeorgia, MD, Director of the Neurocritical Care Center at University Hospitals Neurological Institute, Co-Director of the Stroke and Cerebrovascular Center at UH Neurological Institute, and Professor of Neurology at Case Western Reserve University School of Medicine, where he holds the Maxeen Stone and John A. Flower Endowed Chair in Neurology. “It also provides another biomarker that, combined with other vitals, gives a holistic view of the patient.”

THE EVOLUTION OF EEG

EEG records electrical patterns in the brain and helps diagnose seizures and epilepsy. Until recently, using EEG in an ICU setting was a cumbersome process. If a doctor suspected a patient was having or at risk of having a seizure, someone from the epilepsy department would have to wheel in an EEG machine at that doctor's request. A technician would run the machine for about 30 minutes, and then staff would wheel it back out. Afterward, an epilepsy specialist would study the readings and prepare a report, which the treating physician often didn’t receive until two days later. If you needed an EEG at 2 a.m., you'd have to wait.

“That was the standard of care until about five years ago, when we started to think of EEG as a device we could use to monitor patients all the time,” Dr. DeGeorgia says.

That rethinking of how to monitor patients led to the expansion of the NSU and the creation of what is essentially an “epilepsy monitoring unit” built right into the ICU. Critically ill patients can undergo continuous EEG monitoring for days or even weeks, with epilepsy specialists interpreting EEGs in real time 24/7. Dr. DeGeorgia says that 20 to 30 percent of patients in a coma may experience subclinical or nonconvulsive seizures — they are having seizures but have no physical convulsions to suggest they are seizing. “Before continuous EEG, we didn't know,” he says.

REIMAGINING EEG

In addition to picking up convulsive and nonconvulsive seizures, continuous EEG detects subtle changes in brain waves that may indicate worsening brain injury, ischemia and cerebral vasospasm. 

In addition, the NSU uses newer techniques such as digital and quantitative EEG.  Digital EEG functions much like traditional EEG, but without paper. Quantitative EEG processes EEG signals using sophisticated mathematical and statistical analyses. It is often used as an adjunct to digital EEG. “You get 24 hours in one snapshot,” says Dr. DeGeorgia. “You can look for subtle changes that otherwise would be difficult to recognize with traditional EEG recordings.”

One patient, he recalls, felt sleepier than is typical after brain tumor resection surgery. Before continuous EEG, doctors would have assumed she had suffered a side effect from anesthesia and treated accordingly. Using EEG, doctors discovered she was experiencing seizures at the surgery site and then prescribed appropriate medication for her condition.

INTEGRATING DATA FOR BETTER INSIGHTS

At UH Cleveland Medical Center, Dr. DeGeorgia, in collaboration with engineers at Case Western Reserve University, has been focusing on a way to integrate EEG and data from other ICU devices. The system, called the Integrated Medical Environment™ (tIME), aims to deliver better insights that will improve efficiency and ultimately result in better outcomes. 

A marriage of computational science and critical care, tIME is still in the testing phase, but it promises to turn raw numbers into helpful information that guides treatment.

To speak with a specialist in neurocritical care, call 440-745-7562.