Continuous electroencephalographic-monitoring in the ICU: an overview of current strengths and future challenges

Acute liver failure

Acute liver failure (ALF) is a life-threatening disorder characterised by rapid deterioration of liver function, coagulopathy, and hepatic encephalopathy in the absence of pre-existing liver disease. The cause of ALF varies across the world. Common causes of ALF in adults include drug toxicity, hepatotropic and non-hepatotropic viruses, herbal and dietary supplements, antituberculosis drugs, and autoimmune hepatitis. The cause of liver failure affects the management and prognosis, and therefore extensive investigation for cause is strongly suggested. Sepsis with multiorgan failure and cerebral oedema remain the leading causes of death in patients with ALF and early identification and appropriate management can alter the course of ALF. Liver transplantation is the best current therapy, although the role of artificial liver support systems, particularly therapeutic plasma exchange, can be useful for patients with ALF, especially in non-transplant centres. In this Seminar, we discuss the cause, prognostic models, and management of ALF.

The Role of Routine Electroencephalography in the Diagnosis of Seizures in Medical Intensive Care Units

Seizures should be diagnosed and treated to ensure optimal health outcomes in critically ill patients admitted in the medical intensive care unit (MICU). Continuous electroencephalography is still infrequently used in the MICU. We investigated the effectiveness of routine EEG (rEEG) in detecting seizures in the MICU. A total of 560 patients admitted to the MICU between October 2018 and March 2023 and who underwent rEEG were reviewed. Seizure-related rEEG constituted 47% of all rEEG studies. Totally, 39% of the patients experienced clinical seizures during hospitalization; among them, 48% experienced the seizure, and 13% experienced their first seizure after undergoing an rEEG study. Seventy-seven percent of the patients had unfavorable short-term outcomes. Patients with cardiovascular diseases were the most likely to have the suppression/burst suppression (SBS) EEG pattern and the highest mortality rate. The rhythmic and periodic patterns (RPPs) and electrographic seizure (ESz) EEG pattern were associated with seizures within 24 h after rEEG, which was also related to unfavorable outcomes. Significant predictors of death were age > 59 years, the male gender, the presence of cardiovascular disease, a Glasgow Coma Scale score ≤ 5, and the SBS EEG pattern, with a predictive performance of 0.737 for death. rEEG can help identify patients at higher risk of seizures. We recommend repeated rEEG in patients with ESz or RPP EEG patterns to enable a more effective monitoring of seizure activities.

Survey on the Updated German S3 Guideline for Intensive Care in Cardiac Surgery Patients

BACKGROUND

The German guideline on intensive care treatment of cardiac surgical patients provides evidence-based recommendations on management and monitoring. It remains unclear if, respectively, to which degree the guidelines are implemented into the daily practice. Therefore, this study aims to characterize the implementation of guideline recommendations in German cardiac surgical intensive care units (ICUs).

METHODS

An internet-based online survey (42 questions, 9 topics) was sent to 158 German head physicians of cardiac surgical ICUs. To compare the effect over time, most questions were based on a previously performed survey (2013) after introduction of the last guideline update in 2008.

RESULTS

A total of n = 65 (41.1%) questionnaires were included. Monitoring changed to increased provision of available transesophageal echocardiography specialists in 86% (2013: 72.6%), SvO2 measurement in 93.8% (2013: 55.1%), and electroencephalography in 58.5% (2013: 2.6%). The use of hydroxyethyl starch declined (9.4% vs. 2013: 38.7%), gelatin 4% presented the most administered colloid with 23.4% (2013: 17.4%). Low cardiac output syndrome was primarily treated with levosimendan (30.8%) and epinephrine (23.1%), while norepinephrine (44.6%) and dobutamine (16.9%) represented the most favored drug combination. The main way of distribution was web-based (50.9%), with increasing impact on therapy regimens (36.9% vs. 2013: 24%).

CONCLUSION

Changes were found in all questioned sectors compared with the preceding survey, with persisting variability between ICUs. Recommendations of the updated guideline have increasingly entered clinical practice, with participants valuing the updated publication as clinically relevant.

Amplitude Integrated Electroencephalography: Simulated Assessment of Neonatal Seizure Detection in PICU Patients

OBJECTIVES

Amplitude integrated electroencephalography (aEEG) is a mainstay of care in neonatal ICUs; however, knowledge gaps exist in relation to its accuracy for identifying seizures in older children. We aimed to review the diagnostic accuracy of existing neonatal seizure detection criteria for seizure detection in older children in hospital.

DESIGN

Retrospective study.

SETTING

PICU/Neurophysiology Department in Dublin.

PATIENTS

One hundred twenty patients (2 mo to 16 yr old) were chosen from a database of formal 10-20 system, 21-lead electroencephalography recordings (2012-2020), comprising 30 studies with seizures, 90 without.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Electroencephalography studies containing electrographic seizures (ESzs) were annotated to describe number, duration, distribution, and spread. Two-channel aEEG (using leads C3-P3, C4-P4) recordings were generated and independently reviewed by a professional specialist in clinical neurophysiology blinded to outcome and without reference to the raw electroencephalography trace. Logistic regression was used to identify factors associated with correct seizure identification on aEEG. Median patient age was 6.1 years. Abnormal recordings featured 123 seizures. Status epilepticus (SE) was evident by electroencephalography in 10 cases. Using neonatal criteria, aEEG had a sensitivity of 70% and negative predictive value of 90% for identifying any ESz. Accurate detection of individual seizures was diminished when seizures were very short or occurred during waking. Sensitivity for individual seizures was 81% when seizures less than 1 minute were excluded. aEEG correctly identified SE in 70% of the 10 cases, although ESz were confirmed to be present in 80% of this subpopulation.

CONCLUSIONS

aEEG criteria for neonatal seizure identification can be applied with caution to older children and should be supplemented by formal electroencephalography. Seizure identification is better for longer seizures and those arising from sleep. SE is not always recognized by aEEG among older children.

Rapid-Response Electroencephalography in Seizure Diagnosis and Patient Care: Lessons From a Community Hospital

ABSTRACT

BACKGROUND: Nonconvulsive seizures are a major source of in-hospital morbidity and a cause of unexplained encephalopathy in critically ill patients. Electroencephalography (EEG) is essential to confirm nonconvulsive seizures and can guide patient-specific workup, treatment, and prognostication. In a 208-bed community hospital, EEG services were limited to 1 part-time EEG technician and 1 EEG machine shared between inpatient and outpatient settings. Its use was restricted to typical business hours. A nursing-led quality improvement (QI) project endeavored to enhance access to EEG by introducing a point-of-care rapid-response EEG program. METHODS: For this project, a multidisciplinary protocol was developed to deploy a Food and Drug Administration-cleared, point-of-care rapid-response EEG platform (Ceribell Inc) in a community hospital's emergency department and inpatient units to streamline neurodiagnostic workups. This QI project compared EEG volume, study location, time-to-EEG, number of cases with seizures captured on EEG, and hospital-level financial metrics of diagnosis-related group reimbursements and length of stay for the 6 months before (pre-QI, using conventional EEG) and 6 months after implementing the rapid-response protocol (post-QI). RESULTS: Electroencephalography volume increased from 35 studies pre-QI to 115 post-QI (3.29-fold increase), whereas the median time from EEG order to EEG start decreased 7.6-fold (74 [34-187] minutes post-QI vs 562 [321-1034] minutes pre-QI). Point-of-care EEG was also associated with more confirmed seizure diagnoses compared with conventional EEG (27/115 post-QI vs 0/35 pre-QI). This resulted in additional diagnosis-related group reimbursements and hospital revenue. Availability of point-of-care EEG was also associated with a shorter median length of stay. CONCLUSION: A nurse-led, rapid-response EEG protocol at a community hospital resulted in significant improvements in EEG accessibility and seizure diagnosis with hospital-level financial benefits. By expanding access to EEG, confirming nonconvulsive seizures, and increasing care efficiency, rapid-response EEG protocols can enhance patient care.

Implementation of Tele-Intensive Care Unit Services During the COVID-19 Pandemic: A Systematic Literature Review and Updated Experience from Shandong Province

Background: While the use of telemedicine had been expanding before the initial outbreak of COVID-19, the pandemic has dramatically accelerated its implementation and expanded its usage in many hospitals. Tele-intensive care unit (ICU) is a specialized type of telemedicine that adapts available technologies to the unique needs of critically ill patients. We published an editorial in 2020 describing our initial experiences of Tele-ICU application in Shandong Province. Here, we update our insights gained over the past 2 years, and we provide a systematic review of the literature to compare our perspectives with those from other institutions. Methods: We performed a systematic literature review of publications describing the use of telemedicine in an ICU setting during COVID-19. The PubMed database was searched for studies published after January 1, 2020, which offered detailed descriptions of tele-ICU usage. Extracted data included details regarding tele-ICU technologies, descriptions of the institution, usage cases, assessments of tele-ICU effectiveness, and site-reported opinions (e.g., advantages, disadvantages). Results: We screened 162 studies resulting from the PubMed literature search, along with one expert recommendation. Of the 112 full-text articles retrieved, 11 were selected for inclusion in this qualitative summary. All were retrospective descriptions of tele-ICU experiences at a single site. Some pairs of included articles reported results from the same institution, with seven unique sites being described. Three sites employed centralized models of tele-ICU, while four allowed staff to participate from distant locations. Five sites collected user-reported feedback regarding tele-ICU. While the advantages and disadvantages described rarely overlapped directly between sites, many reported positive opinions of tele-ICU use overall. Conclusions: The potential applications of tele-ICU technologies vary widely, making them highly adaptable to the needs of individual institutions. Tele-ICU has proven invaluable to some hospitals during COVID-19 due to its effectiveness at aiding patient care while mitigating risk to health care workers.

Amplitude Integrated Electroencephalography - Reference Values in Children aged 2 months to 16 years

AIM

Amplitude integrated electroencephalography (aEEG) is a bedside neuromonitoring tool, standard within neonatal critical care provision. Its application in children is increasing but normative data underpinning such use are lacking. We present a dataset of normative aEEG values for children aged 2 months to 16 years.

METHODS

This retrospective observational cohort study derives aEEG normative amplitude characteristics from electroencephalograms (EEGs) recorded in Children's Health Ireland at Crumlin. aEEG was derived from 350 normal EEGs, recorded in children aged 2 months to 16 years. Supplementary aEEGs were derived from children with abnormal EEG traces. Median upper and lower margin amplitudes, and bandwidth were calculated from 5-minute waking and sleeping EEG epochs.

RESULTS

aEEG amplitudes vary with age and state, increasing over the first two years of life before diminishing. Upper and lower margin amplitudes, and bandwidth are greater during sleep for children < 6 years. Reference ranges may be cohorted into 2 groups (upper and lower reference limits; < 6 years - 38μV/7μV awake, 54μV/10μV asleep; > 6 years - 33μV/5μV awake, 36μV/6μV asleep) CONCLUSION: aEEG traces evolve with age in childhood and differ from neonatal values. We provide a comprehensive set of aEEG normatives to facilitate clinical interpretation in older children.

Teaching Important Basic EEG Patterns of Bedside Electroencephalography to Critical Care Staffs: A Prospective Multicenter Study

BACKGROUND

Continuous electroencephalography (cEEG) is commonly recommended for neurocritical care patients. Routine implementation of such monitoring requires the specific training of professionals. The aim of this research was to evaluate the effectiveness of a training program on initiation of the basic interpretation of cEEG for critical care staff in a prospective multicenter study.

METHODS

After completion of a pretest, participants (senior physicians, fellows, residents, medical students, and nurses) recruited in six French ICUs participated in a face-to-face electroencephalogram (EEG) training program followed by additional e-learning sessions at day 1 (post-course), day 15, day 30, and day 90, based on training tests followed by illustrated and commented answers. Each test was designed to evaluate knowledge and skills through correct recognition of ten predefined EEG sequences covering the most common normal and abnormal patterns. The primary objective was to achieve a success rate > 80% correct answers at day 90 by at least 75% of the participants.

RESULTS

Among 250 participants, 77/108 (71.3%) who completed the full training program achieved at least 80% correct answers at day 90. Paired comparisons between the scores obtained at each evaluation showed an increase over time. The rate of correct answers at day 90 was > 80% for all common predefined EEG sequences, except for the recognition of periodic and burst-suppression patterns and reactivity, which were identified in only 42.6% (95% CI 36.4-48.8), 60.2% (54.1-66.3), and 70.4% (64.7-76.1) of the tests, respectively.

CONCLUSIONS

A training strategy for the basic interpretation of EEG in ICUs, consisting of a face-to-face EEG course supplemented with reinforcement of knowledge by e-learning, was associated with significant resignation and an effectiveness of training allowing 71% of learners to accurately recognize important basic EEG patterns encountered in critically ill patients.

TRIAL REGISTRATION

ClinicalTrials.gov number: NCT03545776.

The Use of Continuous EEG Monitoring in Intensive Care Units in The Netherlands: A National Survey

Background

Currently, continuous electroencephalographic monitoring (cEEG) is the only available diagnostic tool for continuous monitoring of brain function in intensive care unit (ICU) patients. Yet, the exact relevance of routinely applied ICU cEEG remains unclear, and information on the implementation of cEEG, especially in Europe, is scarce. This study explores current practices of cEEG in adult Dutch ICU departments focusing on organizational and operational factors, development over time and factors perceived relevant for abstaining its use.

Methods

A national survey on cEEG in adults among the neurology and adult intensive care departments of all Dutch hospitals (n = 82) was performed.

Results

The overall institutional response rate was 78%. ICU cEEG is increasingly used in the Netherlands (in 37% of all hospitals in 2016 versus in 21% in 2008). Currently in 88% of university, 55% of teaching and 14% of general hospitals use ICU cEEG. Reasons for not performing cEEG are diverse, including perceived non-feasibility and lack of data on the effect of cEEG use on patient outcome. Mostly, ICU cEEG is used for non-convulsive seizures or status epilepticus and prognostication. However, cEEG is never or rarely used for monitoring cerebral ischemia and raised intracranial pressure in traumatic brain injury. Review and reporting practices differ considerably between hospitals. Nearly all hospitals perform non-continuous review of cEEG traces. Methods for moving toward continuous review of cEEG traces are available but infrequently used in practice.

Conclusions

cEEG is increasingly used in Dutch ICUs. However, cEEG practices vastly differ between hospitals. Future research should focus on uniform cEEG practices including unambiguous EEG interpretation to facilitate collaborative research on cEEG, aiming to provide improved standard patient care and robust data on the impact of cEEG use on patient outcome.

A pragmatic approach to intravenous anaesthetics and electroencephalographic endpoints for the treatment of refractory and super-refractory status epilepticus in critical care

Status epilepticus is a common neurological emergency, with overall mortality around 20%. Over half of cases are first time presentations of seizures. The pathological process by which spontaneous seizures are generated arises from an imbalance in excitatory and inhibitory neuronal networks, which if unchecked, can result in alterations in intracellular signalling pathways and electrolyte shifts, which bring about changes in the blood brain barrier, neuronal cell death and eventually cerebral atrophy. This narrative review focusses on the treatment of status epilepticus in adults. Anaesthetic agents interrupt neuronal activity by enhancing inhibitory or decreasing excitatory transmission, primarily via GABA and NMDA receptors. Intravenous anaesthetic agents are commonly used as second or third line drugs in the treatment of refractory status epilepticus, but the optimal timing and choice of anaesthetic drug has not yet been established by high quality evidence. Titration of antiepileptic and anaesthetic drugs in critically ill patients presents a particular challenge, due to alterations in drug absorbtion and metabolism as well as changes in drug distrubution, which arise from fluid shifts and altered protein binding. Furthermore, side effects associated with prolonged infusions of anaesthetic drugs can lead to multi-organ dysfunction and a need for critical care support. Electroencelography can identify patterns of burst suppression, which may be a target to guide weaning of intravenous therapy. Continuous elctroencephalography has the potential to directly impact clinical care, but despite its utility, major barriers exist which have limited its widespread use in clinical practice. A flow chart outlining the timing and dosage of anaesthetic agents used at our institution is provided.

Value and mechanisms of EEG reactivity in the prognosis of patients with impaired consciousness: a systematic review

Background

Electroencephalography (EEG) is a well-established tool for assessing brain function that is available at the bedside in the intensive care unit (ICU). This review aims to discuss the relevance of electroencephalographic reactivity (EEG-R) in patients with impaired consciousness and to describe the neurophysiological mechanisms involved.

Methods

We conducted a systematic search of the term “EEG reactivity and coma” using the PubMed database. The search encompassed articles published from inception to March 2018 and produced 202 articles, of which 42 were deemed relevant, assessing the importance of EEG-R in relationship to outcomes in patients with impaired consciousness, and were therefore included in this review.

Results

Although definitions, characteristics and methods used to assess EEG-R are heterogeneous, several studies underline that a lack of EEG-R is associated with mortality and unfavorable outcome in patients with impaired consciousness. However, preserved EEG-R is linked to better odds of survival. Exploring EEG-R to nociceptive, auditory, and visual stimuli enables a noninvasive trimodal functional assessment of peripheral and central sensory ascending pathways that project to the brainstem, the thalamus and the cerebral cortex. A lack of EEG-R in patients with impaired consciousness may result from altered modulation of thalamocortical loop activity by afferent sensory input due to neural impairment. Assessing EEG-R is a valuable tool for the diagnosis and outcome prediction of severe brain dysfunction in critically ill patients.

Conclusions

This review emphasizes that whatever the etiology, patients with impaired consciousness featuring a reactive electroencephalogram are more likely to have a favorable outcome, whereas those with a nonreactive electroencephalogram are prone to having an unfavorable outcome. EEG-R is therefore a valuable prognostic parameter and warrants a rigorous assessment. However, current assessment methods are heterogeneous, and no consensus exists. Standardization of stimulation and interpretation methods is needed.