EEG – a Frontline Tool for the ED
Using EEG in the ED
Emergency Departments (ED) of hospitals nationwide have seen significant increased visits over the last 20 years, with an even larger increase in adult and pediatric patients presenting with altered mental status (AMS). The role for EEG evaluation and monitoring in the ED is well documented, though in many facilities there are challenges to obtaining an EEG recording and having it accurately read in a timely manner. Several innovative approaches have evolved to address the obstacles to appropriately using EEG in the ED more effectively in evaluating and managing patients with AMS.
EEG Needs in the ED
About four to ten percent of patients coming into the Emergency Department (ED) have altered mental status. Several studies have found that up to 5% of patients with AMS are experiencing NCSE (non-convulsive status epilepticus) requiring immediate treatment. Without available EEG recordings and qualified readers, these patients are in danger. There are many illnesses that lead to AMS, such as cerebrovascular diseases, acute encephalopathy, central nervous system infection, brain tumor and traumatic brain injury.
Though imaging technologies are often used to assess patients with AMS, EEG provides a better, efficient and more cost-effective tool in the Emergency Department
Challenges in obtaining EEG studies in the ED
Many hospital EDs lack one or more of these essential components to assess patients with AMS:
- EEG recording equipment
- Staff trained to apply electrodes and record the EEG at the time it is needed
- Access to expertise in reading the EEG
Having EEG recording systems on standby can be financially inefficient as most standard EEG systems cost $30,000 or more. More importantly, if the equipment is even available, a reliable EEG recording requires a complicated process and a trained professional. But technologists are often not available to respond in a timely manner, if at all.
Finally, the EEG itself is a physiologic record that requires training to interpret correctly. Usually an Epileptologist or Neurophysiologist is needed to read the EEG and report any abnormalities requiring treatment. Access to this expertise may be limited at many EDs especially afterhours.
Different approaches to obtain an EEG in the ED
Reduced channel EEG with quick setup
Several products have recently come on the market that proport to be quick to setup without the need of a trained EEG technologist and can transmit EEG data from a reduced set of electrodes. They are a reasonable approach to assessing patients with altered mental state.
They lack a full set of standard 10-20 leads but would capture generalized seizures or slowing. Data produced from these systems still need to be reviewed by a knowledgeable and trained physician. Automated data transmission and the use of algorithms to detect probable seizure activity may make these systems more useful in making clinical decisions.
Electrode cap for quick setup
EEGs done in the ED using a standard commercial EEG electrode cap facilitated faster testing (setup under 20 minutes) – in one facility, findings from 82 patients tested in one year, seizures occurred in 33% of patients and EEG made an impact in clinical decisions 51% of the time.
This approach can also be done by healthcare staff other than EEG Technologists and if coupled with an easy to use, semi-automated EEG system that can also produce the data needed for clinical evaluation. This is especially true if the EEG Study can be accessed remotely by a trained neurophysiologist.
Access to Expertise
Regardless of the approach used to acquire EEG data, evaluating the EEG usually requires review by an epileptologist or neurophysiologist trained in interpreting the recorded waveforms. Very few physicians staffing the ED have the training and experience to interpret EEG recordings. They rely on consulting neurologists to analyze the EEG frequencies and identify possible seizure activity.
The lack of available neurophysiologists is a significant limiting factor to implementing EEG evaluations for patients with altered mental status in the ED. Third-party services, such as CortiCare’s Nationwide Neurophysiology Network, helps address this challenge, with on-call physicians who can remotely view the EEG, interpret the recording, and even suggest a therapeutic action.
To increase the use of EEG recordings as a critical tool in evaluating patients presenting with altered mental status, EDs must have EEG recording equipment that can be employed by staff members with minimal training and have access to EEG experts to read the EEG record.
References
Nagayama M, Yang S, Geocadin R, Kaplan P, Hoshiyama E, Shiromaru-Sugimoto A, Kawamura M. Novel clinical features of nonconvulsive status epilepticus. https://www.ncbi.nlm.
nih.gov/pmc/articles/PMC5605999/NCSE has diverse causes such, injury, and postoperative complications. NCBI, 2017.
Wendy C. Ziai, Dan Schlattman, Rafael Llinas, Santosh Venkatesha, Melvin Truesdale, Anastasia Schevchenko, Peter W. Kaplan, Emergent EEG in the emergency department in patients with altered mental states, Clinical Neurophysiology, Volume 123, Issue 5, 2012, Pages 910-917, ISSN 1388-2457,https://doi.org/10.1016/j.clinph.2011.07.053. (http://www.sciencedirect.com/science/article/pii/S1388245711006316)
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