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Objectives To review and update the evidence on predictors of poor outcome (death, persistent vegetative state or severe neurological disability) in adult comatose survivors of cardiac arrest, either treated or not treated with controlled temperature, to identify knowledge gaps and to suggest a reliable prognostication strategy. Methods GRADE-based systematic review followed by expert consensus achieved using Web-based Delphi methodology, conference calls and face-to-face meetings. Predictors based on clinical examination, electrophysiology, biomarkers and imaging were included. Results and conclusions Evidence from a total of 73 studies was reviewed. The quality of evidence was low or very low for almost all studies. In patients who are comatose with absent or extensor motor response at [greater than or equal to]72 h from arrest, either treated or not treated with controlled temperature, bilateral absence of either pupillary and corneal reflexes or N20 wave of short-latency somatosensory evoked potentials were identified as the most robust predictors. Early status myoclonus, elevated values of neuron-specific enolase at 48-72 h from arrest, unreactive malignant EEG patterns after rewarming, and presence of diffuse signs of postanoxic injury on either computed tomography or magnetic resonance imaging were identified as useful but less robust predictors. Prolonged observation and repeated assessments should be considered when results of initial assessment are inconclusive. Although no specific combination of predictors is sufficiently supported by available evidence, a multimodal prognostication approach is recommended in all patients., Author(s): Claudio Sandroni [sup.1], Alain Cariou [sup.2], Fabio Cavallaro [sup.1], Tobias Cronberg [sup.3], Hans Friberg [sup.4], Cornelia Hoedemaekers [sup.5], Janneke Horn [sup.6], Jerry P. Nolan [sup.7], Andrea O. Rossetti [sup.8], [...]

Objective: Outcome prediction in patients after cardiac arrest (CA) is challenging. Electroencephalographic reactivity (EEG-R) might be a reliable predictor. We aimed to determine the prognostic value of EEG-R using a standardized assessment.Methods: In a prospective cohort study, a strictly defined EEG-R assessment protocol was executed twice per day in adult patients after CA. EEG-R was classified as present or absent by 3 EEG readers, blinded to patient characteristics. Uncertain reactivity was classified as present. Primary outcome was best Cerebral Performance Category score (CPC) in 6 months after CA, dichotomized as good (CPC = 1-2) or poor (CPC = 3-5). EEG-R was considered reliable for predicting poor outcome if specificity was ≥95%. For good outcome prediction, a specificity of ≥80% was used. Added value of EEG-R was the increase in specificity when combined with EEG background, neurological examination, and somatosensory evoked potentials (SSEPs).Results: Of 160 patients enrolled, 149 were available for analyses. Absence of EEG-R for poor outcome prediction had a specificity of 82% and a sensitivity of 73%. For good outcome prediction, specificity was 73% and sensitivity 82%. Specificity for poor outcome prediction increased from 98% to 99% when EEG-R was added to a multimodal model. For good outcome prediction, specificity increased from 70% to 89%.Interpretation: EEG-R testing in itself is not sufficiently reliable for outcome prediction in patients after CA. For poor outcome prediction, it has no substantial added value to EEG background, neurological examination, and SSEPs. For prediction of good outcome, EEG-R seems to have added value. ANN NEUROL 2019. [ABSTRACT FROM AUTHOR]

Prognostication of comatose patients after cardiac arrest aims to identify patients with a large probability of favourable or unfavouble outcome, usually within the first week after the event. Electroencephalography (EEG) is a technique that is increasingly used for this purpose and has many advantages, such as its non-invasive nature and the possibility to monitor the evolution of brain function over time. At the same time, use of EEG in a critical care environment faces a number of challenges. This narrative review describes the current role and future applications of EEG for outcome prediction of comatose patients with postanoxic encephalopathy. [ABSTRACT FROM AUTHOR]

Aim Of the Study: Estimation of cerebral anaerobic metabolism in survivors and non-survivors after cardiac arrest.Methods: We performed an observational study in twenty comatose patients after cardiac arrest and 19 healthy control subjects. We measured mean flow velocity in the middle cerebral artery (MFVMCA) by transcranial Doppler. Arterial and jugular blood samples were used for calculation of the jugular venous-to-arterial CO2/arterial to-jugular venous O2 content difference ratio.Results: After cardiac arrest, MFVMCA increased from 26.0[18.6-40.4]cm/sec on admission to 63.9[48.3-73.1]cm/sec after 72h (p<0.0001), with no significant differences between survivors and non-survivors (p=0.4853). The MFVMCA in controls was 59.1[52.8-69.0]cm/sec. The oxygen extraction fraction (O2EF) was 38.9[24.4-47.7]% on admission and decreased significantly to 17.3[12.1-26.2]% at 72h (p<0.0001). The decrease in O2EF was more pronounced in non-survivors (p=0.0173). O2EF in the control group was 35.4[32.4-38.7]%. The jugular bulb-arterial CO2 to arterial-jugular bulb O2 content difference ratio was >1 at all time points after cardiac arrest and did not change during admission, with no differences between survivors and non-survivors. Values in cardiac arrest patients were similar to those in normal subjects.Conclusions: In this study, low CBF after cardiac arrest is not associated with anaerobic metabolism. Hypoperfusion appears to be the consequence of a decrease of neuronal functioning and metabolic needs. Alternatively, hypoperfusion may decrease cerebral metabolism. Subsequently, metabolism increases in survivors, consistent with resumption of neuronal activity, whereas in non-survivors lasting low metabolism reflects irreversible neuronal damage. [ABSTRACT FROM AUTHOR]

Magnetic resonance imaging (MRI) is increasingly reported as a potential tool for neuroprognostication after cardiac arrest. Diffusion weighted imaging (DWI) is an MRI sequence that visualizes the diffusion of water molecules and is sensitive to the detection of cytotoxic edema, which reduces diffusivity. [Extracted from the article]

The article details a study which examined the key components of cerebral and systemic inflammatory response over time among cardiac arrest patients during mild therapeutic hypothermia and rewarming. The study included 10 comatose patients who experienced out-of-hospital cardiac arrest. It found that complement activation occurs during rewarming from mild therapeutic hypothermia after cardiac arrest.

The article discusses a study which investigated changes in partial pressure of carbon dioxide in the arterial blood in comatose patients after out-of-hospital cardiac arrest treated with mild hypothermia. The observational study examined several factors such as cerebral blood flow, cerebral oxygen extraction and cerebrovascular reactivity. It was found that the mean flow velocity in the middle cerebral artery was low during mild hypothermia.

The authors reflect on a study by S. Voicu and colleagues which examined the effect of α-stat and pH-stat blood gas management on cerebral blood flow (CBF) in post-cardiac arrest patients who undergone hypothermia treatment. Topics include cerebrospinal fluid alkalosis, post-cardiac arrest brain injury, and hypercapnic acidosis.

The article focuses on a study which assessed the cerebral blood flow and cerebral oxygen extraction in adult patients after pulseless electrical activity/asystole or resistant ventricular fibrillation and were treated with mild therapeutic hypothermia for 72 hours. Study authors concluded that temperature alone is not a major determinant of cerebral blood flow regulation following cardiac arrest. They also described the influence of low mean cerebral artery flow on cerebral metabolic activity.

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. [ABSTRACT FROM AUTHOR]

Aim: This study estimated the critical closing pressure (CrCP) of the cerebrovascular circulation during the post-cardiac arrest syndrome and determined if CrCP differs between survivors and non-survivors. We also compared patients after cardiac arrest to normal controls.Methods: A prospective observational study was performed at the ICU of a tertiary university hospital in Nijmegen, the Netherlands. We studied 11 comatose patients successfully resuscitated from a cardiac arrest and treated with mild therapeutic hypothermia and 10 normal control subjects. Mean flow velocity (MFV) in the middle cerebral artery was measured by transcranial Doppler at several time points after admission to the ICU. CrCP was determined by a cerebrovascular impedance model.Results: MFV was similar in survivors and non-survivors upon admission to the ICU, but increased stronger in non-survivors compared to survivors throughout the observation period (P<0.001). MFV was significantly lower in survivors immediately after cardiac arrest compared to normal controls (P<0.001), with a gradual restoration toward normal values. CrCP decreased significantly from 61.4[51.0-77.1]mmHg to 41.7[39.9-51.0]mmHg in the first 48h, after which it remained stable (P<0.001). CrCP was significantly higher in survivors compared to non-survivors (P=0.002). CrCP immediately after cardiac arrest was significantly higher compared to the control group (P=0.02).Conclusions: CrCP is high after cardiac arrest with high cerebrovascular resistance and low MFV. This suggests that cerebral perfusion pressure should be maintained at a sufficient high level to avoid secondary brain injury. Failure to normalize the cerebrovascular profile may be a parameter of poor outcome. [ABSTRACT FROM AUTHOR]

Objectives: After cardiac arrest, patients are highly vulnerable toward infections, possibly due to a suppressed state of the immune system called "immunoparalysis." We investigated if immunoparalysis develops following cardiac arrest and whether the release of danger-associated molecular patterns could be involved. Design: Observational study. Setting: ICU of a university medical center. Patients: Fourteen post-cardiac arrest patients treated with mild therapeutic hypothermia for 24 hours and 11 control subjects. Measurements and Main Results: Plasma cytokines showed highest levels within 24 hours after cardiac arrest and decreased during the next 2 days. By contrast, ex vivo production of cytokines interleukin-6, tumor necrosis factor-α, and interleukin-10 by lipopolysaccharide-stimulated leukocytes was severely impaired compared with control subjects, with most profound effects observed at day 0, and only partially recovering afterward. Compared with incubation at 37°C, incubation at 32°C resulted in higher interleukin-6 and lower interleukin-10 production by lipopolysaccharide-stimulated leukocytes of control subjects, but not of patients. Plasma nuclear DNA, used as a marker for general danger-associated molecular pattern release, and the specific danger-associated molecular patterns (EN-RAGE and heat shock protein 70) were substantially higher in patients at days 0 and 1 compared with control subjects. Furthermore, plasma heat shock protein 70 levels were negatively correlated with ex vivo production of inflammatory mediators interleukin-6, tumor necrosis factor-α, and interleukin-10. Extracellular newly identified receptor for advanced glycation end products-binding protein levels only showed a significant negative correlation with ex vivo production of interleukin-6 and tumor necrosis factor-α and a borderline significant inverse correlation with interleukin-10. No significant correlations were observed between plasma nuclear DNA levels and ex vivo cytokine production. Interventions: None. Conclusions: Release of danger-associated molecular patterns during the first days after cardiac arrest is associated with the development of immunoparalysis. This could explain the increased susceptibility toward infections in cardiac arrest patients. [ABSTRACT FROM AUTHOR]

Objectives: To determine blood viscosity in adult comatose patients treated with mild therapeutic hypothermia after cardiac arrest and to assess the relation between blood viscosity, cerebral blood flow, and cerebral oxygen extraction. Design: Observational study. Setting: Tertiary care university hospital. Patients: Ten comatose patients with return of spontaneous circulation after out-of-hospital cardiac arrest. Intervention: Treatment with mild therapeutic hypothermia for 24 hours followed by passive rewarming to normothermia. Measurements and Main Results: Median viscosity at shear rate 50/s was 5.27 mPa · s (4.29-5.91 mPa · s) at admission; it remained relatively stable during the first 12 hours and decreased significantly to 3.00 mPa · s (2.72-3.58 mPa · s) at 72 hours (p < 0.001). Median mean flow velocity in the middle cerebral artery was low (27.0 cm/s [23.8-30.5 cm/s]) at admission and significantly increased to 63.0 cm/s (51.0-80.0 cm/s) at 72 hours. Median jugular bulb saturation at the start of the study was 61.5% (55.5-75.3%) and significantly increased to 73.0% (69.0-81.0%) at 72 hours. Median hematocrit was 0.41 L/L (0.36-0.44 L/L) at admission and subsequently decreased significantly to 0.32 L/L (0.27-0.35 L/L) at 72 hours. Median C-reactive protein concentration was low at admission (2.5 mg/L [2.5-6.5 mg/L]) and increased to 101 mg/L (65-113.3 mg/L) in the following hours. Median fibrinogen concentration was increased at admission 2,795 mg/L (2,503-3,565 mg/L) and subsequently further increased to 6,195 mg/L (5,843-7,368 mg/L) at 72 hours. There was a significant negative association between blood viscosity and the mean flow velocity in the middle cerebral artery (p = 0.0008). Conclusions: Changes in blood viscosity in vivo are associated with changes in flow velocity in the middle cerebral artery. High viscosity early after cardiac arrest may reduce cerebral blood flow and may contribute to secondary brain injury. Further studies are needed to determine the optimal viscosity during the different stages of the postcardiac arrest syndrome. [ABSTRACT FROM AUTHOR]

Abstract: Introduction: Outcome studies in patients with anoxic-ischemic encephalopathy focus on the early and reliable prediction of an outcome no better than a vegetative state or severe disability. We determined the effect of mild therapeutic hypothermia on the validity of the currently used clinical practice parameters. Methods: We conducted a retrospective cohort study of adult comatose patients after cardiac arrest treated with hypothermia. All data were collected from medical charts and laboratory files and analyzed from the day of admission to the intensive care unit until day 7, discharge from the intensive care unit or death using the Utstein definitions for the registration of the data. Results: We analyzed the data of 103 patients. The combination of an M1 or M2 on the Glasgow Coma Scale or absent pupillary reactions or absent corneal reflexes on day 3 was present in 80.6% of patients with an unfavourable and 11.1% of patients with a favourable outcome. The combination of M1 or M2 and absent pupillary reactions to light and absent corneal reflexes on day 3 was present in 14.9% of patients with an unfavourable and none of the patients with a favourable outcome. None of the patients with a favourable outcome had a bilaterally absent somatosensory evoked potential of the median nerve. The value of electroencephalogram patterns in predicting outcome was low, except for reactivity to noxious stimuli. Conclusions: No single clinical or electrophysiological parameter has sufficient accuracy to determine prognosis and decision making in patients after cardiac arrest, treated with hypothermia. [Copyright &y& Elsevier]

The article discusses a study on use benefits of mild therapeutic hypothermia in patients following cardiac arrest. The study involved all patient admitted to an intensive care unit (ICU) in The Netherlands due to cardiac arrest between January 1, 1999 and January 1, 2009. It found that therapeutic hypothermia cuts hospital mortality rate.