Interrater Reliability of Expert Electroencephalographers Identifying Seizures and Rhythmic and Periodic Patterns in EEGs

BACKGROUND AND OBJECTIVES

The validity of brain monitoring using electroencephalography (EEG), particularly to guide care in patients with acute or critical illness, requires that experts can reliably identify seizures and other potentially harmful rhythmic and periodic brain activity, collectively referred to as "ictal-interictal-injury continuum" (IIIC). Previous interrater reliability (IRR) studies are limited by small samples and selection bias. This study was conducted to assess the reliability of experts in identifying IIIC.

METHODS

This prospective analysis included 30 experts with subspecialty clinical neurophysiology training from 18 institutions. Experts independently scored varying numbers of ten-second EEG segments as "seizure (SZ)," "lateralized periodic discharges (LPDs)," "generalized periodic discharges (GPDs)," "lateralized rhythmic delta activity (LRDA)," "generalized rhythmic delta activity (GRDA)," or "other." EEGs were performed for clinical indications at Massachusetts General Hospital between 2006 and 2020. Primary outcome measures were pairwise IRR (average percent agreement [PA] between pairs of experts) and majority IRR (average PA with group consensus) for each class and beyond chance agreement (κ). Secondary outcomes were calibration of expert scoring to group consensus, and latent trait analysis to investigate contributions of bias and noise to scoring variability.

RESULTS

Among 2,711 EEGs, 49% were from women, and the median (IQR) age was 55 (41) years. In total, experts scored 50,697 EEG segments; the median [range] number scored by each expert was 6,287.5 [1,002, 45,267]. Overall pairwise IRR was moderate (PA 52%, κ 42%), and majority IRR was substantial (PA 65%, κ 61%). Noise-bias analysis demonstrated that a single underlying receiver operating curve can account for most variation in experts' false-positive vs true-positive characteristics (median [range] of variance explained ([Formula: see text]): 95 [93, 98]%) and for most variation in experts' precision vs sensitivity characteristics ([Formula: see text]: 75 [59, 89]%). Thus, variation between experts is mostly attributable not to differences in expertise but rather to variation in decision thresholds.

DISCUSSION

Our results provide precise estimates of expert reliability from a large and diverse sample and a parsimonious theory to explain the origin of disagreements between experts. The results also establish a standard for how well an automated IIIC classifier must perform to match experts.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that an independent expert review reliably identifies ictal-interictal injury continuum patterns on EEG compared with expert consensus.

Development of Expert-Level Classification of Seizures and Rhythmic and Periodic Patterns During EEG Interpretation

BACKGROUND AND OBJECTIVES

Seizures (SZs) and other SZ-like patterns of brain activity can harm the brain and contribute to in-hospital death, particularly when prolonged. However, experts qualified to interpret EEG data are scarce. Prior attempts to automate this task have been limited by small or inadequately labeled samples and have not convincingly demonstrated generalizable expert-level performance. There exists a critical unmet need for an automated method to classify SZs and other SZ-like events with expert-level reliability. This study was conducted to develop and validate a computer algorithm that matches the reliability and accuracy of experts in identifying SZs and SZ-like events, known as "ictal-interictal-injury continuum" (IIIC) patterns on EEG, including SZs, lateralized and generalized periodic discharges (LPD, GPD), and lateralized and generalized rhythmic delta activity (LRDA, GRDA), and in differentiating these patterns from non-IIIC patterns.

METHODS

We used 6,095 scalp EEGs from 2,711 patients with and without IIIC events to train a deep neural network, SPaRCNet, to perform IIIC event classification. Independent training and test data sets were generated from 50,697 EEG segments, independently annotated by 20 fellowship-trained neurophysiologists. We assessed whether SPaRCNet performs at or above the sensitivity, specificity, precision, and calibration of fellowship-trained neurophysiologists for identifying IIIC events. Statistical performance was assessed by the calibration index and by the percentage of experts whose operating points were below the model's receiver operating characteristic curves (ROCs) and precision recall curves (PRCs) for the 6 pattern classes.

RESULTS

SPaRCNet matches or exceeds most experts in classifying IIIC events based on both calibration and discrimination metrics. For SZ, LPD, GPD, LRDA, GRDA, and "other" classes, SPaRCNet exceeds the following percentages of 20 experts-ROC: 45%, 20%, 50%, 75%, 55%, and 40%; PRC: 50%, 35%, 50%, 90%, 70%, and 45%; and calibration: 95%, 100%, 95%, 100%, 100%, and 80%, respectively.

DISCUSSION

SPaRCNet is the first algorithm to match expert performance in detecting SZs and other SZ-like events in a representative sample of EEGs. With further development, SPaRCNet may thus be a valuable tool for an expedited review of EEGs.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that among patients with epilepsy or critical illness undergoing EEG monitoring, SPaRCNet can differentiate (IIIC) patterns from non-IIIC events and expert neurophysiologists.

Quantitative epileptiform burden and electroencephalography background features predict post-traumatic epilepsy

BACKGROUND

Post-traumatic epilepsy (PTE) is a severe complication of traumatic brain injury (TBI). Electroencephalography aids early post-traumatic seizure diagnosis, but its optimal utility for PTE prediction remains unknown. We aim to evaluate the contribution of quantitative electroencephalograms to predict first-year PTE (PTE1).

METHODS

We performed a multicentre, retrospective case-control study of patients with TBI. 63 PTE1 patients were matched with 63 non-PTE1 patients by admission Glasgow Coma Scale score, age and sex. We evaluated the association of quantitative electroencephalography features with PTE1 using logistic regressions and examined their predictive value relative to TBI mechanism and CT abnormalities.

RESULTS

In the matched cohort (n=126), greater epileptiform burden, suppression burden and beta variability were associated with 4.6 times higher PTE1 risk based on multivariable logistic regression analysis (area under the receiver operating characteristic curve, AUC (95% CI) 0.69 (0.60 to 0.78)). Among 116 (92%) patients with available CT reports, adding quantitative electroencephalography features to a combined mechanism and CT model improved performance (AUC (95% CI), 0.71 (0.61 to 0.80) vs 0.61 (0.51 to 0.72)).

CONCLUSIONS

Epileptiform and spectral characteristics enhance covariates identified on TBI admission and CT abnormalities in PTE1 prediction. Future trials should incorporate quantitative electroencephalography features to validate this enhancement of PTE risk stratification models.

Intravenous ganaxolone for the treatment of refractory status epilepticus: Results from an open-label, dose-finding, phase 2 trial

OBJECTIVE

Patients with refractory status epilepticus (RSE) have failed treatment with benzodiazepines and ≥1 second-line intravenous (IV) antiseizure medication (ASM). Guidelines recommend IV anesthesia when second-line ASMs have failed, but potential harms can outweigh the benefits. Novel treatments are needed to stop and durably control RSE without escalation to IV anesthetics. Ganaxolone is an investigational neuroactive steroid in development for RSE treatment. This study's objective was to determine the appropriate dosing for IV ganaxolone in RSE and obtain a preliminary assessment of efficacy and safety.

METHODS

This was an open-label, phase 2 trial conducted from February 19, 2018 to September 18, 2019, at three sites in the United States. Patients were aged ≥12 years, had convulsive or nonconvulsive SE, and failed to respond to ≥1 second-line IV ASM. Twenty-one patients were screened; 17 were enrolled. Patients received IV ganaxolone added to standard-of-care ASMs. Ganaxolone infusion was initiated as an IV bolus (over 3 min) with continuous infusion of decreasing infusion rates for 48-96 h followed by an 18-h taper. There were three ganaxolone dosing cohorts: low, 500 mg/day; medium, 650 mg/day; and high, 713 mg/day. The primary end point was the number of patients not requiring escalation to IV anesthetic treatment within 24 h of ganaxolone initiation.

RESULTS

Most of the 17 enrolled patients (65%) had nonconvulsive SE, and had failed a median of three prior ASMs, including first-line benzodiazepine and second-line IV ASM therapy. Median time to SE cessation following ganaxolone initiation was 5 min. No patient required escalation to third-line IV anesthetics during the 24-h period following ganaxolone initiation. Two treatment-related serious adverse events (sedation) were reported. Of the three deaths, none was considered related to ganaxolone; all occurred 9-22 days after completing ganaxolone.

SIGNIFICANCE

IV ganaxolone achieved rapid and durable seizure control in patients with RSE, and showed acceptable safety and tolerability.

Electrographic Seizure Detection by Neuroscience Intensive Care Unit Nurses via Bedside Real-Time Quantitative EEG

Objective

Our primary objective was to determine the performance of real-time neuroscience intensive care unit (neuro-ICU) nurse interpretation of quantitative EEG (qEEG) at the bedside for seizure detection. Secondary objectives included determining nurse time to seizure detection and assessing factors that influenced nurse accuracy.

Methods

Nurses caring for neuro-ICU patients undergoing continuous EEG (cEEG) were trained using a 1-hour qEEG panel (rhythmicity spectrogram and amplitude-integrated EEG) bedside display. Nurses' hourly interpretations were compared with post hoc cEEG review by 2 neurophysiologists as the gold standard. Diagnostic performance, time to seizure detection compared with standard of care (SOC), and effects of other factors on nurse accuracy were calculated.

Results

A total of 109 patients and 65 nurses were studied. Eight patients had seizures during the study period (7%). Nurse sensitivity and specificity for the detection of seizures were 74% and 92%, respectively. Mean nurse time to seizure detection was significantly shorter than SOC by 132 minutes (Cox proportional hazard ratio 6.96). Inaccurate nurse interpretation was associated with increased hours monitored and presence of brief rhythmic discharges.

Conclusions

This prospective study of real-time nurse interpretation of qEEG for seizure detection in neuro-ICU patients showed clinically adequate sensitivity and specificity. Time to seizure detection was less than that of SOC.

Trial Registration Information

Clinical trial registration number NCT02082873.

Classification of Evidence

This study provides Class I evidence that neuro-ICU nurse interpretation of qEEG detects seizures in adults with a sensitivity of 74% and a specificity of 92% compared with traditional cEEG review.

Anticoagulation after Spontaneous Intraparenchymal Hemorrhage in Patients with Mechanical Heart Valves and Concomitant Atrial Fibrillation

Aim Patients with mechanical heart valves and coexisting atrial fibrillation (AFib-MHV) who suffer an intraparenchymal hemorrhage (IPH, defined as bleeding solely within the brain parenchyma and/or ventricle) are at a high risk of thromboembolism without anticoagulation. Data are lacking regarding the safety of early re-initiation of anticoagulation in these patients.

Patients and Methods We performed a descriptive, single-institution retrospective analysis of patients with AFib-MHV who suffered a non-traumatic, supratentorial IPH between July 2013 and June 2017. We analyzed the patients and IPH characteristics, anticoagulation and antiplatelet use, the occurrence of thrombotic and hemorrhage complications, and discharge disposition. We described the timing of initiation of anticoagulation and outcomes after IPH while in-patient.

Results Six patients with AFib-MHV suffered a spontaneous IPH. Four were initiated on anticoagulation prior to discharge, of whom two were initiated within 3 days post-hemorrhage. These patients suffered no bleeding complications and were discharged home with a modified Rankin Scale of 1.

Conclusion Patients with AFib-MHV who suffer a spontaneous IPH are a rare population to study. Further studies to guide the management of restarting anticoagulation in this select population are warranted.

Primary brain tumor patients admitted to a US intensive care unit: a descriptive analysis

Purpose:

To describe our population of primary brain tumor (PBT) patients, a subgroup of cancer patients whose intensive care unit (ICU) outcomes are understudied.

Methods:

Retrospective analysis of PBT patients admitted to an ICU between 2013 to 2018 for an unplanned need. Using descriptive analyses, we characterized our population and their outcomes.

Results:

Fifty-nine PBT patients were analyzed. ICU mortality was 19% (11/59). The most common indication for admission was seizures (n = 16, 27%).

Conclusion:

Our ICU mortality of PBT patients was comparable to other solid tumor patients and the general ICU population and better than patients with hematological malignancies. Further study of a larger population would inform guidelines for triaging PBT patients who would most benefit from ICU-level care.

Purpose: Data are lacking regarding outcomes of patients with primary brain tumors (PBTs) admitted to an intensive care unit (ICU), which may it difficult for ICU providers to know who of these patients will best benefit from ICU-level care. We aimed to describe our patient population to contribute to the limited data. Methods: We performed a retrospective analysis of critically ill PBT patients in our ICU. Results: Of 59 patients analyzed, ICU mortality was 19% (11/59), and the most common indication for admission was seizures (n = 16, 27%). Conclusion: Our ICU mortality of PBT patients was comparable to other solid tumor patients and the general ICU population and better than patients with hematological malignancies.

CN-105 in Participants with Acute Supratentorial Intracerebral Hemorrhage (CATCH) Trial

BACKGROUND

Endogenous apolipoprotein (apo) E mediates neuroinflammatory responses and recovery after brain injury. Exogenously administered apoE-mimetic peptides effectively penetrate the central nervous system compartment and downregulate acute inflammation. CN-105 is a novel apoE-mimetic pentapeptide with excellent evidence of functional and histological improvement in preclinical models of intracerebral hemorrhage (ICH). The CN-105 in participants with Acute supraTentorial intraCerebral Hemorrhage (CATCH) trial is a first-in-disease-state multicenter open-label trial evaluating safety and feasability of CN-105 administration in patients with acute primary supratentorial ICH.

METHODS

Eligible patients were aged 30-80 years, had confirmed primary supratentorial ICH, and were able to intiate CN-105 administration (1.0 mg/kg every 6 h for 72 h) within 12 h of symptom onset. A priori defined safety end points, including hematoma volume, pharmacokinetics, and 30-day neurological outcomes, were analyzed. For clinical outcomes, CATCH participants were compared 1:1 with a closely matched contemporary ICH cohort through random selection. Hematoma volumes determined from computed tomography images on days 0, 1, 2, and 5 and ordinal modified Rankin Scale score at 30 days after ICH were compared.

RESULTS

In 38 participants enrolled across six study sites in the United States, adverse events occurred at an expected rate without increase in hematoma expansion or neurological deterioration. CN-105 treatment had an odds ratio (95% confidence interval) of 2.69 (1.31-5.51) for lower 30-day modified Rankin Scale score, after adjustment for ICH score, sex, and race/ethnicity, as compared with a matched contemporary cohort.

CONCLUSIONS

CN-105 administration represents an excellent translational candidate for treatment of acute ICH because of its safety, dosing feasibility, favorable pharmacokinetics, and possible improvement in neurological recovery.

Deep active learning for Interictal Ictal Injury Continuum EEG patterns

OBJECTIVES

Seizures and seizure-like electroencephalography (EEG) patterns, collectively referred to as "ictal interictal injury continuum" (IIIC) patterns, are commonly encountered in critically ill patients. Automated detection is important for patient care and to enable research. However, training accurate detectors requires a large labeled dataset. Active Learning (AL) may help select informative examples to label, but the optimal AL approach remains unclear.

METHODS

We assembled >200,000 h of EEG from 1,454 hospitalized patients. From these, we collected 9,808 labeled and 120,000 unlabeled 10-second EEG segments. Labels included 6 IIIC patterns. In each AL iteration, a Dense-Net Convolutional Neural Network (CNN) learned vector representations for EEG segments using available labels, which were used to create a 2D embedding map. Nearest-neighbor label spreading within the embedding map was used to create additional pseudo-labeled data. A second Dense-Net was trained using real- and pseudo-labels. We evaluated several strategies for selecting candidate points for experts to label next. Finally, we compared two methods for class balancing within queries: standard balanced-based querying (SBBQ), and high confidence spread-based balanced querying (HCSBBQ).

RESULTS

Our results show: 1) Label spreading increased convergence speed for AL. 2) All query criteria produced similar results to random sampling. 3) HCSBBQ query balancing performed best. Using label spreading and HCSBBQ query balancing, we were able to train models approaching expert-level performance across all pattern categories after obtaining ∼7000 expert labels.

CONCLUSION

Our results provide guidance regarding the use of AL to efficiently label large EEG datasets in critically ill patients.

Acute Provoked Seizures-Work-Up and Management in Adults

Acute provoked seizures, also known as acute symptomatic seizures, occur secondary to a neurological or systemic precipitant, commonly presenting as a first-time seizure. In this article, we will discuss etiology, emergent protocols, medical work-up, initial treatment, and management of these seizures. The definitions, classifications, and management of convulsive status epilepticus and nonconvulsive status epilepticus in an acute setting will also be reviewed.

A Trial of Real-Time Electrographic Seizure Detection by Neuro-ICU Nurses Using a Panel of Quantitative EEG Trends

BACKGROUND

Non-convulsive seizures (NCS) are a common occurrence in the neurologic intensive care unit (Neuro-ICU) and are associated with worse outcomes. Continuous electroencephalogram (cEEG) monitoring is necessary for the detection of NCS; however, delays in interpretation are a barrier to early treatment. Quantitative EEG (qEEG) calculates a time-compressed simplified visual display from raw EEG data. This study aims to evaluate the performance of Neuro-ICU nurses utilizing bedside, real-time qEEG interpretation for detecting recurrent NCS.

METHODS

This is a prospective, single-institution study of patients admitted to the Duke Neuro-ICU between 2016 and 2018 who had NCS identified on traditional cEEG review. The accuracy of recurrent seizure detection on hourly qEEG review by bedside Neuro-ICU nurses was compared to the gold standard of cEEG interpretation by two board-certified neurophysiologists. The nurses first received brief qEEG training, individualized for their specific patient. The bedside qEEG display consisted of rhythmicity spectrogram (left and right hemispheres) and amplitude-integrated EEG (left and right hemispheres) in 1-h epochs.

RESULTS

Twenty patients were included and 174 1-h qEEG blocks were analyzed. Forty-seven blocks contained seizures (27%). The sensitivity was 85.1% (95% CI 71.1-93.1%), and the specificity was 89.8% (82.8-94.2%) for the detection of seizures for each 1-h block when compared to interpretation of conventional cEEG by two neurophysiologists. The false positive rate was 0.1/h. Hemispheric seizures (> 4 unilateral EEG electrodes) were more likely to be correctly identified by nurses on qEEG than focal seizures (≤ 4 unilateral electrodes) (p = 0.03).

CONCLUSIONS

After tailored training sessions, Neuro-ICU nurses demonstrated a good sensitivity for the interpretation of bedside real-time qEEG for the detection of recurrent NCS with a low false positive rate. qEEG is a promising tool that may be used by non-neurophysiologists and may lead to earlier detection of NCS.

Assessment of the Validity of the 2HELPS2B Score for Inpatient Seizure Risk Prediction

Importance

Seizure risk stratification is needed to boost inpatient seizure detection and to improve continuous electroencephalogram (cEEG) cost-effectiveness. 2HELPS2B can address this need but requires validation.

Objective

To use an independent cohort to validate the 2HELPS2B score and develop a practical guide for its use.

Design, Setting, and Participants

This multicenter retrospective medical record review analyzed clinical and EEG data from patients 18 years or older with a clinical indication for cEEG and an EEG duration of 12 hours or longer who were receiving consecutive cEEG at 6 centers from January 2012 to January 2019. 2HELPS2B was evaluated with the validation cohort using the mean calibration error (CAL), a measure of the difference between prediction and actual results. A Kaplan-Meier survival analysis was used to determine the duration of EEG monitoring to achieve a seizure risk of less than 5% based on the 2HELPS2B score calculated on first- hour (screening) EEG. Participants undergoing elective epilepsy monitoring and those who had experienced cardiac arrest were excluded. No participants who met the inclusion criteria were excluded.

Main Outcomes and Measures

The main outcome was a CAL error of less than 5% in the validation cohort.

Results

The study included 2111 participants (median age, 51 years; 1113 men [52.7%]; median EEG duration, 48 hours) and the primary outcome was met with a validation cohort CAL error of 4.0% compared with a CAL of 2.7% in the foundational cohort (P = .13). For the 2HELPS2B score calculated on only the first hour of EEG in those without seizures during that hour, the CAL error remained at less than 5.0% at 4.2% and allowed for stratifying patients into low- (2HELPS2B = 0; <5% risk of seizures), medium- (2HELPS2B = 1; 12% risk of seizures), and high-risk (2HELPS2B, ≥2; risk of seizures, >25%) groups. Each of the categories had an associated minimum recommended duration of EEG monitoring to achieve at least a less than 5% risk of seizures, a 2HELPS2B score of 0 at 1-hour screening EEG, a 2HELPS2B score of 1 at 12 hours, and a 2HELPS2B score of 2 or greater at 24 hours.

Conclusions and Relevance

In this study, 2HELPS2B was validated as a clinical tool to aid in seizure detection, clinical communication, and cEEG use in hospitalized patients. In patients without prior clinical seizures, a screening 1-hour EEG that showed no epileptiform findings was an adequate screen. In patients with any highly epileptiform EEG patterns during the first hour of EEG (ie, a 2HELPS2B score of ≥2), at least 24 hours of recording is recommended.

Blood pressure reduction and outcome after endovascular therapy with successful reperfusion: a multicenter study

BACKGROUND

Elevated systolic blood pressure (SBP) after mechanical thrombectomy (MT) correlates with worse outcome. However, the association between SBP reduction (SBPr) and outcome after successful reperfusion with MT is not well established.

OBJECTIVE

To investigate the association between SBPr in the first 24 hours after successful reperfusion and the functional and safety outcomes of MT.

METHODS

A multicenter retrospective study, which included 10 comprehensive stroke centers, was carried out. Patients with acute ischemic stroke and anterior circulation large vessel occlusions who achieved successful reperfusion via MT were included. SBPr was calculated using the formula 100×([admission SBP-mean SBP]/admission SBP). Poor outcome was defined as a modified Rankin Scale (mRS) score of 3-6 at 90 days. Safety endpoints included symptomatic intracerebral hemorrhage, mortality, and requirement for hemicraniectomy during admission. A generalized mixed linear model was used to study the association between SBPr and outcomes.

RESULTS

A total of 1361 patients were included in the final analysis. SBPr as a continuous variable was inversely associated with poor outcome (OR=0.97; 95% CI 0.95 to 0.98; p<0.001) but not with the safety outcomes. Subanalysis based on reperfusion status showed that SBPr was associated with lower odds of poor outcome only in patients with complete reperfusion (modified Thrombolysis in Cerebral Infarction (mTICI 3)) but not in patients with incomplete reperfusion (mTICI 2b). When SBPr was divided into categories (<1%, 1%-10%, 11%-20%, >20%), the rate of poor outcome was highest in the first group.

CONCLUSION

SBPr in the first 24 hours after successful reperfusion was inversely associated with poor outcome. No association between SBPr and safety outcome was found.

Randomized trial of lacosamide versus fosphenytoin for nonconvulsive seizures

OBJECTIVE

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.

METHODS

The TRENdS (Treatment of Recurrent Electrographic Nonconvulsive Seizures) study was a noninferiority, prospective, multicenter, randomized treatment trial of patients diagnosed with nonconvulsive seizures (NCSs) by continuous electroencephalography (cEEG). Treatment was randomized to intravenous (IV) LCM 400mg or IV fPHT 20mg phenytoin equivalents/kg. The primary endpoint was absence of electrographic seizures for 24 hours as determined by 1 blinded EEG reviewer. The frequency with which NCS control was achieved in each arm was compared, and the 90% confidence interval (CI) was determined. Noninferiority of LCM to fPHT was to be concluded if the lower bound of the CI for relative risk was >0.8.

RESULTS

Seventy-four subjects were enrolled (37 LCM, 37 fPHT) between August 21, 2012 and December 20, 2013. The mean age was 63.6 years; 38 were women. Seizures were controlled in 19 of 30 (63.3%) subjects in the LCM arm and 16 of 32 (50%) subjects in the fPHT arm. LCM was noninferior to fPHT (p = 0.02), with a risk ratio of 1.27 (90% CI = 0.88-1.83). Treatment emergent adverse events (TEAEs) were similar in both arms, occurring in 9 of 35 (25.7%) LCM and 9 of 37 (24.3%) fPHT subjects (p = 1.0).

INTERPRETATION

LCM was noninferior to fPHT in controlling NCS, and TEAEs were comparable. LCM can be considered an alternative to fPHT in the treatment of NCSs detected on cEEG. Ann Neurol 2018;83:1174-1185.

Prospective Trial of Cerebrospinal Fluid Filtration After Aneurysmal Subarachnoid Hemorrhage via Lumbar Catheter (PILLAR)

Background and Purpose- The PILLAR (Extracorporeal Filtration of Subarachnoid Hemorrhage via Spinal Catheter) study is a first-in-human trial of cerebrospinal fluid (CSF) filtration in aneurysmal subarachnoid hemorrhage. The study evaluates the safety and feasibility of a novel filtration system to rapidly remove blood and blood breakdown products from CSF after securement of a ruptured aneurysm. Methods- Patients with aneurysmal subarachnoid hemorrhage had a dual-lumen lumbar, intrathecal catheter placed after aneurysm securement and received up to 24 hours of CSF filtration (neurapheresis therapy). The catheter aspirated blood-contaminated CSF from the lumbar cistern and returned filtered CSF to the thoracic subarachnoid space. Neuro checks were performed q2 hours, and CSF samples were collected for cell counts, total protein, and gram stain. Computed tomography scans were acquired at baseline and post-filtration. Clinical follow-up occurred at 2 weeks and 30 days. Results- Thirteen patients had a catheter placed (mean time 24:13 hours after ictus). The system processed 632.0 mL (180.6-1447.6 mL) CSF in 15:07 hours (5:32-24:00 hours) of filtration. The mean initial CSF red blood cell count, 2.78×10⁵ cells/µL, reduced to 1.17×10⁵ cells/µL after filtration (52.9% reduction), and total protein reduced 71%. Independent analysis of baseline and postfiltration computed tomographies found notable cisternal blood decrease, with 46.5% mean Hijdra Score reduction. Three mild, anticipated adverse events were reported. Conclusions- The initial safety and feasibility of Neurapheresis therapy in aneurysmal subarachnoid hemorrhage demonstrated the potential to safely filter CSF and remove blood and blood byproducts. Future studies are warranted. Clinical Trial Registration- URL: https://www.clinicaltrials.gov. Unique identifier: NCT0287263.

Blood Pressure and Outcome After Mechanical Thrombectomy With Successful Revascularization

Background and Purpose- Successful reperfusion can be achieved in more than two-thirds of patients treated with mechanical thrombectomy. Therefore, it is important to understand the effect of blood pressure (BP) on clinical outcomes after successful reperfusion. In this study, we investigated the relationship between BP on admission and during the first 24 hours after successful reperfusion with clinical outcomes. Methods- This was a multicenter study from 10 comprehensive stroke centers. To ensure homogeneity of the studied cohort, we included only patients with anterior circulation who achieved successful recanalization at the end of procedure. Clinical outcomes included 90-day modified Rankin Scale, symptomatic intracerebral hemorrhage (sICH), mortality, and hemicraniectomy. Results- A total of 1245 patients were included in the study. Mean age was 69±14 years, and 51% of patients were female. Forty-nine percent of patients had good functional outcome at 90-days, and 4.7% suffered sICH. Admission systolic BP (SBP), mean SBP, maximum SBP, SBP SD, and SBP range were associated with higher risk of sICH. In addition, patients in the higher mean SBP groups had higher rates of sICH. Similar results were found for hemicraniectomy. With respect to functional outcome, mean SBP, maximum SBP, and SBP range were inversely associated with the good outcome (modified Rankin Scale score, 0-2). However, the difference in SBP parameters between the poor and good outcome groups was modest. Conclusions- Higher BP within the first 24 hours after successful mechanical thrombectomy was associated with a higher likelihood of sICH, mortality, and requiring hemicraniectomy.

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.

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.

Phenytoin, levetiracetam, and pregabalin in the acute management of refractory status epilepticus in patients with brain tumors

BACKGROUND

There were nearly 700,000 patients in the United States in 2010 living with brain tumor diagnoses. The incidence of seizures in this population is as high as 70% and is historically difficult to control. Approximately 30-40% of brain tumors patients who present with status epilepticus (SE) will not respond to typical therapy consisting of benzodiazepines and phenytoin (PHT), resulting in patients with refractory status epilepticus (RSE). RSE is usually treated with anesthetic doses of propofol or midazolam infusions. This therapy can have significant risk, particularly in patients with cancer.

METHODS

A retrospective chart review was performed on 23 patients with primary or metastatic brain tumors whose SE was treated with intravenous PHT, levetiracetam (LEV), and oral pregabalin (PGB).

RESULTS

In all the patients under study, PHT or LEV was used as first-line therapy. PGB was typically used as third-line treatment. The median daily dose of PGB was 375 mg (usually divided BID or TID), and the median daily dose of LEV 3000 mg (usually divided BID). Cessation of SE was seen in 16/23 (70%) after administration of PHT, LEV, and PGB. SE was aborted, on average, 24 h after addition of the third antiepileptic drug. Only one patient in the responder group required intubation. Mortality rate was zero in the responder group. No adverse reactions to this medication regimen were observed.

CONCLUSION

Our study suggests that the administration of PHT, LEV, and PGB in brain tumor patients with RSE is safe and highly effective.

Membrane and synaptic effects of corticotropin-releasing factor on periaqueductal gray neurons of the rat

Corticotropin-releasing factor (CRF) has been identified as a major component of the hypothalamic-pituitary-adrenal (HPA) axis. By stimulating the release of adrenocorticotropin hormone (ACTH), CRF acts as a key mediator of the stress response. However, CRF receptors and neuronal elements are present in many extrahypothalamic regions of the brain. A region that contains both CRF-ergic neurons and CRF receptors is the midbrain periaqueductal gray (PAG). The physiological effects of CRF in the PAG are unknown. In this study, an in vitro preparation, extracellular and intracellular patch-clamp recordings, were used to examine the effects of CRF, applied through an injecting electrode, on PAG neurons. Recordings were made from 147 neurons in the PAG. CRF injecting electrode concentrations of 0.05 and 1 microM were tested. At the higher concentration, CRF had a predominant excitatory effect on the neurons, and at the lower concentration, CRF produced no significant effect on the neurons. The excitatory effect was dose dependent and was often associated with a depolarization in membrane potential in intracellular recordings. Application of the CRF antagonist, alpha-helical CRF, blocked this excitatory effect. It is concluded that CRF has a predominant excitatory effect on PAG neurons. It is also concluded that CRF is not acting presynaptically. This excitatory effect of CRF on PAG neurons may lead to activation of a descending analgesic pathway.

The effects of diphenhydramine and SR142948A on periaqueductal gray neurons and on the interactions between the medial preoptic nucleus and the periaqueductal gray

The midbrain periaqueductal gray contains both neurotensin type-1 and type-2 receptors. Behavioral studies have shown that the analgesic effect of neurotensin is mediated through its interaction with the type-2 receptors. These receptors specifically bind the type-1 histamine antagonist, levocabastine. Recently, it has been shown that another histamine-1 antagonist, diphenhydramine, blocks the analgesic effect of neurotensin. In addition, it has been shown that a non-peptide neurotensin antagonist, SR142948A, binds to both types of neurotensin receptors and blocks the analgesic effect of exogenously applied neurotensin. Major afferents to the periaqueductal gray arise from the medial preoptic nucleus of the hypothalamus. This region contains neurotensinergic neurons, and the expression of neurotensin mRNA in this region increases following cold-water swim stress that leads to opioid-independent analgesia. The goal of this study was to determine whether the responses of periaqueductal gray neurons to stimulation of the medial preoptic nucleus are modified by local injection of diphenhydramine and SR142948A. Because the cellular basis of the effects of diphenhydramine on periaqueductal gray neurons had not been reported, we also examined the effects of diphenhydramine on the baseline-firing rate and synaptic transmission using in vivo and in vitro methods. The results of the in vitro studies indicate that diphenhydramine concentrations above 500 nM significantly reduce the baseline firing of the periaqueductal gray neurons without a significant effect on the frequency of postsynaptic potentials. At concentrations below 100 nM, diphenhydramine has little effect on the baseline-firing rate but partially blocks the response to neurotensin. The results of the in vivo studies showed similar effects of diphenhydramine. At high concentrations it inhibited periaqueductal gray neurons, but at low concentrations it had no effect on the baseline-firing rate and it blocked the response to neurotensin and to medial preoptic nucleus stimulation. Unlike diphenhydramine, SR142948A had virtually no effect on the baseline-firing rate but blocked the response to neurotensin and to stimulation of the medial preoptic nucleus. It is concluded that: (1) SR142948A, at a dose that completely blocks the effect of exogenously applied neurotensin on periaqueductal gray neurons, has little effect on their baseline-firing rates. (2) Because of its effect on the baseline-firing rate, only low doses of diphenhydramine can be used as an antagonist of the neurotensin analgesic effect. (3) Responses of periaqueductal gray neurons to medial preoptic nucleus stimulation is, in part, mediated by a neurotensinergic network within the periaqueductal gray.