Electro-clinical characteristics and prognostic significance of post anoxic myoclonus

The Evolving Role of Electroencephalography in Postarrest Care

Electroencephalography is an accessible, portable, noninvasive and safe means of evaluating a patient's brain activity. It can aid in diagnosis and management decisions for post-cardiac arrest patients with seizures, myoclonus and other non-epileptic movements. It also plays an important role in a multimodal approach to neuroprognostication predicting both poor and favorable outcomes. Individuals ordering, performing and interpreting these tests, regardless of the indication, should understand the supporting evidence, logistical considerations, limitations and impact the results may have on postarrest patients and their families as outlined herein.

Multimodal approaches supporting the diagnosis, prognosis and investigation of neural correlates of disorders of consciousness: A systematic review

The limits of the standard, behaviour-based clinical assessment of patients with disorders of consciousness (DoC) prompted the employment of functional neuroimaging, neurometabolic, neurophysiological and neurostimulation techniques, to detect brain-based covert markers of awareness. However, uni-modal approaches, consisting in employing just one of those techniques, are usually not sufficient to provide an exhaustive exploration of the neural underpinnings of residual awareness. This systematic review aimed at collecting the evidence from studies employing a multimodal approach, that is, combining more instruments to complement DoC diagnosis, prognosis and better investigating their neural correlates. Following the PRISMA guidelines, records from PubMed, EMBASE and Scopus were screened to select peer-review original articles in which a multi-modal approach was used for the assessment of adult patients with a diagnosis of DoC. Ninety-two observational studies and 32 case reports or case series met the inclusion criteria. Results highlighted a diagnostic and prognostic advantage of multi-modal approaches that involve electroencephalography-based (EEG-based) measurements together with neuroimaging or neurometabolic data or with neurostimulation. Multimodal assessment deepened the knowledge on the neural networks underlying consciousness, by showing correlations between the integrity of the default mode network and the different clinical diagnosis of DoC. However, except for studies using transcranial magnetic stimulation combined with electroencephalography, the integration of more than one technique in most of the cases occurs without an a priori-designed multi-modal diagnostic approach. Our review supports the feasibility and underlines the advantages of a multimodal approach for the diagnosis, prognosis and for the investigation of neural correlates of DoCs.

Critical Care Management of Patients After Cardiac Arrest: A Scientific Statement from the American Heart Association and Neurocritical Care Society

The critical care management of patients after cardiac arrest is burdened by a lack of high-quality clinical studies and the resultant lack of high-certainty evidence. This results in limited practice guideline recommendations, which may lead to uncertainty and variability in management. Critical care management is crucial in patients after cardiac arrest and affects outcome. Although guidelines address some relevant topics (including temperature control and neurological prognostication of comatose survivors, 2 topics for which there are more robust clinical studies), many important subject areas have limited or nonexistent clinical studies, leading to the absence of guidelines or low-certainty evidence. The American Heart Association Emergency Cardiovascular Care Committee and the Neurocritical Care Society collaborated to address this gap by organizing an expert consensus panel and conference. Twenty-four experienced practitioners (including physicians, nurses, pharmacists, and a respiratory therapist) from multiple medical specialties, levels, institutions, and countries made up the panel. Topics were identified and prioritized by the panel and arranged by organ system to facilitate discussion, debate, and consensus building. Statements related to postarrest management were generated, and 80% agreement was required to approve a statement. Voting was anonymous and web based. Topics addressed include neurological, cardiac, pulmonary, hematological, infectious, gastrointestinal, endocrine, and general critical care management. Areas of uncertainty, areas for which no consensus was reached, and future research directions are also included. Until high-quality studies that inform practice guidelines in these areas are available, the expert panel consensus statements that are provided can advise clinicians on the critical care management of patients after cardiac arrest.

Critical Care Management of Patients After Cardiac Arrest: A Scientific Statement From the American Heart Association and Neurocritical Care Society

The critical care management of patients after cardiac arrest is burdened by a lack of high-quality clinical studies and the resultant lack of high-certainty evidence. This results in limited practice guideline recommendations, which may lead to uncertainty and variability in management. Critical care management is crucial in patients after cardiac arrest and affects outcome. Although guidelines address some relevant topics (including temperature control and neurological prognostication of comatose survivors, 2 topics for which there are more robust clinical studies), many important subject areas have limited or nonexistent clinical studies, leading to the absence of guidelines or low-certainty evidence. The American Heart Association Emergency Cardiovascular Care Committee and the Neurocritical Care Society collaborated to address this gap by organizing an expert consensus panel and conference. Twenty-four experienced practitioners (including physicians, nurses, pharmacists, and a respiratory therapist) from multiple medical specialties, levels, institutions, and countries made up the panel. Topics were identified and prioritized by the panel and arranged by organ system to facilitate discussion, debate, and consensus building. Statements related to postarrest management were generated, and 80% agreement was required to approve a statement. Voting was anonymous and web based. Topics addressed include neurological, cardiac, pulmonary, hematological, infectious, gastrointestinal, endocrine, and general critical care management. Areas of uncertainty, areas for which no consensus was reached, and future research directions are also included. Until high-quality studies that inform practice guidelines in these areas are available, the expert panel consensus statements that are provided can advise clinicians on the critical care management of patients after cardiac arrest.

Post-hypoxic status epilepticus - A distinct subtype of status epilepticus with poor prognosis

OBJECTIVE

To evaluate the clinical outcome of patients with possible and definitive post-hypoxic status epilepticus (SE) and to describe the SE types in patients with definitive post-hypoxic SE.

METHODS

Patients with definitive or possible SE resulting from hypoxic brain injury after cardiac arrest (CA) were prospectively recruited. Intermittent EEG was used for the diagnosis of SE according to clinical practice. Two raters blinded to outcome analyzed EEGs retrospectively for possible and definitive SE patterns and background features (frequency, continuity, reactivity, and voltage). Definitive SE was classified according to semiology (ILAE). Mortality and Cerebral Performance Categories (CPC) score were evaluated 1 month after CA.

RESULTS

We included 64 patients of whom 92% died. Among the survivors, only one patient had a good neurological outcome (CPC 1). No patient survived with a burst suppression pattern, low voltage, or electro-cerebral silence in any EEG. Possible or definitive SE was diagnosed in a median of 47 h (IQR 39-72 h) after CA. EEG criteria for definitive electrographic SE were fulfilled in 39% of patients; in 38% - for electroclinical SE and in 23% - for ictal-interictal continuum (IIC). The outcome did not differ significantly between the three groups. The only patient with good functional outcome belonged to the IIC group. Comatose non-convulsive SE (NCSE) without subtle motor phenomenon occurred in 20% of patients with definitive electrographic SE and outcome was similar to other types of SE.

SIGNIFICANCE

Possible or definitive SE due to hypoxic brain injury is associated with poor prognosis. The outcome of patients with electrographic SE, electroclinical SE, and IIC did not differ significantly. Outcome was similar in patients with definitive electrographic SE with and without prominent motor features.

Guidelines for Neuroprognostication in Comatose Adult Survivors of Cardiac Arrest

BACKGROUND

Among cardiac arrest survivors, about half remain comatose 72 h following return of spontaneous circulation (ROSC). Prognostication of poor neurological outcome in this population may result in withdrawal of life-sustaining therapy and death. The objective of this article is to provide recommendations on the reliability of select clinical predictors that serve as the basis of neuroprognostication and provide guidance to clinicians counseling surrogates of comatose cardiac arrest survivors.

METHODS

A narrative systematic review was completed using Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology. Candidate predictors, which included clinical variables and prediction models, were selected based on clinical relevance and the presence of an appropriate body of evidence. The Population, Intervention, Comparator, Outcome, Timing, Setting (PICOTS) question was framed as follows: "When counseling surrogates of comatose adult survivors of cardiac arrest, should [predictor, with time of assessment if appropriate] be considered a reliable predictor of poor functional outcome assessed at 3 months or later?" Additional full-text screening criteria were used to exclude small and lower-quality studies. Following construction of the evidence profile and summary of findings, recommendations were based on four GRADE criteria: quality of evidence, balance of desirable and undesirable consequences, values and preferences, and resource use. In addition, good practice recommendations addressed essential principles of neuroprognostication that could not be framed in PICOTS format.

RESULTS

Eleven candidate clinical variables and three prediction models were selected based on clinical relevance and the presence of an appropriate body of literature. A total of 72 articles met our eligibility criteria to guide recommendations. Good practice recommendations include waiting 72 h following ROSC/rewarming prior to neuroprognostication, avoiding sedation or other confounders, the use of multimodal assessment, and an extended period of observation for awakening in patients with an indeterminate prognosis, if consistent with goals of care. The bilateral absence of pupillary light response > 72 h from ROSC and the bilateral absence of N20 response on somatosensory evoked potential testing were identified as reliable predictors. Computed tomography or magnetic resonance imaging of the brain > 48 h from ROSC and electroencephalography > 72 h from ROSC were identified as moderately reliable predictors.

CONCLUSIONS

These guidelines provide recommendations on the reliability of predictors of poor outcome in the context of counseling surrogates of comatose survivors of cardiac arrest and suggest broad principles of neuroprognostication. Few predictors were considered reliable or moderately reliable based on the available body of evidence.

To Treat or Not to Treat: Ethics of Management of Refractory Status Myoclonus Following Pediatric Anoxic Brain Injury

The development of status myoclonus (SM) in a postcardiac arrest patient has historically been thought of as indicative of not only a poor neurologic outcome but of neurologic devastation. In many instances, this may lead clinicians to initiate conversations about withdrawal of life sustaining therapies (WLST) regardless of the time from return of spontaneous circulation (ROSC). Recent studies showing a percentage of patients may make a good recovery has called into question whether a self-fulfilling prophecy has developed where the concern for a poor neurologic outcome leads clinicians to prematurely discuss WLST. The issue is only further complicated by changing terminology, lack of neuro-axis localization, and limited data regarding association with electroencephalogram (EEG) characteristics, all of which could aid in the understanding of the severity of neurologic injury associated with SM. Here we review the initial literature reporting SM as indicative of poor neurologic outcome, the studies that call this into question, the various definitions of SM and related terms as well as data regarding association with EEG backgrounds. We propose that improved prognostication on outcomes results from combining the presence of SM with other clinical variables (eg EEG patterns, MRI findings, and clinical exam). We discuss the ethical implications of using SM as a prognostic tool and its impact on decisions about life-sustaining care in children following cardiac arrest. We advocate for prognostication efforts to be delayed for at least 72 hours following ROSC and thus to treat SM in those early hours and days.

Neurophysiological and Clinical Correlates of Acute Posthypoxic Myoclonus

SUMMARY

Prognostication following cardiorespiratory arrest relies on the neurological examination, which is supported by neuroimaging and neurophysiological testing. Acute posthypoxic myoclonus (PHM) is a clinical entity that has prognostic significance and historically has been considered an indicator of poor outcome, but this is not invariably the case. "Malignant" and more "benign" forms of acute PHM have been described and differentiating them is key in understanding their meaning in prognosis. Neurophysiological tests, electroencephalogram in particular, and clinical phenotyping are crucial in defining subtypes of acute PHM. This review describes the neurophysiological and phenotypic markers of malignant and benign forms of acute PHM, a clinical approach to evaluating acute PHM following cardiorespiratory arrest in determining prognosis, and gaps in our understanding of acute PHM that require further study.

Electroencephalogram in the intensive care unit: a focused look at acute brain injury

Over the past decades, electroencephalography (EEG) has become a widely applied and highly sophisticated brain monitoring tool in a variety of intensive care unit (ICU) settings. The most common indication for EEG monitoring currently is the management of refractory status epilepticus. In addition, a number of studies have associated frequent seizures, including nonconvulsive status epilepticus (NCSE), with worsening secondary brain injury and with worse outcomes. With the widespread utilization of EEG (spot and continuous EEG), rhythmic and periodic patterns that do not fulfill strict seizure criteria have been identified, epidemiologically quantified, and linked to pathophysiological events across a wide spectrum of critical and acute illnesses, including acute brain injury. Increasingly, EEG is not just qualitatively described, but also quantitatively analyzed together with other modalities to generate innovative measurements with possible clinical relevance. In this review, we discuss the current knowledge and emerging applications of EEG in the ICU, including seizure detection, ischemia monitoring, detection of cortical spreading depolarizations, assessment of consciousness and prognostication. We also review some technical aspects and challenges of using EEG in the ICU including the logistics of setting up ICU EEG monitoring in resource-limited settings.

Revisiting EEG as part of the multidisciplinary approach to post-cardiac arrest care and prognostication: A review

Since the 1960s, EEG has been used to assess the neurologic function of patients in the hours and days after cardiac arrest. Accurate and reliable prognostication after cardiac arrest is vital for tailoring aggressive patient care for those with a high likelihood of recovery and setting appropriate goals of care for those who have a high likelihood of a poor outcome. Attempts to define EEG's role in this process has evolved over the years. In this review, we provide important historical context about EEG's use, it's perceived unreliability in the post-cardiac arrest patient in the past and provide a detailed analysis of how this role has changed recently. A review of the 71 most recent and highest quality studies demonstrates that the introduction of a uniform classification and a timed approach to EEG analysis have positioned EEG as a complementary tool in the multimodal approach for prognostication. The review was created and intended for medical staff in the intensive care units and emphasizes EEG patterns and timing which portend both favorable and poor prognoses. Also, the review addresses the overall quality of the existing studies and discusses future directions to address the knowledge gaps in this field.

Post-cardiac arrest myoclonus and in ICU mortality: insights from the Parisian Registry of Cardiac Arrest (PROCAT)

BACKGROUND

Post-cardiac arrest myoclonus (PCAM) is a frequent finding in resuscitated patients after cardiac arrest (CA), with rather poor prognostic significance. In this study, we evaluated the association of PCAM within intensive care unit (ICU) mortality from a university hospital CA patients' registry.

METHODS

Clinical data of consecutive CA survivors admitted in the intensive care unit (ICU) between January and December 2016 at the Paris Cochin University Hospital were assessed from the Parisian registry of cardiac arrest (PROCAT) and analyzed. Neurologic outcome was assessed using the Cerebral Performance Categories (CPC) scale at ICU discharge. Prevalence of PCAM and their association with mortality at ICU discharge were computed.

RESULTS

One hundred thirty-two (132) patients were included (73.5% males), median age of 66 years. Among them, 37 (28%) developed PCAM during their ICU stay. Only two patients with PCAM survived (5.4%). PCAM was strongly associated with mortality at ICU discharge (odds ratio 17.5 [4.2-123.2]). Sensitivity, specificity, PPV, and NPV of PCAM for prediction of death were 41%, 96%, 95%, and 46%, respectively.

CONCLUSION

PCAM was observed in nearly one-third of CA patients admitted in ICU. Patients with PCAM had a significantly higher likelihood of ICU mortality and a low likelihood of a good outcome. The prognostic value of PCAM seems rather bleak but remains nuanced and merits study in larger-scale prospective studies taking into account confounding factors.

Status Myoclonus with Post-cardiac-arrest Syndrome: Implications for Prognostication

BACKGROUND

Status myoclonus (SM) after cardiac arrest (CA) may signify devastating brain injury. We hypothesized that SM correlates with severe neurologic and systemic post-cardiac-arrest syndrome (PCAS).

METHODS

Charts of patients admitted with CA to Mayo Clinic Saint Marys Hospital between 2005 and 2019 were retrospectively reviewed. Data included the neurologic examination, ancillary neurologic tests, and systemic markers of PCAS. Nonsustained myoclonus was clinically differentiated from SM. The cerebral performance category score at discharge was assessed; poor outcome was a cerebral performance category score > 2 prior to withdrawal of life-sustaining therapies or death.

RESULTS

Of 296 patients included, 276 (93.2%) had out-of-hospital arrest and 202 (68.5%) had a shockable rhythm; the mean time to return of spontaneous circulation was 32 ± 19 min. One hundred seventy-six (59.5%) patients had a poor outcome. One hundred one (34.1%) patients had myoclonus, and 74 (73.2%) had SM. Neurologic predictors of poor outcome were extensor or absent motor response to noxious stimulus (p = 0.02, odds ratio [OR] 3.8, confidence interval [CI] 1.2-12.4), SM (p = 0.01, OR 10.3, CI 1.5-205.4), and burst suppression on EEG (p = 0.01, OR 4.6, CI 1.4-17.4). Of 74 patients with SM, 73 (98.6%) had a poor outcome. A nonshockable rhythm (p < 0.001, OR 4.5, CI 2.6-7.9), respiratory arrest (p < 0.001, OR 3.5, CI 1.7-7.2), chronic kidney disease (p < 0.001, OR 3.1, CI 1.6-6.0), and a pressor requirement (p < 0.001, OR 4.4, CI 1.8-10.6) were associated with SM. No patients with SM, anoxic-ischemic magnetic resonance imaging findings, and absent electroencephalographic reactivity had a good outcome.

CONCLUSIONS

Sustained status myoclonus after CPR is observed in patients with other reliable indicators of severe acute brain injury and systemic PCAS. These clinical determinants should be incorporated as part of a comprehensive approach to prognostication after CA.

Long-term electro-clinical profile of sudden cardiac arrest survivors

OBJECTIVE

Recent research has explored the use of continuous EEG (cEEG) monitoring for prognostication of spontaneous cardiac arrest (SCA). However, there is limited literature on the long-term (post-hospital discharge) electrographic findings among SCA survivors and their clinical correlates. Our study aims to fill this critical knowledge gap.

METHODS

We retrospectively used our EEG database to identify adults (≥18 years) with SCA history who underwent an outpatient laboratory-based EEG between 01/01/2011 and 12/31/2018. After electronic medical records (EMR) review, patients with epilepsy history and unclear/poorly documented SCA history were excluded. Outpatient EEGs were reviewed by authors. Acute EEG findings were extracted from the EEG database and EMR. In addition, we extracted data on acute and long-term neuroimaging findings (CT/MRI), post-SCA seizures, and anti-seizure medications (ASM) status. Descriptive analysis and Fisher's exact test were performed.

RESULTS

We included 32 SCA survivors (50% women; mean age = 52.1 ± 13.6 years) in the study. During a median clinical follow-up of 28.2 months, 3 patients suffered only clinical seizures, 3 only chronic post-hypoxic myoclonus, and 5 had both [11 (34.4%) in total]. Interictal epileptiform discharges (IEDs) were noted in one-third of the patients, which localized to vertex and frontocentral regions in all but one patient. Five (15.6%) of them did not suffer a clinical seizure despite the presence of EAs. Patients who developed epilepsy were significantly more likely to have abnormal neuroimaging findings [10/11 (90.9%)] during the follow-up compared to the rest of the patients [OR = 25 (95% CI 2.6->100, P = .002)]. Half of the study cohort was taking ASM at the last follow-up.

SIGNIFICANCE

Our small study reveals a signature location of IEDs in SCA survivors. Neuroimaging abnormalities seem to be a better indicator of epilepsy development, while EEG may reveal markers of potential epileptogenicity in the absence of clinical seizures. Future, larger studies are needed to confirm our findings.

Update on the management of status epilepticus

PURPOSE OF REVIEW

Randomized controlled trials investigating the initial pharmacological treatment of status epilepticus have been recently published. Furthermore, status epilepticus arising in comatose survivors after cardiac arrest has received increasing attention in the last years. This review offers an updated assessment of status epilepticus treatment in these different scenarios.

RECENT FINDINGS

Initial benzodiazepines underdosing is common and correlates with development of status epilepticus refractoriness. The recently published ESETT trial provides high-level evidence regarding the equivalence of fosphenytoin, valproate, and levetiracetam as a second-line option. Myoclonus or epileptiform transients on electroencephalography occur in up to 1/3 of patients surviving a cardiac arrest. Contrary to previous assumptions regarding an almost invariable association with death, at least 1/10 of them may awaken with reasonably good prognosis, if treated. Multimodal prognostication including clinical examination, EEG, somatosensory evoked potentials, biochemical markers, and neuroimaging help identifying patients with a chance to recover consciousness, in whom a trial with antimyoclonic compounds and at times general anesthetics is indicated.

SUMMARY

There is a continuous, albeit relatively slow progress in knowledge regarding different aspect of status epilepticus; recent findings refine some treatment strategies and help improving patients' outcomes. Further high-quality studies are clearly needed to further improve the management of these patients, especially those with severe, refractory status epilepticus forms.

Postcardiac Arrest Neuroprognostication Practices: A Survey of Brazilian Physicians

Supplemental Digital Content is available in the text.

End-of-life care and decisions on withdrawal of life-sustaining therapies vary across countries, which may affect the feasibility of future multicenter cardiac arrest trials. In Brazil, withdrawal of life-sustaining therapy is reportedly uncommon, allowing the natural history of postcardiac arrest hypoxic-ischemic brain injury to present itself. We aimed to characterize approaches to neuroprognostication of cardiac arrest survivors among physicians in Brazil.

Neuro-anatomical localization of EEG identical bursts in patients with and without post-anoxic myoclonus

BACKGROUND

The electroencephalograph (EEG) pattern of burst suppression with identical bursts (BSIB), with or without myoclonus, occurs often after resuscitation from cardiac arrest. These patterns are associated with severe brain injury but their neuropathological basis is unknown. Using EEG source localization, we tested whether post-cardiac arrest myoclonus was associated with specific anatomical distribution of BSIB.

METHODS

We performed a single center, case-control study of EEG-monitored post-cardiac arrest patients with BSIB. We determined the presence of myoclonus from clinical notes and video recordings. We generated normalized source density maps (sLORETA) for the first 0.5 s of each burst projected onto a standard anatomic model, and compared proportion of EEG power in the precentral gyrus (motor cortex) to the rest of the brain.

RESULTS

We included 20 patients, 10 with and 10 without myoclonus. Patients with myoclonus had greater electrical activation localized to the precentral gyrus compared to those without (median 3.25 [IQR 2.74-3.59] vs 2.68 [IQR 2.66-2.71], P = 0.04). There was no difference between groups in region of burst origin.

CONCLUSION

Among patients with BSIB after cardiac arrest, those with clinical myoclonus have more electrocortical activation in the precentral gyrus.

Brain injury after cardiac arrest: from prognostication of comatose patients to rehabilitation

More patients are surviving cardiac arrest than ever before; however, the burden now lies with estimating neurological prognoses in a large number of patients who were initially comatose, in whom the ultimate outcome is unclear. Neurologists, neurointensivists, and clinical neurophysiologists must accurately balance the concern that overly conservative prognostication could leave patients in a severely disabled state, with the possibility that inaccurately pessimistic prognostication could lead to the withdrawal of life-sustaining treatment in patients who might otherwise have a good functional outcome. Prognostic tools have improved greatly, including electrophysiological tests, neuroimaging, and chemical biomarkers. Conclusions about the prognosis should be delayed at least 72 h after arrest to allow for the clearance of sedative drugs. Cognitive impairments, emotional problems, and fatigue are common among patients who have survived cardiac arrest, and often go unrecognised despite being related to caregiver burden and a decreased participation in society. Through simple screening, these problems can be identified, and patients can be provided with adequate information and rehabilitation.

MRI-EEG correlation for outcome prediction in postanoxic myoclonus: A multicenter study

OBJECTIVE

To examine the prognostic ability of the combination of EEG and MRI in identifying patients with good outcome in postanoxic myoclonus (PAM) after cardiac arrest (CA).

METHODS

Adults with PAM who had an MRI within 20 days after CA were identified in 4 prospective CA registries. The primary outcome measure was coma recovery to command following by hospital discharge. Clinical examination included brainstem reflexes and motor activity. EEG was assessed for best background continuity, reactivity, presence of epileptiform activity, and burst suppression with identical bursts (BSIB). MRI was examined for presence of diffusion restriction or fluid-attenuated inversion recovery changes consistent with anoxic brain injury. A prediction model was developed using optimal combination of variables.

RESULTS

Among 78 patients, 11 (14.1%) recovered at discharge and 6 (7.7%) had good outcome (Cerebral Performance Category < 3) at 3 months. Patients who followed commands were more likely to have pupillary and corneal reflexes, flexion or better motor response, EEG continuity and reactivity, no BSIB, and no anoxic injury on MRI. The combined EEG/MRI variable of continuous background and no anoxic changes on MRI was associated with coma recovery at hospital discharge with sensitivity 91% (95% confidence interval [CI], 0.59-1.00), specificity 99% (95% CI, 0.92-1.00), positive predictive value 91% (95% CI, 0.59-1.00), and negative predictive value 99% (95% CI, 0.92-1.00).

CONCLUSIONS

EEG and MRI are complementary and identify both good and poor outcome in patients with PAM with high accuracy. An MRI should be considered in patients with myoclonus showing continuous or reactive EEGs.

Prediction of regaining consciousness despite an early epileptiform EEG after cardiac arrest

Objective

After cardiac arrest (CA), epileptiform EEG, occurring in about 1/3 of patients, often but not invariably heralds poor prognosis. We tested the hypothesis that a combination of specific EEG features identifies patients who may regain consciousness despite early epileptiform patterns.

Methods

We retrospectively analyzed a registry of comatose patients post-CA (2 Swiss centers), including those with epileptiform EEG. Background and epileptiform features in EEGs 12–36 hours or 36–72 hours from CA were scored according to the American Clinical Neurophysiology Society nomenclature. Best Cerebral Performance Category (CPC) score within 3 months (CPC 1–3 vs 4–5) was the primary outcome. Significant EEG variables were combined in a score assessed with receiver operating characteristic curves, and independently validated in a US cohort; its correlation with serum neuron-specific enolase (NSE) was also tested.

Results

Of 488 patients, 107 (21.9%) had epileptiform EEG <72 hours; 18 (17%) reached CPC 1–3. EEG 12–36 hours background continuity ≥50%, absence of epileptiform abnormalities (p< 0.00001 each), 12–36 and 36–72 hours reactivity (p< 0.0001 each), 36–72 hours normal background amplitude (p= 0.0004), and stimulus-induced discharges (p= 0.0001) correlated with favorable outcome. The combined 6-point score cutoff ≥2 was 100% sensitive (95% confidence interval [CI], 78%–100%) and 70% specific (95% CI, 59%–80%) for CPC 1–3 (area under the curve [AUC], 0.98; 95% CI, 0.94–1.00). Increasing score correlated with NSE (ρ = −0.46,p= 0.0001). In the validation cohort (41 patients), the score was 100% sensitive (95% CI, 60%–100%) and 88% specific (95% CI, 73%–97%) for CPC 1–3 (AUC, 0.96; 95% CI, 0.91–1.00).

Conclusion

Prognostic value of early epileptiform EEG after CA can be estimated combining timing, continuity, reactivity, and amplitude features in a score that correlates with neuronal damage.

Neuroprognostication Practices in Postcardiac Arrest Patients: An International Survey of Critical Care Providers

OBJECTIVES

To characterize approaches to neurologic outcome prediction by practitioners who assess prognosis in unconscious cardiac arrest individuals, and assess compliance to available guidelines.

DESIGN

International cross-sectional study.

SETTING

We administered a web-based survey to members of Neurocritical Care Society, Society of Critical Care Medicine, and American Academy of Neurology who manage unconscious cardiac arrest patients to characterize practitioner demographics and current neuroprognostic practice patterns.

SUBJECTS

Physicians that are members of aforementioned societies who care for successfully resuscitated cardiac arrest individuals.

INTERVENTIONS

Not applicable.

MEASUREMENTS AND MAIN RESULTS

A total of 762 physicians from 22 countries responses were obtained. A significant proportion of respondents used absent corneal reflexes (33.5%) and absent pupillary reflexes (36.2%) at 24 hours, which is earlier than the recommended 72 hours in the standard guidelines. Certain components of the neurologic examination may be overvalued, such as absent motor response or extensor posturing, which 87% of respondents considered being very or critically important prognostic indicators. Respondents continue to rely on myoclonic status epilepticus and neuroimaging, which were favored over median nerve somatosensory evoked potentials for prognostication, although the latter has been demonstrated to have a higher predictive value. Regarding definitive recommendations based on poor neurologic prognosis, most physicians seem to wait until the postarrest timepoints proposed by current guidelines, but up to 25% use premature time windows.

CONCLUSIONS

Neuroprognostic approaches to hypoxic-ischemic encephalopathy vary among physicians and are often not consistent with current guidelines. The overall inconsistency in approaches and deviation from evidence-based recommendations are concerning in this disease state where mortality is so integrally related to outcome prediction.

The Influence of Therapeutics on Prognostication After Cardiac Arrest

PURPOSE OF REVIEW

The goal of this review is to highlight the influence of therapeutic maneuvers on neuro-prognostication measures administered to comatose survivors of cardiac arrest. We focus on the effect of sedation regimens in the setting of targeted temperature management (TTM), one of the principle interventions known to improve neurological recovery after cardiac arrest. Further, we discuss the critical need for novel markers, as well as refinement of existing markers, among patients receiving extracorporeal membrane oxygenation (ECMO) in the setting of failed conventional resuscitation, known as extracorporeal cardiopulmonary resuscitation (ECPR).

RECENT FINDINGS

Automated pupillometry may have some advantage over standard pupillary examination for prognostication following TTM, sedation, or the use of ECMO after cardiac arrest. New serum biomarkers such as Neurofilament light chain have shown good predictive abilities and need further validation in these populations. There is a high-level uncertainty in brain death declaration protocols particularly related to apnea testing and appropriate ancillary tests in patients receiving ECMO. Both sedation and TTM alone and in combination have been shown to affect prognostic markers to varying degrees. The optimal approach to analog-sedation is unknown, and requires further study. Moreover, validation of known prognostic markers, as well as brain death declaration processes in patients receiving ECMO is warranted. Data on the effects of TTM, sedation, and ECMO on biomarkers (e.g., neuron-specific enolase) and electrophysiology measures (e.g., somatosensory-evoked potentials) is sparse. The best approach may be one customized to the individual patient, a precision-medicine approach.