Validation of the Scandinavian guidelines for minor and moderate head trauma in children: protocol for a pragmatic, prospective, observational, multicentre cohort study.

INTRODUCTION: Mild traumatic brain injury is common in children and it can be challenging to accurately identify those in need of urgent medical intervention. The Scandinavian guidelines for management of minor and moderate head trauma in children, the Scandinavian Neurotrauma Committee guideline 2016 (SNC16), were developed to aid in risk stratification and decision-making in Scandinavian emergency departments (EDs). This guideline has been validated externally with encouraging results, but internal validation in the intended healthcare system is warranted prior to broad clinical implementation. OBJECTIVE: We aim to validate the diagnostic accuracy of the SNC16 to predict clinically important intracranial injuries (CIII) in paediatric patients suffering from blunt head trauma, assessed in EDs in Sweden and Norway. METHODS AND ANALYSIS: This is a prospective, pragmatic, observational cohort study. Children (aged 0-17 years) with blunt head trauma, presenting with a Glasgow Coma Scale of 9-15 within 24 hours postinjury at an ED in 1 of the 16 participating hospitals, are eligible for inclusion. Included patients are assessed and managed according to the clinical management routines of each hospital. Data elements for risk stratification are collected in an electronic case report form by the examining doctor. The primary outcome is defined as CIII within 1 week of injury. Secondary outcomes of importance include traumatic CT findings, neurosurgery and 3-month outcome. Diagnostic accuracy of the SNC16 to predict endpoints will be assessed by point estimate and 95% CIs for sensitivity, specificity, likelihood ratio, negative predictive value and positive predictive value. ETHICS AND DISSEMINATION: The study is approved by the ethical board in both Sweden and Norway. Results from this validation will be published in scientific journals, and a tailored development and implementation process will follow if the SNC16 is found safe and effective. TRIAL REGISTRATION NUMBER: NCT05964764.

Agreement between self-reported and objectively assessed physical activity among out-of-hospital cardiac arrest survivors.

BACKGROUND: Low level of physical activity is a risk factor for new cardiac events in out-of-hospital cardiac arrest (OHCA) survivors. Physical activity can be assessed by self-reporting or objectively by accelerometery. AIM: To investigate the agreement between self-reported and objectively assessed physical activity among OHCA survivors HYPOTHESIS: Self-reported levels of physical activity will show moderate agreement with objectively assessed levels of physical activity. METHOD: Cross-sectional study including OHCA survivors in Sweden, Denmark, and the United Kingdom. Two questions about moderate and vigorous intensity physical activity during the last week were used as self-reports. Moderate and vigorous intensity physical activity were objectively assessed with accelerometers (ActiGraph GT3X-BT) worn upon the right hip for 7 consecutive days. RESULTS: Forty-nine of 106 OHCA survivors answered the two questions for self-reporting and had 7 valid days of accelerometer assessment. More physically active days were registered by self-report compared with accelerometery for both moderate intensity (median 5 [3:7] vs. 3 [0:5] days; p < 0.001) and vigorous intensity (1 [0:3] vs. 0 [0:0] days; p < 0.001). Correlations between self-reported and accelerometer assessed physical activity were sufficient (moderate intensity: rs = 0.336, p = 0.018; vigorous intensity: rs = 0.375, p = 0.008), and agreements were fair and none to slight (moderate intensity: k = 0.269, p = 0.001; vigorous intensity: k = 0.148, p = 0.015). The categorization of self-reported versus objectively assessed physical activity showed that 26% versus 65% had a low level of physical activity. CONCLUSION: OHCA survivors reported more physically active days compared with the results of the accelerometer assessment and correlated sufficiently and agreed fairly and none to slightly.

Management of traumatic brain injury in adult-A cross-sectional national study.

Background: Mild traumatic brain injury (mTBI) is a common cause for seeking care. Previous studies have shown considerable variations in TBI management. New guidelines may have influenced management routines. Methods: This is a descriptive cross-sectional study, collecting data through structured questionnaires. All Swedish emergency hospitals that manage and treat adult patients with mTBI (Reaction Level Scale [RLS] 1-3, Glasgow Coma Scale [GCS] 13-15, age > 18 years) for the initial 24 h after injury were included in this study. Results: The response rate among hospitals fulfilling the study criteria's was 61/67 (91%). We observed a distinct predominance of nonspecialists being responsible for the initial management of these patients, with general surgeons and ED-physicians being the dominating specialties. A total of 45/61 (74%) of the hospitals use a guideline when managing TBI, with 12 hospitals (20%) stating that no guideline was used. Conclusion: In general, established guidelines are used for the management of TBI in Sweden. However, some of these are outdated and several hospitals used local guidelines not based upon reliable evidence-based methodology. Most patients with TBI are managed by nonspecialist doctors, stressing the need of a reliable guideline.

Neuropsychological outcome after cardiac arrest: results from a sub-study of the targeted hypothermia versus targeted normothermia after out-of-hospital cardiac arrest (TTM2) trial.

BACKGROUND: Cognitive impairment is common following out-of-hospital cardiac arrest (OHCA), but the nature of the impairment is poorly understood. Our objective was to describe cognitive impairment in OHCA survivors, with the hypothesis that OHCA survivors would perform significantly worse on neuropsychological tests of cognition than controls with acute myocardial infarction (MI). Another aim was to investigate the relationship between cognitive performance and the associated factors of emotional problems, fatigue, insomnia, and cardiovascular risk factors following OHCA. METHODS: This was a prospective case-control sub-study of The Targeted Hypothermia versus Targeted Normothermia after Out-of-Hospital Cardiac Arrest (TTM2) trial. Eight of 61 TTM2-sites in Sweden, Denmark, and the United Kingdom included adults with OHCA of presumed cardiac or unknown cause. A matched non-arrest control group with acute MI was recruited. At approximately 7 months post-event, we administered an extensive neuropsychological test battery and questionnaires on anxiety, depression, fatigue, and insomnia, and collected information on the cardiovascular risk factors hypertension and diabetes. RESULTS: Of 184 eligible OHCA survivors, 108 were included, with 92 MI controls enrolled. Amongst OHCA survivors, 29% performed z-score ≤ - 1 (at least borderline-mild impairment) in ≥ 2 cognitive domains, 14% performed z-score ≤ - 2 (major impairment) in ≥ 1 cognitive domain while 54% performed without impairment in any domain. Impairment was most pronounced in episodic memory, executive functions, and processing speed. OHCA survivors performed significantly worse than MI controls in episodic memory (mean difference, MD = - 0.37, 95% confidence intervals [- 0.61, - 0.12]), verbal (MD = - 0.34 [- 0.62, - 0.07]), and visual/constructive functions (MD = - 0.26 [- 0.47, - 0.04]) on linear regressions adjusted for educational attainment and sex. When additionally adjusting for anxiety, depression, fatigue, insomnia, hypertension, and diabetes, executive functions (MD = - 0.44 [- 0.82, - 0.06]) were also worse following OHCA. Diabetes, symptoms of anxiety, depression, and fatigue were significantly associated with worse cognitive performance. CONCLUSIONS: In our study population, cognitive impairment was generally mild following OHCA. OHCA survivors performed worse than MI controls in 3 of 6 domains. These results support current guidelines that a post-OHCA follow-up service should screen for cognitive impairment, emotional problems, and fatigue. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03543371. Registered 1 June 2018.

Veno-arterial CO2 difference and lactate for prediction of early mortality after cardiac arrest.

Patients admitted to intensive care after cardiac arrest are at risk of circulatory shock and early mortality due to cardiovascular failure. The aim of this study was to evaluate the ability of the veno-arterial pCO2 difference (∆pCO2 ; central venous CO2 - arterial CO2 ) and lactate to predict early mortality in postcardiac arrest patients. This was a pre-planned prospective observational sub-study of the target temperature management 2 trial. The sub-study patients were included at five Swedish sites. Repeated measurements of ∆pCO2 and lactate were conducted at 4, 8, 12, 16, 24, 48, and 72 h after randomization. We assessed the association between each marker and 96-h mortality and their prognostic value for 96-h mortality. One hundred sixty-three patients were included in the analysis. Mortality at 96 h was 17%. During the initial 24 h, there was no difference in ∆pCO2 levels between 96-h survivors and non-survivors. ∆pCO2 measured at 4 h was associated with an increased risk of death within 96 h (adjusted odds ratio: 1.15; 95% confidence interval [CI]: 1.02-1.29; p = .018). Lactate levels were associated with poor outcome over multiple measurements. The area under the receiving operating curve to predict death within 96 h was 0.59 (95% CI: 0.48-0.74) and 0.82 (95% CI: 0.72-0.92) for ∆pCO2 and lactate, respectively. Our results do not support the use of ∆pCO2 to identify patients with early mortality in the postresuscitation phase. In contrast, non-survivors demonstrated higher lactate levels in the initial phase and lactate identified patients with early mortality with moderate accuracy.

Protocolised reduction of non-resuscitation fluids versus usual care in patients with septic shock (REDUSE): a protocol for a multicentre feasibility trial.

INTRODUCTION: Administration of large volumes of fluids is associated with poor outcome in septic shock. Recent data suggest that non-resuscitation fluids are the major source of fluids in the intensive care unit (ICU) patients suffering from septic shock. The present trial is designed to test the hypothesis that a protocol targeting this source of fluids can reduce fluid administration compared with usual care. METHODS AND ANALYSIS: The design will be a multicentre, randomised, feasibility trial. Adult patients admitted to ICUs with septic shock will be randomised within 12 hours of admission to receive non-resuscitation fluids either according to a restrictive protocol or to receive usual care. The healthcare providers involved in the care of participants will not be blinded. The participants, outcome assessors at the 6-month follow-up and statisticians will be blinded. Primary outcome will be litres of fluids administered within 3 days of randomisation. Secondary outcomes will be proportion of randomised participants with outcome data on all-cause mortality; days alive and free of mechanical ventilation within 90 days of inclusion; any acute kidney injury and ischaemic events in the ICU (cerebral, cardiac, intestinal or limb ischaemia); proportion of surviving randomised patients who were assessed by European Quality of Life 5-Dimensions 5-Level questionnaire and Montreal Cognitive Assessment; proportion of all eligible patients who were randomised and proportion of participants experiencing at least one protocol violation. ETHICS AND DISSEMINATION: Ethics approval has been obtained in Sweden. Results of the primary and secondary outcomes will be submitted for publication in a peer-reviewed journal. TRIAL REGISTRATION NUMBER: NCT05249088.

Health-related quality of life and long-term symptoms among patients with non-severe covid-19 - a prospective cohort study.

BACKGROUND: The vast majority of covid-19 patients experience non-severe disease. Nonetheless, long-term symptoms may be common and the impact on quality of life is uncertain. This study aims to examine these aspects in a prospective, longitudinal cohort. METHODS: Non-hospitalised patients with PCR-confirmed covid-19 were prospectively invited to self-report assessments of background data, symptoms and recovery, illness perception (BIPQ) and health-related quality of life (HR-Qol) measured by EQ5D-VAS. RESULTS: 154 patients were included (mean age 46 years, 69% female). The majority of participants (65%) had symptoms for 1-4 weeks and 12% more than 6 months. The most common symptoms were initially malaise, fatigue, headache, fever and cough and the most common long-term symptoms were impaired physical condition, fatigue, anosmia and headache. The BIPQ index had a negative correlation with the EQ5D-VAS score after the infection, but not with long-term symptoms. Mean differences in the EQ5D-VAS score were significantly lower after the infection and patients with long-term symptoms had a more pronounced negative effect in EQ5D-VAS scores. CONCLUSION: We found that most patients with non-severe covid-19 reported symptoms for 1-4 weeks and approximately 10% developed long-term symptoms. Non-severe covid-19 seems to have a negative influence on HR-Qol, especially in patients with long-term symptoms and with a greater burden from the disease. None of the initial symptoms could predict the presence of long-term symptoms.

Brain injury markers in blood predict signs of hypoxic ischaemic encephalopathy on head computed tomography after cardiac arrest.

BACKGROUND/AIM: Signs of hypoxic ischaemic encephalopathy (HIE) on head computed tomography (CT) predicts poor neurological outcome after cardiac arrest. We explore whether levels of brain injury markers in blood could predict the likelihood of HIE on CT. METHODS: Retrospective analysis of CT performed at 24-168 h post cardiac arrest on clinical indication within the Target Temperature Management after out-of-hospital cardiac arrest-trial. Biomarkers prospectively collected at 24- and 48 h post-arrest were analysed for neuron specific enolase (NSE), neurofilament light (NFL), total-tau and glial fibrillary acidic protein (GFAP). HIE was assessed through visual evaluation and quantitative grey-white-matter ratio (GWR) was retrospectively calculated on Swedish subjects with original images available. RESULTS: In total, 95 patients were included. The performance to predict HIE on CT (performed at IQR 73-116 h) at 48 h was similar for all biomarkers, assessed as area under the receiving operating characteristic curve (AUC) NSE 0.82 (0.71-0.94), NFL 0.79 (0.67-0.91), total-tau 0.84 (0.74-0.95), GFAP 0.79 (0.67-0.90). The predictive performance of biomarker levels at 24 h was AUC 0.72-0.81. At 48 h biomarker levels below Youden Index accurately excluded HIE in 77.3-91.7% (negative predictive value) and levels above Youden Index correctly predicted HIE in 73.3-83.7% (positive predictive value). NSE cut-off at 48 h was 48 ng/ml. Elevated biomarker levels irrespective of timepoint significantly correlated with lower GWR. CONCLUSION: Biomarker levels can assess the likelihood of a patient presenting with HIE on CT and could be used to select suitable patients for CT-examination during neurological prognostication in unconscious cardiac arrest patients.

Patients' Health Experiences of Post COVID-19 Condition-A Qualitative Study.

Patients who suffer from long-term symptoms of COVID-19, described as post COVID-19 condition, are a new and large group of patients. There is a lack of knowledge concerning health experiences in this patient group. The aim of this study was to explore patients' health experiences of post COVID-19 condition. Data collection was performed through 14 semi-structured interviews. The qualitative content analysis resulted in six sub-categories, three categories, and an overall theme. Patients experienced symptoms of varying duration-ranging from 5-21 months. The results showed that patients' health experiences of post COVID-19 condition moved between uncertainty and new insights. This was shown by patients experiencing: (1) loss of abilities, including losing smell and taste and lacking energy, (2) loss of control, including being foreign to oneself and seeking answers, and (3) revaluation of life, including accepting the transformed body and prioritizing health. This study illustrates that patients living with post COVID-19 condition need to be treated with flexibility, based on each individual's unique challenges and experiences of the symptoms and the consequences for their health.

Prognostic accuracy of head computed tomography for prediction of functional outcome after out-of-hospital cardiac arrest: Rationale and design of the prospective TTM2-CT-substudy.

Background: Head computed tomography (CT) is a guideline recommended method to predict functional outcome after cardiac arrest (CA), but standardized criteria for evaluation are lacking. To date, no prospective trial has systematically validated methods for diagnosing hypoxic-ischaemic encephalopathy (HIE) on CT after CA. We present a protocol for validation of pre-specified radiological criteria for assessment of HIE on CT for neuroprognostication after CA. Methods/design: This is a prospective observational international multicentre substudy of the Targeted Hypothermia versus Targeted Normothermia after out-of-hospital cardiac arrest (TTM2) trial. Patients still unconscious 48 hours post-arrest at 13 participating hospitals were routinely examined with CT. Original images will be evaluated by examiners blinded to clinical data using a standardized protocol. Qualitative assessment will include evaluation of absence/presence of "severe HIE". Radiodensities will be quantified in pre-specified regions of interest for calculation of grey-white matter ratios (GWR) at the basal ganglia level. Functional outcome will be dichotomized into good (modified Rankin Scale 0-3) and poor (modified Rankin Scale 4-6) at six months post-arrest. Prognostic accuracies for good and poor outcome will be presented as sensitivities and specificities with 95% confidence intervals (using pre-specified cut-offs for quantitative analysis), descriptive statistics (Area Under the Receiver Operating Characteristics Curve), inter- and intra-rater reliabilities according to STARD guidelines. Conclusions: The results from this prospective trial will validate a standardized approach to radiological evaluations of HIE on CT for prediction of functional outcome in comatose CA patients.The TTM2 trial and the TTM2 CT substudy are registered at ClinicalTrials.gov NCT02908308 and NCT03913065.

Oxygen targets and 6-month outcome after out of hospital cardiac arrest: a pre-planned sub-analysis of the targeted hypothermia versus targeted normothermia after Out-of-Hospital Cardiac Arrest (TTM2) trial.

BACKGROUND: Optimal oxygen targets in patients resuscitated after cardiac arrest are uncertain. The primary aim of this study was to describe the values of partial pressure of oxygen values (PaO2) and the episodes of hypoxemia and hyperoxemia occurring within the first 72 h of mechanical ventilation in out of hospital cardiac arrest (OHCA) patients. The secondary aim was to evaluate the association of PaO2 with patients' outcome. METHODS: Preplanned secondary analysis of the targeted hypothermia versus targeted normothermia after OHCA (TTM2) trial. Arterial blood gases values were collected from randomization every 4 h for the first 32 h, and then, every 8 h until day 3. Hypoxemia was defined as PaO2 < 60 mmHg and severe hyperoxemia as PaO2 > 300 mmHg. Mortality and poor neurological outcome (defined according to modified Rankin scale) were collected at 6 months. RESULTS: 1418 patients were included in the analysis. The mean age was 64 ± 14 years, and 292 patients (20.6%) were female. 24.9% of patients had at least one episode of hypoxemia, and 7.6% of patients had at least one episode of severe hyperoxemia. Both hypoxemia and hyperoxemia were independently associated with 6-month mortality, but not with poor neurological outcome. The best cutoff point associated with 6-month mortality for hypoxemia was 69 mmHg (Risk Ratio, RR = 1.009, 95% CI 0.93-1.09), and for hyperoxemia was 195 mmHg (RR = 1.006, 95% CI 0.95-1.06). The time exposure, i.e., the area under the curve (PaO2-AUC), for hyperoxemia was significantly associated with mortality (p = 0.003). CONCLUSIONS: In OHCA patients, both hypoxemia and hyperoxemia are associated with 6-months mortality, with an effect mediated by the timing exposure to high values of oxygen. Precise titration of oxygen levels should be considered in this group of patients. TRIAL REGISTRATION: clinicaltrials.gov NCT02908308 , Registered September 20, 2016.

Ventilatory settings in the initial 72 h and their association with outcome in out-of-hospital cardiac arrest patients: a preplanned secondary analysis of the targeted hypothermia versus targeted normothermia after out-of-hospital cardiac arrest (TTM2) trial.

PURPOSE: The optimal ventilatory settings in patients after cardiac arrest and their association with outcome remain unclear. The aim of this study was to describe the ventilatory settings applied in the first 72 h of mechanical ventilation in patients after out-of-hospital cardiac arrest and their association with 6-month outcomes. METHODS: Preplanned sub-analysis of the Target Temperature Management-2 trial. Clinical outcomes were mortality and functional status (assessed by the Modified Rankin Scale) 6 months after randomization. RESULTS: A total of 1848 patients were included (mean age 64 [Standard Deviation, SD = 14] years). At 6 months, 950 (51%) patients were alive and 898 (49%) were dead. Median tidal volume (VT) was 7 (Interquartile range, IQR = 6.2-8.5) mL per Predicted Body Weight (PBW), positive end expiratory pressure (PEEP) was 7 (IQR = 5-9) cmH20, plateau pressure was 20 cmH20 (IQR = 17-23), driving pressure was 12 cmH20 (IQR = 10-15), mechanical power 16.2 J/min (IQR = 12.1-21.8), ventilatory ratio was 1.27 (IQR = 1.04-1.6), and respiratory rate was 17 breaths/minute (IQR = 14-20). Median partial pressure of oxygen was 87 mmHg (IQR = 75-105), and partial pressure of carbon dioxide was 40.5 mmHg (IQR = 36-45.7). Respiratory rate, driving pressure, and mechanical power were independently associated with 6-month mortality (omnibus p-values for their non-linear trajectories: p < 0.0001, p = 0.026, and p = 0.029, respectively). Respiratory rate and driving pressure were also independently associated with poor neurological outcome (odds ratio, OR = 1.035, 95% confidence interval, CI = 1.003-1.068, p = 0.030, and OR = 1.005, 95% CI = 1.001-1.036, p = 0.048). A composite formula calculated as [(4*driving pressure) + respiratory rate] was independently associated with mortality and poor neurological outcome. CONCLUSIONS: Protective ventilation strategies are commonly applied in patients after cardiac arrest. Ventilator settings in the first 72 h after hospital admission, in particular driving pressure and respiratory rate, may influence 6-month outcomes.

Biomarkers of brain injury after cardiac arrest; a statistical analysis plan from the TTM2 trial biobank investigators.

Background: Several biochemical markers in blood correlate with the magnitude of brain injury and may be used to predict neurological outcome after cardiac arrest. We present a protocol for the evaluation of prognostic accuracy of brain injury markers after cardiac arrest. The aim is to define the best predictive marker and to establish clinically useful cut-off levels for routine implementation. Methods: Prospective international multicenter trial within the Targeted Hypothermia versus Targeted Normothermia after Out-of-Hospital Cardiac Arrest (TTM2) trial in collaboration with Roche Diagnostics International AG. Samples were collected 0, 24, 48, and 72 hours after randomisation (serum) and 0 and 48 hours after randomisation (plasma), and pre-analytically processed at each site before storage in a central biobank. Routine markers neuron-specific enolase (NSE) and S100B, and neurofilament light, total-tau and glial fibrillary acidic protein will be batch analysed using novel Elecsys® electrochemiluminescence immunoassays on a Cobas e601 instrument. Results: Statistical analysis will be reported according to the Standards for Reporting Diagnostic accuracy studies (STARD) and will include comparisons for prediction of good versus poor functional outcome at six months post-arrest, by modified Rankin Scale (0-3 vs. 4-6), using logistic regression models and receiver operating characteristics curves, evaluation of mortality at six months according to biomarker levels and establishment of cut-off values for prediction of poor neurological outcome at 95-100% specificities. Conclusions: This prospective trial may establish a standard methodology and clinically appropriate cut-off levels for the optimal biomarker of brain injury which predicts poor neurological outcome after cardiac arrest.

Management of paediatric traumatic brain injury in Sweden: a national cross-sectional survey.

BACKGROUND: Previous studies have shown variations in management routines for children with traumatic brain injury (TBI) in Sweden. It is unknown if this management has changed after the publication of the Scandinavian Neurotrauma Committee guidelines in 2016 (SNC16). Also, knowledge of current practice routines may guide development of an efficient implementation strategy for the guidelines. The aim of this study is therefore to describe current management routines in paediatric TBI on a hospital/organizational level in Sweden. Secondary aims are to analyse differences in management over time, to assess the current dissemination status of the SNC16 guideline and to analyse possible variations between hospitals. METHODS: This is a sequential, cross-sectional, structured survey in five sections, covering initial management routines for paediatric TBI in Sweden. Respondents, with profound knowledge of local management routines and recommendations, were identified for all Swedish hospitals with an emergency department managing children (age 0-17 year) via phone/mail before distribution of the survey. Responses were collected via an on-line survey system during June 2020-March 2021. Data are presented as descriptive statistics and comparisons were made using Fisher exact test, when applicable. RESULTS: 71 of the 76 identified hospitals managed patients with TBI of all ages and 66 responded (response rate 93%). 56 of these managed children and were selected for further analysis. 76% (42/55) of hospitals have an established guideline to aid in clinical decision making. Children with TBI are predominately managed by inexperienced doctors (84%; 47/56), primarily from non-paediatric specialities (75%; 42/56). Most hospitals (75%; 42/56) have the possibility to admit and observe children with TBI of varying degrees and almost all centres have complete access to neuroradiology (96%; 54/56). In larger hospitals, it was more common for nurses to discharge patients without doctor assessment when compared to smaller hospitals (6/9 vs. 9/47; p < 0.001). Presence of established guidelines (14/51 vs. 42/55; p < 0.001) and written observation routines (16/51 vs. 29/42; p < 0.001) in hospitals have increased significantly since 2006. CONCLUSIONS: TBI management routines for children in Sweden still vary, with some differences occurring over time. Use of established guidelines, written observation routines and information for patients/guardians have all improved. These results form a baseline for current management and may also aid in guideline implementation.

GFAP and S100B: What You Always Wanted to Know and Never Dared to Ask.

Traumatic brain injury (TBI) is a major global health issue, with outcomes spanning from intracranial bleeding, debilitating sequelae, and invalidity with consequences for individuals, families, and healthcare systems. Early diagnosis of TBI by testing peripheral fluids such as blood or saliva has been the focus of many research efforts, leading to FDA approval for a bench-top assay for blood GFAP and UCH-L1 and a plasma point-of-care test for GFAP. The biomarker S100B has been included in clinical guidelines for mTBI (mTBI) in Europe. Despite these successes, several unresolved issues have been recognized, including the robustness of prior data, the presence of biomarkers in tissues beyond the central nervous system, and the time course of biomarkers in peripheral body fluids. In this review article, we present some of these issues and provide a viewpoint derived from an analysis of existing literature. We focus on two astrocytic proteins, S100B and GFAP, the most commonly employed biomarkers used in mTBI. We also offer recommendations that may translate into a broader acceptance of these clinical tools.

Ventilation management and outcomes in out-of-hospital cardiac arrest: a protocol for a preplanned secondary analysis of the TTM2 trial.

INTRODUCTION: Mechanical ventilation is a fundamental component in the management of patients post cardiac arrest. However, the ventilator settings and the gas-exchange targets used after cardiac arrest may not be optimal to minimise post-anoxic secondary brain injury. Therefore, questions remain regarding the best ventilator management in such patients. METHODS AND ANALYSIS: This is a preplanned analysis of the international randomised controlled trial, targeted hypothermia versus targeted normothermia after out-of-hospital cardiac arrest (OHCA)-target temperature management 2 (TTM2). The primary objective is to describe ventilatory settings and gas exchange in patients who required invasive mechanical ventilation and included in the TTM2 trial. Secondary objectives include evaluating the association of ventilator settings and gas-exchange values with 6 months mortality and neurological outcome. Adult patients after an OHCA who were included in the TTM2 trial and who received invasive mechanical ventilation will be eligible for this analysis. Data collected in the TTM2 trial that will be analysed include patients' prehospital characteristics, clinical examination, ventilator settings and arterial blood gases recorded at hospital and intensive care unit (ICU) admission and daily during ICU stay. ETHICS AND DISSEMINATION: The TTM2 study has been approved by the regional ethics committee at Lund University and by all relevant ethics boards in participating countries. No further ethical committee approval is required for this secondary analysis. Data will be disseminated to the scientific community by abstracts and by original articles submitted to peer-reviewed journals. TRIAL REGISTRATION NUMBER: NCT02908308.

Dynamics of IgG-avidity and antibody levels after Covid-19.

BACKGROUND: A potentially important aspect of the humoral immune response to Covid-19 is avidity, the overall binding strength between antibody and antigen. As low avidity is associated with a risk of re- infection in several viral infections, avidity might be of value to predict risk for reinfection with covid-19. OBJECTIVES: The purpose of this study was to describe the maturation of IgG avidity and the antibody-levels over time in patients with PCR-confirmed non-severe covid-19. STUDY DESIGN: Prospective longitudinal cohort study including patients with RT-PCR confirmed covid-19. Blood samples were drawn 1, 3 and 6 months after infection. Antibody levels and IgG-avidity were analysed. RESULTS: The majority had detectable s- and n-antibodies (88,1%, 89,1%, N = 75). The level of total n-antibodies significantly increased from 1 to 3 months (median value 28,3 vs 39,3 s/co, p<0.001) and significantly decreased from 3 to 6 months (median value 39,3 vs 17,1 s/co, p<0.001). A significant decrease in the IgG anti-spike levels (median value 37,6, 24,1 and 18,2 RU/ml, p<0.001) as well as a significant increase in the IgG-avidity index (median values 51,6, 66,0 and 71,0%, p<0.001) were seen from 1 to 3 to 6 months. CONCLUSION: We found a significant ongoing increase in avidity maturation after Covid-19 whilst the levels of antibodies were declining, suggesting a possible aspect of long-term immunity.

Caregiver burden and health-related quality of life amongst caregivers of out-of-hospital cardiac arrest survivors.

AIMS: To describe burden and health-related quality of life amongst caregivers of out-of-hospital cardiac arrest survivors and explore the potential association with cognitive function of the survivors. Caregivers of patients with ST-elevation myocardial infarction were used as controls. METHODS: Data were collected from the cognitive substudy of the Targeted Temperature Management-trial. Caregiver burden was assessed with the 22-item Zarit Burden Interview, with scores ≤20 considered as no burden. Health-related quality of life was assessed with the SF-36v2®, with T-scores 47-53 representing the norm. Cardiac arrest survivors were categorized based on the results from cognitive assessments as having "no cognitive impairment" or "cognitive impairment". RESULTS: Follow-up 6 months post event was performed for caregivers of 272 cardiac arrest survivors and 108 matched myocardial infarction controls, included at an intended ratio of 2:1. In general, caregivers of cardiac arrest survivors and controls reported similar caregiver burden. The overall scores for quality of life were within normative levels and similar for caregivers of cardiac arrest survivors and control patients. Compared to those with no cognitive impairment, caregivers of cognitively impaired cardiac arrest survivors (n = 126) reported higher levels of burden (median 18 versus 8, p < 0.001) and worse quality of life in five of eight domains, particularly "Role-Emotional" (mean 45.7 versus 49.5, p = 0.002). CONCLUSIONS: In general, caregivers of cardiac arrest survivors and myocardial infarction controls reported similar levels of burden and quality of life. Cognitive outcome and functional dependency of the cardiac arrest survivor impact burden and quality of life of the caregiver.

Serum markers of brain injury can predict good neurological outcome after out-of-hospital cardiac arrest.

PURPOSE: The majority of unconscious patients after cardiac arrest (CA) do not fulfill guideline criteria for a likely poor outcome, their prognosis is considered "indeterminate". We compared brain injury markers in blood for prediction of good outcome and for identifying false positive predictions of poor outcome as recommended by guidelines. METHODS: Retrospective analysis of prospectively collected serum samples at 24, 48 and 72 h post arrest within the Target Temperature Management after out-of-hospital cardiac arrest (TTM)-trial. Clinically available markers neuron-specific enolase (NSE) and S100B, and novel markers neurofilament light chain (NFL), total tau, ubiquitin carboxy-terminal hydrolase L1 (UCH-L1) and glial fibrillary acidic protein (GFAP) were analysed. Normal levels with a priori cutoffs specified by reference laboratories or defined from literature were used to predict good outcome (no to moderate disability, Cerebral Performance Category scale 1-2) at 6 months. RESULTS: Seven hundred and seventeen patients were included. Normal NFL, tau and GFAP had the highest sensitivities (97.2-98% of poor outcome patients had abnormal serum levels) and NPV (normal levels predicted good outcome in 87-95% of patients). Normal S100B and NSE predicted good outcome with NPV 76-82.2%. Normal NSE correctly identified 67/190 (35.3%) patients with good outcome among those classified as "indeterminate outcome" by guidelines. Five patients with single pathological prognostic findings despite normal biomarkers had good outcome. CONCLUSION: Low levels of brain injury markers in blood are associated with good neurological outcome after CA. Incorporating biomarkers into neuroprognostication may help prevent premature withdrawal of life-sustaining therapy.