Prehospital high-dose methylprednisolone in resuscitated out-of-hospital cardiac arrest patients (STEROHCA): a randomized clinical trial

Mechanistic insights into the neuroprotective effects of low-intensity transcranial ultrasound stimulation in post-cardiac arrest brain injury: Modulation of the Piezo1-Dkk3/PI3K-Akt pathway

Post-cardiac arrest brain injury (PCABI) remains a significant challenge, marked by high mortality and disability rates due to persistent neuroinflammation. This study explored the neuroprotective potential of low-intensity transcranial ultrasound stimulation (LITUS) in mitigating brain damage after cardiopulmonary resuscitation (CPR) using a murine model and in vitro assays. LITUS treatment improved 24-h survival rates and neurological recovery in cardiac arrest (CA) mice, as evidenced by behavioral assessments and reduced neurological deficit scores. Proteomic analyses revealed modulation of Piezo1-Dkk3/PI3K-Akt signaling pathway, characterized by decreased pro-inflammatory cytokines (IL-1β, IL-6, TNF-α). Mechanistic studies demonstrated that LITUS enhanced Piezo1 and Dkk3 activation, promoting calcium influx and anti-inflammatory responses. The Piezo1 antagonist GsMTx4 abrogated these effects, underscoring Piezo1's specific role. Additionally, in vitro experiments using oxygen/glucose deprivation and reoxygenation (OGD/R)-treated BV2 microglial cells confirmed that LITUS reduced inflammatory responses and enhanced cellular recovery via the Piezo1-Dkk3 axis. These findings highlight LITUS as a promising non-invasive therapeutic strategy to ameliorate PCABI by modulating neuroinflammation through the Piezo1-Dkk3/PI3K-Akt pathway. This work provides a basis for translational research and potential clinical applications in improving outcomes for CPR survivors.

Metabolic profiles associate with mortality and neurological outcomes in out-of-hospital cardiac arrest patients

BACKGROUND

Out-of-hospital cardiac arrest (OHCA) is associated with high mortality and poor neurological outcome, with significant metabolic changes upon return of spontaneous circulation (ROSC). This study aimed to investigate the association of metabolic derangements with outcomes in patients resuscitated from OHCA.

METHODS

Blood samples from 156 consecutive unconscious OHCA patients in the Targeted Temperature Management trial were analyzed at hospital admission. Metabolic parameters including free fatty acids (FFAs), glucose, lactate, 3-hydroxybutyrate (3-OHB), and insulin were measured. Hierarchical clustering categorized patients based on metabolic response patterns. Thirty-day mortality and neurological outcomes were compared across these clusters.

RESULTS

The median age was 62 years (IQR 54-68) and 87% were male. Hierarchical clustering identified three distinct metabolic profiles. Cluster A showed severe metabolic distress with elevated lactate, high insulin resistance, and modest FFA/3-OHB levels. Cluster B had low FFA/3-OHB levels while Cluster C showed high FFA/3-OHB levels; both were associated with lower lactate and insulin resistance compared with Cluster A. Cluster A was linked to greater cardiac arrest severity, including longer time to ROSC, increased defibrillations, and higher adrenaline use. Thirty-day mortality rates were: Cluster A, 68%; B, 33%; C, 21% (log-rank P < 0.001). Neurological deaths were lowest in Clusters C. Baseline FFA levels were independently associated with neurological death.

CONCLUSION

This study identifies distinct metabolic profiles associated with neurological recovery after cardiac arrest, suggesting a potential link between metabolic states and outcomes that may reflect adaptive brain resilience. These findings highlight the need for further research to explore whether metabolic-targeted interventions could enhance recovery.

Balloon occlusion of the aorta during cardiac arrest -a death blow to the intestines?

BACKGROUND

The use of Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) in non-traumatic cardiac arrest may result in worsened intestinal ischaemia. What are the consequences?

MAIN TEXT

Human data on REBOA in non-traumatic cardiac arrest is limited. In general, cardiac output is reduced during resuscitation, and mesenteric blood flow may be further reduced by intravenous adrenaline (epinephrine). Balloon occlusion of the thoracic aorta will potentially lead to a complete cessation of intestinal blood flow. Experimental studies demonstrate that intestinal damage increases with REBOA inflation time, and that 45-60 min of ischaemia may result in irreversible damage. However, it is unclear when intestinal ischaemia starts to affect patient-oriented outcomes. A barrier for assessing the consequences of intestinal ischemia is that it is a challenge to diagnose. A biomarker for intestinal injury, Intestinal Fatty Acid Binding Protein (IFABP), was elevated in all cardiac arrest patients and had a striking association with mortality in one study. In another study, all patients with intestinal ischemia diagnosed on CT died. However, intestinal ischemia could be a marker of whole-body ischemia and not an independent contributor to poor outcome. The clinical importance of worsened intestinal ischemia by REBOA during cardiac arrest is not established.

CONCLUSION

The impact of intestinal ischaemia following cardiac arrest is uncertain, but ischaemia is likely to be exacerbated by REBOA. However, inflation of the balloon will occur when the patient is still in cardiac arrest and is a means to achieve ROSC. Hence, we argue that the added intestinal ischaemia caused by REBOA may be of limited clinical importance, but this is still to be answered.

Association of white blood cell count with one-year mortality after cardiac arrest

Introduction

Post-resuscitation care of cardiac arrest patients may be complicated by systemic inflammation elicited in response to whole-body ischaemia-reperfusion injury. We assessed the association between early WBC with one-year mortality in a large, unselected population of cardiac arrest patients.

Methods

We collected a retrospective multicentre cohort of ICU-treated CA patients from the Finnish national ICU registry. We used locally estimated scatterplot smoothing (LOESS) curve to assess the association between the most abnormal WBC of the first 24 h in the ICU with the likelihood of death within a year. Multivariable logistic regression analyses were performed to assess the independent association between WBC and one-year mortality. In nested cohort analysis, we tested the association of delay from collapse to return of spontaneous circulation (ROSC) with WBC in linear regression models.

Results

The LOESS curve was U-shaped, with the lowest predicted mortality at 7.5 109/L WBC. Based on this cut-off value, patients were divided into high (≥ 7.5 109/L) and low (< 7.5 109/L) WBC groups. In 4229 patients with high WBC, higher WBC was independently associated with increased one-year mortality (adjusted odds ratio (OR) 1.03 per 109/L, 95 % confidence interval (CI) 1.02-1.04, p < 0.001). In 776 patients with low WBC, lower WBC was independently associated with increased one-year mortality (adjusted OR 0.88 per 109/L, 95 % CI 0.80-0.96, p < 0.001). In a nested cohort analysis, longer ROSC-delay was associated with higher WBC in patients with a shockable rhythm (β = 0.10, R2 = 0.04, p < 0.001).

Conclusions

In this large retrospective cohort, WBC was independently associated with one-year mortality after CA. Mortality was lowest in patients with WBC close to the upper limit of the normal reference range. Although WBC is not useful for outcome prognostication in individual patients, our results support the concept of excess inflammation being a harmful component of the post-cardiac arrest syndrome.

Interleukin 6 blockage alters the plasma metabolome in out-of-hospital cardiac arrest

BACKGROUND

Comatose patients resuscitated from out-of-hospital cardiac arrest (OHCA) exhibit a systemic inflammatory response, as indicated by elevated interleukin-6 (IL-6) levels, which is associated with increased mortality. Tocilizumab, an IL-6 receptor antagonist that reduced C-reactive protein response and markers of myocardial injury in a phase II OHCA trial.

AIM

To describe the early effects of tocilizumab on circulating levels of metabolites in comatose patients resuscitated from OHCA.

METHOD

Patients from the phase-II double-blinded randomized trial (NCT: 03863015) were included in this substudy. A total of 85 comatose patients resuscitated from OHCA were randomized at the time of arrival to the hospital to either tocilizumab 8 mg/kg or placebo, of which 80 received the intervention and did not later withdraw from the study. Plasma samples before randomization and 48 h later were analyzed by a targeted metabolomics approach quantifying 60 circulating metabolites.

RESULTS

Of 80 enrolled patients (median age 62 years (IQR: 54-72), men 66 (83 %)), 39 were randomized to tocilizumab group and 41 to placebo. Comorbidities and cardiac arrest characteristics were overall well-balanced. At hospital arrival, levels of metabolites from the tricarboxylic acid (TCA) cycle were associated with time to return of spontaneous circulation and independently with early levels of IL-6 (all p < 0.05). The early levels of medium-chain acylcarnitines were associated with age, NT-proBNP, estimated glomerular filtration rate, and marker of neurological injury (neurofilament light chain) (all p < 0.01). At 48 h, tocilizumab increased the levels of plasma amino acids, especially threonine, glycine, and serine, by more than a factor of 1.5 (p < 0.01). Two eicosanoids 15(S)-HETE and 12(S)-HETE were 1.9 times higher (p < 0.01).

CONCLUSION

Blocking the IL-6 receptor with tocilizumab early after OHCA impacts circulating metabolites, particularly those within the glycine, serine, and threonine pathways, highlighting the connection between acute systemic inflammation and metabolism. Further, early levels of TCA metabolites are independently associated with early inflammatory response and early medium-chain acylcarnitine with later markers of neurological injury.

Drug therapy versus placebo or usual care for comatose survivors of cardiac arrest; a systematic review with meta-analysis

BACKGROUND

In Europe, approximately 291,000 cardiac arrests occur annually. Despite critical care therapy, hospital mortality remains high. This systematic review assessed whether, in comatose survivors of cardiac arrest, any drug therapy, compared to placebo or usual care, improves outcomes.

METHODS

We searched Medline, EMBASE, the Cochrane Central Register of Controlled Trials, and The International Clinical Trials Registry Platform for randomized controlled trials of drug therapy in comatose survivors of cardiac arrest (last searched 20th October 2024). The primary outcome was mortality at 30 days/hospital discharge. Other outcomes reflected those of the Core Outcome Set for Cardiac Arrest. Risk of bias was assessed using Cochrane Risk-Of-Bias Version 1. Studies of steroids, coenzyme Q10 and thiamine were meta-analysed.

RESULTS

From 2562 records, 207 full texts were screened and 45 studies (5800 patients) investigating 30 therapies were included. Studies were grouped thematically as supportive drug therapies (n = 10), neuroprotective agents (n = 19), and anti-inflammatory/antioxidants (n = 16). Four studies reported reduced mortality at 30 days/hospital discharge: one of the anticholinergic penehyclidine hydrochloride, two of intra-arrest vasopressin and methylprednisolone plus hydrocortisone for post resuscitation shock, and one of the traditional Chinese medicine, shenfu. Studies of steroids, coenzyme Q10 and thiamine were meta-analysed. We could not detect an effect on mortality with steroids (n = 739, risk ratio (RR), 0.93; 95 % CI 0.83-1.04, p = 0.21; I2 = 60 %, low certainty), coenzyme Q10 (n = 107, RR, 0.91; 95 % CI 0.61-1.37, p = 0.65; I2 = 0 %, low certainty), or thiamine (n = 149, RR, 1.11; 95 % CI 0.88-1.40, p = 0.39; I2 = 0 %, very low certainty).

CONCLUSION

In comatose survivors of cardiac arrest, the majority of trials of drug therapy reported no effect on mortality. Meta-analyses of steroids, coenzyme Q10 and thiamine demonstrated no evidence of an effect on mortality. However, the low certainty of evidence warrants further research.

Extracerebral multiple organ dysfunction and interactions with brain injury after cardiac arrest

Cardiac arrest and successful resuscitation cause whole-body ischemia and reperfusion, leading to brain injury and extracerebral multiple organ dysfunction. Brain injury is the leading cause of death and long-term disability in resuscitated survivors, and was conceptualized and treated as an isolated injury, which has neglected the brain-visceral organ crosstalk. Extracerebral organ dysfunction is common and is significantly associated with mortality and poor neurological prognosis after resuscitation. However, detailed description of the characteristics of post-resuscitation multiple organ dysfunction is lacking, and the bidirectional interactions between brain and visceral organs need to be elucidated to explore new treatment for neuroprotection. This review aims to describe current concepts of post-cardiac arrest brain injury and specific characteristics of post-resuscitation dysfunction in cardiovascular, respiratory, renal, hepatic, adrenal, gastrointestinal, and neurohumoral systems. Additionally, we discuss the crosstalk between brain and extracerebral organs, especially focusing on how visceral organ dysfunction and other factors affect brain injury progression. We think that clarifying these interactions is of profound significance on how we treat patients for neural/systemic protection to improve outcome.

Inflammatory response after prehospital high-dose glucocorticoid to patients resuscitated from out-of-hospital cardiac arrest: A sub-study of the STEROHCA trial

BACKGROUND

The post-cardiac arrest syndrome (PCAS) after out-of-hospital cardiac arrest (OHCA) is characterized by a series of pathological events, including inflammation. In the randomized "STERoid for OHCA" (STEROHCA) trial, prehospital high-dose glucocorticoid decreased interleukin (IL) 6 and C-reactive protein levels following resuscitated OHCA. The aim of this predefined sub-study was to assess the inflammatory response the first three days of admission.

METHODS

The STEROHCA trial enrolled 137 OHCA patients randomized to either a single prehospital injection of methylprednisolone 250 mg or placebo. Inflammatory markers, including pro- and anti-inflammatory cytokines, were analyzed in plasma samples, from 0-, 24-, 48-, and 72 h post-admission. Mixed-model analyses were applied using log-transformed data to assess group differences.

RESULTS

The 137 patients included in this sub-study had a median age of 67 years (57 to 74), and the 180-day survival rates were 75% (n = 51/68) and 64% (n = 44/69) in the glucocorticoid and placebo group, respectively. A total of 130 (95%) patients had at least one plasma sample available. The anti-inflammatory cytokine IL-10 was increased at hospital admission in the glucocorticoid group (ratio 2.74 (1.49-5.05), p = 0.006), but the intervention showed the strongest effect after 24 h, decreasing pro-inflammatory levels of IL-6 (ratio 0.06 (0.03-0.10), p < 0.001), IL-8 (ratio 0.53 (0.38-0.75), p < 0.001), macrophage chemokine protein-1 (MCP-1, ratio 0.02 (0.13-0.31), p < 0.001), macrophage inflammatory protein-1-beta (MIP-1b, ratio 0.28 (0.18-0.45), p < 0.001), and tumor necrosis factor-α (TNF-α, ratio 0.6 (0.4-0.8), p = 0.01).

CONCLUSION

Administering high-dose glucocorticoid treatment promptly after resuscitation from OHCA influenced the inflammatory response with a reduction in several systemic proinflammatory cytokines after 24 h.

TRIAL REGISTRATION

EudraCT number: 2020-000855-11; submitted March 30, 2020. URL: https://www.

CLINICALTRIALS

gov; Unique Identifier: NCT04624776.

The detrimental effects of intestinal injury mediated by inflammation are limited in cardiac arrest patients: A prospective cohort study

Background

Ischaemic intestines could be a driver of critical illness through an inflammatory response. We have previously published reports on a biomarker for intestinal injury, plasma Intestinal Fatty Acid Binding Protein (IFABP), and inflammatory biomarkers after out-of-hospital cardiac arrest (OHCA). In this post-hoc study we explored the potential indirect effects of intestinal injury mediated through the inflammatory response on organ dysfunction and mortality.

Methods

We measured IFABP and twenty-one inflammatory biomarkers in 50 patients at admission to intensive care unit after OHCA. First, we stratified patients on median IFABP and compared biomarkers between "low" and "high" IFABP. Second, by causal mediation analysis, we assessed effects of IFABP through the two most important inflammatory biomarkers, interleukin (IL)-6 and terminal complement complex (TCC), on day two circulatory variables, Sequential Organ Failure Assessment (SOFA)-score, and 30-day mortality.

Results

Cytokines and complement activation were higher in the high IFABP group. In mediation analysis, patients on the 75th percentile of IFABP, compared to the 25th percentile, had 53% (95% CI, 33-74; p < 0.001) higher risk of dying, where 13 (95% CI, 3-23; p = 0.01) percentage points were mediated through an indirect effect of IL-6. Similarly, the indirect effect of IFABP through IL-6 on SOFA-score was significant, but smaller than potential other effects. Effects through IL-6 on circulatory variables, and all effects through TCC, were not statistically significant and/or small.

Conclusion

Effects of intestinal injury mediated through inflammation on organ dysfunction and mortality were limited. Small, but significant, effects through IL-6 were noted.Trial registration: ClinicalTrials.gov: NCT02648061.

The agreement between jugular bulb and cerebrospinal fluid lactate levels in patients with out-of-hospital cardiac arrest

We investigated the agreement between the jugular bulb (JB) and cerebrospinal fluid (CSF) lactate levels. The study was conducted from July 2021 to June 2023 as a prospective observational cohort study at a single center. The right jugular vein was accessed, and the placement of JB catheter tip was confirmed using lateral cervical spine X-ray. A lumbar catheter was inserted between the 3rd and 4th lumbar spine of the patient. Lactate levels were measured immediately, 24 h, 48 h, and 72 h after ROSC. In patients with a good neurological prognosis, kappa between JB and CSF lactate levels measured immediately, at 24 h, 48 h, and 72 h after ROSC were 0.08, 0.36, 0.14, - 0.05 (p = 0.65, 0.06, 0.48, and 0.75, respectively). However, in patients with a poor neurological prognosis, kappa between JB and CSF lactate levels measured immediately, at 24 h, 48 h, and 72 h after ROSC were 0.38, 0.21, 0.22, 0.12 (p = 0.001, 0.04, 0.04, and 0.27, respectively). This study demonstrated that JB lactate levels exhibited significant agreement with arterial lactate levels, compared to CSF lactate levels. Therefore, this should be considered when using JB lactate to monitor cerebral metabolism.

Inflammation, endothelial injury, and the acute respiratory distress syndrome after out-of-hospital cardiac arrest

Background

Acute respiratory distress syndrome (ARDS) is often seen in patients resuscitated from out-of-hospital cardiac arrest (OHCA). We aim to test whether inflammatory or endothelial injury markers are associated with the development of ARDS in patients hospitalized after OHCA.

Methods

We conducted a prospective, cohort, pilot study at an urban academic medical center in 2019 that included a convenience sample of adults with non-traumatic OHCA. Blood and pulmonary edema fluid (PEF) were collected within 12 hours of hospital arrival. Samples were assayed for cytokines (interleukin [IL]-1, tumor necrosis factor-α [TNF-α], tumor necrosis factor receptor1 [TNFR1], IL-6), epithelial injury markers (pulmonary surfactant-associated protein D), endothelial injury markers (Angiopoietin-2 [Ang-2] and glycocalyx degradation products), and other proteins (matrix metallopeptidase-9 and myeloperoxidase). Patients were followed for 7 days for development of ARDS, as adjudicated by 3 blinded reviewers, and through hospital discharge for mortality and neurological outcome. We examined associations between biomarker concentrations and ARDS, hospital mortality, and neurological outcome using multivariable logistic regression. Latent phase analysis was used to identify distinct biological classes associated with outcomes.

Results

41 patients were enrolled. Mean age was 58 years, 29% were female, and 22% had a respiratory etiology for cardiac arrest. Seven patients (17%) developed ARDS within 7 days. There were no significant associations between individual biomarkers and development of ARDS in adjusted analyses, nor survival or neurologic status after adjusting for use of targeted temperature management (TTM) and initial cardiac arrest rhythm. Elevated Ang-2 and TNFR-1 were associated with decreased survival (RR = 0.6, 95% CI = 0.3-1.0; RR = 0.5, 95% CI = 0.3-0.9; respectively), and poor neurologic status at discharge (RR = 0.4, 95% CI = 0.2-0.8; RR = 0.4, 95% CI = 0.2-0.9) in unadjusted associations.

Conclusion

OHCA patients have markedly elevated plasma and pulmonary edema fluid biomarker concentrations, indicating widespread inflammation, epithelial injury, and endothelial activation. Biomarker concentrations were not associated with ARDS development, though several distinct biological phenotypes warrant further exploration. Latent phase analysis demonstrated that patients with low biomarker levels aside from TNF-α and TNFR-1 (Class 2) fared worse than other patients. Future research may benefit from considering other tools to predict and prevent development of ARDS in this population.