PURPOSE:To explore modifications of the 2021 European Resuscitation Council/European Society of Intensive Care Medicine (ERC/ESICM) guideline algorithm for neuroprognostication after cardiac arrest to improve its prognostic accuracy. METHODS:Post-hoc analysis of four prospective multicentre studies (TTM, TTM2, KORHN and ProNeCA). We raised the Glasgow Coma Scale motor (GCS-M) inclusion threshold at 72 h after cardiac arrest from the current GCS-M < 4 to GCS-M < 6 (all unconscious patients). Secondly, we included good outcome predictors (GCS-M 4-5, neuron-specific enolase < 17 µg/L, benign electroencephalography patterns ≤ 72 h post-arrest and normal magnetic resonance imaging at 72-168 h post-arrest) in the algorithm. Functional outcome was assessed dichotomously at six months, including modified Rankin Scale 0-3, Cerebral Performance Category 1-2 or Glasgow Outcome Scale 4-5 (no symptoms to moderate disability) as good outcome. RESULTS:We analysed 3,388 patients, of whom 2,079 had GCS-M < 4 at ≥ 72 h. Of the 874 patients identified by the 2021 ERC/ESICM poor outcome criteria, 870 had poor functional outcome (specificity: 99.6% [95%CI 99.0-99.9]). Using the GCS-M < 6 threshold, 366 more patients entered the algorithm (N = 2,445). Seven more patients with poor outcomes were identified, with close to identical specificity. Good outcome predictors thereafter identified 673 patients with potential recovery, of whom 411 (61%) had a good functional outcome at six months. With the updated algorithm, the number of prognosticated patients with an indeterminate prognosis decreased from 1,205/2,079 (58%) to 891/2,445 (36%). CONCLUSION:Raising the GCS-M inclusion threshold and adding favourable predictors to the 2021 ERC/ESICM prognostication algorithm reduced prognostic uncertainty without increasing falsely pessimistic predictions.

PURPOSE:To assess the risk of self-fulfilling prophecy from withdrawal of life-sustaining therapy (WLST) in comatose cardiac arrest patients undergoing neuroprognostication. METHODS:Post-hoc multicentre study matching adults resuscitated from out-of-hospital cardiac arrests, in WLST-permitting cohorts (TTM and TTM2), and non-WLST-permitting cohorts (KORHN and ProNeCA). We matched patients in a 1:1 ratio based on a propensity score, assessing the risk of WLST due to a presumed poor neurological prognosis and criteria predictive of poor neurological outcome, as outlined in the 2021 European Resuscitation Council/European Society of Intensive Care Medicine (ERC/ESICM) guidelines. Functional outcome was compared at six months. RESULTS:We included 1717 patients, of whom 497 (29 %) had WLST due to neurological criteria at a median of 143 h (IQR 108-177). 303 (61 %) patients with WLST retrospectively fulfilled ≥ 2 ERC/ESICM criteria predictive of poor outcome. No patients with ≥ 2 ERC/ESICM criteria had good functional outcome at six months, neither in the WLST cohort nor among the matched controls. One patient (0.3 %) with an indeterminate prognosis (≤1 ERC/ESICM criteria) had a good functional outcome in the WLST cohort versus 18-26 % of the matched controls. In exploratory weighted estimates, up to 18 % of patients with indeterminate prognosis may have survived with a good functional outcome, if WLST had not occurred. CONCLUSION:In patients with at least 2 ERC/ESICM criteria predictive of poor outcome, the risk of self-fulfilling prophecy from WLST was negligible. However, in patients with an indeterminate prognosis, the practice of WLST was associated with a lower likelihood of good functional outcome.

If an out-of-hospital cardiac arrest (OHCA) takes longer than 15 minutes, the chances of survival are greatly reduced. With a shockable rhythm (VF/VT), there is often a treatable underlying cause, which most often can only be treated in a hospital. The patient can be transported, and circulation can be restored in the hospital, using extracorporeal cardiopulmonary resuscitation (ECPR) to gain time to treat the underlying problem. There are observational studies and one single-centre study that support the use of ECPR in refractory OHCA. However, two recent larger trials could not establish a significant benefit for ECPR. As many of these patients in refractory cardiac arrest will ultimately not survive, we will need solid cost-benefit analyses to evaluate the value of ECPR. We also need to explore the possibility of starting ECPR on scene, to reduce low-flow time even more, and hopefully improve the outcome of out-of-hospital cardiac arrest patients.

Background: Out-of-hospital cardiac arrest (OHCA) survivors generally report good health-related quality of life, but physical aspects of health seem more affected than other domains. Limitations in physical function after surviving OHCA have received little attention. Aims: To describe physical function 6 months after OHCA and compare it with a group of ST elevation myocardial infarction (STEMI) controls, matched for country, age, sex and time of the cardiac event. A second aim was to explore variables potentially associated with self-reported limitations in physical function in OHCA survivors. Methods: A cross-sectional sub-study of the Targeted Temperature Management at 33 degrees C versus 36 degrees C (TTM) trial with a follow-up 6 months post-event. Physical function was the main outcome assessed with the self-reported Physical Functioning-10 items scale (PF-10). PF-10 is presented as T-scores (0-100), where 50 represents the norm mean. Scores <47 at a group level, or <45 at an individual level indicate limitations in physical function. Results: 287 OHCA survivors and 119 STEMI controls participated. Self-reported physical function by PF-10 was significantly lower for OHCA survivors compared to STEMI controls (mean 46.0, SD 11.2 vs. 48.8, SD 9.0, p= 0.025). 38% of OHCA survivors compared to 26% of STEMI controls reported limitations in physical function at an individual level (p = 0.022). The most predictive variables for self-reported limitations in physical function in OHCA survivors were older age, female sex, cognitive impairment, and symptoms of anxiety and depression after 6 months. Conclusion: Self-reported limitations in physical function are more common in OHCA survivors compared to STEMI controls.

PURPOSE OF REVIEW:Brain death, also known as death by neurologic criteria (DNC), is a well-established concept. In this article, we present a short history of the concept and give an overview of recent changes and a practical update on diagnosis and definitions of brain death/DNC. Unresolved issues will be discussed.RECENT FINDINGS:There is variability in brain death/DNC determination worldwide. In recent years, successful attempts have been made to harmonize these criteria and, consequently, to improve public trust in the process and diagnosis. An international multidisciplinary collaboration has been created and it has published minimum criteria, provided guidance for professionals and encouragement to revise or develop guidelines on brain death/DNC worldwide.SUMMARY:There are two sets of criteria for declaration of death. First, if there is neither cardiac output nor respiratory effort, then cardiopulmonary criteria are used. Second, if both the cerebrum and brainstem have completely and permanently lost all functions, and there is a persistent coma, absent brainstem reflexes and no spontaneous respiratory effort, death can be declared on the basis of brain death/DNC. Although attempts to formulate uniform criteria are ongoing, consensus has been reached on the minimum criteria. Some inconsistencies and questions remain.

BACKGROUND: The evidence for temperature control for comatose survivors of cardiac arrest is inconclusive. Controversy exists as to whether the effects of hypothermia differ per the circumstances of the cardiac arrest or patient characteristics. METHODS: An individual patient data meta-analysis of the Targeted Temperature Management at 33°C versus 36°C after Cardiac Arrest (TTM) and Hypothermia versus Normothermia after Out-of-Hospital Cardiac Arrest (TTM2) trials was conducted. The intervention was hypothermia at 33°C and the comparator was normothermia. The primary outcome was all-cause mortality at 6 months. Secondary outcomes included poor functional outcome (modified Rankin scale score of 4 to 6) at 6 months. Predefined subgroups based on the design variables in the original trials were tested for interaction with the intervention as follows: age (older or younger than the median), sex (female or male), initial cardiac rhythm (shockable or nonshockable), time to return of spontaneous circulation (above or below the median), and circulatory shock on admission (presence or absence). RESULTS: The primary analyses included 2800 patients, with 1403 assigned to hypothermia and 1397 to normothermia. Death occurred for 691 of 1398 participants (49.4%) in the hypothermia group and 666 of 1391 participants (47.9%) in the normothermia group (relative risk with hypothermia, 1.03; 95% confidence interval [CI], 0.96 to 1.11; P=0.41). A poor functional outcome occurred for 733 of 1350 participants (54.3%) in the hypothermia group and 718 of 1330 participants (54.0%) in the normothermia group (relative risk with hypothermia, 1.01; 95% CI, 0.94 to 1.08; P=0.88). Outcomes were consistent in the predefined subgroups. CONCLUSIONS: Hypothermia at 33°C did not decrease 6-month mortality compared with normothermia after out-of-hospital cardiac arrest. (Funded by Vetenskapsrådet; ClinicalTrials.gov numbers NCT02908308 and NCT01020916.)

Background and Objectives EEG is widely used for prediction of neurologic outcome after cardiac arrest. To better understand the relationship between EEG and neuronal injury, we explored the association between EEG and neurofilament light (NfL) as a marker of neuroaxonal injury, evaluated whether highly malignant EEG patterns are reflected by high NfL levels, and explored the association of EEG backgrounds and EEG discharges with NfL. Methods We performed a post hoc analysis of the Target Temperature Management After Out-of-Hospital Cardiac Arrest trial. Routine EEGs were prospectively performed after the temperature intervention >= 36 hours postarrest. Patients who awoke or died prior to 36 hours postarrest were excluded. EEG experts blinded to clinical information classified EEG background, amount of discharges, and highly malignant EEG patterns according to the standardized American Clinical Neurophysiology Society terminology. Prospectively collected serum samples were analyzed for NfL after trial completion. The highest available concentration at 48 or 72 hours postarrest was used. Results A total of 262/939 patients with EEG and NfL data were included. Patients with highly malignant EEG patterns had 2.9 times higher NfL levels than patients with malignant patterns and NfL levels were 13 times higher in patients with malignant patterns than those with benign patterns (95% CI 1.4-6.1 and 6.5-26.2, respectively; effect size 0.47; p < 0.001). Both background and the amount of discharges were independently strongly associated with NfL levels (p < 0.001). The EEG background had a stronger association with NfL levels than EEG discharges (R-2 = 0.30 and R-2 = 0.10, respectively). NfL levels in patients with a continuous background were lower than for any other background (95% CI for discontinuous, burst-suppression, and suppression, respectively: 2.26-18.06, 3.91-41.71, and 5.74-41.74; effect size 0.30; p < 0.001 for all). NfL levels did not differ between suppression and burst suppression. Superimposed discharges were only associated with higher NfL levels if the EEG background was continuous. Discussion Benign, malignant, and highly malignant EEG patterns reflect the extent of brain injury as measured by NfL in serum. The extent of brain injury is more strongly related to the EEG background than superimposed discharges. Combining EEG and NfL may be useful to better identify patients misclassified by single methods.

Rationale: Delirium is common in critically ill patients and is associated with deleterious outcomes. Nonpharmacological interventions are recommended in current delirium guidelines, but their effects have not been unequivocally established. Objectives: To determine the effects of a multicomponent nursing intervention program on delirium in the ICU. Methods: A stepped-wedge cluster-randomized controlled trial was conducted in ICUs of 10 centers. Adult critically ill surgical, medical, or trauma patients at high risk of developing delirium were included. A multicomponent nursing intervention program focusing on modifiable risk factors was implemented as standard of care. The primary outcome was the number of delirium-free and coma-free days alive in 28 days after ICU admission. Measurements and Main Results: A total of 1,749 patients were included. Time spent on interventions per 8-hour shift was median (interquartile range) 38 (14-116) minutes in the intervention period and median 32 (13-73) minutes in the control period (P= 0.44). Patients in the intervention period had a median of 23 (4-27) delirium-free and coma-free days alive compared with a median of 23 (5-27) days for patients in the control group (mean difference, -1.21 days; 95% confidence interval, -2.84 to 0.42 d; P= 0.15). In addition, the number of delirium days was similar: median 2 (1-4) days (ratio of medians, 0.90; 95% confidence interval, 0.75 to 1.09; P = 0.27). Conclusions: In this large randomized controlled trial in adult ICU patients, a limited increase in the use of nursing interventions was achieved, and no change in the number of delirium-free and coma-free days alive in 28 days could be determined.

A prospective cohort study recently published in JAMA looked at the difference in survival to hospital discharge between intra-arrest transport vs continued on-scene resuscitation among patients with out-of-hospital cardiac arrest (OHCA). The conclusion of this study is that intra-arrest transport is associated with a lower survival compared to continuous on-site treatment. Research by the Amsterdam Resuscitation Study (ARREST) shows that in OHCA patients who are transported intra-arrest, survival decreases significantly if the time on-scene increases. Patients who are transported within 20 minutes have the highest chance of survival. This suggests that the decision for transport should be made early in the resuscitation process. National and regional circumstances (availability of a mobile medical team, distance to hospital etc.), and pre-hospital resuscitation treatments may make that different scenarios can be considered. In some scenarios extracorporeal cardiopulmonary resuscitation (eCPR) can be brought to the patient; in other scenarios the patient can be transported to the eCPR.

Background: The SpO(2)/FiO(2) is a useful oxygenation parameter with prognostic capacity in patients with ARDS. We investigated the prognostic capacity of SpO(2)/FiO(2) for mortality in patients with ARDS due to COVID-19. Methods: This was a post-hoc analysis of a national multicenter cohort study in invasively ventilated patients with ARDS due to COVID-19. The primary endpoint was 28-day mortality. Results: In 869 invasively ventilated patients, 28-day mortality was 30.1%. The SpO(2)/FiO(2) on day 1 had no prognostic value. The SpO(2)/FiO(2) on day 2 and day 3 had prognostic capacity for death, with the best cut-offs being 179 and 199, respectively. Both SpO(2)/FiO(2) on day 2 (OR, 0.66 [95%-CI 0.46-0.96]) and on day 3 (OR, 0.70 [95%-CI 0.51-0.96]) were associated with 28-day mortality in a model corrected for age, pH, lactate levels and kidney dysfunction (AUROC 0.78 [0.76-0.79]). The measured PaO2/FiO(2) and the PaO2/FiO(2) calculated from SpO(2)/FiO(2) were strongly correlated (Spearman's r = 0.79). Conclusions: In this cohort of patients with ARDS due to COVID-19, the SpO(2)/FiO(2) on day 2 and day 3 are independently associated with and have prognostic capacity for 28-day mortality. The SpO(2)/FiO(2) is a useful metric for risk stratification in invasively ventilated COVID-19 patients. (C) 2021 The Authors. Published by Elsevier Inc.

Outcome prognostication after cardiac arrest (CA) is challenging. Current multimodal prediction approaches would benefit from new biomarkers. MicroRNAs constitute a novel class of disease markers and circulating levels of brain-enriched ones have been associated with outcome after CA. To determine whether these levels reflect the extent of brain damage in CA patients, we assessed their correlation with neuron-specific enolase (NSE), a marker of brain damage. Blood samples taken 48 h after return of spontaneous circulation from two groups of patients from the Targeted Temperature Management trial were used. Patients were grouped depending on their neurological outcome at six months. Circulating levels of microRNAs were assessed by sequencing. NSE was measured at the same time-point. Among the 673 microRNAs detected, brain-enriched miR9-3p, miR124-3p and miR129-5p positively correlated with NSE levels (allp< 0.001). Interestingly, these correlations were absent when only the good outcome group was analyzed (p> 0.5). Moreover, these correlations were unaffected by demographic and clinical characteristics. All three microRNAs predicted neurological outcome at 6 months. Circulating levels of brain-enriched microRNAs are correlated with NSE levels and hence can reflect the extent of brain injury in patients after CA. This observation strengthens the potential of brain-enriched microRNAs to aid in outcome prognostication after CA.

OBJECTIVE:Neurological outcome prediction is crucial early after cardiac arrest. Serum biomarkers released from brain cells after hypoxic-ischaemic injury may aid in outcome prediction. The only serum biomarker presently recommended in the European Resuscitation Council prognostication guidelines is neuron-specific enolase (NSE), but NSE has limitations. In this study, we therefore analyzed the outcome predictive accuracy of the serum biomarkers glial fibrillary acidic protein (GFAP) and ubiquitin C-terminal hydrolase-L1 (UCH-L1) in patients after cardiac arrest. METHODS:Serum GFAP and UCH-L1 were collected at 24, 48 and 72 h after cardiac arrest. The primary outcome was neurological function at 6-month follow-up assessed by the cerebral performance category scale (CPC), dichotomized into good (CPC1-2) and poor (CPC3-5). Prognostic accuracies were tested with receiver-operating characteristics by calculating the area under the receiver-operating curve (AUROC) and compared to the AUROC of NSE. RESULTS:717 patients were included in the study. GFAP and UCH-L1 discriminated between good and poor neurological outcome at all time-points when used alone (AUROC GFAP 0.88-0.89; UCH-L1 0.85-0.87) or in combination (AUROC 0.90-0.91). The combined model was superior to GFAP and UCH-L1 separately and NSE (AUROC 0.75-0.85) at all time-points. At specificities ≥95%, the combined model predicted poor outcome with a higher sensitivity than NSE at 24 h and with similar sensitivities at 48 and 72 h. CONCLUSION:GFAP and UCH-L1 predicted poor neurological outcome with high accuracy. Their combination may be of special interest for early prognostication after cardiac arrest where it performed significantly better than the currently recommended biomarker NSE.

Background Arginine vasopressin has complex actions in critically ill patients, involving vasoregulatory status, plasma volume, and cortisol levels. Copeptin, a surrogate marker for arginine vasopressin, has shown promising prognostic features in small observational studies and is used clinically for early rule out of acute coronary syndrome. The objective of this study was to explore the association between early measurements of copeptin, circulatory status, and short-term survival after out-of-hospital cardiac arrest. Methods Serial blood samples were collected at 24, 48, and 72 h as part of the target temperature management at 33 °C versus 36 °C after cardiac arrest trial, an international multicenter randomized trial where unconscious survivors after out-of-hospital cardiac arrest were allocated to an intervention of 33 or 36 °C for 24 h. Primary outcome was 30-day survival with secondary endpoints circulatory cause of death and cardiovascular deterioration composite; in addition, we examined the correlation with extended the cardiovascular sequential organ failure assessment (eCvSOFA) score. Results Six hundred ninety patients were included in the analyses, of whom 203 (30.3%) developed cardiovascular deterioration within 24 h, and 273 (39.6%) died within 30 days. Copeptin measured at 24 h was found to be independently associated with 30-day survival, hazard ratio 1.17 [1.06–1.28], p = 0.001; circulatory cause of death, odds ratio 1.03 [1.01–1.04], p = 0.001; and cardiovascular deterioration composite, odds ratio of 1.05 [1.02–1.08], p < 0.001. Copeptin at 24 h was correlated with eCvSOFA score with rho 0.19 [0.12–0.27], p < 0.001. Conclusion Copeptin is an independent marker of severity of the post cardiac arrest syndrome, partially related to circulatory failure. Trial registration Clinical Trials, NCT01020916 . Registered November 26, 2009.

BACKGROUND:Less than 500 participants have been included in randomized trials comparing hypothermia with regular care for out-of-hospital cardiac arrest patients, and many of these trials were small and at a high risk of bias. Consequently, the accrued data on this potentially beneficial intervention resembles that of a drug following small phase II trials. A large confirmatory trial is therefore warranted. METHODS:The TTM2-trial is an international, multicenter, parallel group, investigator-initiated, randomized, superiority trial in which a target temperature of 33°C after cardiac arrest will be compared with a strategy to maintain normothermia and early treatment of fever (≥37.8°C). Participants will be randomized within 3 hours of return of spontaneous circulation with the intervention period lasting 40 hours in both groups. Sedation will be mandatory for all patients throughout the intervention period. The clinical team involved with direct patient care will not be blinded to allocation group due to the inherent difficulty in blinding the intervention. Prognosticators, outcome-assessors, the steering group, the trial coordinating team, and trial statistician will be blinded. The primary outcome will be all-cause mortality at 180 days after randomization. We estimate a 55% mortality in the control group. To detect an absolute risk reduction of 7.5% with an alpha of 0.05 and 90% power, 1900 participants will be enrolled. The main secondary neurological outcome will be poor functional outcome (modified Rankin Scale 4-6) at 180 days after arrest. DISCUSSION:The TTM2-trial will compare hypothermia to 33°C with normothermia and early treatment of fever (≥37.8°C) after out-of-hospital cardiac arrest.

Ward doctors in regular medical departments have to be competent in declaring the death of a patient. The majority of literature on confirmation of death focuses on special circumstances, including intensive care patients and cases involving organ donation. There is no consensus regarding the procedure and criteria for declaration of death in a 'normal' patient on a medical ward. In this article we describe the death criteria, changes that occur in the body following death, and how death can be declared in in a 'normal' patient on a medical ward and in special circumstances.

Purpose: To investigate age-related differences in outcomes of critically ill patients with sepsis around the world. Methods: We performed a secondary analysis of data from the prospective ICON audit, in which all adult ( >16 years ) patients admitted to participating ICUs between May 8 and 18, 2012, were included, except admissions for routine postoperative observation. For this sub-analysis, the 10,012 patients with completed age data were included. They were divided into five age groups - <= 50, 51-60, 61-70, 71-80, >80 years. Sepsis was defined as infection plus at least one organ failure. Results: A total of 2963 patients had sepsis, with similar proportions across the age groups (<= 50 = 25.2%: 51-60 = 30.3%; 61-70 = 32.8%; 71-80 = 30.7%; >80 = 30.9%). Hospital mortality increased with age and in patients >80 years was almost twice that of patients <= 50 years (493% vs 25.2%, p < .05). The maximum rate of increase in mortality was about 0.75% per year, occurring between the ages of 71 and 77 years. In multilevel analysis, age > 70 years was independently associated with increased risk of dying. Conclusions: The odds for death in ICU patients with sepsis increased with age with the maximal rate of increase occurring between the ages of 71 and 77 years. (C) 2019 Elsevier Inc. All rights reserved.

Purpose Postresuscitation neuroprognostication is guided by neurophysiological tests, biomarker measurement, and clinical examination. Recent investigations suggest that circulating microRNAs (miRNA) may help in outcome prediction after cardiac arrest. We assessed the ability of miR-574-5p to predict neurological outcome after cardiac arrest, in a sex-specific manner. Methods In this substudy of the Target Temperature Management (TTM) Trial, we enrolled 590 cardiac arrest patients for which blood samples were available. Expression levels of miR-574-5p were measured by quantitative PCR in plasma samples collected 48 h after cardiac arrest. The endpoint of the study was poor neurological outcome at 6 months (cerebral performance category scores 3 to 5). Results Eighty-one percent of patients were men, and 49% had a poor neurological outcome. Circulating levels of miR-574-5p at 48 h were higher in patients with a poor neurological outcome at 6 months (p < 0.001), both in women and in men. Circulating levels of miR-574-5p were univariate predictors of neurological outcome (odds ratio (OR) [95% confidence interval (CI)]: 1.5 [1.26-1.78]). After adjustment with clinical variables and NSE, circulating levels of miR-574-5p predicted neurological outcome in women (OR [95% CI]: 1.9 [1.09-3.45]), but not in men (OR [95% CI]: 1.0 [0.74-1.28]). Conclusion miR-574-5p is associated with neurological outcome after cardiac arrest in women.

Purpose: This study investigates the association between mean arterial pressure (MAP) and renal function after out-of-hospital cardiac arrest (OHCA). Materials and methods: Post-hoc analysis of 851 comatose OHCA-patients surviving >48 h included in the targeted temperature management (TTM)-trial. Results: Patients were stratified by mean MAP during TTM in the following groups; <70 mmHg (22%), 70-80 mmHg (43%), and > 80 mmHg (35%). Median (interquartile range) eGFR (ml/min/1.73 m(2)) 48 h after OHCA was inversely associated with MAP-group (70 (47-102), 84 (56-113), 94 (61-124), p <.001, for the <70-group, 70-80-group and > 80-group respectively). After adjusting for potential confounders, in a mixed model including eGFR after 1.2 and 3 days this association remained significant (p(group_adjusted) = 0.0002). Higher mean MAP was independently associated with lower odds of renal replacement therapy (odds ratio(adj)(usted) = 0.77 [95% confidence interval, 0.65-0.91] per 5 mmHg increase; p = .0021). Conclusions: Low mean MAP during TTM was independently associated with decreased renal function and need of renal replacement therapy in a large cohort of comatose OHCA-patients. Increasing MAP above the recommended 65 mmHg could potentially be renal-protective. This hypothesis should be investigated in prospective trials. (C) 2018 Elsevier Inc. All rights reserved.

Exposure to hyperoxemia and hypoxemia is common in out-of-hospital cardiac arrest (OHCA) patients following return of spontaneous circulation (ROSC), but its effects on neurological outcome are uncertain, and study results are inconsistent. Exploratory post hoc substudy of the Target Temperature Management (TTM) trial, including 939 patients after OHCA with return of spontaneous circulation (ROSC). The association between serial arterial partial pressures of oxygen (PaO2) during 37 h following ROSC and neurological outcome at 6 months, evaluated by Cerebral Performance Category (CPC), dichotomized to good (CPC 1–2) and poor (CPC 3–5), was investigated. In our analyses, we tested the association of hyperoxemia and hypoxemia, time-weighted mean PaO2, maximum PaO2 difference, and gradually increasing PaO2 levels (13.3–53.3 kPa) with poor neurological outcome. A subsequent analysis investigated the association between PaO2 and a biomarker of brain injury, peak serum Tau levels. Eight hundred sixty-nine patients were eligible for analysis. Three hundred patients (35%) were exposed to hyperoxemia or hypoxemia at some time point after ROSC. Our analyses did not reveal a significant association between hyperoxemia, hypoxemia, time-weighted mean PaO2 exposure or maximum PaO2 difference and poor neurological outcome at 6-month follow-up after correction for co-variates (all analyses p = 0.146–0.847). We were not able to define a PaO2 level significantly associated with the onset of poor neurological outcome. Peak serum Tau levels at either 48 or 72 h after ROSC were not associated with PaO2. Hyperoxemia or hypoxemia exposure occurred in one third of the patients during the first 37 h of hospitalization and was not significantly associated with poor neurological outcome after 6 months or with the peak s-Tau levels at either 48 or 72 h after ROSC.