Targeted temperature management at 33°C versus 36°C after cardiac arrest

Perioperative Extracorporeal Cardiopulmonary Resuscitation in Adults: A Single-center Retrospective Review and Analysis

BACKGROUND

Extracorporeal cardiopulmonary resuscitation (CPR) for refractory in-hospital cardiac arrest has been associated with improved survival compared with conventional CPR. Perioperative patients represent a unique cohort of the inpatient population. This study aims to describe and analyze the characteristics and outcomes of patients who received extracorporeal CPR for perioperative cardiac arrest.

METHODS

A single-center retrospective review of perioperative extracorporeal CPR in adults from January 2015 to August 2022 was performed. Patient demographics, cardiac arrest variables, and outcome data were obtained and analyzed. The primary study outcome was survival with favorable neurologic outcome.

RESULTS

A total of 33 patients received extracorporeal CPR for perioperative cardiac arrest. Of the 33 patients, 24 (73%) had a cardiac arrest in the cardiac catheterization laboratory, while 9 (27%) had a cardiac arrest in the operating room or interventional radiology suite. Survival to discharge was 57.6%, of whom 17 (89.5%) had neurologically favorable outcomes with cerebral performance category scores of 1 or 2 at discharge. The mean total CPR time was significantly lower in the survivor group than in the nonsurvivor group (16.5 vs . 25.0 min; P < 0.05). Survivors had significantly lower lactate levels (73 mg/dl vs . 115 mg/dl; P = 0.005) and higher pH levels (7.17 vs. 7.03; P = 0.005) compared with nonsurvivors.

CONCLUSIONS

The use of extracorporeal CPR for adults with perioperative cardiac arrest can be associated with excellent survival with neurologically favorable outcomes in carefully selected patients. Longer CPR time, higher lactate levels, and lower pH were associated with increased mortality. Given the small sample size, no other prognostic factors were identified, although certain trends were detected between survival groups.

Changes Over 7 Years in Temperature Control Treatment and Outcomes After Out-of-Hospital Cardiac Arrest: A Japanese, Multicenter Cohort Study

Temperature control is the only neuroprotective intervention suggested in current international guidelines for patients with return of spontaneous circulation after cardiac arrest, but the prevalence of temperature control therapy, temperature settings, and outcomes have not been clearly reported. We aimed to investigate changes over 7 years in provision of temperature control treatment among out-of-hospital cardiac arrest (OHCA) patients in Kanto region, Japan. Data of all adult OHCA patients who survived for more than 24 hours in the prospective cohort studies, SOS-KANTO 2012 (conducted from 2012 to 2013) and SOS-KANTO 2017 (conducted from 2019 to 2021), in Japan were included. We compared the prevalence of temperature control and the proportion of mild (≥35°C) and moderate (from 32°C to 34.9°C) hypothermia between the two study groups. We also performed a Cox regression analysis to evaluate 30-day mortality adjusted by temperature control therapy (none, moderate hypothermia, or mild hypothermia), age, sex, past medical history, witnessed status, bystander cardiopulmonary resuscitation, initial rhythm, location of arrest, and dataset (SOS-KANTO 2012 or 2017). We analyzed data from 2936 patients (n = 1710, SOS-KANTO 2012; n = 1226, SOS-KANTO 2017). Use of temperature control was lower (45.3% vs. 41.4%, p = 0.04), moderate hypothermia was lower (p < 0.01), and mild hypothermia was higher (p < 0.01) in SOS-KANTO 2017 compared with SOS-KANTO 2012. The survival rate was significantly higher for patients with mild (p < 0.01) and moderate (p < 0.01) hypothermia compared with those who did not receive temperature control therapy. Overall, the incidence of moderate hypothermia decreased and that of mild hypothermia increased and the use of temperature control decreased between the two studies conducted 7 years apart in the Kanto area, Japan. Temperature control management might improve survival of patients with OHCA.

Blood glucose levels in out-of-hospital cardiac arrest undergoing targeted temperature management and ECPR

AIM

Targeted temperature management (TTM) for patients undergoing extracorporeal cardiopulmonary resuscitation (ECPR) has not been fully studied. This study aimed to investigate the association between blood glucose levels during TTM and neurological outcomes in out-of-hospital cardiac arrest (OHCA) patients undergoing ECPR.

METHODS

This was a secondary analysis of the SAVE-J II study, a retrospective, multicenter study of OHCA patients treated with ECPR in Japan. The average inpatient blood glucose levels for days 2-4 was divided into four categories (Category 1: 80-140 mg/dL, Category 2: 140-180 mg/dL, Category 3: 180-300 mg/dL, and Category 4: 300 mg/dL or more). The primary outcome was a favorable neurological status.

RESULTS

Multivariable analyses were performed for 891 enrolled patients. There were 153, 278, 142, and 18 patients in categories 1, 2, 3, and 4, respectively. Category 3 blood glucose levels were significantly more associated with unfavorable outcomes than Category 2 (adjusted OR, 0.45; 95 % CI, 0.24-0.81; p = 0.01). Although not statistically significant, Category 1 blood glucose levels may indicate a potential trend toward favorable neurological outcomes compared to Category 2. [adjusted OR, 1.41; 95 % CI, 0.96-2.08; p = 0.079].

CONCLUSIONS

During TTM, blood glucose levels of 180 mg/dL or more were significantly more associated with unfavorable outcomes than those of 140-180 mg/dL, in patients on ECPR. Further studies to evaluate more intensive glucose control than the current target of 140-180 mg/dL are required.

Association of targeted temperature management on progression to brain death after severe anoxic brain injury following cardiac arrest: an observational study

OBJECTIVE

Targeted temperature management (TTM), through its physiological effects on intracranial pressure, may impede the progression to brain death (BD) in severe anoxic brain injury post-cardiac arrest (CA). We examined the potential association between the use of TTM and the occurrence of BD after CA.

DESIGN

Monocentric, retrospective study.

SETTING

Intensive care unit, Versailles Hospital, France.

PARTICIPANTS

Comatose survivors of CA who died from BD or postanoxic encephalopathy (PAE) after 24 hours.

MAIN OUTCOME MEASURES

PAE deaths corresponded to withdrawal of life-sustaining therapy (WLST) due to irreversible postanoxic coma or vegetative state according to prognostication guidelines. BD corresponded to the cessation of cerebral vascularisation secondary to intracranial hypertension. The diagnosis of BD was definite by clinical diagnosis of deep coma according to the Glasgow Coma Scale 3, loss of all brainstem reflexes and the demonstration of apnoea during a hypercapnia test. A cerebral omputed tomography (CT) scan or two isoelectric and unreactive electroencephalograms were used to confirm BD. To identify the independent association between TTM and BD, we conducted a multivariable logistic regression analysis.

RESULTS

Out of 256 patients included between 2005 and 2021, 54.3% received TTM for at least 24 hours, and 56 patients (21.9%) died from BD. In the multivariable analysis, TTM for 24 hours or more was not associated with a decrease in BD (Odds Ratio 1.08, 95% CI 0.51 to 2.32). Factors associated with BD included a total duration of no-flow plus low-flow exceeding 30 min, CA due to neurological causes or hanging and a high arterial partial pressure of carbon dioxide between days 1 and 2 after admission.

CONCLUSIONS

This exploratory analysis of post-CA patients with severe anoxic brain injury did not find an association between TTM ≥24 hours and a reduction in BD. Further studies are needed to identify specific subgroups of post-CA patients for whom TTM may be especially futile or even harmful.

Impact of mild hypercapnia on renal function after out-of-hospital cardiac arrest

BACKGROUND

Acute kidney injury (AKI) is a serious complication of out-of-hospital cardiac arrest (OHCA). Post-resuscitation cardiogenic shock (CS) is a key contributing factor. Targeting a higher arterial carbon dioxide tension may affect AKI after OHCA in patients with or without CS.

METHODS

Pre-planned exploratory study of a multi-national randomised trial comparing targeted mild hypercapnia or targeted normocapnia. The primary outcome was AKI defined by Kidney Disease: Improving Global Outcomes (KDIGO) criteria with modifications. Secondary outcomes included use of renal replacement therapy (RRT) and favourable neurological outcome (Glasgow Outcome Scale Extended, score 5-8) at six-months according to AKI. Exploratory objectives included evaluation of secondary outcomes in patients with both CS and AKI.

RESULTS

We studied 1668 of 1700 TAME patients. AKI occurred in 1203 patients (72.1%) with 596 (49.6%) in the targeted mild hypercapnia group and 607 (50.4%) in the targeted normocapnia group. Stage 3 AKI occurred in 193 patients (23.3%) and 196 patients (23.4%), respectively and RRT in 82 (9.9%) vs 75 patients (8.9%), respectively. At six-months, 237 of 429 no-AKI patients (55.2%) had a favourable neurological outcome compared to 445 of 1111 AKI patients (40.1%) (p < 0.0001). AKI occurred more frequently (P < 0.001) in patients with CS, affecting 936 patients (77.8%). For CS and AKI patients, there were no significant differences any secondary outcome.

CONCLUSIONS

AKI occurred in approximately two-thirds and RRT in approximately one in ten TAME patients without differences according to treatment allocation. CS significantly increased the prevalence of AKI but this effect was not modified by carbon dioxide allocation.

The Pediatric Influence of Cooling Duration on Efficacy in Cardiac Arrest Patients (P-ICECAP): Statistical Methods Planned in the Bayesian, Adaptive, Duration Finding Trial

OBJECTIVES

To determine the optimal cooling duration for children after out-of-hospital cardiac arrest (OHCA) using an adaptive Bayesian trial design.

DESIGN

The Pediatric Influence of Cooling duration on Efficacy in Cardiac Arrest Patients (P-ICECAP) trial is a randomized, response-adaptive duration/dose-finding clinical trial with blinded outcome assessment. Participants are randomized to one of several cooling durations (0, 12, 18, 24, 36, 48, 60, 72, 84, or 96 hr). The first 150 participants are randomized 1:1:1 to 24-, 48-, and 72-hour durations. Response-adaptive randomization is used thereafter to allocate participants based on emerging duration-response data.

SETTING

PICUs.

PATIENTS

Up to 900 pediatric patients 2 days to younger than 18 years old who have survived OHCA and been admitted to an ICU.

INTERVENTIONS

Duration of targeted temperature management using a surface temperature control device.

MEASUREMENTS AND MAIN RESULTS

The primary outcome is the Vineland Adaptive Behavior Scales-Third Edition mortality composite score, assessed at 12 months. Secondary outcomes include changes in the Pediatric Cerebral Performance Category and Pediatric Resuscitation after Cardiac Arrest scores, as well as survival at 12 months. Bayesian modeling is employed to evaluate the duration-response curve and determine the optimal cooling duration. The trial is designed to adaptively update randomization probabilities every 10 weeks, maximizing the allocation of participants to potentially optimal cooling durations. Over 90% power is achieved for the hypothesized scenarios.

CONCLUSIONS

The P-ICECAP trial aims to identify the shortest cooling duration that provides the maximum treatment effect for pediatric OHCA patients. The adaptive design allows for flexibility and efficiency in handling various clinical scenarios, potentially transforming pediatric cardiac arrest care by optimizing hypothermia treatment protocols.

Neuroprotective Effects of Inhaled Xenon Gas on Brain Structural Gray Matter Changes After Out-of-Hospital Cardiac Arrest Evaluated by Morphometric Analysis: A Substudy of the Randomized Xe-Hypotheca Trial

BACKGROUND

We have earlier reported that inhaled xenon combined with hypothermia attenuates brain white matter injury in comatose survivors of out-of-hospital cardiac arrest (OHCA). A predefined secondary objective was to assess the effect of inhaled xenon on the structural changes in gray matter in comatose survivors after OHCA.

METHODS

Patients were randomly assigned to receive either inhaled xenon combined with target temperature management (33 °C) for 24 h (n = 55, xenon group) or target temperature management alone (n = 55, control group). A change of brain gray matter volume was assessed with a voxel-based morphometry evaluation of high-resolution structural brain magnetic resonance imaging (MRI) data with Statistical Parametric Mapping. Patients were scheduled to undergo the first MRI between 36 and 52 h and a second MRI 10 days after OHCA.

RESULTS

Of the 110 randomly assigned patients in the Xe-Hypotheca trial, 66 patients completed both MRI scans. After all imaging-based exclusions, 21 patients in the control group and 24 patients in the xenon group had both scan 1 and scan 2 available for analyses with scans that fulfilled the quality criteria. Compared with the xenon group, the control group had a significant decrease in brain gray matter volume in several clusters in the second scan compared with the first. In a between-group analysis, significant reductions were found in the right amygdala/entorhinal cortex (p = 0.025), left amygdala (p = 0.043), left middle temporal gyrus (p = 0.042), left inferior temporal gyrus (p = 0.008), left parahippocampal gyrus (p = 0.042), left temporal pole (p = 0.042), and left cerebellar cortex (p = 0.005). In the remaining gray matter areas, there were no significant changes between the groups.

CONCLUSIONS

In comatose survivors of OHCA, inhaled xenon combined with targeted temperature management preserved gray matter better than hypothermia alone.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov: NCT00879892.

Impact of Mild Hypothermia As Adjunctive Therapy in Patients With ST-Elevation Myocardial Infarction: A Meta-Analysis and Trial Sequential Analysis of Randomized Controlled Trials

BACKGROUND

The prevention of reperfusion injury remains an unmet need in ST-elevation myocardial infarction (STEMI) patients. Several randomized controlled trials (RCTs) evaluated mild hypothermia as adjunctive therapy during STEMI, with conflicting results.

AIMS

To summarize the evidence about the efficacy and safety of mild hypothermia in patients with STEMI, as well as its conclusiveness through a trial sequential analysis (TSA).

METHODS

PubMed and Scopus electronic databases were screened for eligible studies until August 12, 2024. Efficacy endpoints were all-cause death, infarct size (IS), left ventricular ejection fraction (LVEF), the occurrence of microvascular obstruction (MVO), thrombolysis in myocardial infarction (TIMI) flow grade 3, and the resolution of ST-segment elevation (i.e., > 50-70% from baseline) after the procedure. Safety endpoints included: the incidence of atrial fibrillation (AF), infections, any bleeding, major bleeding, acute and subacute stent thrombosis (STh), cardiogenic shock/pulmonary oedema, and ventricular fibrillation/tachycardia. "Door-to-balloon time" was indicated as the procedural endpoint. Two pre-specified subgroup analyses were planned according to the mean ischemic time and the site of hypothermia induction (intra-coronary vs. extra-coronary). A TSA was run to explore whether the effect estimate of each efficacy outcome could be influenced by further studies.

RESULTS

Ten RCTs were included. Hypothermia did not provide a benefit for any of the specified efficacy endpoints. Furthermore, it enhanced the risk of infection, the risk of STh in patients with a mean ischemic time of less than 4 h, and the risk of AF in patients undergoing extra-coronary hypothermia. Finally, it was also associated with an increased "door-to-balloon time", and a trend toward an increased risk of any bleeding. No significant difference was found for the other endpoints. TSA showed conclusive evidence of an absence of benefit of hypothermia on IS, MVO, LVEF, and TIMI three flow.

CONCLUSIONS

Mild hypothermia is not beneficial and causes relevant delays in clinical management of STEMI patients, raising safety issues mainly related to the occurrence of STh, AF, and infections.

Brain Injury after Cardiac Arrest: Refining Prognosis

This study critically reviews prognostication, brings into focus its "refinement" over the decades, and provides a template for clinicians who must judge the functioning of patients who awaken. This includes the use of diagnostic tests, including neuroimaging, electrophysiology, and laboratory testing that may aid in evaluating neurologic recovery. The article reviews recent guidelines and provides advice informed by many years of clinical experience.

Ghrelin for neuroprotection in post-cardiac arrest coma: a 1-year follow-up of cognitive and psychosocial outcomes

AIMS

Effective treatments to improve brain recovery after cardiac arrest are needed. Ghrelin showed efficacy in experimental models and was associated with lower neuron-specific enolase levels in the clinical Ghrelin in Coma (GRECO) trial. Here, we present cognitive and psychosocial outcomes at 1-year follow-up.

METHODS AND RESULTS

GRECO was a Phase 2 multicentre, double-blind, randomized, placebo-controlled trial in comatose patients after cardiac arrest. The intervention was intravenous acyl-ghrelin 600 μg twice daily or placebo for 1 week, starting within 12 h after the arrest. Patients were assessed after 1 year using cognitive tests and questionnaires measuring participation, health-related quality of life, mood, and caregiver strain. Composite z-scores of the cognitive tests were computed by comparing the scores with those of a norm population and averaging the tests for memory, attention, and executive functioning separately. Groups were compared based on composite z-scores and cut-off scores for psychosocial outcomes. Of the 160 participants originally included, 66 of the 85 participants who survived to 1 year after OHCA completed the psychosocial and cognitive follow-up. The intervention group scored numerically higher across the cognitive domains compared with the control group, but the differences were not statistically significant (memory median = -0.850 vs. -1.385, U = 424.5, P = 0.587; attention median = -0.733 vs. -0.717, U = 420.5, P = 0.548; and executive functioning median = -0.311 vs. -0.482, U = 408.5, P = 0.323). There were significantly fewer signs of depression in the intervention group (U = 322.5, P = 0.014).

CONCLUSION

This predefined secondary analysis found that ghrelin treatment was associated with non-significantly but consistently better cognitive outcomes and significantly fewer signs of depression. This is in line with the primary outcomes.

CLINICAL TRIAL REGISTRATION

Clinicaltrialsregister.eu: EUCTR2018-000005-23-NL.

Association Between the Timing of Coronary Angiography, Targeted Temperature Management, and Neurological Outcomes After Out-of-Hospital Cardiac Arrest: A Nationwide Population-Based Registry Study in Korea

BACKGROUND

Coronary angiography (CAG) and targeted temperature management (TTM) may improve clinical outcomes after out-of-hospital cardiac arrest. This study aimed to assess whether the intervention effects differed according to timing and percutaneous coronary intervention (PCI) performance.

METHODS AND RESULTS

Adult patients with presumed cardiac cause who underwent CAG and TTM within 24 hours following out-of-hospital cardiac arrest were included from the Korean nationwide out-of-hospital cardiac arrest registry. We investigated the associations between the timing of interventions and whether CAG was performed before TTM initiation (CAG-first) and good neurological outcomes. Intervention times were divided into 4 quartiles, and odds ratios (ORs) were calculated with the fourth quartile as the reference. A total of 844 patients were enrolled. CAG and TTM were initiated a median of 2.4 hours (interquartile range [IQR], 1.8-3.2) and 4.3 hours (IQR, 3.2-6.0) after OHCA, respectively. Univariable analysis revealed associations between the earliest intervention groups and good neurological outcomes. However, after adjustment, neither the intervention time nor intervention prioritization was associated with good outcomes. The first quartile of CAG time (<1.8 hours) was associated with good outcomes in the subgroup with PCI (n=570) (adjusted OR [aOR], 1.93 [95% CI, 1.10-3.40]). In the subgroup without PCI (n=274), early TTM initiation (<3.2 hours) and CAG-first were significantly associated with outcomes (aOR, 3.08 [95% CI, 1.36-6.96]; aOR, 0.44 [95% CI, 0.20-0.97]; respectively).

CONCLUSIONS

Neither intervention time nor intervention prioritization was associated with good outcomes. However, early CAG and TTM independently predicted good outcomes in the subgroups with PCI and without PCI, respectively.

Personalized neuron-specific enolase level based on EEG pattern for prediction of poor outcome after cardiac arrest

BACKGROUND

After cardiac arrest (CA), the European recommendations suggest to use a neuron-specific enolase (NSE) level > 60 µg/L at 48-72 h to predict poor outcome. However, the prognostic performance of NSE can vary depending on electroencephalogram (EEG). The objective was to determine whether the NSE threshold which predicts poor outcome varies according to EEG patterns and the effect of electrographic seizures on NSE level.

METHODS

A retrospective study was conducted in a tertiary CA center, using a prospective registry of 155 adult patients comatose 72 h after CA. EEG patterns were classified according to the Westhall classification (benign, malignant or highly malignant). Neurological outcome was evaluated using the CPC scale at 3 months (CPC 3-5 defining a poor outcome).

RESULTS

Participants were 64 years old (IQR [53; 72,5]), and 74% were male. 83% were out-of-hospital CA and 48% were initial shockable rhythm. Electrographic seizures were observed in 5% and 8% of good and poor outcome patients, respectively (p = 0.50). NSE blood levels were significantly lower in the good outcome (median 20 µg/L IQR [15; 30]) compared to poor outcome group (median 110 µg/l IQR [49;308], p < 0,001). Benign EEG was associated with lower level of NSE compared to malignant and highly malignant patterns (p < 0.001). The NSE level was not significantly increased in patients with seizures as compared with malignant patterns (p = 0.15). In patients with a malignant EEG, a NSE > 45.2 µg/L was predictive of unfavorable outcome with 100% specificity and a higher sensitivity (70.8%) compared to the recommended NSE cut-off of 60 µg/l (Se = 66%). Combined to electrographic seizures, a NSE > 53.5 µg/L predicts poor outcome with 100% specificity and a higher sensitivity (77.7%) compared to the recommended cut-off (Se = 66.6%). Combined to a benign EEG, a NSE level > 78.2 µg/L was highly predictive of a poor outcome with a higher specificity (Sp = 100%) compared to the recommended cut-off (Sp = 94%).

CONCLUSION

In comatose patients after AC, a personalized approach of NSE according to EEG pattern could improve the specificity and sensitivity of this biomarker for poor outcome prediction. Compared to others malignant EEG, no significant difference of NSE level was observed in case of electrographic seizures.

Fever Prevention and Neurological Recovery in In-Hospital Cardiac Arrest Survivors at a Limited-Resource Setting

Temperature management plays a critical role in the neurological recovery of cardiac arrest survivors. While advanced device-based temperature control systems are prevalent in high-resource settings, their implementation in low-resource environments remains a challenge. This study aimed to examine the impact of fever prevention on neurological outcomes in cardiac arrest survivors managed without device-based temperature control. We conducted a retrospective study of adult in-hospital cardiac arrest survivors at an academic institution from 2013 to 2020. Patients were included if they were ≥18 years old, survived for at least 72 hours post-return of spontaneous circulation (ROSC), and experienced cardiac arrest in inpatient wards, intensive care units, or the emergency department. Fever was defined as a rectal temperature ≥37.5°C, and neurological outcomes were assessed using the Cerebral Performance Category (CPC) scale at 1 month post-ROSC. A good neurological outcome was defined as CPC 1 or 2. Statistical analyses included chi-square tests and logistic regression to identify predictors of outcomes. Of the 427 patients included, 58.8% experienced fever, and 12.8% achieved a good neurological outcome. Patients with fever were significantly less likely to have favorable outcomes (p < 0.01). Logistic regression revealed that each 1°C increase in body temperature beyond 37.5°C was associated with a 31% reduction in the likelihood of a good outcome (p < 0.01). Other predictors of poor outcomes included prolonged low-flow states and higher pre-arrest frailty scores. Fever is strongly associated with poor neurological outcomes in cardiac arrest survivors, particularly in low-resource settings without device-based temperature management. Effective fever prevention strategies, such as intravenous antipyretics and physical cooling methods, should be prioritized to improve outcomes.

Comparison of hypothermic and normothermic targeted temperature management in out-of-hospital cardiac arrest patients with acute coronary syndrome: a nationwide retrospective study

BACKGROUND

Targeted temperature management (TTM) is considered a beneficial treatment for improving outcomes in patients with OHCA due to acute coronary syndrome (ACS). The comparative benefits of hypothermic TTM (32-34°C) versus normothermic TTM (35-36°C) are unclear. This study compares these TTM strategies in improving neurological outcomes and survival rates in OHCA patients with ACS.

METHODS

We conducted a retrospective analysis using data from the Japanese Association for Acute Medicine Out-of-Hospital Cardiac Arrest (JAAM-OHCA) registry, encompassing 68,110 OHCA patients between June 2014 and December 2020. After applying inclusion and exclusion criteria, 1,217 adult patients with ACS who received TTM were eligible for the study. Patients were categorized into two groups based on their TTM strategy: hypothermic TTM (32-34°C) and normothermic TTM (35-36°C). The primary outcome was 30-day favorable neurological outcome, defined by the Cerebral Performance Category (CPC) scale (CPC 1-2). Secondary outcomes included 30-day survival and adverse event incidence. Statistical analysis involved multivariable logistic regression and propensity score adjustments with inverse probability weighting (IPW) to account for potential confounders.

RESULTS

Of the 1,217 patients, 369 received normothermic TTM and 848 received hypothermic TTM. In both groups, most patients were male, with a median age in the 60s. Approximately 70% had a shockable rhythm at the scene, one-third had a shockable rhythm in-hospital, around 70% had ST segment elevation, and about half received extracorporeal membrane oxygenation. The proportions of patients with 30-day favorable neurological outcomes were 36.6% (135) in the normothermic group and 36.6% (310) in the hypothermic group. No difference in neurological outcomes was observed in the multivariable regression analysis (adjusted OR 1.14, 95% CI 0.84-1.54), and the result was consistent in the IPW analysis (OR 1.11, 95% CI 0.84-1.47). Other outcomes also showed no significant differences.

CONCLUSION

In this nationwide, retrospective study using the JAAM-OHCA registry, we found no significant differences in 30-day favorable neurological outcome, 30-day survival, and adverse event incidences between hypothermic TTM (32-34°C) and normothermic TTM (35-36°C) in adult patients with OHCA due to ACS.

Risk scoring systems for early prediction of short-term mortality in resuscitated out-of-hospital cardiac arrest patients

INTRODUCTION

Out-of-hospital cardiac arrest (OHCA) is a critical condition associated with high mortality rates and neurological impairment among survivors. In comatose OHCA patients who achieve return of spontaneous circulation, early risk stratification is important to inform treatment pathways and potentially improve outcomes. A range of prognostic tools have been developed to predict survival and neurological recovery. Each tool incorporates a unique combination of clinical, biochemical and physiological markers.

AREAS COVERED

This review article evaluates the required clinical data, predictive performances and practical applicability of major risk scores. A literature review was conducted in PubMed and Embase for studies published between January 2000 and October 2024. The review emphasizes the variability in discriminative power among the selected scores, with some models offering high sensitivity and specificity in outcome prediction, while others prioritize simplicity and accessibility.

EXPERT OPINION

Despite the advancements of these tools, limitations persist in data dependency and the clinical adaptability, highlighting areas for future improvement. Integrating artificial intelligence and real-time analytics could enhance predictive accuracy, offering dynamic prognostic capabilities that adapt to individual patient trajectories. This evolution must be grounded in ethical considerations to ensure predictive technologies complement rather than replace clinical judgment, balancing technology's potential with the complexities of individualized patient care.

Evoked potentials in patients with disorders of consciousness

Acute coma in the intensive care unit and persistent disorders of consciousness (DoC) in neuro-rehabilitation are frequent in patients with hypoxic-ischemic encephalopathy after cardiac arrest (CA), traumatic brain injury, intracranial hemorrhage, or ischemic stroke. Reliable prognostication of long-term neurologic outcomes cannot be made by clinical examination alone in the early phase for many patients, and thus, additional investigations are necessary. Evoked potentials provide inexpensive, real-time, high temporal resolution, bedside, quantifiable information on different sensory pathways into the brain including local and global cortical processing. Short-latency somatosensory evoked potentials can reliably predict poor neurologic long-term outcome in the early phase after CA and are recommended by guidelines as one investigation within an early multimodal assessment. Middle-latency and event-related or cognitive evoked potentials provide information on the integrity of more advanced cortical processing, some closely related to consciousness. This information can help to identify those comatose patients with a good prognosis in the acute phase and help to better understand their precise clinical state and the chances of further recovery in patients with persistent DoC in neuro-rehabilitation. Further studies are necessary to improve the applicability of research findings in the clinical sphere.

The Electrographic Effects of Ketamine on Patients With Refractory Status Epilepticus After Cardiac Arrest: A Single-Center Retrospective Cohort

PURPOSE

To investigate the effects of ketamine on patients with refractory status epilepticus after cardiac arrest.

METHODS

In this retrospective cohort, selected EEG segments from patients after cardiac arrest were classified into different EEG patterns (based on background continuity and burden of epileptiform discharges) and spectral profiles (based on the presence of frequency components). For patients who received ketamine, EEG data were compared before, during, and after ketamine infusion; for the no-ketamine group, EEG data were compared at three separated time points during recording. Ketamine usage was determined by clinical providers. Electrographic improvement in epileptiform activity was scored, and the odds ratio was calculated using the Fisher exact test. Functional outcome measures at time of discharge were also examined.

RESULTS

Of a total of 38 patients with postcardiac arrest refractory status epilepticus, 13 received ketamine and 25 did not. All patients were on ≥2 antiseizure medications including at least one sedative infusion (midazolam). For the ketamine group, eight patients had electrographic improvement, compared with only two patients in the no-ketamine group, with an odds ratio of 7.19 (95% confidence interval 1.16-44.65, P value of 0.0341) for ketamine versus no ketamine. Most of the patients who received ketamine had myoclonic status epilepticus, and overall neurologic outcomes were poor with no patients having a favorable outcome.

CONCLUSIONS

For postarrest refractory status epilepticus, ketamine use was associated with electrographic improvement, but with the available data, it is unclear whether ketamine use or EEG improvement can be linked to better functional recovery.

Real-world cost-effectiveness of targeted temperature management in out-of-hospital cardiac arrest survivors: results from an academic medical center

BACKGROUND

Targeted temperature management (TTM) is a common therapeutic intervention, yet its cost-effectiveness remains uncertain. This study aimed to evaluate the real-world cost-effectiveness of TTM compared with that of conventional care in adult out-of-hospital cardiac arrest (OHCA) survivors using clinical patient-level data.

METHODS

We conducted a retrospective cohort study at an academic medical center in the USA to assess the cost-effectiveness of TTM in adult non-traumatic OHCA survivors between 1 January, 2019 and 30 June, 2023. The primary outcome was survival to hospital discharge. Incremental cost-effectiveness ratios (ICERs) were calculated and compared with various decision makers' willingness to pay. Cost-effectiveness acceptability curves were utilized to evaluate the economic attractiveness of TTM. Uncertainty about the incremental cost and effect was explored with a 95% confidence ellipse.

RESULTS

Among 925 non-traumatic OHCA survivors, only 30 (3%) received TTM. After adjusting for potential confounders, the TTM group did not demonstrate a significantly lower cost (delta cost -$5,141, 95% confidence interval [95% CI]: $-35,347 to $25,065, P=0.79) and higher survival to hospital discharge (delta effect 6%, 95% CI: -11% to 23%, P=0.41). Additionally, a 95% confidence ellipse indicated uncertainty reflected by evidence that the true value of the ICER could be in any of the quadrants of the cost-effectiveness plane.

CONCLUSION

Although TTM did not demonstrate a clear survival benefit in this study, its potential cost-effectiveness warrants further investigation with larger sample sizes. These findings highlight the need for additional research to optimize TTM use in OHCA care and inform resource allocation decisions.

Application of high-quality targeted temperature management guided by multimodal brain monitoring in brain protection of patients with cardiac arrest: A case series

RATIONALE

Cardiac arrest (CA) is an acute emergency with high mortality and is closely associated with the risk of brain damage or systemic ischemia-reperfusion injury, post-traumatic stress symptoms.

PATIENT CONCERNS

Targeted temperature management in the intensive care unit can improve the neurological outcomes of patients who are comatose after resuscitation from CA. However, there is often a lack of specific evaluation methods for optimal target temperature settings.

DIAGNOSES

From November 2021 to October 2022, 9 CA patients received prompt cardiopulmonary resuscitation and return of spontaneous circulation after approximately 10 to 30 minutes of cardiopulmonary resuscitation in Xiangya Hospital, Central South University.

INTERVENTIONS

We retrospectively reviewed 9 CA patients' medical data, including demographic characteristics, hemodynamic change, clinically relevant score, imageological examination, transcranial Doppler ultrasonography, electroencephalogram (EEG), somatosensory-evoked potential, and laboratory data.

OUTCOMES

According to the result of each patient's transcranial Doppler ultrasonography, somatosensory-evoked potential, and EEG to formulate an individualized target temperature. Contrary to the internationally recommended target of hypothermia, we found that not all patients require hypothermia therapy to maintain normal cerebrovascular autonomic regulation function. And neuron-specific enolase and S100β in patients showed a downward trend after hypothermia therapy. Compared with before hypothermia treatment, clinically relevant scores were reduced in patients with good prognosis. Intracranial congestion or ischemia was improved and intracranial pressure was reduced in all patients during hypothermia treatment. For patients with good EEG response, the ratio of gray matter in the brain increased and the neurological prognosis was significantly improved. Finally, after 6 months of follow-up, we found 3 patients died and 1 patient had a long-term vegetative state, the other patients had a good prognosis.

LESSONS

Individualized targeted temperature management under the guidance of multimodal brain monitoring plays an important role in brain protection of patients with CA.

Hypothermia improves neuronal network recovery in a human-derived in vitro model of oxygen-deprivation

Mild therapeutic hypothermia showed potential neuroprotective properties during and after cerebral hypoxia or ischemia in experimental animal studies. However, in clinical trials, where hypothermia is mainly applied after reperfusion, results were divergent and neurophysiological effects unclear. In our current study, we employed human-derived neuronal networks to investigate how treatment with hypothermia during hypoxia influences neuronal functionality and whether it improves post-hypoxic recovery. We differentiated neuronal networks from human induced pluripotent stem cells on micro-electrode arrays (MEAs). We studied the effect of hypothermia (34°C)-as well hyperthermia (39°C) - on neuronal functionality during and after hypoxia using MEAs. We also studied the effects on the number of synaptic puncta and cell viability by immunocytochemistry. In comparison to neuronal networks under normothermia, we found that hypothermia during hypoxia improved functional neuronal network recovery, expressed as enhanced neuronal network activity. This was associated with prevention of synaptic loss during and after the hypoxic phase. Furthermore, hypothermia improved cell viability after the hypoxic phase. Instead, hyperthermia during hypoxia had detrimental effects, with an irreversible loss of neuronal network function, loss of synaptic puncta and decreased cell viability. Our results show potential neuroprotective properties of hypothermia occurring during hypoxia, indicating that administering hypothermia to bridge the time to reperfusion may be beneficial in clinical settings.

A Machine Learning-Based Decision Support System for the Prognostication of Neurological Outcomes in Successfully Resuscitated Out-of-Hospital Cardiac Arrest Patients

Background/Objectives: This study uses machine learning and multicenter registry data for analyzing the determinants of a favorable neurological outcome in patients with out-of-hospital cardiac arrest (OHCA) and developing decision support systems for various subgroups. Methods: The data came from the Korean Cardiac Arrest Research Consortium registry, with 2679 patients who underwent OHCA aged 18 or above with the return of spontaneous circulation (ROSC). The dependent variable was a favorable neurological outcome (Cerebral Performance Category score 1-2), and 68 independent variables were included, e.g., first monitored rhythm, in-hospital cardiopulmonary resuscitation (CPR) duration and post-ROSC pH. A random forest was used for identifying the major determinants of the favorable neurological outcome and developing decision support systems for the various subgroups stratified by the major variables. Results: Based on the random forest variable importance, the major determinants of the OHCA patient outcomes were the in-hospital CPR duration (0.0824), in-hospital electrocardiogram on emergency room arrival (0.0692), post-ROSC pH (0.0579), prehospital ROSC before emergency room arrival (0.0565), coronary angiography (0.0527), age (0.0415), first monitored rhythm (EMS) (0.0402), first monitored rhythm (community) (0.0401), early coronary angiography within 24 h (0.0304) and time from scene arrival to CPR stop (0.0301). It was also found that the patients could be divided into six subgroups in terms of their prehospital ROSC and first monitored rhythm (EMS), and that a decision tree could be developed as a decision support system for each subgroup to find the effective cut-off points regarding the in-hospital CPR duration, post-ROSC pH, age and hemoglobin. Conclusions: We identified the major determinants of favorable neurological outcomes in successfully resuscitated patients who underwent OHCA using machine learning. This study demonstrates the strengths of a random forest as an effective decision support system for each stratified subgroup (prehospital ROSC and first monitored rhythm by EMS) to find its own optimal cut-off points for the major in-hospital variables (in-hospital CPR duration, post-ROSC pH, age and hemoglobin).

2024 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations: Summary From the Basic Life Support; Advanced Life Support; Pediatric Life Support; Neonatal Life Support; Education, Implementation, and Teams; and First Aid Task Forces

This is the eighth annual summary of the International Liaison Committee on Resuscitation International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations; a more comprehensive review was done in 2020. This latest summary addresses the most recent published resuscitation evidence reviewed by the International Liaison Committee on Resuscitation task force science experts. Members from 6 International Liaison Committee on Resuscitation task forces have assessed, discussed, and debated the quality of the evidence, using Grading of Recommendations Assessment, Development, and Evaluation criteria, and their statements include consensus treatment recommendations. Insights into the deliberations of the task forces are provided in the Justification and Evidence-to-Decision Framework Highlights sections. In addition, the task forces list priority knowledge gaps for further research.

Optimizing brain protection after cardiac arrest: advanced strategies and best practices

Cardiac arrest (CA) is associated with high incidence and mortality rates. Among patients who survive the acute phase, brain injury stands out as a primary cause of death or disability. Effective intensive care management, including targeted temperature management, seizure treatment and maintenance of normal physiological parameters, plays a crucial role in improving survival and neurological outcomes. Current guidelines advocate for neuroprotective strategies to mitigate secondary brain injury following CA, although certain treatments remain subjects of debate. Clinical examination and neuroimaging studies, both invasive and non-invasive neuromonitoring methods and serum biomarkers are valuable tools for predicting outcomes in comatose resuscitated patients. Neuromonitoring, in particular, provides vital insights for identifying complications, personalizing treatment approaches and forecasting prognosis in patients with brain injury post-CA. In this review, we offer an overview of advanced strategies and best practices aimed at optimizing brain protection after CA.

Characteristics and outcomes of adults with acute brain injuries admitted to intensive care units in Australia and New Zealand from 2013 to 2022

BACKGROUND

The characteristics and outcomes of patients with acute brain injuries admitted to the intensive care unit (ICU) in Australia and New Zealand (ANZ) are insufficiently described.

OBJECTIVE

This study aimed to describe the epidemiology of acute brain injury in ICU patients in ANZ.

METHODS

A binational retrospective cohort study was conducted using the ANZ Intensive Care Society Adult Patient Database. Adult unplanned admissions from 2013 to 2022 were eligible unless the presence of acute brain injury could not be determined or the admission was for end-of-life care. In cases where a patient had multiple admissions, only the first was included. The population was divided into two cohorts: acute brain injury diagnoses and other diagnoses. The primary outcome was in-hospital mortality. Secondary outcomes included 90- and 180-day mortality, ICU and hospital lengths of stay, duration of invasive ventilation, and the proportion discharged home.

RESULTS

Acute brain injuries accounted for 92 948 of 684 981 unplanned ICU admissions (14%). Hypoxic ischaemic encephalopathy, traumatic brain injury, and seizures were the most common diagnoses. A total of 24 568 of 92 948 (26%) and 62 603 of 592 033 (10%) patients with acute brain injuries and other diagnoses, respectively, died in hospital. Among the patients with brain injury the highest hospital mortality was in hypoxic ischaemic encephalopathy (53%), intracerebral haemorrhage (36%), subarachnoid haemorrhage (22%), and ischaemic stroke (22%); the lowest mortality was in traumatic brain injury (14%), central nervous system infection (10%), and seizures (4%). Acute brain injury patients were more likely to receive invasive mechanical ventilation, had longer ICU and hospital lengths of stay, had higher 90- and 180-day mortality, and were more likely to be discharged to chronic care than other patients.

CONCLUSIONS

Acute brain injuries accounted for a disproportionally high number of in-hospital deaths occurring in our cohort of adults who received unplanned ICU care; however, the mortality rates varied, and patients with central nervous system infections and seizures had similar or lower mortality compared to patients without brain injury.

Diverse NKT cells regulate early inflammation and neurological outcomes after cardiac arrest and resuscitation

Neurological injury drives most deaths and morbidity among patients hospitalized for out-of-hospital cardiac arrest (OHCA). Despite its clinical importance, there are no effective pharmacological therapies targeting post-cardiac arrest (CA) neurological injury. Here, we analyzed circulating immune cells from a large cohort of patients with OHCA, finding that lymphopenia independently associated with poor neurological outcomes. Single-cell RNA sequencing of immune cells showed that T cells with features of both innate T cells and natural killer (NK) cells were increased in patients with favorable neurological outcomes. We more specifically identified an early increase in circulating diverse NKT (dNKT) cells in a separate cohort of patients with OHCA who had good neurological outcomes. These cells harbored a diverse T cell receptor repertoire but were consistently specific for sulfatide antigen. In mice, we found that sulfatide-specific dNKT cells trafficked to the brain after CA and resuscitation. In the brains of mice lacking NKT cells (Cd1d-/-), we observed increased inflammatory chemokine and cytokine expression and accumulation of macrophages when compared with wild-type mice. Cd1d-/- mice also had increased neuronal injury, neurological dysfunction, and worse mortality after CA. To therapeutically enhance dNKT cell activity, we treated mice with sulfatide lipid after CA, showing that it improved neurological function. Together, these data show that sulfatide-specific dNKT cells are associated with good neurological outcomes after clinical OHCA and are neuroprotective in mice after CA. Strategies to enhance the number or function of dNKT cells may thus represent a treatment approach for CA.

Associations of long-term hyperoxemia, survival, and neurological outcomes in extracorporeal cardiopulmonary resuscitation patients undergoing targeted temperature management: A retrospective observational analysis of the SAVE-J Ⅱ study

Background

Extracorporeal cardiopulmonary resuscitation (ECPR) can improve survival rates and neurological outcomes of patients with out-of-hospital cardiac arrest (OHCA). High levels of partial pressure of arterial oxygen (PaO2) negatively affect survival and neurological outcomes in patients with OHCA. However, research on associations of hyperoxemia with survival and neurological outcomes after ECPR remains limited, especially considering targeted temperature management (TTM) administration to patients. Additionally, few reports have examined the impact of hyperoxemia beyond 24 h. In this study, we aimed to examine the effect of prolonged hyperoxemia on survival and neurological outcomes after ECPR for OHCA in patients undergoing TTM.

Methods

We performed a secondary observational analysis of data from the SAVE-J Ⅱ study, a retrospective, multicenter registry study of ECPR of patients with OHCA. Data on arterial PaO2 after ECPR for intensive care unit days 2-4 were collected and averaged. Patients were divided into two groups: hyperoxic (PaO2 ≥ 300 mmHg) and non-hyperoxic (PaO2 < 300 mmHg). Each variable was compared between the groups. Additionally, survival and mortality rates at discharge were compared, and factors associated with survival (primary outcome) and neurological outcomes (secondary outcome) at discharge were examined.

Results

The multivariate analysis for survival at discharge showed that age, initial ventricular fibrillation/ventricular tachycardia (VF/VT) waveform, P = 0.0004), and hyperoxemia were significant factors. For neurological outcomes at discharge, significant factors included age, initial VF/VT waveform, hemoglobin level at presentation, and hyperoxemia.

Conclusions

Prolonged hyperoxemia was significantly associated with worse survival and neurological outcomes after ECPR for OHCA in patients who underwent TTM.

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.

Practice survey on recent changes in post cardiac arrest care and temperature management in French intensive care units

BACKGROUND

Recent guidelines for post-cardiac arrest (CA) management have undergone significant changes regarding targeted therapeutic management (TTM), transitioning from hypothermia to temperature control. We aimed to assess changes in post-CA management in French intensive care units following the new recommendations.

METHODS

Two declarative web surveys were conducted from March to August 2023. We compared the doctors' survey to that previously published in 2015. We contacted 389 departments from 276 French centers.

RESULTS

Three hundred thirty-four physicians from 189 distinct ICUs departments participated in the survey. TTM was used by 95.5 % of respondents. TTM with temperature feedback device was used by 64 % of respondents. In multivariate analysis, use of TTM with temperature feedback was associated with university hospital responder [OR 1.99 (1.19-3.34, p = 0.009)], high CA admissions rate [OR 2.25 (1.13-4.78, p = 0.026)], use of a written CA procedure [OR 1.76 (1.07-2.92, p = 0.027)] and presence of a cath-lab performing coronary angiography [OR 2.42 (1.33-4.44, p = 0.004)]. The targeted temperature rose from 32 to 34 °C in 2015, to 35-36 °C in 2023 (p < 0.001). Proportions of TTM with temperature feedback devices switched from 45 % to 65 % (p < 0.001). 660 nurses responses from 150 ICUs were analyzed. According to TTM users, gel-coated water circulating pads and intravascular cooling were considered the most effective devices and were found to be easily adjustable.

CONCLUSIONS

These surveys provide insights into post-resuscitation care and TTM practice in France. One year after their publication, the latest recommendations concerning TTM have not been fully implemented, as the majority of ICUs continue to use moderate hypothermia. They widely reported employing specific TTM, with the use of TTM with temperature feedback devices increasing significantly. Heterogeneity exists regarding the TTM systems used, with a significant proportion lacking temperature feedback. This aspect requires specific attention, depending on local constraints and devices costs.

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.

The Impact on Patient Prognosis of Changes to the Method of Notifying Staff About Accepting Patients With Out-of-Hospital Cardiac Arrest

Background

Our hospital is a designated emergency hospital and accepts many patients with out-of-hospital cardiac arrest (OHCA). Previously, after receiving a direct call from emergency services to request acceptance of an OHCA patient, the emergency room (ER) chief nurse notified medical staff. However, this method delayed ER preparations, so a Code Blue system (CB) was introduced in which the pending arrival of an OHCA patient was broadcast throughout the hospital.

Methods

In this study, we retrospectively analyzed the impact of introducing CB at our hospital on OHCA patient prognosis to examine whether the introduction of CB is clinically meaningful. We compared consecutive cases treated before introduction of the CB (March 3, 2022, to March 22, 2023) with those treated afterwards (March 23, 2023, to July 23, 2024).

Results

A total of 30 cases per group were included. The mean number of medical staff present at admissions increased significantly from 5.4 ± 0.6 to 15.0 ± 3.0 (P < 0.001). Although not statistically significant, the introduction of the CB increased the return of spontaneous circulation (ROSC) rate from 20% to 30%, survival to discharge rate from 3% to 10%, and social reintegration rate from 0% to 3%. ROSC occurred in 15 patients. Among OHCA patients with cardiac disease, the ROSC rate tended to increase from 0% to 43% (P = 0.055). In addition, in OHCA patients with cardiac disease whose electrocardiogram initially showed ventricular fibrillation or pulseless electrical activity, the ROSC rate increased from 0% to 100%. ROSC tended to be influenced by the total number of staff and physicians present and the number of staff such as medical clerks, clinical engineers, and radiology technicians (P = 0.095, 0.076, 0.088, respectively).

Conclusions

Introduction of a CB may increase the ROSC rate and the number of patients surviving to discharge. It also appears to improve the quality of medical care by quickly gathering all necessary medical staff so that they can perform their predefined roles.

2024 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations: Summary From the Basic Life Support; Advanced Life Support; Pediatric Life Support; Neonatal Life Support; Education, Implementation, and Teams; and First Aid Task Forces

This is the eighth annual summary of the International Liaison Committee on Resuscitation International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations; a more comprehensive review was done in 2020. This latest summary addresses the most recent published resuscitation evidence reviewed by the International Liaison Committee on Resuscitation task force science experts. Members from 6 International Liaison Committee on Resuscitation task forces have assessed, discussed, and debated the quality of the evidence, using Grading of Recommendations Assessment, Development, and Evaluation criteria, and their statements include consensus treatment recommendations. Insights into the deliberations of the task forces are provided in the Justification and Evidence-to-Decision Framework Highlights sections. In addition, the task forces list priority knowledge gaps for further research.

Regional variation in temperature control after out-of-hospital cardiac arrest

Introduction

We evaluated hospitals for variation in temperature control (TC) use after out-of-hospital cardiac arrest (OHCA) in a regional emergency medical services system and assessed association of hospital-level TC utilization with survival.

Methods

A retrospective cohort study of adults with non-traumatic OHCA who survived to hospital admission from 2016 to 2018 in King County, Washington. Hospitals with < 80 OHCA cases were excluded. Primary exposure was hospital-level proportion of TC. Measured outcomes were survival to hospital discharge and neurologically favorable survival (defined as Cerebral Performance Category 1 or 2). Logistic regression modeling clustered patients by treating hospital and evaluated associations between TC and outcomes with covariate adjustment.

Results

Of 1,035 eligible patients admitted to eight hospitals, 69% were male, 38% had an initial shockable rhythm, and 61% had presumed cardiac etiology for OHCA. TC was initiated in 787 patients (74%) and ranged from 57 to 87% across hospitals. Overall, 34% of patients survived neurologically intact, 74% of whom received TC. In the adjusted model, public OHCA location (OR: 1.7 [95% CI 1.3-2.3]), witnessed arrest (OR: 1.6 [1.2-2.2]), and shockable rhythm (OR: 5.5 [3.9-7.8]) were more strongly associated with survival than TC utilization (OR: 0.6 [0.4-0.8]). Similar results were seen for neurologically favorable survival and did not vary significantly by hospital.

Conclusions

Hospital-level TC utilization was not associated with improved survival or neurologically favorable survival after OHCA. Future studies should examine which aspects of the post-cardiac arrest care bundle most strongly influence outcomes.

Potassium disorders at intensive care unit admission and functional outcomes after cardiac arrest

BACKGROUND

Abnormal serum potassium levels are commonly found in the intensive care unit (ICU) population. We aimed to determine the prevalence of potassium disorders at ICU admission and its association with functional outcomes in comatose patients resuscitated from cardiac arrest.

METHODS

We performed a post hoc analysis of pooled data from four randomised clinical trials involving comatose post-cardiac arrest patients admitted to ICU after return of spontaneous circulation (ROSC). Reference serum potassium levels were defined as between 3.0 and 4.9  mmol/L. An unfavourable functional outcome was defined as a cerebral performance category of 3 to 5 at 180 days. We compared potassium disturbances categorically in a mixed effects logistic regression model including initial rhythm, delay from collapse to return of spontaneous circulation, bystander cardiopulmonary resuscitation, lactate and urea at ICU admission, with normokalaemia set as the reference group.

RESULTS

We included 1133 patients (557 from the HYPERION, 346 from the TTH48, 120 from the COMACARE, and 110 from the Xe-HYPOTHECA trials) with a median age of 64 years (interquartile range 55-72) and a predominance of males (72 %); a total of 712 (64 %) patients had unfavourable functional outcomes. On admission, 221 patients (19.5 %) experienced hyperkalaemia and 35 (3.1 %) patients experienced hypokalaemia. Fewer patients in the normokalaemia group (513/877, 58.5 %) had an unfavourable functional outcome compared to the hypokalaemia (24/35, 68.6 %) and hyperkalaemia groups (180/221, 81.4 %; p < 0.001). Hyperkalaemia was associated with higher odds for an unfavourable functional outcome (adjusted odds ratio (OR) 1.85, 95 % confidence interval (CI) 1.10-3.12, p = 0.02), while hypokalaemia was not (OR 1.36 95 % CI 0.51-3.60, p = 0.53). The associations were not significant in a subgroup analysis adjusted for the modified cardiac arrest hospital prognosis score in 833 patients (OR 1.74, 95 % CI 0.91-3.34, p = 0.10 for hyperkalaemia and OR 1.48, 95 % CI 0.40-5.44, p = 0.55 for hypokalaemia).

CONCLUSIONS

Of the comatose patients admitted to ICU after cardiac arrest, one in five experienced a potassium disorder on ICU admission. Hyperkalaemia was associated with unfavourable functional outcomes at 180 days, while hypokalaemia was not.

Differential Effects of Targeted Temperature Management on Sex-Dependent Outcomes After Experimental Asphyxial Cardiac Arrest

Asphyxial cardiac arrest (ACA) survivors face lasting neurological disability from hypoxic ischemic brain injury. Sex differences in long-term outcomes after cardiac arrest (CA) are grossly understudied and underreported. We used rigorous targeted temperature management (TTM) to understand its influence on survival and lasting sex-specific neurological and neuropathological outcomes in a rodent ACA model. Adult male and female rats underwent either sham or 5-minute no-flow ACA with 18 hours TTM at either ∼37°C (normothermia) or ∼36°C (mild hypothermia). Survival, temperature, and body weight (BW) were recorded over the 14-day study duration. All rats underwent neurological deficit score (NDS) assessment on days 1-3 and day 14. Hippocampal pathology was assessed for cell death, degenerating neurons, and microglia on day 14. Although ACA females were less likely to achieve return of spontaneous circulation (ROSC), post-ROSC physiology and biochemical profiles were similar between sexes. ACA females had significantly greater 14-day survival, NDS, and BW recovery than ACA males at normothermia (56% vs. 29%). TTM at 36°C versus 37°C improved 14-day survival in males, producing similar survival in male (63%) versus female (50%). There were no sex or temperature effects on CA1 histopathology. We conclude that at normothermic conditions, sex differences favoring females were observed after ACA in survival, NDS, and BW recovery. We achieved a clinically relevant ACA model using TTM at 36°C to improve long-term survival. This model can be used to more fully characterize sex differences in long-term outcomes and test novel acute and chronic therapies.

Does targeted temperature management at 33 °C improve outcome after cardiac arrest?

PURPOSE OF REVIEW

Following successful resuscitation from cardiac arrest, a complex set of pathophysiologic processes are acutely triggered, leading to substantial morbidity and mortality. Postarrest management remains a major challenge to critical care providers, with few proven therapeutic strategies to improve outcomes. One therapy that has received substantial focus is the intentional lowering of core body temperature for a discrete period of time following resuscitation. In this review, we will discuss the key trials and other evidence surrounding TTM and present opposing arguments, one 'against' the use of postarrest TTM and another 'for' the use of this therapeutic approach.

RECENT FINDINGS

Targeted temperature management, has been a topic of enormous controversy, as recently a number of clinical trials show conflicting results on the effect of TTM. Fundamental questions, about the dosing of TTM (e.g. use at 33 °C versus higher temperatures), or the use of TTM at all (as opposed to passive fever avoidance), remain active topics of global discussion. Systematic reviews on this topic also show variable results.

SUMMARY

There are several arguments for and against the use of TTM targeting 33 °C for alleviating brain injury after cardiac arrest. More studies are on the way that will hopefully provide more robust evidence and hopefully allow for consensus on this important topic.

Early coronary angiography in patients with myocardial infarction without ST elevation after out-of-hospital cardiac arrest: a systematic review and meta-analysis

Background

Early coronary angiography (CAG) in post-cardiac arrest patients without ST-segment elevation is a topic of debate. This meta-analysis aimed to assess its impact on outcomes.

Methods

A search of Medline and Cochrane up to February 2023 was conducted to identify randomized controlled trials and observational studies comparing patients undergoing early CAG vs. delayed/no CAG after experiencing out-of-hospital cardiac arrest. A random-effects model pooled odds ratios (ORs) with 95% confidence intervals (CIs). Meta-regression explored factors modifying effect sizes.

Results

We identified 16 studies (7 RCTs, 9 observational studies) involving 4,737 patients. Early CAG significantly reduced long-term mortality [OR: 0.66 (0.51-0.85)], and increased favorable cerebral performance category (CPC) 1-2 at discharge [OR: 1.49 (1.09-2.03)]. Observational study subgroup showed decreased short-term mortality, long-term mortality, and CPC 1-2 at discharge, unlike RCT subgroup. Meta-regression revealed type 2 diabetes mellitus and follow-up time influencing short-term mortality and CPC 1-2 at discharge, respectively.

Conclusion

Early CAG in post-cardiac arrest patients without ST elevation is associated with long-term clinical benefits, particularly evident in observational studies. Interpretation should be cautious.

Feasibility and Safety of Targeted Temperature Management During Interhospital Transport of Post-Cardiac Arrest Patients

OBJECTIVES

Early initiation of targeted temperature management (TTM) is crucial for post-resuscitation care. Although TTM is initiated prior to transport and continued during interhospital transport (IHT), its feasibility and safety during IHT for cardiac arrest patients have not been thoroughly assessed. This study aims to evaluate the feasibility and safety of interhospital TTM for post-resuscitation patients.

METHODS

A retrospective analysis of post-cardiac arrest patients transported by a dedicated critical care transport team between January 2016 and April 2023 was conducted. Adult patients resuscitated from cardiac arrest without mental recovery were enrolled. The study population was divided into those who received TTM during IHT (IHT-TTM group) and those who did not (non-IHT-TTM group). The primary outcome was body temperature drop during transport, with hypotension, or desaturation during transport considered as secondary outcomes. Multivariable conditional logistic regression analysis was performed after frequency matching.

RESULTS

Among 593 post-cardiac arrest patients, 332 were included in the analysis after exclusions. Of these, 44 (13.3%) received TTM during IHT. Conditional logistic regression analysis showed significantly higher likelihood for a drop in body temperature during IHT for the IHT-TTM group, with an odds ratio (OR) of 12.91 (95%CI: 5.28-31.53). No significant association was found for hypotension (OR (95%CI): 0.72 (0.13-3.97)), or desaturation during IHT (0.65 (0.15-2.82)).

CONCLUSIONS

Administration of TTM during IHT for post-cardiac arrest patients appears to be feasible and safe. These findings support the implementation of dedicated critical care transport systems capable of providing TTM during IHT for post-cardiac arrest patients.

Magnetic resonance imaging in comatose adults resuscitated after out-of-hospital cardiac arrest: A posthoc study of the Targeted Therapeutic Mild Hypercapnia after Resuscitated Cardiac Arrest trial

BACKGROUND

Neuroimaging with magnetic resonance imaging (MRI) may assist clinicians in evaluating brain injury and optimising care in comatose adults resuscitated after out-of-hospital cardiac arrest (OHCA). However, contemporary international data on its use are lacking.

AIM

The primary aim was to compare the patient characteristics, early postresuscitation care, and neurological outcomes of patients according to MRI use.

METHODS

We performed a posthoc analysis of the Targeted Therapeutic Mild Hypercapnia after Resuscitated Cardiac Arrest (TAME) trial, a multinational randomised trial comparing targeted mild hypercapnia or normocapnia in comatose adults after OHCA.

RESULTS

After exclusions, 1639 patients enrolled in the TAME trial were analysed. Of these, 149 (9%) had an MRI. Compared to non-MRI patients, MRI patients were younger (58.9 versus 61.7 years, p: 0.02), had a longer median time from OHCA to return of spontaneous circulation (30 versus 25 min, p < 0.0001), and had a higher average arterial lactate level (8.78 versus 6.74 mmol/L, p < 0.0001) on admission to hospital. MRI patients were more likely to receive additional advanced diagnostic assessments during intensive care unit admission (p < 0.0001). At 6 months, 23 of 140 patients (16.4%) in the MRI group had a favourable neurological outcome, compared with 659 of 1399 patients (47.1%) in the no-MRI group (p < 0.001). On multivariable modelling, country of enrolment was the dominating predictor in the likelihood of an MRI being performed.

CONCLUSIONS

In the TAME trial, 9% of patients had an MRI during their intensive care unit admission. Among these patients, only 16% had a favourable neurological outcome at 6 months.

TARGETED TEMPERATURE MANAGEMENT AT 36°C IMPROVES SURVIVAL AND PROTECTS TISSUES BY MITIGATING THE DELETERIOUS INFLAMMATORY RESPONSE FOLLOWING HEMORRHAGIC SHOCK

ABSTRACT

Hemorrhagic shock (HS) is a life-threatening condition with high mortality rates despite current treatments. This study investigated whether targeted temperature management (TTM) could improve outcomes by modulating inflammation and protecting organs following HS. Using a rat model of HS, TTM was applied at 33°C and 36°C after fluid resuscitation. Surprisingly, TTM at 33°C increased mortality, while TTM at 36°C significantly improved survival rates. It also reduced histological damage in lung and kidney tissues, lowered serum lactate levels, and protected against apoptosis and excessive reactive oxygen species production. TTM at 36°C inhibited the release of high mobility group box 1 protein (HMGB1), a key mediator of inflammation, and decreased proinflammatory cytokine levels in the kidneys and lungs. Moreover, it influenced macrophage behavior, suppressing the harmful M1 phenotype while promoting the beneficial M2 polarization. Cytokine array analysis confirmed reduced levels of proinflammatory cytokines with TTM at 36°C. These results collectively highlight the potential of TTM at 36°C as a therapeutic approach to improve outcomes in HS. By addressing multiple aspects of injury and inflammation, including modulation of macrophage responses and cytokine profiles, TTM at 36°C offers promising implications for critical care management after HS, potentially reducing mortality and improving patient recovery.

Neuroinflammation and the immune system in hypoxic ischaemic brain injury pathophysiology after cardiac arrest

Hypoxic ischaemic brain injury after resuscitation from cardiac arrest is associated with dismal clinical outcomes. To date, most clinical interventions have been geared towards the restoration of cerebral oxygen delivery after resuscitation; however, outcomes in clinical trials are disappointing. Therefore, alternative disease mechanism(s) are likely to be at play, of which the response of the innate immune system to sterile injured tissue in vivo after reperfusion has garnered significant interest. The innate immune system is composed of three pillars: (i) cytokines and signalling molecules; (ii) leucocyte migration and activation; and (iii) the complement cascade. In animal models of hypoxic ischaemic brain injury, pro-inflammatory cytokines are central to propagation of the response of the innate immune system to cerebral ischaemia-reperfusion. In particular, interleukin-1 beta and downstream signalling can result in direct neural injury that culminates in cell death, termed pyroptosis. Leucocyte chemotaxis and activation are central to the in vivo response to cerebral ischaemia-reperfusion. Both parenchymal microglial activation and possible infiltration of peripherally circulating monocytes might account for exacerbation of an immunopathological response in humans. Finally, activation of the complement cascade intersects with multiple aspects of the innate immune response by facilitating leucocyte activation, further cytokine release and endothelial activation. To date, large studies of immunomodulatory therapies have not been conducted; however, lessons learned from historical studies using therapeutic hypothermia in humans suggest that quelling an immunopathological response might be efficacious. Future work should delineate the precise pathways involved in vivo in humans to target specific signalling molecules.

Temperature Control Parameters Are Important: Earlier Preinduction Is Associated With Improved Outcomes Following Out-of-Hospital Cardiac Arrest

STUDY OBJECTIVE

Temperature control trials in cardiac arrest patients have not reliably conferred neuroprotective benefit but have been limited by inconsistent treatment parameters. To evaluate the presence of a time dependent treatment effect, we assessed the association between preinduction time and clinical outcomes.

METHODS

In this retrospective, single academic center study between 2014 and 2022, consecutive out-of-hospital cardiac arrest (OHCA) patients treated with temperature control were identified. Preinduction was defined as the time from hospital arrival to initiation of a closed-loop temperature feedback device [door to temperature control initiation time], and early door to temperature control device time was defined a priori as <3 hours. We assessed the association between good neurologic outcome (cerebral performance category 1 to 2) and door to temperature control device time using logistic regression. The proportion of patients who survived to hospital discharge was evaluated as a secondary outcome. A sensitivity analysis using inverse probability treatment weighting, created using a propensity score, was performed to minimize measurable confounding.

RESULTS

Three hundred and forty-seven OHCA patients were included; the early door to temperature control device cohort included 75 (21.6%) patients with a median (interquartile range) door to temperature control device time of 2.50 (2.03 to 2.75) hours, whereas the late door to temperature control device cohort included 272 (78.4%) patients with a median (interquartile range) door to temperature control device time of 5.18 (4.19 to 6.41) hours. In the multivariable logistic regression model, early door to temperature control device time was associated with improved good neurologic outcome and survival before [adjusted odds ratio (OR) (95% confidence interval) 2.36 (1.16 to 4.81) and 3.02 (1.54 to 6.02)] and after [adjusted OR (95% confidence interval) 1.95 (1.19 to 3.79) and 2.14 (1.33 to 3.36)] inverse probability of treatment weighting, respectively.

CONCLUSION

In our study of OHCA patients, a shorter preinduction time for temperature control was associated with improved good neurologic outcome and survival. This finding may indicate that early initiation in the emergency department will confer benefit. Our findings are hypothesis generating and need to be validated in future prospective trials.

A review on targeted temperature management for cardiac arrest and traumatic brain injury

Therapeutic hypothermia inhibits organ damage by suppressing metabolism, which makes it a therapy of choice for treating various diseases. Specifically, it is often used to treat conditions involving central nervous system disorders where it is expected to positively impact functional prognosis. Although keeping the body temperature at a hypothermic level has been conventionally used, how to manage the body temperature correctly remains a topic of debate. Recently, the concept of temperature management has been proposed to improve the quality of body temperature control and avoid hyperthermia. This review focuses on the effect of temperature on the central nervous system in conditions involving central nervous system disorders and the practice of temperature management in clinical situations.

Management of Patients With Cardiac Arrest Requiring Interfacility Transport: A Scientific Statement From the American Heart Association

People who experience out-of-hospital cardiac arrest often require care at a regional center for continued treatment after resuscitation, but many do not initially present to the hospital where they will be admitted. For patients who require interfacility transport after cardiac arrest, the decision to transfer between centers is complex and often based on individual clinical characteristics, resources at the presenting hospital, and available transport resources. Once the decision has been made to transfer a patient after cardiac arrest, there is little direct guidance on how best to provide interfacility transport. Accepting centers depend on transferring emergency departments and emergency medical services professionals to make important and nuanced decisions about postresuscitation care that may determine the efficacy of future treatments. The consequences of early care are greater when transport delays occur, which is common in rural areas or due to inclement weather. Challenges of providing interfacility transfer services for patients who have experienced cardiac arrest include varying expertise of clinicians, differing resources available to them, and nonstandardized communication between transferring and receiving centers. Although many aspects of care are insufficiently studied to determine implications for specific out-of-hospital treatment on outcomes, a general approach of maintaining otherwise recommended postresuscitation care during interfacility transfer is reasonable. This includes close attention to airway, vascular access, ventilator management, sedation, cardiopulmonary monitoring, antiarrhythmic treatments, blood pressure control, temperature control, and metabolic management. Patient stability for transfer, equity and inclusion, and communication also must be considered. Many of these aspects can be delivered by protocol-driven care.

Optimal timing of ultra-early diffusion-weighted MRI in out-of-hospital cardiac arrest patients based on a retrospective multicenter cohort study

Diffusion-weighted magnetic resonance imaging (DW-MRI) performed before target temperature management, within 6 h of return of spontaneous circulation (ROSC), is defined as ultra-early DW-MRI. In previous studies, high-signal intensity (HSI) on ultra-early DW-MRI can predict poor neurological outcomes (Cerebral Performance Category 3-5 at 6-months post-ROSC). We aimed to assess the optimal-timing for ultra-early DW-MRI to avoid false-negative outcomes post out-of-hospital cardiac arrest, considering cardiopulmonary resuscitation (CPR) factors. The primary outcomes were HSI in the cerebral cortex or deep gray matter on ultra-early DW-MRI. The impact of CPR factors and ROSC to DW-MRI scan-interval on HSI-presence was assessed. Of 206 included patients, 108 exhibited HSI-presence, exclusively associated with poor neurological outcomes. In multivariate regression analysis, ROSC to DW-MRI scan-interval (adjusted odds ratio [aOR], 1.509; 95% confidence interval (CI): 1.113-2.046; P = 0.008), low-flow time (aOR, 1.176; 95%CI: 1.121-1.233; P < 0.001), and non-shockable rhythm (aOR, 9.974; 95%CI: 3.363-29.578; P < 0.001) were independently associated with HSI-presence. ROSC to DW-MRI scan-interval cutoff of ≥ 2.2 h was particularly significant in low-flow time ≤ 21 min or shockable rhythm group. In conclusion, short low-flow time and shockable rhythm require a longer ROSC to DW-MRI scan-interval. Prolonged low-flow time and non-shockable rhythm reduce the need to consider scan-interval.

Variability in temperature control practices amongst the Influence of Cooling duration on Efficacy in Cardiac Arrest Patients (ICECAP) trial

AIM

Temperature control is a complex bundled intervention; the synergistic impact of each individual component is ill defined and underreported. Resultantly, the influence of parameter optimization on temperature control's overall neuroprotective effect remains poorly understood. To characterize variability in temperature control parameters and barriers to short pre-induction and induction times, we surveyed sites enrolling in an ongoing multicenter clinical trial.

METHODS

This was a cross-sectional, survey study evaluating temperature control practices within the Influence of Cooling duration on Efficacy in Cardiac Arrest Patients (ICECAP) trial (NCT04217551). A 23-question web-based survey (Qualtrics) was distributed to the site principal investigators by email. Respondents were asked about site practices pertaining to the use of temperature control, including the request to upload individual institutional protocols. Open-ended responses were analyzed qualitatively by categorizing responses into identified themes. To complement survey level data, records pertaining to the quality of temperature control were extracted from the ICECAP trial database.

RESULTS

The survey response rate was 75% (n = 51) including 23.5% (n = 12) survey respondents who uploaded institutional protocols. Most sites reported having institutional protocols for temperature control (n = 41; 80%), including 62.5% (n = 32) who had separate protocols for initiation of temperature control in the emergency department (ED). Fewer sites had protocols specific to sedation or neuromuscular blockade (NMB) management (n = 35, 68.6%). Use of NMB during temperature control induction was variable; 61.7% (n = 29) of sites induced paralysis less than 20% of the time. While most institutional protocols (n = 11, 83.3%) commented on the importance of early initiation of temperature control, this was incongruent with the largest reported barrier, which was clinical nihilism regarding the importance of early temperature control initiation (n = 30, 62.5%). Within the ICECAP trial database, 1 in 2 patients were treated with NMB however, use of NMB and time to initiation of temperature control device varied widely between sites.

CONCLUSION

Amongst ICECAP trial sites, there was significant variability in resources, methods, and barriers for early temperature control initiation. Defining and standardizing high-quality temperature control must be prioritized, as it may impact the interpretation of past and current clinical trial findings.

Combination of Hydrogen Inhalation and Hypothermic Temperature Control After Out-of-Hospital Cardiac Arrest: A Post hoc Analysis of the Efficacy of Inhaled Hydrogen on Neurologic Outcome Following Brain Ischemia During PostCardiac Arrest Care II Trial

OBJECTIVE

The Efficacy of Inhaled Hydrogen on Neurologic Outcome Following Brain Ischemia During Post-Cardiac Arrest Care (HYBRID) II trial (jRCTs031180352) suggested that hydrogen inhalation may reduce post-cardiac arrest brain injury (PCABI). However, the combination of hypothermic target temperature management (TTM) and hydrogen inhalation on outcomes is unclear. The aim of this study was to investigate the combined effect of hydrogen inhalation and hypothermic TTM on outcomes after out-of-hospital cardiac arrest (OHCA).

DESIGN

Post hoc analysis of a multicenter, randomized, controlled trial.

SETTING

Fifteen Japanese ICUs.

PATIENTS

Cardiogenic OHCA enrolled in the HYBRID II trial.

INTERVENTIONS

Hydrogen mixed oxygen (hydrogen group) versus oxygen alone (control group).

MEASUREMENTS AND MAIN RESULTS

TTM was performed at a target temperature of 32-34°C (TTM32-TTM34) or 35-36°C (TTM35-TTM36) per the institutional protocol. The association between hydrogen + TTM32-TTM34 and 90-day good neurologic outcomes was analyzed using generalized estimating equations. The 90-day survival was compared between the hydrogen and control groups under TTM32-TTM34 and TTM35-TTM36, respectively. The analysis included 72 patients (hydrogen [ n = 39] and control [ n = 33] groups) with outcome data. TTM32-TTM34 was implemented in 25 (64%) and 24 (73%) patients in the hydrogen and control groups, respectively ( p = 0.46). Under TTM32-TTM34, 17 (68%) and 9 (38%) patients achieved good neurologic outcomes in the hydrogen and control groups, respectively (relative risk: 1.81 [95% CI, 1.05-3.66], p < 0.05). Hydrogen + TTM32-TTM34 was independently associated with good neurologic outcomes (adjusted odds ratio 16.10 [95% CI, 1.88-138.17], p = 0.01). However, hydrogen + TTM32-TTM34 did not improve survival compared with TTM32-TTM34 alone (adjusted hazard ratio: 0.22 [95% CI, 0.05-1.06], p = 0.06).

CONCLUSIONS

Hydrogen + TTM32-TTM34 was associated with improved neurologic outcomes after cardiogenic OHCA compared with TTM32-TTM34 monotherapy. Hydrogen inhalation is a promising treatment option for reducing PCABI when combined with TTM32-TTM34.

Mild therapeutic hypothermia after cardiac arrest - effect on survival with good neurological outcome outside of randomised controlled trials: A registry-based analysis

BACKGROUND

For nearly 20 years, in international guidelines, mild therapeutic hypothermia (MTH) was an important component of postresuscitation care. However, recent randomised controlled trials have questioned its benefits. At present, international guidelines only recommend actively preventing fever, but there are ongoing discussions about whether the majority of cardiac arrest patients could benefit from MTH treatment.

OBJECTIVE

The aim of this study was to compare the outcome of adult patients treated with and without MTH after cardiac arrest.

DESIGN

Observational cohort study.

SETTING

German Resuscitation Registry covering more than 31 million inhabitants of Germany and Austria.

PATIENTS

All adult patients between 2006 and 2022 with out-of-hospital or in-hospital cardiac arrest and comatose on admission.

MAIN OUTCOME MEASURES

Primary endpoint: hospital discharge with good neurological outcome [cerebral performance categories (CPC) 1 or 2]. Secondary endpoint: hospital discharge. We used a multivariate binary logistic regression analysis to identify the effects on outcome of all known influencing variables.

RESULTS

We analysed 33 933 patients (10 034 treated with MTH, 23 899 without MTH). The multivariate regression model revealed that MTH was an independent predictor of CPC 1/2 survival and of hospital discharge with odds ratio (95% confidence intervals) of 1.60 (1.49 to 1.72), P < 0.001 and 1.89 (1.76 to 2.02), P < 0.001, respectively.

CONCLUSION

Our data indicate the existence of a positive association between MTH and a favourable neurological outcome after cardiac arrest. It therefore seems premature to refrain from giving MTH treatment for the entire spectrum of patients after cardiac arrest. Further prospective studies are needed.