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Background/objective: Post-cardiac arrest patients are vulnerable to hypoxic-ischaemic brain injury (HIBI), but HIBI may not be identified until computed tomography (CT) scan of the brain is obtained post-resuscitation and stabilization. We aimed to evaluate the association of clinical arrest characteristics with early CT findings of HIBI to identify those at the highest risk for HIBI., Methods: This is a retrospective analysis of out-of-hospital cardiac arrest (OHCA) patients who underwent whole-body imaging. Head CT reports were analyzed with an emphasis on findings suggestive of HIBI; HIBI was present if any of the following were noted on the neuroradiologist read: global cerebral oedema, sulcal effacement, blurred grey-white junction, and ventricular compression. The primary exposure was duration of cardiac arrest. Secondary exposures included age, cardiac vs noncardiac etiology, and witnessed vs unwitnessed arrest. The primary outcome was CT findings of HIBI., Results: A total of 180 patients (average age 54 years, 32% female, 71% White, 53% witnessed arrest, 32% cardiac etiology of arrest, mean CPR duration of 15 ± 10 minutes) were included in this analysis. CT findings of HIBI were seen in 47 (48.3%) patients. Multivariate logistic regression demonstrated a significant association between CPR duration and HIBI (adjusted OR = 1.1, 95% CI 1.01-1.11, p < 0.01)., Conclusion: Signs of HIBI are commonly seen on CT head within 6 hours of OHCA, occurring in approximately half of patients, and are associated with CPR duration. Determining risk factors for abnormal CT findings can help clinically identify patients at higher risk for HIBI and target interventions appropriately., Competing Interests: Declaration of Competing Interest Vasisht Srinivasan: None. Jane Hall: Institutional consulting work. Sarah Wahlster: Institutional pilot grant funding. Nicholas J Johnson: Consulting with Neuroptics, Inc., Opticyte Inc, participation in SCCM and Penn TTM Academy. Kelley Branch: Consulting with Janssen, Bayer, Sana, participation on DSMB/advisory board with Janssen and Bayer, leadership role with Society of Cardiovascular CT., (Copyright © 2023 Elsevier B.V. All rights reserved.)

The cerebral oxygen cascade includes three key stages: (a) convective oxygen delivery representing the bulk flow of oxygen to the cerebral vascular bed; (b) diffusion of oxygen from the blood into brain tissue; and (c) cellular utilisation of oxygen for aerobic metabolism. All three stages may become dysfunctional after resuscitation from cardiac arrest and contribute to hypoxic-ischaemic brain injury (HIBI). Improving convective cerebral oxygen delivery by optimising cerebral blood flow has been widely investigated as a strategy to mitigate HIBI. However, clinical trials aimed at optimising convective oxygen delivery have yielded neutral results. Advances in the understanding of HIBI pathophysiology suggest that impairments in the stages of the oxygen cascade pertaining to oxygen diffusion and cellular utilisation of oxygen should also be considered in identifying therapeutic strategies for the clinical management of HIBI patients. Culprit mechanisms for these impairments may include a widening of the diffusion barrier due to peri-vascular oedema and mitochondrial dysfunction. An integrated approach encompassing both intra-parenchymal and non-invasive neuromonitoring techniques may aid in detecting pathophysiologic changes in the oxygen cascade and enable patient-specific management aimed at reducing the severity of HIBI., (© 2023. The Author(s).)

Background: Impaired cerebrovascular reactivity (CVR) is one feature of post cardiac arrest encephalopathy. We studied the incidence and features of CVR by near infrared spectroscopy (NIRS) and associations with outcome and biomarkers of brain injury., Methods: A post-hoc analysis of 120 comatose OHCA patients continuously monitored with NIRS and randomised to low- or high-normal oxygen, carbon dioxide and mean arterial blood pressure (MAP) targets for 48 h. The tissue oximetry index (TO x ) generated by the moving correlation coefficient between cerebral tissue oxygenation measured by NIRS and MAP was used as a dynamic index of CVR with TO x  > 0 indicating impaired reactivity and TO x  > 0.3 used to delineate the lower and upper MAP bounds for disrupted CVR. TO x was analysed in the 0-12, 12-24, 24-48 h time-periods and integrated over 0-48 h. The primary outcome was the association between TO x and six-month functional outcome dichotomised by the cerebral performance category (CPC1-2 good vs. 3-5 poor). Secondary outcomes included associations with MAP bounds for CVR and biomarkers of brain injury., Results: In 108 patients with sufficient data to calculate TO x , 76 patients (70%) had impaired CVR and among these, chronic hypertension was more common (58% vs. 31%, p = 0.002). Integrated TO x for 0-48 h was higher in patients with poor outcome than in patients with good outcome (0.89 95% CI [- 1.17 to 2.94] vs. - 2.71 95% CI [- 4.16 to - 1.26], p = 0.05). Patients with poor outcomes had a decreased upper MAP bound of CVR over time (p = 0.001), including the high-normal oxygen (p = 0.002), carbon dioxide (p = 0.012) and MAP (p = 0.001) groups. The MAP range of maintained CVR was narrower in all time intervals and intervention groups (p < 0.05). NfL concentrations were higher in patients with impaired CVR compared to those with intact CVR (43 IQR [15-650] vs 20 IQR [13-199] pg/ml, p = 0.042)., Conclusion: Impaired CVR over 48 h was more common in patients with chronic hypertension and associated with poor outcome. Decreased upper MAP bound and a narrower MAP range for maintained CVR were associated with poor outcome and more severe brain injury assessed with NfL. Trial registration ClinicalTrials.gov, NCT02698917 ., (© 2021. The Author(s).)

Background: Birth-related acute profound hypoxic-ischaemic brain injury has specific patterns of damage including the paracentral lobules.Objective: To test the hypothesis that there is anatomically coherent regional volume loss of the corpus callosum as a result of this hemispheric abnormality.Materials and Methods: Study subjects included 13 children with proven acute profound hypoxic-ischaemic brain injury and 13 children with developmental delay but no brain abnormalities. A computerised system divided the corpus callosum into 100 segments, measuring each width. Principal component analysis grouped the widths into contiguous anatomical regions. We conducted analysis of variance of corpus callosum widths as well as support vector machine stratification into patient groups.Results: There was statistically significant narrowing of the mid-posterior body and genu of the corpus callosum in children with hypoxic-ischaemic brain injury. Support vector machine analysis yielded over 95% accuracy in patient group stratification using the corpus callosum centile widths.Conclusion: Focal volume loss is seen in the corpus callosum of children with hypoxic-ischaemic brain injury secondary to loss of commissural fibres arising in the paracentral lobules. Support vector machine stratification into the hypoxic-ischaemic brain injury group or the control group on the basis of corpus callosum width is highly accurate and points towards rapid clinical translation of this technique as a potential biomarker of hypoxic-ischaemic brain injury. [ABSTRACT FROM AUTHOR]

Background A cardiac arrest can lead to hypoxic-ischaemic brain injury which can result in cognitive and emotional impairments and may negatively affect daily functioning, participation in society and quality of life. Furthermore, the impact on the family of the patient can be high. We designed an intervention called 'Stand still..., and move on', which is a concise, individualised, semi-structured intervention for survivors of cardiac arrest and their caregivers, consisting of between one and six face-to-face consultations provided by a trained nurse. The intervention is directed at early detection of cognitive and emotional problems, provision of information, promotion of self-management and referral to specialised care if necessary. The effectiveness of the intervention is being examined in a randomised controlled trial [ISRCTN74835019]. Alongside this trial we performed a process evaluation which aims to investigate the feasibility of the intervention by assessing: 1) the attendance and dose delivered; 2) performance according to protocol; and 3) the opinion of patients, caregivers and nurses on the intervention. Methods Participants of this process evaluation were 97 patients allocated to the intervention group of the RCT, their 91 caregivers, and six nurses who conducted the intervention. Measurement instruments used were evaluation forms for patients and caregivers, registration and evaluation forms for nurses, and semi-structured interviews with nurses. Results Seventy-nine of the patients (81%) allocated to the intervention group and 65 caregivers (71%) participated in the intervention. The mean (SD) number of consultations per patient was 1.8 (1.0), and most consultations were conducted at the patients' home. The intervention was performed largely according to protocol, except that the intervention usually started later than intended, consultations were longer than expected, and the topic of self-management was not regularly addressed. Patients marked the quality of the intervention with a mean score of 7.5 and the performance of the nurse with an 8.0 out of ten. Overall, the intervention was positively evaluated by patients, caregivers and nurses. Conclusions The intervention 'Stand still..., and move on' is a promising intervention which was performed largely according to protocol and seems feasible for implementation after some adaptations, if it is found to be effective. [ABSTRACT FROM AUTHOR]