Serum neuron-specific enolase as early predictor of outcome after cardiac arrest

S-100B and neuron-specific enolase as predictors of neurological outcome in patients after cardiac arrest and return of spontaneous circulation: a systematic review

INTRODUCTION

Neurological prognostic factors after cardiopulmonary resuscitation (CPR) in patients with cardiac arrest (CA) as early and accurately as possible are urgently needed to determine therapeutic strategies after successful CPR. In particular, serum levels of protein neuron-specific enolase (NSE) and S-100B are considered promising candidates for neurological predictors, and many investigations on the clinical usefulness of these markers have been published. However, the design adopted varied from study to study, making a systematic literature review extremely difficult. The present review focuses on the following three respects for the study design: definitions of outcome, value of specificity and time points of blood sampling.

METHODS

A Medline search of literature published before August 2008 was performed using the following search terms: "NSE vs CA or CPR", "S100 vs CA or CPR". Publications examining the clinical usefulness of NSE or S-100B as a prognostic predictor in two outcome groups were reviewed. All publications met with inclusion criteria were classified into three groups with respect to the definitions of outcome; "dead or alive", "regained consciousness or remained comatose", and "return to independent daily life or not". The significance of differences between two outcome groups, cutoff values and predictive accuracy on each time points of blood sampling were investigated.

RESULTS

A total of 54 papers were retrieved by the initial text search, and 24 were finally selected. In the three classified groups, most of the studies showed the significance of differences and concluded these biomarkers were useful for neurological predictor. However, in view of blood sampling points, the significance was not always detected. Nevertheless, only five studies involved uniform application of a blood sampling schedule with sampling intervals specified based on a set starting point. Specificity was not always set to 100%, therefore it is difficult to indiscriminately assess the cut-off values and its predictive accuracy of these biomarkers in this meta analysis.

CONCLUSIONS

In such circumstances, the findings of the present study should aid future investigators in examining the clinical usefulness of these markers and determination of cut-off values.

Neuron-specific enolase and S-100B are associated with neurologic outcome after pediatric cardiac arrest

OBJECTIVE

To characterize the pattern of serum biochemical markers of central nervous system injury (neuron-specific enolase [NSE], S-100B, plasminogen activator inhibitor-1 [PAI-1]) after pediatric cardiac arrest and determine whether there is an association between biomarker concentrations and neurologic outcome.

DESIGN

Prospective, observational study.

SETTING

Urban, tertiary care children's hospital.

PATIENTS

Cardiac arrest survivors, n = 35.

INTERVENTIONS

Serial blood sampling, pediatric cerebral performance category, and standardized neurologic examination.

MEASUREMENTS AND MAIN RESULTS

Serial serum NSE and S-100B concentrations over 96 hrs and PAI-1 at 24 hrs were measured in children (age <18 yrs) who had return of spontaneous circulation following cardiac arrest. Neurologic outcome was prospectively categorized as poor if the change in pre- to postarrest pediatric cerebral performance category was > or =2. Biomarker concentrations were compared between outcome groups and between survival groups using longitudinal analysis correcting for multiple comparisons. Median levels (25th, 75th percentiles) are reported. Receiver operating characteristic analyses were performed at all time points. Biomarker concentrations showed statistically significant differences. Of the 35 patients, neurologic outcomes were poor in 19, with 15 deaths. Median NSE concentrations differed by outcome when measured at > or =48 hrs, and by survival at > or =24 hrs. S-100B concentrations were not significantly associated with neurologic outcome. S-100B levels were associated with survival outcome at > or =48 hrs. PAI-1 levels were not significantly associated with either neurologic or survival outcomes.

CONCLUSIONS

The timing, intensity, and duration of serum NSE and S-100B biomarker concentration patterns are associated with neurologic and survival outcomes following pediatric cardiac arrest. Serum NSE concentrations at > or =48 hrs are associated with neurologic outcome, whereas serum S-100B levels at > or =48 hrs are associated with survival. Prospective analysis of these markers may help to predict outcomes and guide postresuscitative therapies.

Comatose patients with cardiac arrest: predicting clinical outcome with diffusion-weighted MR imaging

PURPOSE

To examine whether the severity and spatial distribution of reductions in apparent diffusion coefficient (ADC) are associated with clinical outcomes in patients who become comatose after cardiac arrest.

MATERIALS AND METHODS

This was an institutional review board-approved, HIPAA-compliant retrospective study of 80 comatose patients with cardiac arrest who underwent diffusion-weighted magnetic resonance imaging. The need to obtain informed consent was waived except when follow-up phone calls were required; in those cases, informed consent was obtained from the families. Mean patient age was 57 years +/- 16 (standard deviation); 31 (39%) patients were women. ADC maps were semiautomatically segmented into the following regions: subcortical white matter; cerebellum; insula; frontal, occipital, parietal, and temporal lobes; caudate nucleus; putamen; and thalamus. Median ADCs were measured in these regions and in the whole brain and were compared (with a two-tailed Wilcoxon test) as a function of clinical outcome. Outcome was defined by both early eye opening in the 1st week after arrest (either spontaneously or in response to external stimuli) and 6-month modified Rankin scale score.

RESULTS

Whole-brain median ADC was a significant predictor of poor outcome as measured by no eye opening (specificity, 100% [95% confidence interval {CI}: 86%, 100%]; sensitivity, 30% [95% CI: 18%, 45%]) or 6-month modified Rankin scale score greater than 3 (specificity, 100% [95% CI: 73%, 100%]; sensitivity, 41% [95% CI: 29%, 54%]), with patients with poor outcomes having significantly lower ADCs for both outcome measures (P <or= .001). Differences in ADC between patients with good and those with poor outcomes varied according to brain region, involving predominantly the occipital and parietal lobes and the putamen, and were dependent on the timing of imaging.

CONCLUSION

Spatial and temporal differences in ADCs may provide insight into mechanisms of hypoxic-ischemic brain injury and, hence, recovery.

[Endovascular or surface cooling?: therapeutic hypothermia after cardiac arrest]

INTRODUCTION

Time course, time necessary to achieve the target temperature and stable maintenance, as well as a controlled rewarming period are important factors influencing the outcome of patients after successful cardiopulmonary resuscitation.

METHODS

After successful cardiopulmonary resuscitation a total of 49 patients were cooled via an endovascular or external cooling device to a target temperature of 33 degrees C. Relevant cooling parameters, such as time between admission and initiation of cooling, achievement of target temperature and stable maintenance of cooling therapy, were compared between both groups.

RESULTS

In the endovascular cooling group the target temperature was reached significantly faster (154 +/- 97 min vs. 268 +/- 95 min, p = 0.0002) and showed stable and controlled maintenance of cooling therapy (deviation from target temperature: 0.189 +/- 0.23 degrees C vs 0.596 +/- 0.61 degrees C, p = 0.00006). The rewarming phase was better controlled and length of ICU stay was shorter in the group with endovascular cooling (8.8 +/- 3 vs. 12.9 +/- 6 days).

CONCLUSION

Endovascular cooling offers the possibility to reach the target temperature significantly faster and a stable maintenance of therapeutic hypothermia. It is capable of a more controlled rewarming period and shortens the length of ICU stay.

Cardiac arrest resuscitation: neurologic prognostication and brain death

PURPOSE OF REVIEW

Persistent coma after cardiac arrest is a source of great emotional and financial cost to grieving family members in particular and the healthcare system in general. Neurologic prognostication helps guide appropriate discussions between family members and healthcare providers. Recent advances in therapeutic care increase the challenges, both medical and financial, on local practitioners.

RECENT FINDINGS

Evidence-based reviews by prestigious associations add additional support and guidance to the practitioner who must guide family members in this very difficult decision process. Therapeutic hypothermia may alter findings, thus skewing the prognostic abilities of many accepted methodologies. This study reviews the usefulness of clinical examination, electrophysiologic studies, biochemical markers, and imaging modalities in predicting poor neurologic recovery in comatose survivors after cardiac arrest resuscitation. Some data from studies of therapeutic hypothermia are presented.

SUMMARY

Evidence-based tests of prognostication for neurologic outcome after cardiac arrest are presented. A review of the practice of withdrawal of life-sustaining therapies and the diagnosis of brain death is also provided. The reader is cautioned that most prognostic studies do not include possible amelioration with the use of therapeutic hypothermia.

Relative quantification of proteins in human cerebrospinal fluids by MS/MS using 6-plex isobaric tags

A new 6-plex isobaric mass tagging technology is presented, and proof of principle studies are carried out using standard protein mixtures and human cerebrospinal fluid (CSF) samples. The Tandem Mass Tags (TMT) comprise a set of structurally identical tags which label peptides on free amino-terminus and epsilon-amino functions of lysine residues. During MS/MS fragmentation, quantification information is obtained through the losses of the reporter ions. After evaluation of the relative quantification with the 6-plex version of the TMT on a model protein mixture at various concentrations, the quantification of proteins in CSF samples was performed using shotgun methods. Human postmortem (PM) CSF was taken as a model of massive brain injury and comparison was carried out with antemortem (AM) CSF. After immunoaffinity depletion, triplicates of AM and PM CSF pooled samples were reduced, alkylated, digested by trypsin, and labeled, respectively, with the six isobaric variants of the TMT (with reporter ions from m/z = 126.1 to 131.1 Th). The samples were pooled and fractionated by SCX chromatography. After RP-LC separation, peptides were identified and quantified by MS/MS analysis with MALDI TOF/TOF and ESI-Q-TOF. The concentration of 78 identified proteins was shown to be clearly increased in PM CSF samples compared to AM. Some of these proteins, like GFAP, protein S100B, and PARK7, have been previously described as brain damage biomarkers, supporting the PM CSF as a valid model of brain insult. ELISA for these proteins confirmed their elevated concentration in PM CSF. This work demonstrates the validity and robustness of the tandem mass tag (TMT) approach for quantitative MS-based proteomics.

Can brain natriuretic peptide predict outcome after cardiac arrest? An observational study

BACKGROUND

No accurate, independent biomarker has been identified that could reliably predict neurological outcome early after cardiac arrest. We speculated that brain natriuretic peptide (BNP) measured at hospital admission may predict patient outcome.

METHODS

BNP-levels were measured in 155 comatose cardiac arrest survivors (108 male, 58 years [IQR 49-68]) (median time to ROSC 11min; IQR 20-30) during a 6-year study period. Cardiovascular co-morbidities and resuscitation history were assessed according to the Utstein-style and patients were followed for 6-month neurological outcome measured by cerebral performance category (CPC) and survival.

RESULTS

Seventy patients (45%) suffered from unfavourable neurological outcome and 79 deaths (51%) occurred during the first 6 months. BNP was significantly associated with an adverse neurological outcome and mortality, independent of the prearrest health condition and cardiac arrest characteristics (median 60 pg/ml; IQR 10-230). Adjusted odds ratios for poor neurological outcome at 6 months were 1.14 (95% CI 0.51-2.53), 1.76 (95% CI 0.80-3.88) and 2.25 (95% CI 1.05-4.81), for increasing quartiles of BNP as compared to the lowest quartile. Adjusted odds ratios for mortality until 6 months were 1.09 (95% CI 0.35-3.40), 2.81 (0.80-9.90) and 4.7 (1.27-17.35) compared to the lowest quartile, respectively.

CONCLUSION

Brain natriuretic peptide levels on admission predict neurological outcome at 6 months and survival after cardiac arrest.

[Early evaluation of neurological prognosis and therapy after cardiopulmonary resuscitation: current opportunities and clinical implications]

The developments of cardiopulmonary resuscitation and intensive care medicine have made possible survival after cardiac arrest. However, only 10-30% of patients with initially successful resuscitation later reach a state without severe neurological impairment. Ethical and socioeconomic reasons therefore make early prognosis important for certain patients. There are no reliable parameters for predictions of good clinical outcome. If clinical information is consistent with severe hypoxic brain damage, cortical somatosensory evoked potentials are absent, and neuron-specific enolase values exceed 33-65 microg/l, recovery of consciousness can be excluded. The same result can be predicted if brain imaging shows severe hypoxemic changes or if a myoclonic status occurs on the first day. In summary, the prognosis in patients with cerebral anoxy and cardiopulmonary resuscitation remains poor. Treatment with hypothermia for 24 h is recommended.

Prediction of cognitive dysfunction after resuscitation from out-of-hospital cardiac arrest using serum neuron-specific enolase and protein S-100

BACKGROUND

More than 50% of patients initially resuscitated from out-of-hospital cardiac arrest die in hospital.

OBJECTIVE

To investigate the prognostic value of serum protein S-100 and neuron-specific enolase (NSE) concentrations for predicting (a) memory impairment at discharge; (b) in-hospital death, after resuscitation from out-of-hospital cardiac arrest.

METHODS

In a prospective study of 143 consecutive survivors of out-of-hospital cardiac arrest, serum samples were obtained within 12, 24-48 and 72-96 hours after the event. S-100 and NSE concentrations were measured. Pre-discharge cognitive assessment of patients (n = 49) was obtained by the Rivermead Behavioural Memory Test (RBMT). The relationship between biochemical brain marker concentrations and RBMT scores, and between marker concentrations and the risk of in-hospital death was examined.

RESULTS

A moderate negative relationship was found between S-100 concentration and memory test score, at all time points. The relationship between NSE and memory test scores was weaker. An S-100 concentration >0.29 microg/l at time B predicted moderate to severe memory impairment with absolute specificity (42.8% sensitivity). S-100 remained an independent predictor of memory function after adjustment for clinical variables and cardiac arrest timing indices. NSE and S-100 concentrations were greater in patients who died than in those who survived, at all time points. Both NSE and S-100 remained predictors of in-hospital death after adjustment for clinical variables and cardiac arrest timing indices. The threshold concentrations yielding 100% specificity for in-hospital death were S-100: 1.20 microg/l (sensitivity 44.8%); NSE 71.0 microg/l (sensitivity 14.0%).

CONCLUSIONS

Estimation of serum S-100 concentration after out-of-hospital cardiac arrest can be used to identify patients at risk of significant cognitive impairment at discharge. Serum S-100 and NSE concentrations measured 24-48 hours after cardiac arrest provide useful additional information.

Biochemical markers (NSE, S-100, IL-8) as predictors of neurological outcome in patients after cardiac arrest and return of spontaneous circulation

Predicting the neurological outcome after resuscitation and a return of spontaneous circulation of resuscitated patients still remains a difficult issue. Over the past decade numerous studies have been elaborated to provide the physician with tools to assess as early as possible the neurological outcome of patients with cardiac arrest and return of spontaneous circulation and to decide about further therapeutic management. We summarise the most important ones, giving special focus to three biochemical markers (neuron specific enolase, a protein soluble in 100% ammonium sulfate and interleukin-8), which, when combined with standard neuro-functional and imaging techniques, can serve as potent predictors of neurological outcome in these patients. Despite current limitations about the prognostic significance of these markers - their inferior sensitivity, the different cut-off levels used by several investigators and their variable unequal rise over time - they can give useful information about short and long-term neurological outcome. A comprehensive set of clinical, electrophysiological, biochemical and imaging measures, obtained in a uniform manner in a cohort of patients without limitations in care, could provide a more objective set of comprehensive prognostic indicators.

Prediction of short-term and long-term outcomes after cardiac arrest: A prospective multivariate approach combining biochemical, clinical, electrophysiological, and neuropsychological investigations*

OBJECTIVE

To determine the prognostic accuracy of biochemical, clinical, electrophysiological, and neuropsychological investigations in predicting outcomes after cardiac arrest.

DESIGN

Prospective study.

SETTING

Intensive care unit of the Hamburg-Eppendorf University Medical Center, Hamburg, Germany.

PATIENTS

A total of 80 patients (mean age, 63.79 +/- 15.85 yrs) after cardiopulmonary resuscitation.

INTERVENTIONS

Serial blood samples (days 2-4), clinical examinations (days 2 and 4), sensory-evoked potentials (day 4), and neuropsychological assessments (<or=1 and 6 months).

MEASUREMENTS AND MAIN RESULTS

We conducted a prospective study into the combined predictive efficacy of serum concentrations of neuron-specific enolase and protein S-100B, standardized clinical examinations, and short- and long-latency sensory-evoked potentials. For the prognostic validation, both the dichotomized 5-point Glasgow-Pittsburgh Cerebral Performance Categories (1-3, favorable outcome; 4-5, unfavorable outcome) and a comprehensive neuropsychological test battery were applied. A multivariate logistic-regression analysis resulted in a model in which 85% of the variance in the dichotomized Glasgow-Pittsburgh Cerebral Performance Categories was explained by neuron-specific enolase at day 4, clinical examination score at day 4, and age. This predictor index had a sensitivity of 92% and a specificity of 93%. In addition, 26 patients (out of 33) underwent neuropsychological testing at 6 months. Significant correlations were found with selected cognitive variables and S-100B at day 3, long-latency sensory-evoked potential at day 4, and neuropsychological bedside screening.

CONCLUSIONS

A multivariate assessment approach should be used to establish an early high-certainty prognosis after cardiac arrest. However, further prospective clinical studies are necessary to confirm this derived predictor index. In addition, an early recording of S-100B, long-latency sensory-evoked potential, and neuropsychological bedside screening reflect a cognitive long-term outcome.

Serum neuron-specific enolase as early predictor of outcome after in-hospital cardiac arrest: a cohort study

Introduction

Outcome after cardiac arrest is mostly determined by the degree of hypoxic brain damage. Patients recovering from cardiopulmonary resuscitation are at great risk of subsequent death or severe neurological damage, including persistent vegetative state. The early definition of prognosis for these patients has ethical and economic implications. The main purpose of this study was to investigate the prognostic value of serum neuron-specific enolase (NSE) in predicting outcomes in patients early after in-hospital cardiac arrest.

Methods

Forty-five patients resuscitated from in-hospital cardiac arrest were prospectively studied from June 2003 to January 2005. Blood samples were collected, at any time between 12 and 36 hours after the arrest, for NSE measurement. Outcome was evaluated 6 months later with the Glasgow outcome scale (GOS). Patients were divided into two groups: group 1 (unfavorable outcome) included GOS 1 and 2 patients; group 2 (favorable outcome) included GOS 3, 4 and 5 patients. The Mann–Whitney U test, Student's t test and Fisher's exact test were used to compare the groups.

Results

The Glasgow coma scale scores were 6.1 ± 3 in group 1 and 12.1 ± 3 in group 2 (means ± SD; p < 0.001). The mean time to NSE sampling was 20.2 ± 8.3 hours in group 1 and 28.4 ± 8.7 hours in group 2 (p = 0.013). Two patients were excluded from the analysis because of sample hemolysis. At 6 months, favorable outcome was observed in nine patients (19.6%). Thirty patients (69.8%) died and four (9.3%) remained in a persistent vegetative state. The 34 patients (81.4%) in group 1 had significantly higher NSE levels (median 44.24 ng/ml, range 8.1 to 370) than those in group 2 (25.26 ng/ml, range 9.28 to 55.41; p = 0.034).

Conclusion

Early determination of serum NSE levels is a valuable ancillary method for assessing outcome after in-hospital cardiac arrest.

The prognostic value of early transcranial Doppler ultrasound following cardiopulmonary resuscitation

The aim of the presented study was to estimate the prognostic value of transcranial Doppler sonography (TCD) for the prediction of clinical outcome of patients after cardiopulmonary resuscitation (CPR) on the basis of the measured flow velocity changes in the basal cerebral arteries. Thirty-nine patients (27 men, 12 women) aged 66 +/- 15 y (+/-SD) who had undergone CPR were involved. Serial TCD examinations of the intracranial arteries were performed 1.5, 4, 8, 16, 24 and 72 h after CPR. Plasma neuron specific enolase (NSE), ventilation parameters (pH, paO(2), paCO(2)) and hemodynamic parameters were registered. Seventeen patients (group 1) survived with moderate or without neurologic deficits. Twenty-two patients (group 2) either died (n = 21) within 9 +/- 14 days or remained in vegetative state (n = 1). NSE levels ranged from 9 to 29 microg/L in group 1 and from 22 to 1242 microg/L in group 2 (p < 0.05). Four and 72 h after CPR, peak systolic flow velocities in the middle cerebral artery (MCA) were significantly higher in group 1 than in group 2 (p < 0.05). Twenty-four h after CPR, peak systolic and diastolic flow velocities in the ACA and PCA were also significantly higher in group 1 than in group 2 (p < 0.05). At this time, patients of group 2 showed significantly higher resistance index-values (RI = (sys-dia)/sys) in the anterior cerebral artery (ACA) and the posterior cerebral artery (PCA) (p < 0.05). A high correlation between peak systolic blood flow velocity in the MCA and systemic systolic blood pressure was observed in group 2 early 4 to 16 h after CPR (r = +0.52 to + 0.81, p < 0.05), while there was no such correlation in group 1. Using serial TCD examinations, patients with severely disabling or fatal outcome could be identified within the first 24 h. Besides established clinical and laboratory parameters, postanoxic myoclonus and NSE, serial TCD examinations following CPR may be helpful to predict the clinical outcome, but further studies with a larger number of patients are necessary to approve this hypothesis.

Arc de cercle and dysautonomia from anoxic injury

Autonomic dysregulation and catatonic posturing are well described following acute cerebral injury. Others have referred to this as diencephalic seizures, sympathetic storms, midbrain dysregulatory syndrome, and, most recently, paroxysmal autonomic instability with dystonia. Some of these syndromes can evolve into malignant catatonia requiring electroconvulsive therapy. Here we report a case of hanging associated anoxic brain injury resulting in severe dysautonomia and an extreme opisthotonus (arc de cercle).

Early prediction of individual outcome following cardiopulmonary resuscitation: systematic review

Following resuscitation from cardiorespiratory arrest 80% of patients are comatose. Of these patients, 20% will survive and regain consciousness. Is it possible to predict an individual's long term outcome at presentation and alter management accordingly? This review examines the current medical literature and demonstrates it is impossible to predict immediately outcome from hypoxic-ischaemic coma except in a small subgroup of patients with poor premorbid factors. As individual prognosis cannot be determined in the emergency department all patients who do not have significant premorbid features should proceed to a period of supportive care in the intensive care unit. Therapeutic hypothermia should be considered for these patients.

Neuroimaging and Serologic Markers of Neurologic Injury after Cardiac Arrest

Determining prognosis in the setting of hypoxic-ischemic injury following cardiac arrest is difficult based solely on clinical parameters in the patient who is critically ill. The article discusses bio- chemical markers in the blood and in the cerebrospinal fluid that are evaluated for prognostic information, along with radiologic indicators of anoxic cerebral damage. It includes a recommended algorithm using a combination of serologic and radiologic markers of cerebral injury for assessing prognosis in the patient who is comatose following cardiac arrest.

Approach to the comatose patient

BACKGROUND

Coma is a medical emergency and may constitute a diagnostic and therapeutic challenge for the intensivist.

OBJECTIVE

To review currently available data on the etiology, diagnosis, and outcome of coma. To propose an evidence-based approach for the clinical management of the comatose patient.

DATA SOURCE

Search of Medline and Cochrane databases; manual review of bibliographies from selected articles and monographs.

DATA SYNTHESIS AND CONCLUSIONS

Coma and other states of impaired consciousness are signs of extensive dysfunction or injury involving the brainstem, diencephalon, or cerebral cortex and are associated with a substantial risk of death and disability. Management of impaired consciousness includes prompt stabilization of vital physiologic functions to prevent secondary neurologic injury, etiological diagnosis, and the institution of brain-directed therapeutic or preventive measures. Neurologic prognosis is determined by the underlying etiology and may be predicted by the combination of clinical signs and electrophysiological tests.

Nonspecific increase of systemic neuron-specific enolase after trauma: clinical and experimental findings

The aim of this clinical and experimental study was to determine whether systemic neuron-specific enolase (NSE) is a useful early marker of traumatic brain injury (TBI) and whether NSE is affected by ischemia/reperfusion damage of abdominal organs. Our study included patients with and without TBI (verified by computerized tomography) admitted within 6 h after trauma and male Sprague-Dawley rats with ischemia and reperfusion of the abdominal organs liver, gut, or kidney. Thirty-eight study patients included 13 with isolated TBI and 18 patients with multiple trauma and TBI. Seven patients had multiple trauma but no TBI. Fifteen rats were anaesthetized and subjected to isolated ischemia of the liver, gut, or kidney (n = 5 each) for 1 h, followed by reperfusion for 3 h. In patients, NSE increased over 2-fold versus the upper normal limit (10 microg/L) within 6 h after trauma, regardless of whether TBI had occurred or not. In rats, NSE increased over 3-fold versus laboratory controls during ischemia of the liver and kidney (both P < 0.0005), but not of the gut. NSE increased over 2-fold after onset of reperfusion of the liver and kidney (both P < 0.05), but not of the gut and increased over 3-fold after 3 h of reperfusion of the liver, gut (both P < 0.005), and kidney (P < 0.0005). Our data show that systemic NSE increases to similar degrees with and without TBI. Therefore, NSE is not a useful early marker of TBI in multiple trauma.

Observations on comatose survivors of cardiopulmonary resuscitation with generalized myoclonus

Background

There is only limited data on improvements of critical medical care is resulting in a better outcome of comatose survivors of cardiopulmonary resuscitation (CPR) with generalized myoclonus. There is also a paucity of data on the temporal dynamics of electroenephalographic (EEG) abnormalities in these patients.

Methods

Serial EEG examinations were done in 50 comatose survivors of CPR with generalized myoclonus seen over an 8 years period.

Results

Generalized myoclonus occurred within 24 hours after CPR. It was associated with burst-suppression EEG (n = 42), continuous generalized epileptiform discharges (n = 5), alpha-coma-EEG (n = 52), and low amplitude (10 μV <) recording (n = 1). Except in 3 patients, these EEG-patterns were followed by another of these always nonreactive patterns within one day, mainly alpha-coma-EEG (n = 10) and continuous generalized epileptiform discharges (n = 9). Serial recordings disclosed a variety of EEG-sequences composed of these EEG-patterns, finally leading to isoelectric or flat recordings. Forty-five patients died within 2 weeks, 5 patients survived and remained in a permanent vegetative state.

Conclusion

Generalized myoclonus in comatose survivors of CPR still implies a poor outcome despite advances in critical care medicine. Anticonvulsive drugs are usually ineffective. All postanoxic EEG-patterns are transient and followed by a variety of EEG sequences composed of different EEG patterns, each of which is recognized as an unfavourable sign. Different EEG-patterns in anoxic encephalopathy may reflect different forms of neocortical dysfunction, which occur at different stages of a dynamic process finally leading to severe neuronal loss.

Late Auditory and Event-Related Potentials Can Be Useful to Predict Good Functional Outcome After Coma

OBJECTIVE

To investigate whether late auditory and event-related potentials, and in particular N100 and mismatch negativity, together with clinical parameters, can help to predict good functional outcome in comatose patients.

DESIGN

Prospective cohort study.

SETTING

Hospital.

PARTICIPANTS

Consecutively sampled comatose patients (N=346) whose etiologies of coma were stroke (125 patients), brain injury (96 patients), anoxia (64 patients), complication of neurosurgery (54 patients), and encephalitis (7 patients).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Glasgow Outcome Scale score at 1 year postonset. Patients in a minimally conscious state and those who awoke and died during the follow-up period were classified separately.

RESULTS

Univariate analysis showed that all variables studied, except brainstem auditory evoked potentials, correlated significantly with functional outcome. Mismatch negativity showed the highest positive predictive value for good outcome. A validated model was obtained with multivariate logistic analysis, including pupillary light reflex, N100, mismatch negativity, etiology, and age.

CONCLUSIONS

Late auditory and event-related potentials, and particularly N100 and mismatch negativity, provide strong prognostic factors for good functional outcome. Furthermore, these components may enhance the accuracy of prognosis when associated with other clinical parameters available at the early stage of coma.

Outcome after cardiac arrest: predictive values and limitations of the neuroproteins neuron-specific enolase and protein S-100 and the Glasgow Coma Scale

BACKGROUND AND PURPOSE

Patients resuscitated from cardiac arrest are at risk of subsequent death or poor neurological outcome up to a persistent vegetative state. We investigated the prognostic value of several epidemiological and clinical markers and two neuroproteins, neuron-specific enolase (NSE) and S-100 protein (S-100), in 97 patients undergoing cardiopulmonary resuscitation (CPR) after non-traumatic cardiac arrest between 1998 and 2002.

RESULTS

52.6% of the patients died, 28.8% survived with severe, moderate or without neurological disorders, and 18.6% remained in a persistent vegetative state. Unconsciousness>48 h after CPR predicted a 60.6-fold (95% CI 14.3287-257.205, p=0.001) and a Glasgow Coma Scale (GCS)<6 points after 72 h a 11.2-fold (CI 95%, 3.55-36.44, p<0.001) risk of poor neurological outcome. Serum levels>or=65 ng/ml for NSE and >or=1.5 microg/l for S-100 increased the risk of death and persistent vegetative state 16.8 (95% CI 2.146-131.520)- and 12.6 (95% CI 1.1093-99.210)-fold, respectively. By combination of the GCS with elevated serum concentrations of both neuroproteins above the cut off levels on third day after CPR a poor neurological outcome was predicted with a specificity of 100%.

CONCLUSION

The combination of GCS with the serum levels of both neuroproteins at 72 h after CPR permit a more reliable prediction of outcome in post arrest coma than the single markers alone, independent of the application of anaesthetic agents.

Neuron-specific enolase as a marker of the severity and outcome of hypoxic ischemic encephalopathy

The aim of this study was to evaluate serum concentrations of neuron-specific enolase (NSE) as a marker of the severity of hypoxic ischemic encephalopathy (HIE) and to elucidate the relation among the concentrations of NSE, grade of HIE and short-term outcome. Forty-three asphyxiated full-term newborn infants who developed symptoms and signs of HIE (Group 1) and 29 full-term newborn infants with meconium-stained amniotic fluid but with normal physical examination (Group 2) were studied with serial neurological examination, Denver developmental screening test (DDST), electroencephalogram and computerized cerebral tomography (CT) for neurological follow-up. Thirty healthy infants were selected as the control group. In the patient groups, two blood samples were taken to measure NSE levels, one between 4 and 48 h and the other 5-7 days after birth. Serum NSE levels were significantly higher in infants with HIE compared to those infants in Group 2 and control group. The mean serum concentrations of the second samples decreased in all groups studied but they were significantly higher in Group 1 compared to those in Group 2. Serum NSE concentrations of initial samples were significantly higher in patients with stage III HIE than in those with stages II and I. The sensitivity and specificity values of serum NSE as a predictor of HIE of moderate or severe degree (cut-off value 40.0 microg/l) were 79 and 70%, respectively, and as a predictor of poor outcome (cut-off value 45.4 microg/l) were calculated as 84 and 70%, respectively. The predictive capacity of serum NSE concentrations for poor outcome seems to be better than predicting HIE of moderate or severe degree. However, earlier and/or CSF samples may be required to establish serum NSE as an early marker for the application of neuroprotective strategies.

NEURON-SPECIFIC-ENOLASE IS INCREASED IN PLASMA AFTER HEMORRHAGIC SHOCK AND AFTER BILATERAL FEMUR FRACTURE WITHOUT TRAUMATIC BRAIN INJURY IN THE RAT

Neuron-specific enolase (NSE) is an acknowledged marker of traumatic brain injury. Several markers originally considered reliable in the setting of traumatic brain injury have been challenged after having been studied more extensively. The aim of our experimental study was to determine whether NSE is a reliable marker of traumatic brain injury early after trauma. Hemorrhagic shock was achieved by bleeding anesthetized rats to a mean arterial pressure (MAP) of 30-35 mmHg through a femoral catheter until incipient decompensation. MAP was maintained at 30-35 mmHg until 40% of shed blood had been administered as Ringer's solution and was then increased and maintained at 40-45 mmHg for 40 min by further administration of Ringer's solution, mimicking the phase of inadequate preclinical resuscitation. Blood samples were drawn at the end of the 40-min period of inadequate resuscitation. Femur fracture was achieved in anesthetized rats by bilateral application of forceps. Blood samples were drawn 30 and 60 min after fracture. Hemorrhagic shock caused NSE increase versus laboratory controls at the end of inadequate resuscitation (P < 0.01). Bilateral femur fracture caused NSE increase versus laboratory controls 30 min after fracture, which was significant 60 min after fracture (P < 0.01). During femur fracture, MAP remained at a level that is not associated with shock in rats. Our findings show for the first time that NSE increases after hemorrhagic shock as well as after femur fracture without hemorrhagic shock in rats. From a clinical point of view, these findings indicate that NSE cannot be considered a reliable marker of traumatic brain injury early after trauma in cases associated with hemorrhagic shock and/or femur fracture.

Evaluation of coma and brain death

Coma is a nonspecific sign of widespread central nervous system impairment resulting from various metabolic and structural etiologies. The rapid recognition of this neurologic emergency and results from the history, physical examination, and early investigative studies are key to the identification and treatment of its underlying cause. The prognosis for recovery depends greatly on the underlying etiology as well as on its optimal treatment, which seeks to preserve neurologic function and maximize the potential for recovery by reversing the primary cause of brain injury, if known, and preventing secondary brain injury from anoxia, ischemia, hypoglycemia, cerebral edema, seizures, infections, and electrolyte and temperature disturbances. Brain death must be diagnosed with similar care and precision, and families approached compassionately about the diagnosis and their decisions regarding organ donation.

Use of neuron-specific enolase for assessing the severity and outcome of neurological disorders in patients

Neuron-specific enolase (NSE) is a glycolytic enzyme present almost exclusively in neurons and neuroendocrine cells. NSE levels in cerebrospinal fluid (CSF) are assumed to be useful to estimate neuronal injury and clinical outcome of patients with serious clinical manifestations such as those observed in stroke, head injury, anoxic encephalopathy, encephalitis, brain metastasis, and status epilepticus. We compared levels of NSE in serum (sNSE) and in CSF (cNSE) among four groups: patients with meningitis (N=11), patients with encephalic injuries associated with impairment of consciousness (ENC, N=7), patients with neurocysticercosis (N=25), and normal subjects (N=8). Albumin was determined in serum and CSF samples, and the albumin quotient was used to estimate blood-brain barrier permeability. The Glasgow Coma Scale score was calculated at the time of lumbar puncture and the Glasgow Outcome Scale (GOS) score was calculated at the time of patient discharge or death. The ENC group had significantly higher cNSE (P=0.01) and albumin quotient (P=0.005), but not sNSE (P=0.14), levels than the other groups (Kruskal-Wallis test). Patients with lower GOS scores had higher cNSE levels (P=0.035) than patients with favorable outcomes. Our findings indicate that sNSE is not sensitive enough to detect neuronal damage, but cNSE seems to be reliable for assessing patients with considerable neurological insult and cases with adverse outcome. However, one should be cautious about estimating the severity of neurological status as well as outcome based exclusively on cNSE in a single patient.

Neuron-specific enolase in patients with neurocysticercosis

BACKGROUND

Neurocysticercosis (NC) is the most frequent parasitic disease of the human nervous system. Its clinical manifestations are varied and depend on the number and location of cysts, as well as the host immune response. Symptoms in NC usually occur when cysts enter into a degenerative phase associated with perilesional inflammation. We speculate that neuron-specific enolase (NSE)--a marker of neuronal injury--could be elevated in patients with degenerating cysts comparing to those with viable cysts.

METHODS

We examined serum NSE (sNSE) and cerebrospinal fluid (CSF) NSE (cNSE) levels in 25 patients with NC: 14 patients with degenerative cysts (D), 8 patients with viable cysts (V) and 3 patients with inactive cysts. Samples of eight normal controls (C) were also obtained. Determination of albumin was performed in serum and CSF samples, and the CSF/serum albumin ratio (albumin quotient, Q(alb)) was used to estimate the blood-brain barrier permeability.

RESULTS

All patients, with the exception of one case, had five or less cysts. Comparisons between V, D and C groups did not demonstrate significant differences of cNSE, Q(alb) and sNSE levels. Further, there were no significant differences of cNSE and sNSE levels between patients with or without intracranial hypertension (ICH).

CONCLUSIONS

These findings suggest that the inflammatory response associated with a relatively small number of degenerating cysts does not provoke significant neuronal damage. Further studies considering patients with a larger number of cysts will be required to assess if there is evidence of neuronal damage in such more severe cases.

Serum neuron-specific enolase and S-100B protein in cardiac arrest patients treated with hypothermia

BACKGROUND AND PURPOSE

High serum levels of neuron-specific enolase (NSE) and S-100B protein are known to be associated with ischemic brain injury and poor outcome after cardiac arrest. Therapeutic hypothermia has been shown to improve neurological outcome after cardiac arrest. The aim of this study was to evaluate the effect of therapeutic hypothermia on levels of serum NSE and S-100B protein, their time course, and their prognostic value in predicting unfavorable outcome after out-of-hospital cardiac arrest.

METHODS

Seventy patients resuscitated from ventricular fibrillation were randomly assigned to hypothermia of 33+/-1 degrees C for 24 hours or to normothermia. Serum NSE and S-100B were sampled at 24, 36, and 48 hours after cardiac arrest. Neurological outcome was dichotomized into good or poor at 6 months after cardiac arrest.

RESULTS

The levels of NSE (P=0.007 by analysis of variance for repeated measurements) but not S-100B were lower in hypothermia- than normothermia-treated patients. A decrease in NSE values between 24 and 48 hours was observed in 30 of 34 patients (88%) in the hypothermia group and in 16 of 32 patients (50%) in the normothermia group (P<0.001). The decrease in NSE values was associated with good outcome at 6 months after cardiac arrest (P=0.005), recovery of consciousness (P<0.001), and survival for at least 6 months after cardiac arrest (P=0.012).

CONCLUSIONS

Decreasing levels of serum NSE but not S-100B over time may indicate selective attenuation of delayed neuronal death by therapeutic hypothermia in victims of cardiac arrest.

Release of neuron-specific enolase and S100 after implantation of cardioverters/defibrillators

OBJECTIVE

Repeated induction of ventricular fibrillation with ensuing alterations in electroencephalogram and jugular venous oxygen saturation is common practice during insertion of transvenous implantable cardioverters/defibrillators. We investigated whether these functional changes are also associated with cerebral injury.

DESIGN

Prospective study.

SETTING

University hospital.

PATIENTS

We studied 45 patients undergoing implantable cardioverter/defibrillator insertion. Eleven patients with cardiac pacemaker implantation, which was performed in the same manner yet without the necessity to induce ventricular fibrillation, served as controls.

MEASUREMENTS AND MAIN RESULTS

Serum neuron-specific enolase and S100 were determined before, immediately postoperatively, and 2 hrs postoperatively. In a randomly composed subgroup, neuron-specific enolase was also determined 6 and 24 hrs after surgery. Implantable cardioverter/defibrillator patients only showed an increase of both markers postoperatively. Median neuron-specific enolase values climbed from a preoperative 9.9 to 12.3 and 14.4 microg/L at 2 and 24 hrs after surgery, respectively. This increase was associated with the number of shocks and the cumulative time in circulatory arrest. The highest median S100 level (0.075 microg/L) was reached 2 hrs after the procedure. Neuron-specific enolase and S100 were extremely elevated (13.7 and 0.970 microg/L, respectively) in one patient after an extended episode of ventricular fibrillation. Plasma hemoglobin levels were in the normal range in implantable cardioverter/defibrillator patients throughout the observation period.

CONCLUSIONS

Apparently, even brief successive periods of global cerebral ischemia cause neuronal damage without obvious severe neurologic deficits. However, they may be related to subtle postoperative neurologic or cognitive dysfunctions that a number of implantable cardioverter/defibrillator patients exhibit after implantation.

Early prediction of neurological outcome after cardiopulmonary resuscitation: a multimodal approach combining neurobiochemical and electrophysiological investigations may provide high prognostic certainty in patients after cardiac arrest

A reliable and reproducible method for precisely predicting the neurological outcome of patients with hypoxic-ischemic encephalopathy after cardiac arrest is urgently needed in neurological intensive care units. We prospectively investigated the predictive power of serum concentrations of neuron-specific enolase (NSE) and protein S-100B (S-100B) measured on days 1, 2, 3 and 7 as well as somatosensory-evoked potentials (SEPs) recorded within 48 h and on day 7 after cardiopulmonary resuscitation (CPR) in 27 patients (14 females, 13 males; mean age 61.3 +/- 17.3 years) with hypoxic-ischemic encephalopathy. During the first 7 days after CPR, median values of NSE and S-100B were increased in patients who remained unconscious after CPR compared to those patients who regained consciousness (significance up to < or =0.001). The best predictor of negative outcome was an NSE cutoff point > or =43 microg/l on day 2; this had a sensitivity of 90.9% and a specificity of 100%. Additional use of S-100B on day 2 did not increase sensitivity, but this could be markedly increased by combining NSE and S-100B on days 1, 3 and 7. SEPs showing bilateral loss of cortical responses identified patients who did not regain consciousness with a specificity of 100%.

Serum neuron-specific enolase predicts outcome in post-anoxic coma: a prospective cohort study

OBJECTIVE

The aim of this study was to investigate whether serial serum neuron-specific enolase (NSE) can be used to predict neurological prognosis in patients remaining comatose after cardiopulmonary resuscitation (CPR). DESIGN. Observational cohort study. Clinicians were blinded to NSE results.

SETTING

Eighteen-bed general ICU.

PATIENTS

Comatose patients admitted to the ICU after CPR.

INTERVENTIONS

Serum NSE was measured at admission and daily for 5 days.

MEASUREMENTS AND RESULTS

Patients received full intensive treatment until recovery or until absence of cortical response to somatosensory evoked potentials more than 48 h after CPR proved irreversible coma. Of the 110 patients included (mean GCS at ICU admission 3, range 3--9), 34 regained consciousness, five of whom died in hospital. Seventy-six patients did not regain consciousness, 72 of whom died in hospital. Serum NSE at 24 h and at 48 h after CPR was significantly higher in patients who did not regain consciousness than in patients who regained consciousness (at 24 h: median NSE 29.9 microg/l, range 1.8-250 vs 9.9 microg/l, range 4.5-21.5, P<0.001; at 48 h: median 37.8 microg/l, range 4.4-411 vs 9.5 microg/l, range 6.2-22.4, P= 0.001). No patient with a serum NSE level >25.0 microg/l at any time regained consciousness. Addition of NSE to GCS and somatosensory evoked potentials increased predictability of poor neurological outcome from 64% to 76%.

CONCLUSIONS

High serum NSE levels in comatose patients at 24 h and 48 h after CPR predict a poor neurological outcome. Addition of NSE to GCS and somatosensory evoked potentials increases predictability of neurological outcome.

The potential value of the protein S-100B level as a criterion for hyperbaric oxygen treatment and prognostic marker in carbon monoxide poisoned patients

Carbon monoxide (CO) poisoning resulting in diffuse tissue hypoxia. Cerebral hypoxia is a major cause of morbidity and mortality after CO poisoning. There are some clinical criteria that could help a physician to make a decision concerning the application of hyperbaric oxygenation therapy. However, it would be convenient to discover an objective biochemical serum marker that could help in the grade evaluation of CO poisoning and indication of therapy in CO-poisoned patients. We present two case reports where the established criteria for the CO poisoning were not optimum for the decision regarding therapy. It seems that the S-100B protein could be used as a biochemical marker of CO induced brain injury. S-100B values could perhaps help us to select patients for hyperbaric oxygen therapy and to predict the short and long term outcome.

Immediate S-100B and neuron-specific enolase plasma measurements for rapid evaluation of primary brain damage in alcohol-intoxicated, minor head-injured patients

The neuroproteins S-100B and neuron-specific enolase (NSE) released into the circulation are suggested to be reliable markers for primary brain damage. However, safe identification of relevant post-traumatic complications after minor head injury (MHI) is often hampered by acute intoxication of the patients. The objective of this study was to determine the diagnostic validity of immediate plasma measurements of S-100B and NSE in comparison with neurological examinations and cerebral computed tomography (CCT) findings in alcohol-intoxicated MHI patients. One hundered thrity-nine MHI individuals were enrolled in this prospective study during Munich's Oktoberfest 2000. Plasma levels of S-100B and NSE as well as serum alcohol and glucose values were determined by fully automated assays immediately after admission. The results were compared with Glasgow Coma Scale score, a brief neurological examination, and the CCT findings. Without being influenced by alcohol, median S-100B levels of the CCT+ group were significantly increased compared with those of the CCT- group (P < 0.001). NSE, alcohol, and glucose levels showed no significant group differences. As calculated by the ROC analysis, a cutoff value of 0.21 ng/mL with an area under the curve of 0.864 clearly differentiates between CCT+ and CCT- patients at a sensitivity of 100%, a specificity of 50.0%, and a positive likelihood ratio of 2.0. Although acute alcohol intoxication did not confound plasma measurements of S-100B and NSE, only S-100B levels below the cutoff level of 0.21 ng/mL seem to indicate absence of primary brain damage. Thus, in addition to routine neurological examinations, S-100B measurements immediately after admission might help to reduce CCT scans in alcohol-intoxicated patients early after MHI.

S-100 protein as early predictor of regaining consciousness after out of hospital cardiac arrest

BACKGROUND AND PURPOSE

Patients resuscitated from cardiac arrest (CA) have a high mortality rate. Prognostic evaluation based on clinical observations is uncertain and would benefit from the use of biochemical markers of hypoxic brain damage. The purpose of the study was to validate the use of the serum astroglial protein S-100 levels at admission with regard to regaining consciousness after out of hospital CA.

METHODS

Fifty-eight patients resuscitated from out-of-hospital CA were followed up until they regained consciousness or until their death or permanent vegetative state occurred. Serum samples for measurement of S-100, using an immunoradiometric assay, were obtained at admission.

RESULTS

At admission, the mean value+/-standard error of the mean of serum S-100 protein was significantly higher in patients who did not regain consciousness compared with patients who regained consciousness, respectively 4.66+/-0.61 microg/l and 0.84+/-0.21 microg/l. A serum S-100 value of >0.7 microg/l at admission was found to be a predictor that consciousness would not be regained, with a specificity of 85%, a sensitivity of 66.6%, a positive predictive value of 84%, a negative predictive value of 78% and an accuracy of 77.6%.

CONCLUSIONS

Serum S-100 protein at admission gives reliable and independent information concerning the short term neurological outcome after resuscitation; and could be a good marker of brain cell damage.

Hypothermia after cardiac arrest: feasibility and safety of an external cooling protocol

BACKGROUND

No proven neuroprotective treatment exists for ischemic brain injury after cardiac arrest. Mild-to-moderate induced hypothermia (MIH) is effective in animal models.

METHODS AND RESULTS

A safety and feasibility trial was designed to evaluate mild-to-moderate induced hypothermia by use of external cooling blankets after cardiac arrest. Inclusion criteria were return of spontaneous circulation within 60 minutes of advanced cardiac life support, hypothermia initiated within 90 minutes, persistent coma, and lack of acute myocardial infarction or unstable dysrhythmia. Hypothermia to 33 degrees C was maintained for 24 hours followed by passive rewarming. Nine patients were prospectively enrolled. Mean time from advanced cardiac life support to return of spontaneous circulation was 11 minutes (range 3 to 30); advanced cardiac life support to initiation of hypothermia was 78 minutes (range 40 to 109); achieving 33 degrees C took 301 minutes (range 90 to 690). Three patients completely recovered, and 1 had partial neurological recovery. One patient developed unstable cardiac dysrhythmia. No other unexpected complications occurred.

CONCLUSIONS

Mild-to-moderate induced hypothermia after cardiac arrest is feasible and safe. However, external cooling is slow and imprecise. Efforts to speed the start of cooling and to improve the cooling process are needed.

Neurologic complications in intensive care

Neurologic complications in intensive care occur as the result of critical illness, intensive care therapies and procedures, or medical or surgical conditions; perioperatively; or because of underlying primary neurologic disease. These complications occur at greater frequency and are often unrecognized because critically ill patients are often intubated, sedated, and/or receiving neuromuscular blocking agents. Encephalopathy is the most common neurologic complication in the ICU and is usually multifactorial in origin. Sepsis is associated with the highest incidence of neurologic complications. Neurologic complications are associated with increased disability, longer hospital stay, and increased mortality. This review focuses on neurologic complications that are the result of critical illnesses and intensive care management.