Neuron-specific enolase and S-100b in prolonged targeted temperature management after cardiac arrest: A randomised study

Managing hemolysis in serum neuron-specific enolase measurements - an automated algorithm for routine practice

Neuron-specific enolase (NSE) derived from neurons and peripheral neuroendocrine cells is a biomarker for neuroendocrine tumors and for prognostication in comatose cardiac arrest survivors. However, as platelets and erythrocytes contain NSE, hemolysis causes falsely elevated NSE. We used native serum and hemolysate derived from the same patients to make serial dilutions, and subsequently measured NSE (mNSE) and hemolytic index (HI) in each dilution. An algorithm suitable for the laboratory information system was developed based on the mNSE, HI and the estimated gradient of hemolytic interference from 30 patients. We estimated the associated uncertainty of the corrected NSE (cNSE) results based on the observed range of the gradient and derived an equation for cNSE for samples with limited hemolysis (i.e. 5 < HI ≤ 30): cNSE = mNSE - HI × (0.34 ± 0.23) µg/L. By semi-quantitatively grading the contribution from limited hemolysis, a texted result noting the hemolysis-associated degree of uncertainty can accompany the cNSE result. The major challenge of hemolysis when using serum NSE as a biomarker can be managed using an automated algorithm for correction of NSE results based on degree of hemolysis. However, laboratorians and clinicians should be aware of the limitations associated with in vivo hemolysis.

Neurofilament Light Chain and Glial Fibrillary Acidic Protein as early prognostic biomarkers after out-of-hospital cardiac arrest

AIMS

Neurofilament Light Chain (NfL) and Glial Fibrillary Acidic Protein (GFAP) are proteins released into the bloodstream upon hypoxic brain injury. We evaluated the biokinetics and examined the prognostic performance of serum NfL and GFAP in comatose out-of-hospital cardiac arrest (OHCA) patients. Furthermore, we compared the prognostic performance to that of serum Neuron Specific Enolase (NSE).

METHODS

This is a sub-study of the "Targeted temperature management for 48 vs 24 hours" (NCT01689077) trial. NfL and GFAP serum values from 82 patients were examined in blood samples collected at 24, 48 and 72 hours (h) after reaching target temperature of 33 ± 1 °C. This temperature was reached within a median of 281-320 minutes after intensive care unit admission. GFAP was analysed at 48 and 72 h. The neuroprognostic performance of NfL and GFAP was evaluated after 6 months follow-up.

RESULTS

NfL and GFAP values were significantly higher in patients with a poor outcome (Cerebral Performance Category (CPC) score 3-5) vs. good outcome (CPC 1-2). NfL 24 h: 1371.5 (462.0; 2125.1) vs. 24.8 (14.0; 61.6). GFAP 48 h: 1285.3 (843.9; 2236.7) vs. 361.2 (200.4; 665.6) (both p < 0.001). Both biomarkers were promising markers of poor functional outcome at 24 and 48 h respectively: NfL 24 h: AUROC 0.95 (95% CI: 0.91-1.00). GFAP 48 h: AUROC 0.88 (95% CI: 0.81-0.96). NfL and GFAP both predicted outcome better than NSE at 48 h (both p < 0.01). At 72 h NfL but not GFAP outperformed NSE (p = 0.01).

CONCLUSION

Serum NfL and GFAP may be strong biomarkers of poor functional outcome after OHCA from an early timepoint.

Are serial neuron-specific enolase levels associated with neurologic outcome of ECPR patients: A retrospective multicenter observational study

AIM OF THE STUDY

This study aims to evaluate whether neuron-specific enolase (NSE) level at 48 h after extracorporeal cardiopulmonary resuscitation (ECPR) is associated with neurologic outcomes at 6 months after hospital discharge.

METHODS

This was a retrospective, multicenter, observational study of adult patients who received ECPR between May 2010 and December 2016. In the two hospitals involved in this study, NSE measurements were a routine part of the protocol for patients who received ECPR. Serial NSE levels were measured in all patients with ECPR. NSE levels were measured 24, 48, and 72 h after ECPR. The primary outcome was Cerebral Performance Categories (CPC) scale at 6 months after hospital discharge according to NSE levels at 48 h after ECPR.

RESULTS

At follow-up 6 months after hospital discharge, favorable neurologic outcomes of CPC 1 or 2 were observed in 9 (36.0%) of the 25 patients, and poor neurologic outcomes of CPC 3, 4, or 5 were observed in 16 (64%) patients. NSE levels at 24 h in the favorable and poor neurologic outcome groups were 58.3 (52.5-73.2) μg/L and 64.2 (37.9-89.8) μg/L, respectively (p = 0.95). NSE levels at 48 h in the favorable and poor neurologic outcome groups were 52.1 (22.3-64.9) μg/L and 302.0 (62.8-360.2) μg/L, respectively (p = 0.01). NSE levels at 72 h were 37.2 (12.5-53.2) μg/L and 240.9 (75.3-370.0) μg/L, respectively (p < 0.01). In receiver operating characteristic (ROC) curve analysis, as the predictor of poor outcome, the optimal cut-off value for NSE level at 48 h was 140.5 μg/L, and the area under the curve (AUC) was 0.844 (p < 0.01). The optimal cut-off NSE level at 72 h was 53.2 μg/L, and the AUC was 0.897 (p < 0.01).

CONCLUSIONS

NSE level at 72 h displayed the highest association with neurologic outcome after ECPR, and NSE level at 48 h was also associated with neurologic outcome after ECPR.

Brain Injury Biomarkers for Predicting Outcome After Cardiac Arrest

This article is one of ten reviews selected from the Annual Update in Intensive Care and Emergency Medicine 2022. Other selected articles can be found online at https://www.biomedcentral.com/collections/annualupdate2022 . Further information about the Annual Update in Intensive Care and Emergency Medicine is available from https://link.springer.com/bookseries/8901 .

S100B as a biomarker of blood-brain barrier disruption after thoracoabdominal aortic aneurysm repair: a secondary analysis from a prospective cohort study

PURPOSE

The objective of this study was to determine whether the magnitude of the peripheral inflammatory response to cardiovascular surgery is associated with increases in blood-brain barrier (BBB) permeability as reflected by changes in cerebrospinal fluid (CSF)/plasma S100B concentrations.

METHODS

We conducted a secondary analysis from a prospective cohort study of 35 patients undergoing elective thoracoabdominal aortic aneurysm repair with (n = 17) or without (n = 18) cardiopulmonary bypass (CPB). Plasma and CSF S100B, interleukin-6 (IL-6), and albumin concentrations were measured at baseline (C₀) and serially for up to five days.

RESULTS

Following CPB, the median [interquartile range] plasma S100B concentration increased from 58 [32-88] pg·mL^-1 at C₀ to a maximum concentration (C_max) of 1,131 [655-1,875] pg·mL^-1 over a median time (t_max) of 6.3 [5.9-7.0] hr. In the non-CPB group, the median plasma S100B increased to a lesser extent. There was a delayed increase in CSF S100B to a median C_max of 436 [406-922] pg·mL^-1 in the CPB group at a t_max of 23.7 [18.5-40.2] hr. In the non-CPB group, the CSF concentrations were similar at all time points. In the CPB group, we did not detect significant correlations between plasma and CSF S100B with plasma IL-6 [r = 0.52 (95% confidence interval [CI], -0.061 to 0.84)] and CSF IL-6 [r = 0.53 (95% CI, -0.073 to 0.85)] concentrations, respectively. Correlations of plasma or CSF S100B levels with BBB permeability were not significant.

CONCLUSION

The lack of parallel increases in plasma and CSF S100B following CPB indicates that S100B may not be a reliable biomarker for BBB disruption after thoracoabdominal aortic aneurysm repair employing CPB.

TRIAL REGISTRATION

www.clinicaltrials.gov (NCT00878371); registered 7 April 2009.

Neuron-specific enolase and long-term neurological outcome after OHCA - A validation study

AIMS

To investigate what NSE levels predict long-term neurological prognosis at 24, 48 and 72 hours after ROSC in a cohort of out-of-hospital cardiac arrest and to validate previously suggested NSE cut-offs, including the latest ERC guidelines (2021).

METHODS

Patients admitted to intensive care units in four hospitals in Southern Sweden between 2014-2018 were included. Blood samples were handled by a single local laboratory. The primary outcome was neurological outcome according to the Cerebral Performance Category (CPC) scale at 2-6 months after cardiac arrest.

RESULTS

368 patients were included for analysis. A ≤2% false positive rate for the prediction of poor neurological outcome was achieved with an NSE cut-off value of >101 μg/L at 48 hours and >80 μg/L at 72 hours. The cut-off suggested by the recent ERC guidelines of >60 μg/L at 48 and/or 72 hours generated a false positive rate of 4.3% (95 %CI 0.9-7.4%).

CONCLUSION

A local validation study of the ability of serum levels of neuron-specific enolase to predict long-term poor neurological outcome after out-of-hospital cardiac arrest generated higher cut-offs than suggested by previous publications.

Comparison of Prognostic Performance between Neuron-Specific Enolase and S100 Calcium-Binding Protein B Obtained from the Cerebrospinal Fluid of Out-of-Hospital Cardiac Arrest Survivors Who Underwent Targeted Temperature Management

We compared the prognostic performances of serum neuron-specific enolase (sNSE), cerebrospinal fluid (CSF) NSE (cNSE), and CSF S100 calcium-binding protein B (cS100B) in out-of-hospital cardiac arrest (OHCA) survivors. This prospective observational study enrolled 45 patients. All samples were obtained immediately and at 24 h intervals until 72 h after the return of spontaneous circulation. The inter- and intragroup differences in biomarker levels, categorized by 3 month neurological outcome, were analyzed. The prognostic performances were evaluated with receiver operating characteristic curves. Twenty-two patients (48.9%) showed poor outcome. At all-time points, sNSE, cNSE, and cS100B were significantly higher in the poor outcome group than in the good outcome group. cNSE and cS100B significantly increased over time (baseline vs. 24, 48, and 72 h) in the poor outcome group than in the good outcome group. sNSE at 24, 48, and 72 h showed significantly lower sensitivity than cNSE or cS100B. The sensitivities associated with 0 false-positive rate (FPR) for cNSE and cS100B were 66.6% vs. 45.5% at baseline, 80.0% vs. 80.0% at 24 h, 84.2% vs. 94.7% at 48 h, and 88.2% (FPR, 5.0%) vs. 94.1% at 72 h. High cNSE and cS100B are strong predictors of poor neurological outcome in OHCA survivors. Multicenter prospective studies may determine the generalizability of these results.

The first national survey on practices of neurological prognostication after cardiac arrest in China, still a lot to do

AIMS

To investigate current awareness and practices of neurological prognostication in comatose cardiac arrest (CA) patients.

METHODS

An anonymous questionnaire was distributed to 1600 emergency physicians in 75 hospitals which were selected randomly from China between January and July 2018.

RESULTS

92.1% respondents fulfilled the survey. The predictive value of brain stem reflex, motor response and myoclonus was confirmed by 63.5%, 44.6% and 31.7% respondents, respectively. Only 30.7% knew that GWR value < 1.1 indicated poor prognosis and only 8.1% know the most commonly used SSEP N20. Status epilepticus, burst suppression and suppression were considered to predict poor outcome by only 35.0%, 27.4% and 20.9% respondents, respectively. Only 46.7% knew NSE and only 24.7% knew S-100. Only a few respondents knew that neurological prognostication should be performed later than 72 hours from CA either in TTM or non-TTM patients. In practice, the most commonly used method was clinical examination (85.4%). Only 67.9% had used brain CT for prognosis and 18.4% for MRI. NSE (39.6%) was a little more widely used than S-100β (18.0%). However, SSEP (4.4%) and EEG (11.4%) were occasionally performed.

CONCLUSIONS

Neurological prognostication in CA survivors had not been well understood and performed by emergency physicians in China. They were more likely to use clinical examination rather than objective tools, especially SSEP and EEG, which also illustrated that multimodal approach was not well performed in practice.

European Resuscitation Council and European Society of Intensive Care Medicine guidelines 2021: post-resuscitation care

The European Resuscitation Council (ERC) and the European Society of Intensive Care Medicine (ESICM) have collaborated to produce these post-resuscitation care guidelines for adults, which are based on the 2020 International Consensus on Cardiopulmonary Resuscitation Science with Treatment Recommendations. The topics covered include the post-cardiac arrest syndrome, diagnosis of cause of cardiac arrest, control of oxygenation and ventilation, coronary reperfusion, haemodynamic monitoring and management, control of seizures, temperature control, general intensive care management, prognostication, long-term outcome, rehabilitation and organ donation.

European Resuscitation Council and European Society of Intensive Care Medicine Guidelines 2021: Post-resuscitation care

The European Resuscitation Council (ERC) and the European Society of Intensive Care Medicine (ESICM) have collaborated to produce these post-resuscitation care guidelines for adults, which are based on the 2020 International Consensus on Cardiopulmonary Resuscitation Science with Treatment Recommendations. The topics covered include the post-cardiac arrest syndrome, diagnosis of cause of cardiac arrest, control of oxygenation and ventilation, coronary reperfusion, haemodynamic monitoring and management, control of seizures, temperature control, general intensive care management, prognostication, long-term outcome, rehabilitation, and organ donation.

Biomarker prognostication of cognitive impairment may be feasible even in out-of hospital cardical arrest survivors with good neurological outcome

BACKGROUND

Patients surviving out-of hospital cardicac arrest, with good neurological outcome according to Cerebral Performance Category, frequently have neuropsychological impairment. We studied whether biomarker data (S-100b and neuron-specific enolase) obtained during the ICU stay predicted cognitive impairment 6 months after resuscitation.

METHODS

Patients (N = 79) with a CPC-score ≤2 were recruited from two trial sites taking part in the TTH48 trial comparing targeted temperature management (TTM) for 48 h vs. 24 h at 33 ± 1 °C. We assessed patients 6 months after the OHCA. We measured biomarkers S-100b and NSE at arrival and at 24, 48 and 72 h after reaching the target temperature of 33 ± 1 °C. Four cognitive domain z-scores were calculated, and global cognitive impairment was defined as z < -1.67 on at least 3 out of 13 cognitive tests. Non-parametric correlations were used to assess the relationship between cognitive domain and biomarkers. ROC curves were used to assess prediction of cognitive impairment from the biomarkers. Logistic regression was used to investigate whether TTM duration moderated biomarker prediction of cognitive impairment.

RESULTS

Cognitive impairment was present in 22% of the patients with memory impairment being the most common. The biomarkers correlated significantly with several cognitive domain scores and NSE at 48 h predicted cognitive impairment with 100% sensitivity and 56% specificity. The predictive properties of NSE at 48 h was unaffected by duration of TTM.

CONCLUSIONS

Early biomarker prognostication of cognitive impairment is feasible even in OHCA survivors with good neurological outcome as defined by CPC. NSE at 48 h predicted cognitive impairment.

Serum S100 Protein Is a Reliable Predictor of Brain Injury After Out-of-Hospital Cardiac Arrest: A Cohort Study

Purpose: To evaluate serum S100 protein at hospital admission and after 48 h in early neuroprognostication of comatose survivors of out-of-hospital cardiac arrest (OHCA). Methods: The study included 48 consecutive patients after OHCA, who survived for at least 72 h after the event. The patients were divided based on their best cerebral performance category (CPC) achieved over a 30 day follow-up period: favorable neurological outcome (CPC 1-2) vs. unfavorable neurological outcome (CPC 3-4). Predictors of an unfavorable neurological outcome were identified by multivariable regression analysis. Analysis of the receiver operating characteristic curve (ROC) was used to determine the cut-off value for S100, having a 0% false-positive prediction rate. Results: Of the 48 patients, 30 (63%) had a favorable and 18 (38%) had an unfavorable neurological outcome. Eleven patients (23%) died over the 30 day follow-up. Increased S100 levels at 48 h after OHCA, but not the baseline S100 levels, were independently associated with unfavorable neurological outcome, with an area under the ROC curve of 0.85 (confidence interval 0.74-0.96). A 48 h S100 value ≥0.37 μg/L had a specificity of 100% and sensitivity of 39% in predicting an unfavorable 30 day neurological outcome. Conclusion: This study showed that S100 values assessed 48 h after an OHCA could independently predict an unfavorable neurological outcome at 30 days.

Single tests of implantable cardioverter defibrillators can be performed in selected patients at a low risk of neuronal damage

BACKGROUND

Defibrillator testing (DFT) is still used in selected patients to ensure adequate therapy. To do so, ventricular fibrillation is induced and terminated by the implanted cardioverter defibrillator (ICD). Studies have shown increases in neuronal damage markers without a measurable clinical effect in patients after defibrillator threshold testing with multiple shocks.

OBJECTIVE

The aim of this study was to measure clinical outcomes, neuronal damage parameters (NSE and S100), and intraoperative cerebral perfusion (Doppler, near infra-red spectroscopy [NIRS]) in patients undergoing single DFT after transvenous ICD implantation and comparing them to untested patients.

METHOD

We included 23 patients. Nine underwent surgery with a single DFT, 14 were not tested. Cognitive impairment was tested using the Mini-Mental-Status Test (MMST) and the DEMTECt 24 h prior and postsurgery. We also measured S100 and Neuron-Specific Enolase (NSE) at these timepoints. During surgery we measured medial cerebral artery velocity and cerebral tissue oxygen saturation (rSO₂ ).

RESULTS

We found no significant differences between the patient groups except for a significant increase in mean arterial blood pressure and an increase in rSO₂ after testing. One patient with cerebral vasculopathy had a significant increase in his NSE values without showing clinical symptoms. This patient also had low rSO₂ measurements and a decrease in medial cerebral artery velocity after DFT, other than the other patients.

CONCLUSION

Single DFT did not lead to signs of neuronal damage or cognitive impairment except in one case with pre-existing cerebral vasculopathy. Therefore, our results support the use of DFT in carefully selected patients.

Neuromarkers and neurological outcome in out-of-hospital cardiac arrest patients treated with therapeutic hypothermia-experience from the HAnnover COoling REgistry (HACORE)

Background

Neuron-specific enolase (NSE) and S-100b have been used to assess neurological damage following out-of-hospital cardiac arrest (OHCA). Cut-offs were derived from small normothermic cohorts. Whether similar cut-offs apply to patients treated with hypothermia remained undetermined.

Methods

We investigated 251 patients with OHCA treated with hypothermia but without routine prognostication. Neuromarkers were determined at day 3, neurological outcome was assessed after hospital discharge by cerebral performance category (CPC).

Results

Good neurological outcome (CPC≤2) was achieved in 41%. Elevated neuromarkers, older age and absence of ST-segment elevation after ROSC were associated with increased mortality. Poor neurological outcome in survivors was additionally associated with history of cerebrovascular events, sepsis and higher admission lactate. Mean NSE was 33μg/l [16–94] vs. 119μg/l [25–406]; p<0.001, for survivors vs. non-survivors, and 21μg/l [16–29] vs. 40μg/l [23–98], p<0.001 for good vs. poor neurological outcome. S-100b was 0.127μg/l [0.063–0.360] vs. 0.772μg/l [0.121–2.710], p<0.001 and 0.086μg/l [0.061–0.122] vs. 0.138μg/l [0.090–0.271], p = 0.009, respectively. For mortality, thresholds of 36μg/l for NSE and 0.128μg/l for S-100b could be determined; for poor neurological outcome 33μg/l (NSE) and 0.123μg/l (S-100b), respectively. Positive predictive value for NSE was 81% (74–88) and 79% (71–85) for S-100b.

Conclusions

Thresholds for NSE and S-100b predicting mortality and poor neurological outcome are similar in OHCA patients receiving therapeutic hypothermia as in those reported before the era of hypothermia. However, both biomarkers do not have enough specificity to predict mortality or poor neurological outcome on their own and should only be additively used in clinical decision making.

Adult Advanced Life Support: 2020 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science with Treatment Recommendations

This 2020 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations for advanced life support includes updates on multiple advanced life support topics addressed with 3 different types of reviews. Topics were prioritized on the basis of both recent interest within the resuscitation community and the amount of new evidence available since any previous review. Systematic reviews addressed higher-priority topics, and included double-sequential defibrillation, intravenous versus intraosseous route for drug administration during cardiac arrest, point-of-care echocardiography for intra-arrest prognostication, cardiac arrest caused by pulmonary embolism, postresuscitation oxygenation and ventilation, prophylactic antibiotics after resuscitation, postresuscitation seizure prophylaxis and treatment, and neuroprognostication. New or updated treatment recommendations on these topics are presented. Scoping reviews were conducted for anticipatory charging and monitoring of physiological parameters during cardiopulmonary resuscitation. Topics for which systematic reviews and new Consensuses on Science With Treatment Recommendations were completed since 2015 are also summarized here. All remaining topics reviewed were addressed with evidence updates to identify any new evidence and to help determine which topics should be the highest priority for systematic reviews in the next 1 to 2 years.

Adult Advanced Life Support: 2020 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations

This 2020 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations for advanced life support includes updates on multiple advanced life support topics addressed with 3 different types of reviews. Topics were prioritized on the basis of both recent interest within the resuscitation community and the amount of new evidence available since any previous review. Systematic reviews addressed higher-priority topics, and included double-sequential defibrillation, intravenous versus intraosseous route for drug administration during cardiac arrest, point-of-care echocardiography for intra-arrest prognostication, cardiac arrest caused by pulmonary embolism, postresuscitation oxygenation and ventilation, prophylactic antibiotics after resuscitation, postresuscitation seizure prophylaxis and treatment, and neuroprognostication. New or updated treatment recommendations on these topics are presented. Scoping reviews were conducted for anticipatory charging and monitoring of physiological parameters during cardiopulmonary resuscitation. Topics for which systematic reviews and new Consensuses on Science With Treatment Recommendations were completed since 2015 are also summarized here. All remaining topics reviewed were addressed with evidence updates to identify any new evidence and to help determine which topics should be the highest priority for systematic reviews in the next 1 to 2 years.

Copeptin as a Prognostic Marker in Prolonged Targeted Temperature Management After Out-of-Hospital Cardiac Arrest

The aim was to investigate blood concentrations of copeptin and the prognostication in 24 versus 48 hours of targeted temperature management (TTM) in patients resuscitated after out-of-hospital cardiac arrest. This is an exploratory biomarker substudy of the trial entitled; "Targeted temperature management for 48 vs 24 hours and neurologic outcome after out-of-hospital-cardiac-arrest: A randomized clinical trial." Patients were randomized to target temperature of 33°C ± 1°C for 24 (TTM24) or 48 (TTM48) hours. The primary outcome was copeptin concentrations compared with TTM at admission, 24, 48, and 72 hours (t24, t48, and t72) after reaching target temperature. Secondary outcomes were the association between copeptin and cerebral performance category (CPC) score after 6 months, and copeptin level between cerebral or noncerebral causes of death. Blood samples from 117 patients were analyzed from two Scandinavian sites. No significant differences in copeptin concentrations were found between TTM24 versus TTM48 at admission 211.3 μg/L (148-276.6) versus 179.8 μg/L (127-232.6) (p = 0.45), t24: 23.3 μg/L (16.5-30.2) versus 18.6 μg/L (13.3-23.9) (p = 0.25), t48: 28.8 μg/L (20.6-36.9) versus 19.7 μg/L (14.3-25.1) (p = 0.06), and t72: 23.3 μg/L (13.8-26.8) versus 31.6 μg/L (22-41.2) (p = 0.05). Copeptin concentrations were significantly higher in poor neurological outcome group at t24, t48, and t72 (p < 0.01), but not at admission (p = 0.19). The prognostic ability of copeptin (area under the receiver operating characteristic curve) was at admission: 0.59 (95% confidence intervals: 0.46-0.72), t24: 0.74 (0.63-0.86), t48: 0.8 (0.7-0.9), and t72: 0.76 (0.65-0.87). Copeptin levels were not significantly different in noncerebral compared with cerebral causes at admission: p = 0.41, t24: p = 0.52, t48: p = 0.15, and t72: p = 0.38. There were no differences in the level of copeptin in TTM24 versus TTM48. Blood concentrations of copeptin were associated with CPC at 6 months, and no association between levels of copeptin and cerebral versus noncerebral causes of death was observed.

Prediction of poor neurological outcome in comatose survivors of cardiac arrest: a systematic review

Purpose

To assess the ability of clinical examination, blood biomarkers, electrophysiology, or neuroimaging assessed within 7 days from return of spontaneous circulation (ROSC) to predict poor neurological outcome, defined as death, vegetative state, or severe disability (CPC 3–5) at hospital discharge/1 month or later, in comatose adult survivors from cardiac arrest (CA).

Methods

PubMed, EMBASE, Web of Science, and the Cochrane Database of Systematic Reviews (January 2013–April 2020) were searched. Sensitivity and false-positive rate (FPR) for each predictor were calculated. Due to heterogeneities in recording times, predictor thresholds, and definition of some predictors, meta-analysis was not performed.

Results

Ninety-four studies (30,200 patients) were included. Bilaterally absent pupillary or corneal reflexes after day 4 from ROSC, high blood values of neuron-specific enolase from 24 h after ROSC, absent N20 waves of short-latency somatosensory-evoked potentials (SSEPs) or unequivocal seizures on electroencephalogram (EEG) from the day of ROSC, EEG background suppression or burst-suppression from 24 h after ROSC, diffuse cerebral oedema on brain CT from 2 h after ROSC, or reduced diffusion on brain MRI at 2–5 days after ROSC had 0% FPR for poor outcome in most studies. Risk of bias assessed using the QUIPS tool was high for all predictors.

Conclusion

In comatose resuscitated patients, clinical, biochemical, neurophysiological, and radiological tests have a potential to predict poor neurological outcome with no false-positive predictions within the first week after CA. Guidelines should consider the methodological concerns and limited sensitivity for individual modalities. (PROSPERO CRD42019141169)

Electronic supplementary material

The online version of this article (10.1007/s00134-020-06198-w) contains supplementary material, which is available to authorized users.

Resuscitating the Globally Ischemic Brain: TTM and Beyond

Cardiac arrest (CA) afflicts ~ 550,000 people each year in the USA. A small fraction of CA sufferers survive with a majority of these survivors emerging in a comatose state. Many CA survivors suffer devastating global brain injury with some remaining indefinitely in a comatose state. The pathogenesis of global brain injury secondary to CA is complex. Mechanisms of CA-induced brain injury include ischemia, hypoxia, cytotoxicity, inflammation, and ultimately, irreversible neuronal damage. Due to this complexity, it is critical for clinicians to have access as early as possible to quantitative metrics for diagnosing injury severity, accurately predicting outcome, and informing patient care. Current recommendations involve using multiple modalities including clinical exam, electrophysiology, brain imaging, and molecular biomarkers. This multi-faceted approach is designed to improve prognostication to avoid "self-fulfilling" prophecy and early withdrawal of life-sustaining treatments. Incorporation of emerging dynamic monitoring tools such as diffuse optical technologies may provide improved diagnosis and early prognostication to better inform treatment. Currently, targeted temperature management (TTM) is the leading treatment, with the number of patients needed to treat being ~ 6 in order to improve outcome for one patient. Future avenues of treatment, which may potentially be combined with TTM, include pharmacotherapy, perfusion/oxygenation targets, and pre/postconditioning. In this review, we provide a bench to bedside approach to delineate the pathophysiology, prognostication methods, current targeted therapies, and future directions of research surrounding hypoxic-ischemic brain injury (HIBI) secondary to CA.

Effects of therapeutic hypothermia on cerebral tissue oxygen saturation in a swine model of post-cardiac arrest

Since the introduction of therapeutic hypothermia (TH), trends have changed in the monitoring indicators used during and after cardiac arrest. During hypothermia, the cerebral metabolic rate of oxygen is reduced, which leads to uncertainty in regional cerebral tissue oxygen saturation (S_ctO₂). The aim of the present study was to evaluate the effect of TH on changes in S_ctO₂ using near-infrared spectroscopy. A total of 23 male domestic pigs were randomized into three groups: TH (n=9), normothermia (NT; n=9) and control (n=5). Animals in the control group underwent surgical preparation only. The animal models were established using 8 min of ventricular fibrillation and 5 min of cardiopulmonary resuscitation. In the TH group, at 5 min after resuscitation, the animals were cooled with a cooling blanket and ice packs for 24 h. S_ctO₂ was recorded throughout the experiment. In all groups, The mean arterial pressure, arterial carbon dioxide partial pressure, arterial oxygen partial pressure, lactate, neuron-specific enolase (NSE) and S100B were measured at baseline and at 1, 3, 6, 12, 24 and 30 h after resuscitation. S_ctO₂ significantly decreased after ventricular fibrillation, compared with the baseline. Following resuscitation, the S_ctO₂ values gradually increased to 55.6±3.8% of baseline in the TH group and 51.2±3.5% in the NT group (P=0.039). Significant differences between the two groups were observed, starting at 6 h after cardiac arrest. Throughout the hypothermic period, NSE and S100B showed an increasing trend, then decreased during rewarming in the TH and NT groups. NSE and S100B showed greater improvement in the TH group compared with the NT group at 6 and 24 h after resuscitation. Following cardiac arrest, therapeutic hypothermia could increase S_ctO₂ after resuscitation and could improve neurological outcome. In conclusion, S_ctO₂ may be a feasible marker for use in the early assessment of brain damage during and after cardiac arrest.

Cardiac arrest: An interdisciplinary review of the literature from 2018

OBJECTIVES

The Interdisciplinary Cardiac Arrest Research Review (ICARE) group was formed in 2018 to conduct a systematic annual search of peer-reviewed literature relevant to cardiac arrest (CA). The goals of the review are to illustrate best practices and help reduce knowledge silos by disseminating clinically relevant advances in the field of CA across disciplines.

METHODS

An electronic search of PubMed using keywords related to CA was conducted. Title and abstracts retrieved by these searches were screened for relevancy, separated by article type (original research or review), and sorted into 7 categories. Screened manuscripts underwent standardized scoring of overall methodological quality and importance. Articles scoring higher than 99 percentiles by category-type were selected for full critique. Systematic differences between editors and reviewer scores were assessed using Wilcoxon signed-rank test.

RESULTS

A total of 9119 articles were identified on initial search; of these, 1214 were scored after screening for relevance and deduplication, and 80 underwent full critique. Prognostication & Outcomes category comprised 25% and Epidemiology & Public Health 17.5% of fully reviewed articles. There were no differences between editor and reviewer scoring.

CONCLUSIONS

The total number of articles demonstrates the need for an accessible source summarizing high-quality research findings to serve as a high-yield reference for clinicians and scientists seeking to absorb the ever-growing body of CA-related literature. This may promote further development of the unique and interdisciplinary field of CA medicine.

The Influence of Therapeutics on Prognostication After Cardiac Arrest

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

Neuron-specific enolase kinetics: an additional tool for neurological prognostication after cardiac arrest

INTRODUCTION AND OBJECTIVES

To analyze neuron-specific enolase (NSE) kinetics as a prognostic biomarker of neurological outcome in cardiac arrest survivors treated with targeted temperature management.

METHODS

We performed a retrospective analysis of patients resuscitated from in- or out-of-hospital cardiac arrest admitted from September 2006 to May 2018 in a single tertiary care center and cooled to 32°C to 34°C for 24 hours. Blood samples for measurement of NSE values were drawn at hospital admission and at 24, 48, and 72hours after return of spontaneous circulation (ROSC). Neurological outcome was evaluated by means of the Cerebral Performance Category (CPC) score at 3 months and was characterized as good (CPC 1-2) or poor (CPC 3-5).

RESULTS

Of 451 patients, 320 fulfilled the inclusion criteria and were analyzed (80.3% male, mean age 61±14.1 years). Among these, 174 patients (54.4%) survived with good neurological status. Poor outcome patients had higher median NSE values at hospital admission and at 24, 48 and 72 hours after ROSC. At 48 and 72 hours after ROSC, NSE predicted poor neurological outcome with areas under the receiver-operating characteristic curves of 0.85 (95%CI, 0.81-0.90) and 0.88 (95%CI, 0.83-0.93), respectively. In addition, delta NSE values between 72hours after ROSC and hospital admission predicted poor neurological outcome with an area under the receiver-operating characteristic curve of 0.90 (95%CI, 0.85-0.95) and was an independent predictor of unfavorable outcome on multivariate analysis (P <.001).

CONCLUSIONS

In cardiac arrest survivors treated with targeted temperature management, delta NSE values between 72 hours after ROSC and hospital admission strongly predicted poor neurological outcome.

Prolonged targeted temperature management reduces memory retrieval deficits six months post-cardiac arrest: A randomised controlled trial

BACKGROUND

Cognitive sequelae, most frequently memory, attention, and executive dysfunctions, occur commonly in out-of-hospital cardiac arrest (OHCA) survivors. Targeted temperature management (TTM) following OHCA is associated with improved cognitive function. However, the relationship between the duration of TTM and cognitive outcome remains unclear. We hypothesised that OHCA survivors that were subjected to prolonged TTM of 48 h (TTM48) would exhibit better cognitive functions compared to those subjected to standard TTM of 24 h (TTM24) six months post-OHCA.

METHODS

A predefined, cognitive post-hoc sub-study was conducted on the multicentre clinical trial: "Target Temperature Management for 48 vs. 24 h and Neurologic Outcome after out-of-hospital cardiac arrest: A Randomised Clinical Trial" (the TTH48 trial). OHCA survivors with perceived good cognitive outcome (CPC score ≤ 2) were invited to a neuropsychological assessment of memory, attention, and executive functions six months post-OHCA.

RESULTS

In total, 79 patients were included in the study. Multivariate regression analysis revealed that TTM48 was associated with a significant better performance on three of 13 cognitive tests specific to memory retrieval after adjusting for age at follow-up and time to return of spontaneous circulation. Overall, patients in the TTM24 group were almost three times more likely (RR = 2.9 (95% CI 1.1-7.4)), p = 0.02) to be cognitively impaired.

CONCLUSIONS

This study reports an association between the duration of TTM and cognitive outcome. In OHCA survivors with perceived good cognitive outcome (CPC ≤ 2), TTM48 was associated with reduced memory retrieval deficits and lower relative risk of cognitive impairment six months after OHCA compared to standard TTM24. ClinicalTrials.gov (identifier: NCT01689077).

Quantitative pupillometry and neuron-specific enolase independently predict return of spontaneous circulation following cardiogenic out-of-hospital cardiac arrest: a prospective pilot study

This study aimed to identify neurological and pathophysiological factors that predicted return of spontaneous circulation (ROSC) among patients with out-of-hospital cardiac arrest (OHCA). This prospective 1-year observational study evaluated patients with cardiogenic OHCA who were admitted to a tertiary medical center, Nippon Medical School Hospital. Physiological and neurological examinations were performed at admission for quantitative infrared pupillometry (measured with NPi-200, NeurOptics, CA, USA), arterial blood gas, and blood chemistry. Simultaneous blood samples were also collected to determine levels of neuron-specific enolase (NSE), S-100b, phosphorylated neurofilament heavy subunit, and interleukin-6. In-hospital standard advanced cardiac life support was performed for 30 minutes.The ROSC (n = 26) and non-ROSC (n = 26) groups were compared, which a revealed significantly higher pupillary light reflex ratio, which was defined as the percent change between maximum pupil diameter before light stimuli and minimum pupil diameter after light stimuli, in the ROSC group (median: 1.3% [interquartile range (IQR): 0.0–2.0%] vs. non-ROSC: (median: 0%), (Cut-off: 0.63%). Furthermore, NSE provided the great sensitivity and specificity for predicting ROSC, with an area under the receiver operating characteristic curve of 0.86, which was created by plotting sensitivity and 1-specificity. Multivariable logistic regression analyses revealed that the independent predictors of ROSC were maximum pupillary diameter (odds ratio: 0.25, 95% confidence interval: 0.07–0.94, P = 0.04) and NSE at admission (odds ratio: 0.96, 95% confidence interval: 0.93–0.99, P = 0.04). Pupillary diameter was also significantly correlated with NSE concentrations (r = 0.31, P = 0.027). Conclusively, the strongest predictors of ROSC among patients with OHCA were accurate pupillary diameter and a neuronal biomarker, NSE. Quantitative pupillometry may help guide the decision to terminate resuscitation in emergency departments using a neuropathological rationale. Further large-scale studies are needed.

Surviving refractory out-of-hospital ventricular fibrillation cardiac arrest: Critical care and extracorporeal membrane oxygenation management

BACKGROUND

Resuscitation of refractory out-of-hospital ventricular fibrillation/ventricular tachycardia (VF/VT) cardiac arrest using extracorporeal membrane oxygenation (ECMO) establishes a complex patient population. We aimed to describe the critical care strategies and outcomes in this population.

METHODS

Between December 1, 2015 and January 1, 2018, 100 consecutive adult patients with refractory VF/VT out-of-hospital cardiac arrest and ongoing CPR were transported to the cardiac catheterization laboratory. ECMO, coronary angiography, and percutaneous coronary intervention were performed. Patients achieving an organized cardiac rhythm were admitted to the cardiac intensive care unit (CICU). All patients were considered eligible for necessary intervention/surgery until declaration of death.

RESULTS

Of 100 appropriately transported patients, 83 achieved CICU admission. 40/83 (48%) discharged functionally intact. Multi-system organ failure occurred in all patients. Cardiac, pulmonary, renal, and liver injury improved within 3-4 days. Neurologic injury caused death in 26/37 (70%) patients. Poor neurologic outcomes were associated with anoxic injury or cerebral edema on admission head CT, decline in cerebral oximetry over the first 48 h, and elevated neuron specific enolase on CICU admission. For survivors, mean time to ECMO decannulation was 3.5 ± 0.2 days, following commands at 5.7 ± 0.8 days, and hospital discharge at 21 ± 3.2 days. 41/83 (49%) patients developed infections. CPR caused traumatic injury requiring procedural/surgical intervention in 22/83 (27%) patients.

CONCLUSIONS

Multi-system organ failure is ubiquitous but treatable with adequate hemodynamic support. Neurologic recovery was prolonged requiring delayed prognostication. Immediate 24/7 availability of surgical and medical specialty expertise was required to achieve 48% functionally intact survival.