Christa B. Swisher

Baseline EEG pattern on continuous ICU EEG monitoring and incidence of seizures.

Purpose: To identify the probability of detecting nonconvulsive seizures based on the initial pattern seen in the first 30 minutes of continuous EEG (cEEG) monitoring. Methods: Continuous EEG monitoring reports from 243 adult patients were reviewed, assessing the baseline cEEG monitoring pattern and the presence of seizures during the entire monitoring period. The baseline EEG patterns were classified into nine categories: seizures, lateralized periodic discharges, generalized periodic discharges, focal epileptiform discharges, burst suppression, asymmetric background, generalized slowing, generalized periodic discharges with triphasic morphology, and normal. Results: Overall, 51 patients (21%) had nonconvulsive seizures at any time during cEEG monitoring. Notably, 112 patients had generalized slowing as the initial EEG pattern, and none of these patients were noted to have seizures. Seizure rates among the types of baseline EEG findings were as follows: lateralized periodic discharges (56%, n = 9), burst suppression (50%, n = 10), generalized periodic discharges (50%, n = 2), normal (33%, n = 3), focal epileptiform discharges (31%, n = 35), and asymmetric background (11%, n = 46). Conclusions: Patients with only generalized slowing seen on the baseline EEG recording are unlikely to develop seizures on subsequent cEEG monitoring. Depending on the clinical circumstance, the standard duration of cEEG recording (24–48 hours) may be unnecessary in patients with generalized slowing as their only cEEG abnormality.

Diagnostic Accuracy of Electrographic Seizure Detection by Neurophysiologists and Non-Neurophysiologists in the Adult ICU Using a Panel of Quantitative EEG Trends.

Purpose: To evaluate the sensitivity and specificity of a panel of quantitative EEG (qEEG) trends for seizure detection in adult intensive care unit (ICU) patients when reviewed by neurophysiologists and non-neurophysiologists. Methods: One hour qEEG panels (n = 180) were collected retrospectively from 45 ICU patients and were distributed to 5 neurophysiologists, 7 EEG technologists, and 5 Neuroscience ICU nurses for evaluation of seizures. Each panel consisted of the following qEEG tools, displayed separately for left and right hemisphere electrodes: rhythmicity spectrogram (rhythmic run detection and display; Persyst Inc), color density spectral array, EEG asymmetry index, and amplitude integrated EEG. The reviewers did not have access to the raw EEG data. Results: For the reviewers ability to detect the presence of seizures on qEEG panels when compared with the gold standard of independent raw EEG review, the sensitivities and specificities are as follows: neurophysiologists 0.87 and 0.61, EEG technologists 0.80 and 0.80, and Neuroscience ICU nurses 0.87 and 0.61, respectively. There was no statistical difference among the three groups regarding sensitivity. Conclusions: Quantitative EEG display panels are a promising tool to aid detection of seizures by non-neurophysiologists as well as by neurophysiologists. However, even when used as a panel, qEEG trends do not appear to be adequate as the sole method for reviewing continuous EEG data.

Use of pregabalin for nonconvulsive seizures and nonconvulsive status epilepticus

PURPOSE To determine the efficacy of pregabalin (PGB) in treatment of frequent nonconvulsive seizures (NCS) and nonconvulsive status epilepticus (NCSE) in critically ill patients. METHODS In this retrospective study, 21 patients were identified as having received pregabalin for the treatment of NCS as determined by continuous electroencephalographic monitoring. The patients were considered to be responders if their seizures were terminated within 24h of initiation of PGB without the addition of another antiepileptic agent. RESULTS Of the 21 patients who received PGB for treatment of NCS or NCSE, 11 (52%) were responders. PGB was administered via a nasogastric tube or orally and was the 2nd to 4th agent used. The average initial dose and total daily dose of PGB was similar in the responders and non-responders (342mg vs. 360mg, respectively). PGB was more effective in aborting NCS (9 patients, 82%) than NCSE (2 patients, 18%). Of the 9 brain tumor patients, PGB resulted in seizure cessation in 67% (6 patients). In contrast, all patients with hypoxic injury (4) did not respond to PGB. The responders were noted to have better clinical outcome (64% vs. 9% discharged home). Most of the patients tolerated the medication without any significant short term adverse effects, except two patients who were noted to have dizziness and sedation. CONCLUSIONS Pregabalin may be safe option for add-on treatment for nonconvulsive seizures in critically ill patients when conventional therapy fails.

Survey of current practices among US epileptologists of antiepileptic drug withdrawal after epilepsy surgery.

In order to identify the current practices of antiepileptic drug (AED) withdrawal after epilepsy surgery, a survey was administered to 204 adult and pediatric epileptologists. The responses from 58 epileptologists revealed wide variations regarding the time course and extent of AED withdrawal after successful epilepsy surgery. For most of the epileptologists, the likelihood of the surgery being successful is an important factor in determining whether or not AEDs are tapered. Most of the respondents started to taper AEDs more rapidly than suggested by previous reports. The majority of the epileptologists were able to stop all AEDs completely in a substantial number of patients. The most important factors considered when deciding to taper AEDs were the presence of ongoing auras and the occurrence of postoperative seizures prior to seizure remission. In the absence of data from well-designed prospective trials, such survey results can inform practice and, hopefully, aid in the design of future trials.

Utilization of Quantitative EEG Trends for Critical Care Continuous EEG Monitoring: A Survey of Neurophysiologists.

Purpose: Quantitative EEG (QEEG) can be used to assist with review of large amounts of data generated by critical care continuous EEG monitoring. This study aimed to identify current practices regarding the use of QEEG in critical care continuous EEG monitoring of critical care patients. Methods: An online survey was sent to 796 members of the American Clinical Neurophysiology Society (ACNS), instructing only neurophysiologists to participate. Results: The survey was completed by 75 neurophysiologists that use QEEG in their practice. Survey respondents reported that neurophysiologists and neurophysiology fellows are most likely to serve as QEEG readers (97% and 52%, respectively). However, 21% of respondents reported nonneurophysiologists are also involved with QEEG interpretation. The majority of nonneurophysiologist QEEG data review is aimed to alert neurophysiologists to periods of concern, but 22% reported that nonneurophysiologists use QEEG to directly guide clinical care. Quantitative EEG was used most frequently for seizure detection (92%) and burst suppression monitoring (59%). A smaller number of respondents use QEEG for monitoring the depth of sedation (29%), ischemia detection (28%), vasospasm detection (28%) and prognosis after cardiac arrest (21%). About half of the respondents do not review every page of the raw critical care continuous EEG record when using QEEG. Respondents prefer a panel of QEEG trends displayed as hemispheric data, when applicable. There is substantial variability regarding QEEG trend preferences for seizure detection and ischemia detection. Conclusions: QEEG is being used by neurophysiologists and nonneurophysiologists for applications beyond seizure detection, but practice patterns vary widely. There is a need for standardization of QEEG methods and practices.

Early withdrawal of non-anesthetic antiepileptic drugs after successful termination of nonconvulsive seizures and nonconvulsive status epilepticus

PURPOSE Multiple antiepileptic drugs (AEDs) are often necessary to treat nonconvulsive seizures (NCS) and nonconvulsive status epilepticus (NCSE). AED polypharmacy places patients at risk for adverse side effects and drug-drug interactions. Identifying the likelihood of seizure relapse when weaning non-anesthetic AEDs may provide guidance in the critical care unit. METHOD Ninety-nine adult patients with successful treatment of electrographic-proven NCS or NCSE on continuous critical care EEG (CCEEG) monitoring were identified retrospectively. Patients were determined to undergo an AED wean if the number of non-anesthetic AEDs was reduced at the time of discharge compared to the number of non-anesthetic AEDs at primary seizure cessation. Primary outcome was recurrent seizures either clinically or by CCEEG during hospitalization. Secondary outcome measures included hospital length of stay and discharge disposition. RESULTS The rate of recurrent seizures in the wean group was not statistically different when compared to the group that did not undergo an AED wean (17% vs. 13%, respectively; p = 0.77). The wean group had a median value of 4 (IQR: 3-4) non-anesthetic AEDs at the time of primary seizure cessation compared with 3 (IQR: 2-3) in the non-wean group (p < 0.0001). However, both groups had similar values of AEDs at discharge (median of 2 (IQR: 2-3) vs. 3 (IQR: 2-3) for wean and non-wean groups respectively; p = 0.40). Discharge disposition (favorable, acceptable, or unfavorable) was similar between groups (p = 0.32). CONCLUSIONS Early weaning of non-anesthetic AEDs does not increase the risk of recurrent seizures in patients treated for NCS or NCSE during their hospitalization.

Novel Dual Lumen Catheter and Filtration Device for Removal of Subarachnoid hemorrhage: First Case Report

BACKGROUND AND IMPORTANCE The amount of subarachnoid blood and the presence of toxic blood breakdown products in the cerebrospinal fluid (CSF) have long been associated with poor outcomes in aneurysmal subarachnoid hemorrhage. The Neurapheresis™ system (Minnetronix Inc, St. Paul, Minnesota) has been developed to filter CSF and remove blood products, and is being investigated for safety and feasibility in the ExtracorPoreal FILtration of subarachnoid hemorrhage via SpinaL CAtheteR (PILLAR) study. We report the first case using this novel device. CLINICAL PRESENTATION A 65-yr-old female presented with a ruptured left posterior communicating artery aneurysm. Following placement of a ventriculostomy and coil embolization of her aneurysm, the patient underwent placement of a lumbar dual lumen catheter for CSF filtration as part of the PILLAR study. In this case, a total of 9 h of filtration during 31 h of catheter indwelling resulted in 309.47 mL of processed CSF without complication. Computed tomography images demonstrated an interval reduction of subarachnoid hemorrhage immediately after filtration. The patient was discharged home on postbleed day 11 and at 30 d showed good recovery. CONCLUSION Safety of the Neurapheresis procedure was confirmed in this first case, and we will continue to evaluate safety of the Neurapheresis system through the PILLAR trial.

S20. EEG features of nonconvulsive seizures in critically ill patients - Findings from the TRENdS trial

Introduction There is little data on the EEG features of seizures seen critically ill patients having nonconvulsive seizures (NCS). The Treatment of Recurrent Electrographic Nonconvulsive Seizures (TRENdS) study enrolled 74 such subjects and randomized them to treatment with lacosamide or fosphenytoin. This study evaluates the EEG features of a subset of these subjects. Methods EEG features of 36 of the 74 subjects enrolled in the TRENdS study were analyzed in detail. The extent of spread, onset frequency, offset frequency and morphology of the most common seizure type was assessed. Results In this cohort, the average number of seizures per subject was 35.9 (range 1–339). Seizures were limited to one quadrant (11, 30.6%) or hemispheric (11, 30.6%) in most subjects. Another 14 (38.8%) subjects had seizures that were generalized, bilateral but not generalized or spread to varying extent. Most subjects had seizures with delta frequency onset (18, 50%), while another 9 (25%) had theta frequencies at onset. Another 9 (25%) subjects had seizure onset frequencies in alpha or beta range, or had seizures with varying onset frequencies. At seizure termination, delta frequencies were noted in 29 (80.6%) subjects, while 7 (19.4%) had various other frequencies. The morphology of the seizures was a rhythmic discharge in 17 (47.2%) subjects, recurrent spike or sharp discharges in 5 (13.9%), recurrent spike and wave discharges in 5 (13.9%) and various other morphologies in 9 (25%) others. Conclusion NCS in this cohort of subjects were mostly limited to one hemisphere. The seizure onset frequencies were most often in the delta and theta range, while delta frequencies were noted most often at offset. Rhythmic discharges were the most common morphology.

Randomized trial of lacosamide versus fosphenytoin for nonconvulsive seizures: Lacosamide vs Fosphenytoin

The optimal treatment of nonconvulsive seizures in critically ill patients is uncertain. We evaluated the comparative effectiveness of the antiseizure drugs lacosamide (LCM) and fosphenytoin (fPHT) in this population.

QEEG Training Module

The goal of this chapter is to provide a training module for residents, neurophysiology fellows, neurocritical care fellows, nurses, EEG technologists, and any other non-neurophysiologists interested in evaluating bedside quantitative EEG (QEEG). Due to the increasing utilization of continuous EEG (cEEG) monitoring in intensive care units (ICUs), large volumes of EEG data are being generated. To assist with evaluation of large amounts of cEEG data, QEEG software programs are frequently employed. While raw EEG interpretation is performed by neurophysiologists, QEEG software provides a compressed and simplified view of the raw EEG signals, potentially allowing for evaluation by non-neurophysiologists. QEEG software can be seen running at the bedside in many ICUs. This chapter will be limited to the basics of QEEG trends for seizure recognition and artifact recognition. While there is ongoing research evaluating the performance of QEEG for other purposes (ischemia detection, evaluation of depth of burst suppression, prognosis in hypoxic-ischemic encephalopathy, etc.), the majority of current clinical QEEG utilization is for seizure detection.