Discontinuous Activity Research Articles

Designated market makers and agricultural futures market quality: Evidence from China's Dalian commodity exchange

AbstractMany financial markets use designated market makers (DMMs), but the impacts of DMMs on agricultural futures markets – and in particular, how to arrange DMMs among contracts expiring in different months – are largely neglected. In 2017, Chinese exchanges started recruiting DMMs for inactive contracts when they become nearby contracts to address the discontinuous trading activity of nearest‐to‐maturity contracts, which enables us to study the benefit and cost of recruiting DMMs for inactive contracts using a quasi‐experimental framework. Leveraging tick‐by‐tick data on corn and soybean meal futures, we find that DMMs improve the market quality of inactive contracts without disrupting the market quality of dominant contracts. Heterogeneity analysis in policy settings suggests that more DMMs are conducive to improving market quality for corn and soybean meal futures. We demonstrate that DMM policy is a feasible measure to facilitate continuous activeness in Chinese agricultural futures markets. Our results are important for exchanges and regulators seeking to better design and implement designated market‐making programs in agricultural futures markets.

Late Holocene morphosedimentary and palaeoenvironmental study of the Middle Drâa river basin (southeastern Morocco)

The alluvial filling of the middle basin of the Drâa River (southeastern Morocco) has recorded hydrogeomorphological responses to environmental changes. A systematic study of the Holocene fluvial terraces along an upstream-downstream section of about a hundred kilometers, combined with a sedimentary multiproxy study, was carried out on the alluvial archives of the Drâa's river. The stratigraphic field studies, combined with granulometric and geochemical X-ray Fluorescence analyses and radiocarbon dating, enable us to propose, for the first time, a reconstruction of the major stages in the morpho-hydrodynamic and paleo-environmental evolution of the middle Drâa river over the past 3500 years. Our results highlight six morpho-hydrodynamic and paleoenvironmental phases. Between 3500–2700 and 1800–1600 cal BP, the Drâa river was highly active, associated with torrential activity, reflecting arid climatic conditions. The lack of sedimentary record observed between 2800 and 2350 cal BP points either to a phase of erosion, or to a minimal and discontinuous activity that left no traces in the studied archives. The periods 2350–1800 (Roman Warm Period) and 1600–550 cal BP (Medieval Climate Anomaly) are characterized by strong fine and more regular alluviation punctuated by episodes of low energy of the Drâa floodplain, sometimes favoring fluviosols development that showed similar characteristics in the three outcrops studied. Finally, from 550 cal BP the fluvial records generally shows signs of anthropization, marked by the formation of anthrosols characteristic of fluvial oasis construction, and associated with the presence of ceramics and hearths, in which eolization features are frequent. The comparison of Drâa evolution in a broader paleohydrological and climatic context, integrating other Moroccan studies and regional data, shows solid connection with the river, lakes, and marine archives from the southern Mediterranean to the Western Sahelian steppe zones, revealing a clear response of this large hydrosystem to regional climatic variations.

Predicting Exporters with Machine Learning

AbstractIn this contribution, we exploit machine learning techniques to evaluate whether and how close firms are to become successful exporters. First, we train various algorithms using financial information on both exporters and non-exporters in France in 2010–2018. Thus, we show that it is possible to predict the distance non-exporters are from export status. In particular, we find that a Bayesian Additive Regression Tree with Missingness In Attributes (BART-MIA) performs better than other techniques with an accuracy of up to 0.90. Predictions are robust to changes in definitions of exporters and in the presence of discontinuous exporting activity. Eventually, we discuss how our exporting scores can be helpful for trade promotion, trade credit, and assessing aggregate trade potential. For example, back-of-the-envelope estimates show that a representative firm with just below-average exporting scores needs up to 44% more cash resources and up to 2.5 times more capital to get to foreign markets.

Petrogenesis and 40Ar/39Ar dating of hydrothermal romanechite from the sub-aerial fault-related Romanèche Mn deposit (France)

This study discusses the hydrothermal formation of romanechite (Ba0.7Mn4.5O10.1.1H2O) in the Romanèche Mn deposit and the significance of its age by combining ore petrogenesis and 40Ar/39Ar ages. Romanechite occurs as a minor phase in various manganese deposit types and remains poorly studied in comparison with other K-bearing Mn oxides (i.e., coronadite group) because of its scarcity, small grain size, intermixing and poor crystallinity. The fault-controlled Romanèche Mn deposit (Massif Central, Eastern France) investigated herein exhibits a well-crystallized and late stage massive romanechite ore occurring in a quartz-barite-fluorite gangue. Petrographical and geochemical data support manganese ore formation under sub-aerial conditions with temperatures close to fluorite precipitation (100–200 °C) and characterized by a Mn-Ba-W-As association. Five out of the eight studied samples have produced 40Ar/39Ar plateau ages ranging from 25.2 ± 0.3 to 18.2 ± 0.5 Ma. Despite a low K content (0.1–0.6 wt% K), the good crystallinity of romanechite due to its epithermal formation likely favours a better production and/or retention of the radiogenic argon than poorly crystallized phases of supergene origin. Therefore, the dataset identifies a period of at least c. 7.6 My of discontinuous hydrothermal activity, which is consistent with graben-related fault reactivation and likely volcanic activity in the Massif Central. Ultimately, this study confirms the feasibility of romanechite 40Ar/39Ar dating.

595: BRAIN DEATH ANCILLARY TEST: AN ETHICAL DILEMMA

Introduction: Since the adoption of pediatric brain death certification in 1987, many legal and ethical dilemmas including practice variations have complicated brain death determination worldwide. We present an infant with a clinical exam consistent with neurologic death yet with intermittent discontinuous background activity on EEG. This case highlights further ethical challenges faced by intensivists in evaluating false positives and negatives in severe neurologic failure. Description: A 32-day-old female presented to the PICU after prolonged out-of-hospital cardiac arrest with fixed and dilated pupils and no spontaneous breathing, cough, or gag reflexes. Post-arrest care was initiated and an EEG was placed with initial very low amplitude to intermittent isoelectric findings, but after 72 hours began to show increased epileptiform activity that transitioned into discontinuous epileptiform activity. On day 20, she had a positive formal apnea test and met clinical criteria after three minutes for death by neurologic criteria. Given previous EEG findings, an EEG was repeated which again showed discontinuous background activity and intermittent low amplitude waves. Discussion: Ancillary testing for brain death is often utilized when a thorough clinical exam or apnea test is not possible. Though EEG was one of the first ancillary tests utilized, reports have suggested a 3.5% chance of false negative in death by neurologic criteria patients. Amongst ancillary tests, EEG has the highest rate of false negative results. The longest documented EEG activity in brain death patients was 14 days, whereas our patient is 3 weeks. Another diagnostic challenge, particularly in neonates, is occurrence of isoelectric findings with an exam not consistent with brain death. These patients may regain minimal cortical function, making institutional policies that use ancillary testing in addition to clinical exam criteria conflicting. In adult brain death guidelines, EEG testing is not recommended as a routine ancillary test due to its lack of sensitivity and specificity; however, it has been retained in many pediatric institutions. Further data is needed to characterize the utility of this practice and bioethical considerations with clinical diagnosis of brain death when isolated electrical activity is present.

A new continuous assay for quantitative assessment of enzymatic degradation of poly(ethylene terephthalate) (PET)

Enzymatic degradation of poly(ethylene terephthalate) (PET) has emerged as a promising route for ecofriendly biodegradation of plastic waste. Several discontinuous activity assays have been developed for assessing PET hydrolyzing enzymes, usually involving manual sampling at different time points during the course of the enzymatic reaction. In this work, we present a novel, compartmentalized UV absorbance assay for continuous detection of soluble hydrolysis products released during enzymatic degradation of PET. The methodology is based on removal of the walls separating two diagonally adjacent wells in UV-transparent microplates, to ensure passage of soluble enzymatic hydrolysis products between the two adjacent wells: One well holds an insoluble PET disk of defined dimensions and the other is used for continuous reading of the enzymatic product formation (at 240 nm). The assay was validated by quantifying the rate of mixing of the soluble PET degradation product BHET (bis(2-hydroxyethyl) terephthalate) between the two adjacent wells. The assay validation also involved a simple adjustment for water evaporation during prolonged assays. With this new assay, we determined the kinetic parameters for two PET hydrolases, DuraPETase and LCCICCG, and verified the underlying assumption of steady-state reaction rates. This new continuous assay enables fast exploration and robust kinetic characterization of PET degrading enzymes.

Mud flow dynamics at gas seeps - Nirano Salse, Italy -

The Nirano Salse, known since the Roman Times, are one of the most beautiful and scenic mud volcanoes areas of Italy with thousands of visitors every year. In this work, we apply novel (for the context) hydrogeological techniques to characterize mud levels in the Salse by means of GPS-RTK positioning and continuous level logging within mud conduits. This is important to quantify the gas–liquid ratio in the conduits and evaluate the potential for dangerous abrupt mud eruptions. The results presented suggest that different mud levels in mud volcanoes clusters are due to the different gas–liquid ratio in the conduits and not necessarily exclude interconnection at depth, a hypothesis, on the other hand, that seems strengthened by mud level time series correlations. The presence of shallow aquifers at a depth of 5 to 30 m is also supported by our field data and allows us to delineate the boundaries of the shallow mud reservoir—pipes system and its overall shape. The shallow aquifers may provide a temporary storage for the ascending gas and when fluid pressure in these aquifers exceeds the tensional strength of the sedimentary rock, leakage of fluids to the surface would occur. In this case, if the gas–liquid ratio is high, mud volcanoes develop into tall gryphons and tend to have a discontinuous activity with sudden eruptions of mud after long periods of quiescence. This, together with the knowledge of shallow conduits localization has an important implication for site safety in proximity to the mud volcanoes. Our inferences based on mud level relationships to mud extrusion dynamics can be applied to lower risk in other mud volcanoes areas of the world with high geo-tourist visits, such as those of Trinidad, Azerbaijan, and Colombia.

Milk Thistle (Silybum Marianum L.) as a Novel Multipurpose Crop for Agriculture in Marginal Environments: A Review

Milk thistle (Silybum marianum (L.) Gaertn.) is a versatile crop that has adapted to the broadly different soil and environmental conditions throughout all continents. To date, the fruits (“seeds”) of the plant are the only reliable source of silymarin, which, given its recognized therapeutic effects and its many present and potential uses, has led to a significant re-discovery and enhancement of the crop in recent years. Overall, although many studies have been carried out globally on the bioactivity, phytochemistry, and genetics of milk thistle, few and discontinuous research activity has been conducted on its basic agronomy as well as on the farm opportunities offered by the cultivation of this species. However, the multiple potential uses of the plant and its reduced need for external inputs suggest that milk thistle can perfectly fit among the most interesting alternative crops, even for marginal environments. The growing interest in natural medicine, the increasing popularity of herbal dietary supplements, and the multiple possibilities for livestock feeding are all arguments supporting the idea that in many rural areas, this crop could represent a significant tool for enhancing and stabilizing farm income. However, several issues still have to be addressed. The species retains some morphological and physiological traits belonging to non-domesticated plants, which make the application of some common agronomic practices challenging. Furthermore, the lack of reliable field data devoted to the definition of suitable cropping protocols represents a major constraint on the spread of this crop among farmers. This review has therefore focused on updating information on the main morphological and phytochemical traits of the crop and its agronomic characteristics and novel uses. Several gaps in technical knowledge have been addressed, and further goals for experimental activity have been outlined in order to guide farmers eager to cope with the cultivation of such a challenging and resource-rich crop.

Early Clinical and Electrophysiological Brain Dysfunction Is Associated With ICU Outcomes in COVID-19 Critically Ill Patients With Acute Respiratory Distress Syndrome: A Prospective Bicentric Observational Study.

OBJECTIVES:Describe the prevalence of acute cerebral dysfunction and assess the prognostic value of an early clinical and electroencephalography (EEG) assessment in ICU COVID-19 patients.DESIGN:Prospective observational study.SETTING:Two tertiary critical care units in Paris, France, between April and December 2020.PATIENTS:Adult critically ill patients with COVID-19 acute respiratory distress syndrome.INTERVENTIONS:Neurologic examination and EEG at two time points during the ICU stay, first under sedation and second 4–7 days after sedation discontinuation.MEASUREMENTS AND MAIN RESULTS:Association of EEG abnormalities (background reactivity, continuity, dominant frequency, and presence of paroxystic discharges) with day-28 mortality and neurologic outcomes (coma and delirium recovery). Fifty-two patients were included, mostly male (81%), median (interquartile range) age 68 years (56–74 yr). Delayed awakening was present in 68% of patients (median awakening time of 5 d [2–16 d]) and delirium in 74% of patients who awoke from coma (62% of mixed delirium, median duration of 5 d [3–8 d]). First, EEG background was slowed in the theta-delta range in 48 (93%) patients, discontinuous in 25 patients (48%), and nonreactive in 17 patients (33%). Bifrontal slow waves were observed in 17 patients (33%). Early nonreactive EEG was associated with lower day-28 ventilator-free days (0 vs 16; p = 0.025), coma-free days (6 vs 22; p = 0.006), delirium-free days (0 vs 17; p = 0.006), and higher mortality (41% vs 11%; p = 0.027), whereas discontinuous background was associated with lower ventilator-free days (0 vs 17; p = 0.010), coma-free days (1 vs 22; p < 0.001), delirium-free days (0 vs 17; p = 0.001), and higher mortality (40% vs 4%; p = 0.001), independently of sedation and analgesia.CONCLUSIONS:Clinical and neurophysiologic cerebral dysfunction is frequent in COVID-19 ARDS patients. Early severe EEG abnormalities with nonreactive and/or discontinuous background activity are associated with delayed awakening, delirium, and day-28 mortality.

Shallow magma convection evidenced by excess degassing and thermal radiation during the dome-forming Sabancaya eruption (2012\u20132020)

We used a large set of satellite- (visible, infrared, and radar images from Planetscope, MODIS, VIIRS, Sentinel2, Landsat 8, and Sentinel 1) and ground-based data (optical images, SO2 flux, shallow seismicity) to describe and characterize the activity of the Sabancaya volcano during the unrest and eruption phases that occurred between 2012 and 2020. The unrest phase (2012–2016) was characterized by increasing gas and thermal flux, sourced by a convective magma column rising along with the remnants of a buried plug still permeable to fluid flow. Conversely, a new conduit, adjacent to the previous one, fed the eruptive phase (2016–2020) which was instead characterized by a discontinuous extrusive activity, with phases of dome growth (at rates from 0.04 to 0.75 m3 s−1) and collapse. The extrusive activity was accompanied by fluctuating thermal anomalies (0.5–25 MW), by irregular SO2 degassing (700–7000 tons day−1), and by variable explosive activity (4–100 events d−1) producing repeated vulcanian ash plumes (500–5000 m above the crater). Magma budget calculation during the eruptive phase indicates a large excess of degassing, with the volume of degassed magma (0.25–1.28 km3) much higher than the volume of erupted magma (< 0.01 km3). Similarly, the thermal energy radiated by the eruption was much higher than that sourced by the dome itself, an unbalance that, by analogy with the degassing, we define as “excess thermal radiation”. Both of these unbalances are consistent with the presence of shallow magma convection that fed the extrusive and explosive activity of the Sabancaya dome.

Discourse and manipulation: Nursing in question.

The history of Brazilian nurses is marked by several challenges, in part resulting from discontinuous and fragile activity boundaries among the health professions that share the same work objective in care services. A field of constant disputes, the Brazilian health system, was the target of a lawsuit filed by the Federal Council of Medicine that temporarily suspended nurses' activities in primary care. This study aimed to demonstrate the manipulative discourse present in the text of the injunction request by medical doctors against legislation by the Brazilian Federal Government in 2017. This is a qualitative and documental study that used the theoretical-methodological framework of critical discourse studies based on Teun Van Dijk's analytical categories. The results pointed to manipulative discourse through a polarization between manipulators' good qualities and intentions and the bad qualities of nurses and Brazilian primary care policies; episodic manipulation by the presentation of documental and historical evidence of the submission of nursing roles; and social manipulation marked by strong emotional appeal. The study demonstrated that manipulative discourse extrapolated linguistic categories in the form of ideology and history.

Existence and uniqueness of solutions of SDEs with discontinuous drift and finite activity jumps

In this letter we prove existence and uniqueness of strong solutions to multi-dimensional SDEs with discontinuous drift and finite activity jumps.

A Comparison of the Effect of Two Types of Continuous and Discontinuous Aerobic Exercise on Patients' Stem Cell Mobilization before Autologous Hematopoietic Stem Cell Transplantation

Background: Transplant success largely depends on the number of hematopoietic stem cells. The release of catecholamines following exercise can, as a treatment in addition to medication, affect the mobilization of stem cells from the bone marrow into the peripheral blood. The aim of the present study is to compare two types of aerobic exercise on stem cell mobilization before autologous transplantation. Materials and Methods: In a quasi-experimental applied study, 60 patients in the age range of 22-69 years referred to Taleghani Hospital were randomly selected and assigned into 3 groups of 20 members (continuous aerobic, discontinuous aerobic and control group). Aerobic exercise program was performed for 7 consecutive days of mobilization period including walking on a treadmill (according to the patient's ability) continuously and discontinuously for 30 minutes in the morning and afternoon. Blood samples were taken the morning before and after mobilization and the CD34 and MNC levels were counted as absolute. Chi-square test, paired t-test, analysis of covariance (ANCOA) and multiple comparison test were used for statistical analysis. All analyses were considered significant at p ≤ 0. Results: Moderate-intensity continuous and discontinuous aerobic activity increases the number of CD34 and MNC cells. A comparison between continuous and discontinuous aerobic activity showed an increase in the amount of these cells. The continuous aerobic activity group was found to have a statistically significant increase compared to the discontinuous group (P≤0.05). Conclusion: Moderate intensity continuous and discontinuous aerobic exercise significantly increased hematopoietic stem cells. However, this increase was greater as a result of continuous aerobic exercise than discontinuous exercise. Regarding the potential role of these cells in transplantation, they could possibly help the transplant process.

Brain Injury in Critical Illness and a Note on the Virus

Brain Injury in Critical Illness and a Note on the Virus

Reliability modeling of two-unit cold standby systems: A periodic switching approach

In the present paper, we use the concept of virtual age to propose a periodic switching policy for assessing the reliability of a two-unit cold standby system. This approach is suitable for units that recover with discontinuous activity and get younger. To restore the units and bring back the state of the system to a desirable condition, the active unit and cold standby unit are periodically replaced with each other at some given time interval. The survival function of the system under the periodic switching policy is derived in terms of the baseline time-to-failure distribution. The results indicate that, when the units have an increasing failure rate, the new switching policy improves the performance of the units which, in turn, increases the reliability of the system. Since the switching is not always failure-free, we derive also the survival function of the system in the case of imperfect switching. By considering the cost of switching and the system profit, we investigate the optimal length of the time interval for switching the active unit with the standby unit such that the mean profit of the system is maximized. To examine the theoretical results, we present some illustrative examples. Finally, we use a Monte-Carlo simulation to evaluate the system reliability.

The eruptive chronology of the Yucamane-Calientes compound volcano: A potentially active edifice of the Central Andes (southern Peru)

We reconstruct the eruptive chronology of the Yucamane–Calientes compound volcano in southern Peru based on extensive fieldwork and a large dataset of geochronological (K-Ar, 40Ar/39Ar, U-Pb, and 14C) and geochemical (major and trace element) analyses. This compound volcano is composed of two edifices that have experienced discontinuous volcanic activity from the middle Pleistocene to the Holocene. The Calientes volcano has been constructed in four successive stages: Calientes I is composed of andesitic lava flows dated at ~500 ka. Subsequently, the Callazas ignimbrite (Calientes II stage) was emplaced ~160–190 ka, followed by the main cone-building stage (Calientes III) at ~130–100 ka. Finally, the Holocene Calientes domes were emplaced and represent the last eruptive products of this edifice. The Yucamane volcano has been constructed in three stages: Yucamane I consists of a succession of andesitic lava flows exposed at the base of the volcano that are older than 40 ka. Yucamane II (~36–30 ka) comprises a thick sequence of block-and-ash-flow deposits that represents an episode of dome growth predating the younger Yucamane cone (Yucamane III) built after 20–25 ka. During the Holocene, Yucamane vulcanian to sub-Plinian activity has emplaced tephra-fall and pyroclastic-density-current deposits. The most recent explosive eruptions occurred ca. 3000 BP and emplaced a tephra-fall and pumice-flow deposits. Most samples from Calientes volcano are andesites and dacites (60.1–67.7 wt% SiO2), while rocks from Yucamane volcano are basaltic-andesites to dacites (53.4–66.9 wt% SiO2). The rocks have a mineral assemblage of plagioclase, amphibole, biotite, orthopyroxene, clinopyroxene, olivine, and Fe-Ti oxides. The analyzed samples are categorized within a high-K, calc-alkaline series. Calientes volcano erupted mostly andesitic magmas, but its history is punctuated by rare eruptions of silica-rich magmas. In contrast, Yucamane volcano follows a different trend characterized by a gradual decrease in silica content through post-glacial time, from the large (VEI 3) sub-Plinian andesitic eruption of ~3 ka to moderate (VEI ≤ 2) vulcanian eruptions of basaltic-andesitic. On the basis of such recurrent and recent (Holocene), low-to-moderate explosive activity, Yucamane must be considered an active and potentially threatening volcano, which may affect the province of Candarave with ~8000 inhabitants.

Electroencephalographic features of discontinuous activity in anesthetized infants and children.

BackgroundDiscontinuous electroencephalographic activity in children is thought to reflect brain inactivation. Discontinuity has been observed in states of pathology, where it is predictive of adverse neurological outcome, as well as under general anesthesia. Though in preterm-infants discontinuity reflects normal brain development, less is known regarding its role in term children, particularly in the setting of general anesthesia. Here, we conduct a post-hoc exploratory analysis to investigate the spectral features of discontinuous activity in children under general anesthesia.MethodsWe previously recorded electroencephalography in children less than forty months of age under general anesthesia (n = 65). We characterized the relationship between age, anesthetic depth, and discontinuous activity, and used multitaper spectral methods to compare the power spectra of subjects with (n = 35) and without (n = 30) discontinuous activity. In the subjects with discontinuous activity, we examined the amplitude and power spectra associated with the discontinuities and analyzed how these variables varied with age.ResultsCumulative time of discontinuity was associated with increased anesthetic depth and younger age. In particular, age-matched children with discontinuity received higher doses of propofol during induction as compared with children without discontinuity. In the tens of seconds preceding the onset of discontinuous activity, there was a decrease in high-frequency power in children four months and older that could be visually observed with spectrograms. During discontinuous activity, there were distinctive patterns of amplitude, spectral edge, and power in canonical frequency bands that varied with age. Notably, there was a decline in spectral edge in the seconds immediately following each discontinuity.ConclusionDiscontinuous activity in children reflects a state of a younger or more deeply anesthetized brain, and characteristic features of discontinuous activity evolve with age and may reflect neurodevelopment.

Epileptic encephalopathy with microcephaly in a patient with asparagine synthetase deficiency: a video‐EEG report∗

Asparagine synthetase deficiency is a rare autosomal recessive neurometabolic disorder caused by mutations in the asparagine synthetase gene. It is characterized by congenital microcephaly, intellectual disability, progressive cerebral atrophy, and intractable seizures. A decrease in asparagine in CSF or plasma guides subsequent investigations in some cases, but normal values are described in other cases. Therefore, reaching a diagnosis is challenging and relies on exome sequencing. We report the case of a child with progressive microcephaly, irritability, startle reflexes, and jitteriness since birth. Focal clonic and myoclonic seizures, status epilepticus, and infantile spasms appeared in the first months of life. At first, the EEG showed multifocal epileptic activity which later turned into modified hypsarrhythmia and discontinuous activity. Brain MRI showed brain atrophy, a simplified gyral pattern, and poor myelination. Plasma asparagine levels were normal. Due to remote parental consanguinity, a study of contiguous regions of runs of homozygosity was performed, showing a 5-Mb region (chr7:95629078-100679007) including the asparagine synthetase gene. The molecular analysis of this gene led to identification of a novel homozygous missense mutation, c.761G>T(p.Gly254Val), in our patient. The peculiar electroclinical phenotype may lead to diagnostic suspicion and molecular analysis which may benefit genetic counselling. [Published with video sequence].

Editors' note: Neurologic outcome of postanoxic refractory status epilepticus after aggressive treatment

In their prospective observational study of 166 survivors of cardiac arrest with anoxic brain injury, Beretta and colleagues categorized patients according to 1 of 4 mutually exclusive EEG patterns: (1) benign, (2) refractory status epilepticus (RSE), (3) generalized periodic discharges (GPDs), or (4) discontinuous/unreactive. The investigators assessed long-term survival and functional outcome based on a minimum of 5 days of EEG monitoring and other clinical and serologic biomarkers. In response, Dr. Nitin Sethi stresses how EEG patterns may vary with time following anoxic brain injury. Dr. Beretta agrees that EEG patterns are likely to fluctuate with time (and treatment) and, for this reason, classified patients according to the most severe pattern observed. Interrater agreement for each of these EEG categories was high (κ = 0.92). Importantly, patients with discontinuous or unreactive background activity or GPDs had extremely poor outcomes (mortality rates of 85% and 98%, respectively), whereas those with RSE had a 53% chance of long-term survival and 44% chance of a good functional outcome. Dr. Sethi also raises several concerns as to when one should initiate EEG monitoring and at what point one should use this electrophysiological data for neuroprognostication. In this investigation, Dr. Beretta and colleagues found a mean duration of RSE to be 4.7 days and therefore suggested 5 days as a reasonable initial assessment point for prognostication. This information may be helpful in the planning of future clinical trials, especially because a pattern of RSE may be associated with a better prognosis than GPD or discontinuous activity. In their prospective observational study of 166 survivors of cardiac arrest with anoxic brain injury, Beretta and colleagues categorized patients according to 1 of 4 mutually exclusive EEG patterns: (1) benign, (2) refractory status epilepticus (RSE), (3) generalized periodic discharges (GPDs), or (4) discontinuous/unreactive. The investigators assessed long-term survival and functional outcome based on a minimum of 5 days of EEG monitoring and other clinical and serologic biomarkers. In response, Dr. Nitin Sethi stresses how EEG patterns may vary with time following anoxic brain injury. Dr. Beretta agrees that EEG patterns are likely to fluctuate with time (and treatment) and, for this reason, classified patients according to the most severe pattern observed. Interrater agreement for each of these EEG categories was high (κ = 0.92). Importantly, patients with discontinuous or unreactive background activity or GPDs had extremely poor outcomes (mortality rates of 85% and 98%, respectively), whereas those with RSE had a 53% chance of long-term survival and 44% chance of a good functional outcome. Dr. Sethi also raises several concerns as to when one should initiate EEG monitoring and at what point one should use this electrophysiological data for neuroprognostication. In this investigation, Dr. Beretta and colleagues found a mean duration of RSE to be 4.7 days and therefore suggested 5 days as a reasonable initial assessment point for prognostication. This information may be helpful in the planning of future clinical trials, especially because a pattern of RSE may be associated with a better prognosis than GPD or discontinuous activity.

Association of antiepileptic drugs with resolution of epileptiform activity after cardiac arrest

IntroductionWe tested the impact of antiepileptic drug (AED) administration on post-cardiac arrest epileptiform electroencephalographic (EEG) activity. MethodsWe studied an observational cohort of comatose subjects treated at a single academic medical center after cardiac arrest from September 2010 to January 2018. We aggregated the observed EEG patterns into 5 categories: suppressed; discontinuous background with superimposed epileptiform activity; discontinuous background without epileptiform features; continuous background with epileptiform activity; and continuous background without epileptiform activity. We calculated overall probabilities of transitions between EEG states in a multistate model, then used Aalen’s additive regression to test if AEDs or hypothermia are associated with a change in these probabilities. ResultsOverall, 828 subjects had EEG-monitoring for 42,840 h with a median of 40 [IQR 23–64] h per subject. Among patients with epileptiform findings on initial monitoring, 50% transitioned at least once to a non-epileptiform, non-suppressed state. By contrast, 19% with non-epileptiform initial activity transitioned to an epileptiform state at least once. Overall, 568 (78%) patients received at least one AED. Among patients with continuous EEG background activity, valproate, levetiracetam and lower body temperature were each associated with an increased probability of transition from epileptiform states to non-epileptiform states, where patients with discontinuous EEG background activity no agent linked to an increased probability of transitioning from epileptiform states. ConclusionAfter cardiac arrest, the impact of AEDs may depend on the presence of continuous cortical background activity. These data serve to inform experimental work to better define the opportunities to improve neurologic care post-cardiac arrest.