Serum S100B protein could help to detect cerebral complications associated with extracorporeal membrane oxygenation (ECMO)

Brain injury plasma biomarkers in patients on veno-arterial extracorporeal membrane oxygenation: A pilot prospective observational study

IntroductionEarly diagnosis of acute brain injury (ABI) is critical for patients on veno-arterial extracorporeal membrane oxygenation (V-A ECMO) to guide anticoagulation strategy; however, neurological assessment in ECMO is often limited by patient sedation.MethodsIn this pilot study of adults from June 2018 to May 2019, plasma samples of glial fibrillary acidic protein (GFAP), neurofilament light chain (NFL), and tubulin associated unit (Tau) were collected daily after V-A ECMO cannulation and measured using a multiplex platform. Primary outcomes were occurrence of ABI, assessed clinically, and neurologic outcome, assessed by modified Rankin Scale (mRS).ResultsOf 20 consented patients (median age = 48.5°years; 55% female), 8 (40%) had ABI and 15 (75%) had unfavorable neurologic outcome at discharge. 10 (50%) patients were centrally cannulated. Median duration on ECMO was 4.5°days (IQR: 2.5-9.5). Peak GFAP, NFL, and Tau levels were higher in patients with ABI vs. without (AUC = 0.77; 0.85; 0.57, respectively) and in patients with unfavorable vs. favorable neurologic outcomes (AUC = 0.64; 0.59; 0.73, respectively). GFAP elevated first, NFL elevated to the highest degree, and Tau showed limited change regardless of ABI.ConclusionFurther studies are warranted to determine how plasma biomarkers may facilitate early detection of ABIs in V-A ECMO to assist timely clinical decision-making.

Management of severe acute encephalopathy in the ICU: an expert consensus statement from the french society of intensive care medicine

INTRODUCTION

Acute encephalopathy in the ICU poses significant diagnostic, therapeutic, and prognostic challenges. Standardized expert guidelines on acute encephalopathy are needed to improve diagnostic methods, therapeutic decisions, and prognostication.

METHODS

The experts conducted a review of the literature, analysed it according to the GRADE (Grading of Recommendation, Assessment, Development and Evaluation) methodology and made proposals for guidelines, which were rated by other experts. Only expert opinions with strong agreement were selected.

RESULTS

The synthesis of expert work and the application of the GRADE method resulted in 39 recommendations. Among the 39 formalized recommendations, 1 had a high level of evidence (GRADE 1 +) and 10 had a low level of evidence (GRADE 2 + or 2-). These recommendations describe indication for ICU admission, use of clinical scores and EEG for diagnosis, detection of complications, and prognostication. The remaining 28 recommendations were based on expert consensus. These recomandations describe common indications for blood and CSF studies, neuroimaging, use of neuromonitoring, and provide guidelines for management in the acute phase.

CONCLUSION

This expert consensus statement aims to provide a structured framework to enhance the consistency and quality of care for ICU patients presenting with acute encephalopathy. By integrating high-quality evidence with expert opinion, it offers a pragmatic approach to addressing the complex nature of acute encephalopathy in the ICU, promoting best practices in patient care and facilitating future research in the field.

Serum neurofilament light chain as a sensitive biomarker for neuromonitoring during extracorporeal membrane oxygenation

The use of extracorporeal membrane oxygenation (ECMO) has grown rapidly, driven by the COVID-19 pandemic. Despite its widespread adoption, neurological complications pose a significant risk, impacting both mortality and survivors' quality of life. Detecting these complications is challenging due to sedation and the heterogeneous nature of ECMO-associated neurological injury. Still, consensus of neurologic monitoring during ECMO is lacking since utilization and effectiveness of current neuromonitoring methods are limited. Especially in view of the heterogeneous nature of neurological injury during ECMO support an easily acquirable biomarker tracing neuronal damage independently from the underlying pathomechanism would be favorable. In a single-center prospective study on 34 severe acute respiratory distress syndrome (ARDS) patients undergoing ECMO, we explored the potential of serum neurofilament light chain levels (NfL) as a biomarker for neurological complications and its predictive power towards the overall outcome of ECMO patients. Individuals experiencing neurological complications (41%) demonstrated a notable rise in NfL levels (Tbaseline median 92.95 pg/ml; T24h median 132 pg/ml (IQR 88.6-924 pg/ml), p = 0.008; T7d median 248 pg/ml (IQR 157-1090 pg/ml), p = 0.001). Moreover, under ECMO therapy, these patients exhibited markedly elevated concentrations compared to those without neurological complications (T24h median 70.75 pg/ml (IQR 22.2-290 pg/ml), p = 0.023; T7d median 128 pg/ml (IQR 51.8-244 pg/ml), p = 0.002). There was no significant difference in the NfL dynamics between surviving patients and those who died during or shortly after ECMO therapy. While NfL indicates neuro-axonal damage during intensive care with ECMO therapy, we could not identify any correlation between survival outcome and the levels of NfL, indicating that NfL may not serve as a prognostic marker for survival. Nevertheless, additional studies involving a larger patient cohort are required.

The Role of S100b Protein Biomarker in Brain Death: A Literature Review

Brain death (BD) represents the irreversible loss of all brain functions, including the brainstem, and is equivalent to clinical death established by neurological criteria. However, clinical diagnosis, mainly based on the absence of primary reflexes post-acute brain injury, remains a challenge in hospital settings. The S100 calcium-binding protein beta (S100b) is used to monitor brain injuries, as recommended by neurotrauma care guidelines in some countries. Its levels are associated with severity and mortality, particularly after traumatic brain injury (TBI) and cerebral hemorrhage. The evaluation of S100b levels in investigating brain death is promising; however, aspects such as cutoff values remain to be elucidated. This paper reviews the literature on the use of S100b as a biomarker in diagnosing brain death. It is noteworthy that there is still no defined cutoff for S100b levels in confirming brain death. Additionally, when considering the use of S100b in emergency situations, a point-of-care methodology should be established to support clinical decision-making quickly and easily in the early identification of patients who are more likely to progress to brain death. In this context, S100b levels may assist in establishing the diagnosis of brain death, complementing existing clinical evidence. This, in turn, can optimize and qualify the organ donation process, reducing costs with ineffective therapies and minimizing the suffering of the families involved.

Association of Sepsis With Neurologic Outcomes of Adult Patients Treated With Venoarterial Extracorporeal Membrane Oxygnenation

OBJECTIVES

Neurologic outcomes of patients under venoarterial extracorporeal membrane oxygenation (VA-ECMO) may be worsened by secondary insults of systemic origin. We aimed to assess whether sepsis, commonly observed during ECMO support, is associated with brain injury and outcomes.

DESIGN

Single-center cohort study of the "exposed-non-exposed" type on consecutive adult patients treated by VA-ECMO.

SETTING

Medical ICU of a university hospital, France, 2013-2020.

PATIENTS

Patients with sepsis at the time of VA-ECMO cannulation ("sepsis" group) were compared with patients without sepsis ("no sepsis" group). The primary outcome measure was poor functional outcome at 90 days, defined by a score greater than or equal to 4 on the modified Rankin scale (mRS), indicating severe disability or death.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A total of 196 patients were included ("sepsis," n = 128; "no sepsis," n = 68), of whom 87 (44.4%) had presented cardiac arrest before VA-ECMO cannulation. A poor functional outcome (mRS ≥ 4) was observed in 99 of 128 patients (77.3%) of the "sepsis" group and 46 of 68 patients (67.6%) of the "no sepsis" group (adjusted logistic regression odds ratio (OR) 1.21, 95% CI, 0.58-2.47; inverse probability of treatment weighting (IPTW) OR 1.24; 95% CI, 0.79-1.95). Subsequent analyses performed according to pre-ECMO cardiac arrest status suggested that sepsis was independently associated with poorer functional outcomes in the subgroup of patients who had experienced pre-ECMO cardiac arrest (adjusted logistic regression OR 3.44; 95% CI, 1.06-11.40; IPTW OR 3.52; 95% CI, 1.68-7.73), whereas no such association was observed in patients without pre-ECMO cardiac arrest (adjusted logistic regression OR 0.69; 95% CI, 0.27-1.69; IPTW OR 0.76; 95% CI, 0.42-1.35). Compared with the "no sepsis" group, "sepsis" patients presented a significant increase in S100 calcium-binding protein beta concentrations at day 1 (0.94 μg/L vs. 0.52 μg/L, p = 0.03), and more frequent EEG alterations (i.e., severe slowing, discontinuous background, and a lower prevalence of sleep patterns), suggesting brain injury.

CONCLUSION

We observed a detrimental role of sepsis on neurologic outcomes in the subgroup of patients who had experienced pre-ECMO cardiac arrest, but not in other patients.

Neurodevelopmental outcomes in congenital heart disease: Usefulness of biomarkers of brain injury

INTRODUCTION

At present, neurodevelopmental abnormalities are the most frequent type of complication in school-aged children with congenital heart disease (CHD). We analysed the incidence of acute neurologic events (ANEs) in patients with operated CHD and the usefulness of neuromarkers for the prediction of neurodevelopment outcomes.

METHODS

Prospective observational study in infants with a prenatal diagnosis of CHD who underwent cardiac surgery in the first year of life. We assessed the following variables: (1) serum biomarkers of brain injury (S100B, neuron-specific enolase) in cord blood and preoperative blood samples; (2) clinical and laboratory data from the immediate postnatal and perioperative periods; (3) treatments and complications; (4) neurodevelopment (Bayley-III scale) at age 2 years.

RESULTS

the study included 84 infants with a prenatal diagnosis of CHD who underwent cardiac surgery in the first year of life. Seventeen had univentricular heart, 20 left ventricular outflow obstruction and 10 genetic syndromes. The postoperative mortality was 5.9% (5/84) and 10.7% (9/84) patients experienced ANEs. The mean overall Bayley-III scores were within the normal range, but 31% of patients had abnormal scores in the cognitive, motor or language domains. Patients with genetic syndromes, ANEs and univentricular heart had poorer neurodevelopmental outcomes. Elevation of S100B in the immediate postoperative period was associated with poorer scores.

CONCLUSIONS

children with a history of cardiac surgery for CHD in the first year of life are at risk of adverse neurodevelopmental outcomes. Patients with genetic syndromes, ANEs or univentricular heart had poorer outcomes. Postoperative ANEs may contribute to poorer outcomes. Elevation of S100B levels in the postoperative period was associated with poorer neurodevelopmental outcomes at 2 years. Studies with larger samples and longer follow-ups are needed to define the role of these biomarkers of brain injury in the prediction of neurodevelopmental outcomes in patients who undergo surgery for management of CHD.

Prevalence of delirium among critically ill patients who received extracorporeal membrane oxygenation therapy: A systematic review and proportional meta-analysis

OBJECTIVES

To pool the overall prevalence of delirium among critically ill patients who received extracorporeal membrane oxygenation (ECMO) support.

METHODOLOGY

This systematic review and proportional meta-analysis was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and Meta-analysis of Observational Studies in Epidemiology (MOOSE) reporting guidelines. Six electronic databases including PubMed, Cochrane Library, Web of Science, EMBASE, CINAHL, and PsycINFO were searched from inception to March 2023. The Newcastle-Ottawa Scale was used to assess the methodological quality of the included studies. A random effects model was used to pool the summary prevalence estimates and 95% CIs using the score statistic and the exact binomial method and incorporates the Freeman-Tukey double arcsine transformation of proportions. Sensitivity analyses including subgroup analysis, meta-regression, and outlier detection were carried out.

SETTING

Intensive care units.

MAIN OUTCOME MEASURES

Prevalence of delirium.

RESULTS

A total of 10 studies involving 8,580 patients were included for meta-analysis. All studies had a low risk of bias in methodological quality. The pooled prevalence rate of 40.79% [95% CI, 17.58%-66.25%] was observed. The between-study heterogeneity (I2) was 98.28%. The subgroup analysis reveals the pooled prevalence of delirium for veno-arterial (V-A) ECMO, veno-venous (V-V) ECMO, and mixed sample of V-A and V-V ECMO were 63.57% [95% CI, 55.77%-71.04%], 51.84% [95% CI, 37.43%-66.12%] and 35.23% [95% CI, 11.84%-62.95%], respectively. Sample size (p = 0.024) was a significant factor associated with the heterogeneity. No evidence for small-study effects was observed (Egger's test: p = 0.5664).

CONCLUSION

This systematic review and proportional meta-analysis reveals a high prevalence of delirium among critically ill patients who received ECMO support.

IMPLICATIONS FOR CLINICAL PRACTICE

The results of this meta-analysis can be epidemiological evidence to inform the awareness of clinicians and researchers in critical care clinical practice and research.

Effect of flow change on brain injury during an experimental model of differential hypoxaemia in cardiogenic shock supported by extracorporeal membrane oxygenation

Differential hypoxaemia (DH) is common in patients supported by femoral veno-arterial extracorporeal membrane oxygenation (V-A ECMO) and can cause cerebral hypoxaemia. To date, no models have studied the direct impact of flow on cerebral damage. We investigated the impact of V-A ECMO flow on brain injury in an ovine model of DH. After inducing severe cardiorespiratory failure and providing ECMO support, we randomised six sheep into two groups: low flow (LF) in which ECMO was set at 2.5 L min-1 ensuring that the brain was entirely perfused by the native heart and lungs, and high flow (HF) in which ECMO was set at 4.5 L min-1 ensuring that the brain was at least partially perfused by ECMO. We used invasive (oxygenation tension-PbTO2, and cerebral microdialysis) and non-invasive (near infrared spectroscopy-NIRS) neuromonitoring, and euthanised animals after five hours for histological analysis. Cerebral oxygenation was significantly improved in the HF group as shown by higher PbTO2 levels (+ 215% vs - 58%, p = 0.043) and NIRS (67 ± 5% vs 49 ± 4%, p = 0.003). The HF group showed significantly less severe brain injury than the LF group in terms of neuronal shrinkage, congestion and perivascular oedema (p < 0.0001). Cerebral microdialysis values in the LF group all reached the pathological thresholds, even though no statistical difference was found between the two groups. Differential hypoxaemia can lead to cerebral damage after only a few hours and mandates a thorough neuromonitoring of patients. An increase in ECMO flow was an effective strategy to reduce such damages.

International survey of neuromonitoring and neurodevelopmental outcome in children and adults supported on extracorporeal membrane oxygenation in Europe

BACKGROUND

Adverse neurological events during extracorporeal membrane oxygenation (ECMO) are common and may be associated with devastating consequences. Close monitoring, early identification and prompt intervention can mitigate early and late neurological morbidity. Neuromonitoring and neurocognitive/neurodevelopmental follow-up are critically important to optimize outcomes in both adults and children.

OBJECTIVE

To assess current practice of neuromonitoring during ECMO and neurocognitive/neurodevelopmental follow-up after ECMO across Europe and to inform the development of neuromonitoring and follow-up guidelines.

METHODS

The EuroELSO Neurological Monitoring and Outcome Working Group conducted an electronic, web-based, multi-institutional, multinational survey in Europe.

RESULTS

Of the 211 European ECMO centres (including non-ELSO centres) identified and approached in 23 countries, 133 (63%) responded. Of these, 43% reported routine neuromonitoring during ECMO for all patients, 35% indicated selective use, and 22% practiced bedside clinical examination alone. The reported neuromonitoring modalities were NIRS (n = 88, 66.2%), electroencephalography (n = 52, 39.1%), transcranial Doppler (n = 38, 28.5%) and brain injury biomarkers (n = 33, 24.8%). Paediatric centres (67%) reported using cranial ultrasound, though the frequency of monitoring varied widely. Before hospital discharge following ECMO, 50 (37.6%) reported routine neurological assessment and 22 (16.5%) routinely performed neuroimaging with more paediatric centres offering neurological assessment (65%) as compared to adult centres (20%). Only 15 (11.2%) had a structured longitudinal follow-up pathway (defined followup at regular intervals), while 99 (74.4%) had no follow-up programme. The majority (n = 96, 72.2%) agreed that there should be a longitudinal structured follow-up for ECMO survivors.

CONCLUSIONS

This survey demonstrated significant variability in the use of different neuromonitoring modalities during and after ECMO. The perceived importance of neuromonitoring and follow-up was noted to be very high with agreement for a longitudinal structured follow-up programme, particularly in paediatric patients. Scientific society endorsed guidelines and minimum standards should be developed to inform local protocols.

The Disconnect Between Extracorporeal Circulation and the Microcirculation: A Review

Extracorporeal circulation (ECC) procedures, such as cardiopulmonary bypass (CPB) and extracorporeal membrane oxygenation (ECMO), take over the function of one or more organs, providing clinicians time to treat underlying pathophysiological conditions. ECMO and CPB carry significant mortality rates for patients, despite prior decades of research focused on the resulting failure of critical organs. Since the focus of these procedures is to support blood flow and provide oxygen-rich blood to tissues, a shift in research toward the effects of ECMO and CPB on the microcirculation is warranted. Along with provoking systemic responses, both procedures disrupt the integrity of red blood cells, causing release of hemoglobin (Hb) from excessive foreign surface contact and mechanical stresses. The effects of hemolysis are especially pronounced in the microcirculation, where plasma Hb leads to nitric oxide scavenging, oxidization, formation of reactive oxygen species, and inflammatory responses. A limited number of studies have investigated the implications of ECMO in the microcirculation, but more work is needed to minimize ECMO-induced reduction of microcirculatory perfusion and consequently oxygenation. The following review presents existing information on the implications of ECMO and CPB on microvascular function and proposes future studies to understand and leverage key mechanisms to improve patient outcomes.

Extracorporeal Cardiopulmonary Resuscitation Guided by End-Tidal Carbon Dioxide-a Porcine Model

Extracorporeal membrane cardiopulmonary resuscitation (ECPR) during cardiopulmonary resuscitation (CPR) for selected cases and end-tidal carbon dioxide (ETCO₂) could be used to guide initiation of ECPR. Ventricular fibrillation was induced in 12 pigs and CPR was performed until ETCO₂ fell below 10 mmHg; then, ECPR was performed. Animals were divided into group short (G_Short) and group long (G_Long), according to time of CPR. Carotid blood flow was higher (p = 0.02) and mean arterial blood pressure lower in G_Long during CPR (p < 0.05). B-Lactate was lower and pH higher in G_Short (p < 0.01). In microdialysis lactate-pyruvate ratio, glycerol and glutamate increased in both groups during CPR, but considerably in G_Long (p < 0.01). No difference could be seen in histopathology of the brain or kidney post-ECPR. No apparent histological differences of tissue damage in brains or levels of S100B in plasma were detected between groups. This might suggest that ETCO₂ could be used as a marker for brain injury following ECPR.

Narrative Review of Neurologic Complications in Adults on ECMO: Prevalence, Risks, Outcomes, and Prevention Strategies

Extracorporeal membrane oxygenation (ECMO), a life-saving technique for patients with severe respiratory and cardiac diseases, is being increasingly utilized worldwide, particularly during the coronavirus disease 2019(COVID-19) pandemic, and there has been a sharp increase in the implementation of ECMO. However, due to the presence of various complications, the survival rate of patients undergoing ECMO remains low. Among the complications, the neurologic morbidity significantly associated with venoarterial and venovenous ECMO has received increasing attention. Generally, failure to recognize neurologic injury in time is reportedly associated with poor outcomes in patients on ECMO. Currently, multimodal monitoring is increasingly utilized in patients with devastating neurologic injuries and has been advocated as an important approach for early diagnosis. Here, we highlight the prevalence and outcomes, risk factors, current monitoring technologies, prevention, and treatment of neurologic complications in adult patients on ECMO. We believe that an improved understanding of neurologic complications presumably offers promising therapeutic solutions to prevent and treat neurologic morbidity.

Brain injury in extracorporeal cardiopulmonary resuscitation: translational to clinical research

The addition of extracorporeal membrane oxygenation (ECMO) to conventional cardiopulmonary resuscitation (CPR), termed extracorporeal cardiopulmonary resuscitation (ECPR), has significantly improved survival in selected patient populations. Despite this advancement, significant neurological impairment persists in approximately half of survivors. ECPR represents a potential advancement for patients who experience refractory cardiac arrest (CA) due to a reversible etiology and do not regain spontaneous circulation. Important risk factors for acute brain injury (ABI) in ECPR include lack of perfusion, reperfusion, and altered cerebral autoregulation. The initial hypoxic-ischemic injury caused by no-flow and low-flow states after CA and during CPR is compounded by reperfusion, hyperoxia during ECMO support, and nonpulsatile blood flow. Additionally, ECPR patients are at risk for Harlequin syndrome with peripheral cannulation, which can lead to preferential perfusion of cerebral vessels with deoxygenated blood. Lastly, the oxygenator membrane is prothrombotic and requires systemic anticoagulation. The two competing phenomena result in thrombus formation, hemolysis, and thrombocytopenia, increasing the risk of ischemic and hemorrhagic ABI. In addition to clinical studies, we assessed available ECPR animal models to identify the mechanisms underlying ABI at the cellular level. Standardized multimodal neurological monitoring may facilitate early detection of and intervention for ABI. With the increasing use of ECPR, it is critical to understand the pathophysiology of ABI, its prevention, and the management strategies for improving the outcomes of ECPR. Translational and clinical research focusing on acute ABI immediately after ECMO cannulation and its short- and long-term neurological outcomes are warranted.

Brain Injury in Extracorporeal Membrane Oxygenation: A Multidisciplinary Approach

Extracorporeal membrane oxygenation (ECMO) represents an established technique to provide temporary cardiac and/or pulmonary support. ECMO, in veno-venous, veno-arterial or in extracorporeal carbon dioxide removal modality, is associated with a high rate of brain injuries. These complications have been reported in 7 to 15% of adults and 20% of neonates, and are associated with poor survival. Thromboembolic events, loss of cerebral autoregulation, alteration of the blood-brain barrier, and hemorrhage related to anticoagulation represent the main causes of severe brain injury during ECMO. The most frequent forms of acute neurological injuries in ECMO patients are intracranial hemorrhage (2-21%), ischemic stroke (2-10%), seizures (2-6%), and hypoxic-ischemic brain injury; brain death may also occur in this population. Other frequent complications are infarction (1-8%) and cerebral edema (2-10%), as well as neuropsychological and psychiatric sequelae, including posttraumatic stress disorder.

Neuron-Specific Enolase Levels in Adults Under Venoarterial Extracorporeal Membrane Oxygenation

Supplemental Digital Content is available in the text.

Objectives:

We aimed to determine if elevations in serum neuron-specific enolase are associated with brain injury and outcomes in adults who require venoarterial extracorporeal membrane oxygenation.

Design:

Prospective observational study.

Setting:

Two ICUs of a university hospital, Paris, France.

Patients:

Consecutive adult patients treated with venoarterial extracorporeal membrane oxygenation for refractory cardiogenic shock or in-hospital refractory cardiac arrest.

Interventions:

None.

Measurements and Main Results:

Serum sampled 1, 3, and 7 days after venoarterial extracorporeal membrane oxygenation cannulation was stored at –80°C and neuron-specific enolase concentrations were measured in batches at the end of the study. The association between neuron-specific enolase concentrations and outcomes (28-d mortality and poor outcome, defined by a score of 4–6 on the modified Rankin scale at 90 d) were explored by multivariable logistic regression, with neuron-specific enolase concentrations dichotomized according to median values. One-hundred three patients were included, of whom 26 (25%) received preextracorporeal membrane oxygenation cardiopulmonary resuscitation. Median (interquartile range) day-1, day-3, and day-7 neuron-specific enolase serum concentrations were 37 μg/L (26–51 μg/L), 25 μg/L (19–37) μg/L, and 22 μg/L (17–31 μg/L). After adjustment for Simplified Acute Physiology Score II, preextracorporeal membrane oxygenation cardiopulmonary resuscitation, and Sepsis Organ Failure Assessment score at time of cannulation, a day-3 neuron-specific enolase greater than 25 μg/L remained independently associated with 28-day mortality (adjusted odds ratio, 4.98; 95% CI, 1.86–13.32) and poor outcome at 90 days (adjusted odds ratio, 4.63; 95% CI, 1.81–11.84). A day-3 neuron-specific enolase threshold greater than 80 μg/L had a 100% specificity for prediction of both mortality (95% CI, 92–100%) and poor functional outcome (95% CI, 89–100%). In a subset of patients who underwent brain CT, neuron-specific enolase concentrations were significantly higher in patients diagnosed with stroke, as compared with those without stroke.

Conclusions:

In adult patients under venoarterial extracorporeal membrane oxygenation, day-3 serum neuron-specific enolase concentrations are independently associated with short-term mortality and poor functional outcomes. These findings deserve validation in a multicenter setting.

Tau Is Elevated in Pediatric Patients on Extracorporeal Membrane Oxygenation

Neurologic injury is a known and feared complication of extracorporeal membrane oxygenation (ECMO). Neurologic biomarkers may have a role in assisting in early identification of such. Axonal biomarker tau has not been investigated in the pediatric ECMO population. The objective of this study is to evaluate plasma levels of tau in pediatric patients supported with ECMO. Eighteen patients requiring ECMO support in a quaternary pediatric intensive care unit at a university-affiliated children's hospital from October 2015 to February 2017 were enrolled. Patients undergoing extracorporeal cardiopulmonary resuscitation or recent history of bypass were excluded. Plasma tau was measured using enzyme-linked immunosorbent assay. Neuroimaging was reviewed for acute neurologic injury, and tau levels were analyzed to assess for correlation. Tau was significantly higher in ECMO patients than in control subjects. Sixty-one percent of subjects had evidence of acute brain injury on neuroimaging, but tau level did not correlate with injury. Subjects with multifocal injury all experienced infarction and had significantly higher tau levels on ECMO day 3 than patients with isolated injury. In addition, peak tau levels of neuro-injured subjects were compared with controls and noninjured ECMO subjects using receiver operating curve analysis. This study demonstrates preliminary evidence of axonal injury in pediatric ECMO patients.

Early EEG for Prognostication Under Venoarterial Extracorporeal Membrane Oxygenation

BACKGROUND/OBJECTIVES

Tools for prognostication of neurologic outcome of adult patients under venoarterial ECMO (VA-ECMO) have not been thoroughly investigated. We aimed to determine whether early standard electroencephalography (_stdEEG) can be used for prognostication in adults under VA-ECMO.

METHODS

Prospective single-center observational study conducted in two intensive care units of a university hospital, Paris, France. Early _stdEEG was performed on consecutive adult patients treated with VA-ECMO for refractory cardiogenic shock or refractory cardiac arrest. The association between _stdEEG findings and unfavorable outcome was investigated. The primary endpoint was 28-day mortality. The secondary endpoint was severe disability or death at 90 days, defined by a score of 4-6 on the modified Rankin scale.

RESULTS

A total of 122 patients were included, of whom 35 (29%) received cardiopulmonary resuscitation before VA-ECMO cannulation. Main _stdEEG findings included low background frequency ≤ 4 Hz (n = 27, 22%) and background abnormalities, i.e., a discontinuous (n = 20, 17%) and/or an unreactive background (n = 12, 10%). Background abnormalities displayed better performances for prediction of unfavorable outcomes, as compared to clinical parameters at time of recording. An unreactive _stdEEG background in combination with a background frequency ≤ 4 Hz had a false positive rate of 0% for prediction of unfavorable outcome at 28 days and 90 days, with sensitivities of 8% and 6%, respectively. After adjustment for confounders, a lower background frequency was independently associated with unfavorable outcome at 28 days (adjusted odds ratio per 1-Hz increment, 95% CI 0.71, 0.52-0.97), whereas no such independent association was observed at 90 days.

CONCLUSION

Standard EEG abnormalities recorded at time of VA-ECMO initiation are predictive of unfavorable outcomes. However, the low sensitivity of these parameters highlights the need for a multimodal evaluation for improving management of care and prognostication.

Neurological Monitoring and Complications of Pediatric Extracorporeal Membrane Oxygenation Support

Extracorporeal membrane oxygenation is extracorporeal life support for life-threatening cardiopulmonary failure. Since its introduction, the use of extracorporeal membrane oxygenation has expanded to patients with more complex comorbidities without change in patient mortality rates. Although many patients survive, significant neurological complications like seizures, ischemic strokes, and intracranial hemorrhage can occur during extracorporeal membrane oxygenation care. The risks of these complications often add to the complexity of decision-making surrounding extracorporeal membrane oxygenation support. In this review, we discuss the pathophysiology and incidence of neurological complications in children supported on extracorporeal membrane oxygenation, factors influencing the incidence of these complications, commonly used neurological monitoring modalities, and outcomes for this complex patient population. We discuss the current literature on the use of electroencephalography for both seizure detection and monitoring of background electroencephalographic changes, in addition to the use of less commonly used imaging modalities like transcranial Doppler. We summarize the knowledge gaps and the lack of clinical consensus guidelines for managing these potentially life-changing neurological complications. Finally, we discuss future work to further understand the pathophysiology of extracorporeal membrane oxygenation-related neurological complications.

The dynamic change of serum S100B levels from day 1 to day 3 is more associated with sepsis-associated encephalopathy

We investigated the role of dynamic changes of serum levels S100B protein in brain injury and poor outcome of sepsis. This is a prospective cohort study designed to include 104 adult patients with sepsis who are admitted to ICU from Jan 2015 to Aug 2016. Sepsis was defined as sepsis 3.0. Patients with a GCS score of <15, or at least one positive CAM-ICU score were thought to have brain dysfunction. 59 patients were diagnosed with SAE and the rest 45 patients were diagnosed with non-SAE. Serum S100B was measured on day 1 and 3 after ICU admission. Primary outcomes included brain dysfunction and 28-day/180-day mortality. The SAE group showed a significantly higher APACHE II score, SOFA scores, length of ICU stay, 28-day and 180-day mortality, serum S100B levels on day 1 and day 3. S100B levels on day 1 of 0.226 μg/L were diagnostic for SAE with 80.0% specificity and 66.1% sensitivity, and the area under (AUC) the curve was 0.728, S100B levels on day 3 of 0.144 μg/L were diagnostic for SAE with 84.44% specificity and 69.49% sensitivity, and the AUC was 0.819. In addition, the AUC for S100B on day 3 for predicting 180-day mortality was larger than for S100B on day 1 (0.731 vs. 0.611). Multiple logistic regression analysis showed that S100B3 (p = 0.001) but not S100B1 (p = 0.927) were independently correlated with SAE. Kaplan-Meier survival analysis showed that patients with S100B levels higher than 0.144 μg/L had a lower probability of survival at day 180. There were more patients with encephalopathy and a higher 28-day or 180-day mortality in the ΔS100B + group than in the ΔS100B- group. Multiple logistic regression analysis showed that SAE and IL-6 on day 3 were independently correlated with S100B dynamic increase. These findings suggest that elevated serum S100B levels on day 3 and the dynamic changes of serum S100B levels from day three to one were more associated with brain dysfunction and mortality than that on day 1 in patients with sepsis.

Serial S100B Sampling Detects Intracranial Lesion Development in Patients on Extracorporeal Membrane Oxygenation

Introduction: Intracranial lesion development is a recognized complication in adults treated with extracorporeal membrane oxygenation (ECMO) and is associated with increased mortality. As neurological assessment during ECMO treatment remains challenging, protein biomarkers of cerebral injury could provide an opportunity to detect intracranial lesion development at an early stage. The aim of this study was to determine if serially sampled S100B could be used to detect intracranial lesion development during ECMO treatment. Methods: We conducted an observational cohort study of all patients treated with ECMO at ECMO Center Karolinska (Karolinska University Hospital, Stockholm, Sweden) between January and August 2018, excluding patients who did not undergo a computerized tomography scan (CT) during treatment. S100B was prospectively collected at hospital admission and then once daily. The primary end-point was any type of CT verified intracranial lesion. Receiver operating characteristics (ROC) curves and Cox proportional hazards models were employed. Results: Twenty-nine patients were included, of which 15 (52%) developed an intracranial lesion and exhibited higher levels of S100B overall. S100B had a robust association with intracranial lesion development, especially during the first 200 hours following admission. The best area-under-curve (AUC) to predict intracranial lesion development was 40 and 140 hours following ECMO initiation, were a S100B level of 0.69μg/L had an AUC of 0.81 (0.628-0.997). S100B levels were markedly increased following the development of intracranial hemorrhage. Conclusions: Serial serum S100B samples in ECMO patients were both significantly elevated and had an increasing trajectory in patients developing intracranial lesions. Larger prospective trials are warranted to validate these findings and to ascertain their clinical utility.

The Role of S100B Protein at 24 Hours of Postnatal Age as Early Indicator of Brain Damage and Prognostic Parameter of Perinatal Asphyxia

Introduction. S100B protein is a cytosolic calcium-binding protein with a molecular weight of 21 kDa, which is present in various cells and concentrated mainly in the glial cells, which play a vital role in the maintenance of cellular homeostasis in the central nervous system. It is possible that increased S100B protein level might be considered as sensitive and specific indicator to predict early brain damage. Aim. To investigate the prognostic value of serum S100B protein in neonates with perinatal asphyxia (PA) at 24 hours of postnatal age. Methods. A systematic review was performed. Inclusion criteria were studies including data of neonates with PA, monitored with serum S100B, and with neurodevelopmental follow-up of at least 2 weeks. The period of bibliographic search was until January 2017. The consulted databases were MEDLINE, PsycINFO, and Embase. A combination of the following subject headings and keywords was adapted for each electronic database: “perinatal asphyxia,” “hypoxic ischemic encephalopathy,” “hypoxia-ischemia, brain,” and “S100B.” Meta-Disc1.4 software was used. Results. From the 1620 articles initially identified, 6 were finally included and reviewed. The overall diagnostic sensitivity of serum S100B was 0.80 (95% confidence interval [CI] = 0.68-0.88) and the specificity was 0.79 (95% CI = 0.70-0.87). But there was lower predictability value, that is, the positive likelihood ratio was only 3.26 (95% CI 1.74-6.12) and the negative likelihood ratio was 0.32 (95% CI = 0.20-0.5). The diagnostic odds ratio was 12.40 (95% CI = 4.66-33.0). Conclusion. Increased serum S100B level at 24 hours of postnatal life can demonstrate brain damage, but it should not be the only one used to predict PA outcome.

Intracranial hemorrhage in adults on ECMO

RATIONALE

Extracorporeal membrane oxygenation (ECMO) use has exploded over the last decade. However, it remains invasive and associated with significant complications, including tamponade, infection, thrombosis, gas embolism and bleeding. The most dreaded complication is intracranial hemorrhage (ICH). In this article, we review the literature on the incidence, diagnosis, risk factors, pathophysiology, prognosis, prevention and management of ICH in adults on ECMO.

MAIN FINDINGS

We found a high incidence of ICH in the literature with a poor prognosis. Important risk factors included pre-ECMO cardiac arrest, sepsis, influenza, renal failure, renal replacement therapy, hemolysis and thrombocytopenia. The optimal anticoagulation strategy is still uncertain. As platelet dysfunction and depletion appear to play an important role in the pathogenesis of ICH in patients on ECMO, a liberal platelet transfusion strategy may be advised. Prompt computed tomography (CT) diagnosis is of great importance as interventions to limit hematoma expansion and secondary neurological injury are most effective if instituted early. Transporting patients to the radiology department can be performed safely while on ECMO. A strategy combining screening CT on admission with a heparin-free period of extracorporeal support was demonstrated to be safe in VV-ECMO patients and resulted in a better prognosis compared to similar cohorts in the literature.

CONCLUSION

Despite major technological improvements and all the experience gained in adults, ECMO remains associated with a high incidence of ICH. There are still wide gaps in our understanding of the disease. Optimal management strategies that minimize the risk of ICH and improve prognosis need to be further studied.

Incidence, Outcome, and Predictors of Intracranial Hemorrhage in Adult Patients on Extracorporeal Membrane Oxygenation: A Systematic and Narrative Review

Background: Intracranial hemorrhage (ICH) is a common complication in adults treated with extracorporeal membrane oxygenation (ECMO).

Objectives: The aim of this study was to conduct a systematic review of the literature on the incidence, outcome and predictors of ECMO-associated ICH in adult patients, supplemented by a narrative review of its pathophysiology, management and future perspectives.

Methods: MEDLINE, EMBASE, Cochrane Database of Systematic Reviews and www.clinicaltrials.gov were systematically searched. Studies that reported incidence, outcome or predictors of ECMO-associated ICH in adults (≥18 years) were eligible for inclusion.

Results: Twenty five articles were included in the systematic review. The incidence of ECMO-associated ICH varied between 1.8 and 21 %. Mortality rates in ICH-cohorts varied between 32 and 100 %, with a relative risk of mortality of 1.27–4.43 compared to non-ICH cohorts. An increased risk of ICH was associated with ECMO-duration, antithrombotic therapy, altered intrinsic coagulation, renal failure, need of blood products, rapid hypercapnia at ECMO initiation, and even pre-ECMO morbidity.

Conclusions: ICH is a common complication in adults treated with ECMO and associated with increased mortality. Treating an ICH during ECMO represents a balance between pro- and anticoagulatory demands. Neurosurgical treatment is associated with severe morbidity, but has been successful in selected cases. Future studies should aim at investigating the validity and feasibility of non-invasive monitoring in early detection of ECMO-associated ICH.

Cerebral Pathophysiology in Extracorporeal Membrane Oxygenation: Pitfalls in Daily Clinical Management

Extracorporeal membrane oxygenation (ECMO) is a life-saving technique that is widely being used in centers throughout the world. However, there is a paucity of literature surrounding the mechanisms affecting cerebral physiology while on ECMO. Studies have shown alterations in cerebral blood flow characteristics and subsequently autoregulation. Furthermore, the mechanical aspects of the ECMO circuit itself may affect cerebral circulation. The nature of these physiological/pathophysiological changes can lead to profound neurological complications. This review aims at describing the changes to normal cerebral autoregulation during ECMO, illustrating the various neuromonitoring tools available to assess markers of cerebral autoregulation, and finally discussing potential neurological complications that are associated with ECMO.

Utility of serum concentration of protein S100 at admission to the medical intensive care unit in prediction of permanent neurological injury

Introduction

Admission to the intensive care unit (ICU) may be preceded by dramatic events leading to permanent neurological injury. Plasma S100 protein levels are proved to be clinically useful in predicting neurological outcome following cardiac arrest. It is unclear, however, whether this may be extrapolated to a broader population of ICU patients.

Aim

To assess the utility of plasma S100 protein in predicting death, permanent neurological damage, or unfavourable outcome at admission to the intensive care unit.

Material and methods

The concentration of plasma S100 protein was established in 102 patients on admission to the ICU, regardless of their neurological status and the reason for admission. The majority of patients were admitted with various cardiac diseases, excluding trauma patients. The patients were classified into three groups with the following binary outcomes: permanent neurological deficit or restoration of consciousness; unfavourable outcome (death or survival with permanent neurological deficit) or favourable outcome; and death or survival.

Results

Plasma S100 protein levels at admission facilitated the identification of patients who later developed a permanent neurological deficit or regained consciousness (p < 0.0001). All patients with plasma S100 protein over 0.532 μg/l at ICU admission either developed a permanent neurological deficit or had an unfavourable outcome (death or survival with permanent neurological deficit). However, sensitivity for this cut-off value was only 48% and 40%, respectively.

Conclusions

Plasma S100 protein levels over 0.532 μg/l are specific but not sensitive for both permanent neurological deficit and unfavourable outcome when assessed in a heterogeneous population at admission to the ICU.

Resistive Index Variability in Anterior Cerebral Artery Measurements During Daily Transcranial Duplex Sonography: A Predictor of Cerebrovascular Complications in Infants Undergoing Extracorporeal Membrane Oxygenation?

OBJECTIVES

The purpose of this study was to determine the value of resistive index (RI) variability in predicting cerebrovascular complications during extracorporeal membrane oxygenation (ECMO).

METHODS

This retrospective study included 36 infants treated by ECMO. The RI was measured on daily transfontanellar duplex sonography, obtained first without fontanel compression and then after gentle compression with the transducer. The age at ECMO cannulation, sex, gestational age at birth, method of delivery, indication, and type and duration of ECMO were recorded.

RESULTS

There was a statistically significant difference in RI variability in infants who developed cerebrovascular complications as opposed to those who did not (P = .002). Resistive index variability of 10% or greater on any day was associated with an increased risk for cerebrovascular complications (P = .0482; χ² = 3.9). Variability in the first 5 days was significantly higher than on following days (P < .0001). The age at ECMO cannulation showed a significant difference, with mean ± SD values of 1.1 ± 0.9 days in the complications group and 2.7 ± 2.2 days in the no-complications group (P = .043).

CONCLUSIONS

Resistive index variability of 10% or greater on any day had a statistically significant risk of cerebrovascular complication development. Extracorporeal membrane oxygenation cannulation at younger than 3 days conferred an increased risk of cerebrovascular complications.

Plasma Biomarkers of Brain Injury as Diagnostic Tools and Outcome Predictors After Extracorporeal Membrane Oxygenation

OBJECTIVE

To determine if elevations in plasma brain injury biomarkers are associated with outcome at hospital discharge in children who require extracorporeal membrane oxygenation.

DESIGN

Prospective observational study.

SETTING

Single tertiary-care academic center.

PARTICIPANTS

Eighty children who underwent extracorporeal membrane oxygenation between June 2010 and December 2013.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We measured six brain injury biomarkers (glial fibrillary acidic protein, monocyte chemoattractant protein 1/chemokine (C-C motif) ligand 2, neuron-specific enolase, S100b, intercellular adhesion molecule-5, and brain-derived neurotrophic factor) daily during extracorporeal membrane oxygenation, using an electrochemiluminescent multiplex assay. We recorded clinical, neuroimaging, and extracorporeal membrane oxygenation course data. We analyzed the association of biomarker concentrations with favorable versus unfavorable outcome at hospital discharge. Favorable outcome was defined as Pediatric Cerebral Performance Category 1, 2, or no change from baseline. Patients had a median age of 3 days (interquartile range, 1 d-10 mo), and 56% were male. Thirty-three of 80 (41%) had unfavorable outcome, and 22 of 70 (31%) had abnormal neuroimaging findings during or after extracorporeal membrane oxygenation. Peak concentrations were significantly higher in patients with unfavorable outcome than in those with favorable outcome for glial fibrillary acidic protein (p = 0.002), monocyte chemoattractant protein 1/chemokine (C-C motif) ligand 2 (p = 0.030), neuron-specific enolase (p = 0.006), and S100b (p = 0.015) and in patients with versus without abnormal neuroimaging findings for glial fibrillary acidic protein (p = 0.001) and intercellular adhesion molecule-5 (p = 0.001). The area under the receiver operator characteristic curve for unfavorable outcome was 0.73 for a noncollinear biomarker combination. After removing collinear biomarkers, the adjusted odds ratios for unfavorable outcome were 2.89 (95% CI, 1.09-7.73) for neuron-specific enolase, using a cutoff of 62.0 ng/mL, and 2.15 (95% CI, 1.06-4.38) for glial fibrillary acidic protein, using a cutoff of 0.46 ng/mL.

CONCLUSIONS

Elevated plasma brain injury biomarker concentrations during the extracorporeal membrane oxygenation course are associated with unfavorable outcome and/or the presence of neuroimaging abnormalities. Combinations of brain-specific proteins increase the sensitivity and specificity for outcome prediction.

Neuromonitoring During Extracorporeal Membrane Oxygenation: A Systematic Review of the Literature

OBJECTIVE

Neurologic injury remains a significant morbidity and risk factor for mortality in critically ill patients undergoing extracorporeal membrane oxygenation. Our goal was to systematically review the literature on the use of neuromonitoring methods during extracorporeal membrane oxygenation.

DATA SOURCES

Electronic searches of PubMed, CINAHL, EMBASE, Web of Science, Cochrane, and Scopus were conducted in March 2014, using a combination of medical subject heading terms and text words to define concepts of extracorporeal life support, neurologic monitoring techniques, evaluation, and outcomes.

STUDY SELECTION

Studies were selected based on inclusion and exclusion criteria defined a priori.

DATA EXTRACTION

Two authors reviewed all citations independently. A standardized data extraction form was used to construct evidence tables by neuromonitoring method. Evidence was graded using the Oxford Evidence-Based Medicine scoring system.

DATA SYNTHESIS

Of 3,459 unique citations, 39 studies met the inclusion criteria. Study designs were retrospective observational cohort studies (n = 20), prospective observational studies (n = 17), case-control studies (n = 2), and no interventional studies. Most studies evaluated newborns (n = 30). Extracorporeal membrane oxygenation neuromonitoring methods included neuroimaging (head ultrasound) (n = 12); intermittent, conventional, multichannel electroencephalography (n = 5); 1- to 2-channel amplitude-integrated electroencephalography (n = 2); Doppler ultrasound (n = 7); cerebral oximetry (n = 6); plasma brain injury biomarkers (n = 4); and other (n = 3). All evidence was graded 2B-4, with the majority of studies graded 3B (20/39 studies) and 4 (10/39 studies). Due to the heterogeneity of the studies included, aggregate analysis was not possible.

CONCLUSIONS

Data supporting the use and effectiveness of current neuromonitoring methods are limited. Most studies have modest sample sizes, are observational in nature, and include patient populations that are of different ages and pathologies, with very limited data for pediatric and adult ages. Well-designed studies with adequate power and standardized short- and long-term outcomes are needed to develop guidelines for neuromonitoring and ultimately neuroprotection in patients on extracorporeal membrane oxygenation.

Serum S100B levels may be associated with cerebral infarction: a meta-analysis

OBJECTIVE

The aim of this paper is to explore the potential association of serum human soluble protein-100B protein (S100B) levels with the diagnosis and prognosis of cerebral infarction (CI).

METHODS

Potential relevant studies were searched for in PubMed, Springerlink, Wiley, EBSCO, Ovid, Web of Science, Wanfang databases, China National Knowledge Infrastructure (CNKI) databases and VIP databases. Two investigators extracted data and assessed studies independently. Statistical analyses were carried out with the version 12.0 STATA statistical software.

RESULTS

A total of 10 case-control studies that assessed the correlation of S100B serum level with CI, including 1211 subjects (patients=773, healthy controls=438) were included. The results showed that S100B serum levels in CI victims were significantly higher compared with those of the control group. According to the subgroup analysis by ethnicity, S100B serum level in CI victims was statistically significant in Asians and the control group, but no statistical significance was found in Caucasians. An additional subgroup analysis was carried out based on sample size, revealing that the S100B serum levels in CI victims in small samples were of statistical significance; however, no statistical significance was discovered in large samples.

CONCLUSIONS

Elevator S100B serum levels might be negatively correlated with CI, suggesting that higher serum levels of S100B could lead to more serious condition and worse prognoses for CI patients. Therefore, S100B serum levels could be regarded as a biomarker for CI, and furthermore, S100B could aide in the diagnosis and prognosis of CI.