Therapeutic hypothermia after cardiac arrest: an advisory statement by the advanced life support task force of the International Liaison Committee on Resuscitation

The compliance with TTM protocol may benefit outcomes in cardiac arrest survivors: A retrospective cohort study

BACKGROUND

Established protocols for implementing high-quality targeted temperature management (TTM) provide guidance concerning the cooling rate, duration of maintenance, and rewarming speed. However, whether compliant to TTM protocols results in improved survival and better neurological recovery has not been examined.

METHODS

A retrospective cohort study enrolled 1141 survivors of non-traumatic adult cardiac arrest with a pre-arrest cerebral performance category (CPC) score of 1-2 from 2015 to 2020 at a tertiary medical center. Of the survivors, 330 patients who underwent TTM were further included. Patients with spontaneous hypothermia (<35 °C) (n = 107) and expired during the TTM (n = 21) were excluded. A total of 202 patients were thus enrolled. One hundred and ten patients underwent TTM that completely complied with the protocol (protocol-complaint group), but 92 patients deviated in some manner from the protocol (protocol non-compliant group).

RESULTS

Fifty patients (50%) and 46 patients (50%) in the protocol-compliant and non-compliant groups, respectively, did not survive to hospital discharge. In the protocol-compliant group, 42 patients (38.2%) had favorable neurological recovery, compared with 32 patients (34.8%) in the protocol non-compliant group. After adjusting for age, initial shockable rhythm, witnessed collapse, and cardiopulmonary resuscitation duration, protocol non-compliant was associated with the poor neurological outcomes (aOR 2.44, 95% CI = 1.13-5.25), but not with in-hospital mortality (aOR 1.31, 95% CI = 0.70-2.47). The most common reason for noncompliance was a prolonged duration reaching the target temperature (n = 33, 58.7%). The number of phases of non-compliant was not significantly associated with in-hospital mortality or poor neurological recovery.

CONCLUSION

Among cardiac arrest survivors undergoing TTM, those who did not receive TTM that in compliance with the protocol were more likely to experience poor neurological recovery than those whose TTM fully complied with the protocols. The most frequently identified deviation was a prolonged duration to reaching the target temperature.

Hypothermia After Cardiac Arrest in Large Animals (HACA-LA): Study protocol of a randomized controlled experimental trial

Background

Induced hypothermia post-cardiac arrest is neuroprotective in animal experiments, but few high-quality studies have been performed in larger animals with human-like brains. The neuroprotective effect of postischemic hypothermia has recently been questioned in human trials. Our aim is to investigate whether hypothermia post-cardiac arrest confers a benefit compared to normothermia in large adult animals. Our hypothesis is that induced hypothermia post cardiac arrest is neuroprotective and that the effect diminishes when delayed two hours.

Methods

Adult female pigs were anesthetized, mechanically ventilated and kept at baseline parameters including normothermia (38 °C). All animals were subjected to ten minutes of cardiac arrest (no-flow) by induced ventricular fibrillation, followed by four minutes of cardiopulmonary resuscitation with mechanical compressions, prior to the first countershock. Animals with sustained return of spontaneous circulation (systolic blood pressure >60 mmHg for ten minutes) within fifteen minutes from start of life support were included and randomized to three groups; immediate or delayed (2 h) intravenous cooling, both targeting 33 °C, or intravenously controlled normothermia (38 °C). Temperature control was applied for thirty hours including cooling time, temperature at target and controlled rewarming (0.5 °C/h). Animals were extubated and kept alive for seven days. The primary outcome measure is histological brain injury on day seven. Secondary outcomes include neurological and neurocognitive recovery, and the trajectory of biomarkers of brain injury.

Conclusion

High-quality animal experiments in clinically relevant large animal models are necessary to close the gap of knowledge regarding neuroprotective effects of induced hypothermia after cardiac arrest.Trial registration:Preclinicaltrials.eu (PCTE0000272), published 2021-11-03.

Enhancing Liver Transplant Outcomes through Liver Precooling to Mitigate Inflammatory Response and Protect Mitochondrial Function

Transplanted organs experience several episodes of ischemia and ischemia-reperfusion. The graft injury resulting from ischemia-reperfusion (IRI) remains a significant obstacle to the successful survival of transplanted grafts. Temperature significantly influences cellular metabolic rates because biochemical reactions are highly sensitive to temperature changes. Consequently, lowering the temperature could reduce the degradative reactions triggered by ischemia. In mitigating IRI in liver grafts, the potential protective effect of localized hypothermia on the liver prior to blood flow obstruction has yet to be explored. In this study, we applied local hypothermia to mouse donor livers for a specific duration before stopping blood flow to liver lobes, a procedure called "liver precooling". Mouse donor liver temperature in control groups was controlled at 37 °C. Subsequently, the liver donors were preserved in cold University of Wisconsin solution for various durations followed by orthotopic liver transplantation. Liver graft injury, function and inflammation were assessed at 1 and 2 days post-transplantation. Liver precooling exhibited a significant improvement in graft function, revealing more than a 47% decrease in plasma aspartate transaminase (AST) and alanine aminotransferase (ALT) levels, coupled with a remarkable reduction of approximately 50% in liver graft histological damage compared to the control group. The protective effects of liver precooling were associated with the preservation of mitochondrial function, a substantial reduction in hepatocyte cell death, and a significantly attenuated inflammatory response. Taken together, reducing the cellular metabolism and enzymatic activity to a minimum level before ischemia protects against IRI during transplantation.

Temperature Control in Acute Brain Injury: An Update

Temperature control in severe acute brain injury (SABI) is a key component of acute management. This manuscript delves into the complex role of temperature management in SABI, encompassing conditions like traumatic brain injury (TBI), acute ischemic stroke (AIS), intracerebral hemorrhage (ICH), aneurysmal subarachnoid hemorrhage (aSAH), and hypoxemic/ischemic brain injury following cardiac arrest. Fever is a common complication in SABI and is linked to worse neurological outcomes due to increased inflammatory responses and intracranial pressure (ICP). Temperature management, particularly hypothermic temperature control (HTC), appears to mitigate these adverse effects primarily by reducing cerebral metabolic demand and dampening inflammatory pathways. However, the effectiveness of HTC varies across different SABI conditions. In the context of post-cardiac arrest, the impact of HTC on neurological outcomes has shown inconsistent results. In cases of TBI, HTC seems promising for reducing ICP, but its influence on long-term outcomes remains uncertain. For AIS, clinical trials have yet to conclusively demonstrate the benefits of HTC, despite encouraging preclinical evidence. This variability in efficacy is also observed in ICH, aSAH, bacterial meningitis, and status epilepticus. In pediatric and neonatal populations, while HTC shows significant benefits in hypoxic-ischemic encephalopathy, its effectiveness in other brain injuries is mixed. Although the theoretical basis for employing temperature control, especially HTC, is strong, the clinical outcomes differ among various SABI subtypes. The current consensus indicates that fever prevention is beneficial across the board, but the application and effectiveness of HTC are more nuanced, underscoring the need for further research to establish optimal temperature management strategies. Here we provide an overview of the clinical evidence surrounding the use of temperature control in various types of SABI.

Combined effects of targeted blood pressure, oxygenation, and duration of device-based fever prevention after out-of-hospital cardiac arrest on 1-year survival: post hoc analysis of a randomized controlled trial

BACKGROUND

The "Blood Pressure and Oxygenation Targets in Post Resuscitation Care" (BOX) trial investigated whether a low versus high blood pressure target, a restrictive versus liberal oxygenation target, and a shorter versus longer duration of device-based fever prevention in comatose patients could improve outcomes. No differences in rates of discharge from hospital with severe disability or 90-day mortality were found. However, long-term effects and potential interaction of the interventions are unknown. Accordingly, the objective of this study is to investigate both individual and combined effects of the interventions on 1-year mortality rates.

METHODS

The BOX trial was a randomized controlled two-center trial that assigned comatose resuscitated out-of-hospital cardiac arrest patients to the following three interventions at admission: A blood pressure target of either 63 mmHg or 77 mmHg; An arterial oxygenation target of 9-10 kPa or 13-14 kPa; Device-based fever prevention administered as an initial 24 h at 36 °C and then either 12 or 48 h at 37 °C; totaling 36 or 72 h of temperature control. Randomization occurred in parallel and simultaneously to all interventions. Patients were followed for the occurrence of death from all causes for 1 year. Analyzes were performed by Cox proportional models, and assessment of interactions was performed with the interventions stated as an interaction term.

RESULTS

Analysis for all three interventions included 789 patients. For the intervention of low compared to high blood pressure targets, 1-year mortality rates were 35% (138 of 396) and 36% (143 of 393), respectively, hazard ratio (HR) 0.92 (0.73-1.16) p = 0.47. For the restrictive compared to liberal oxygenation targets, 1-year mortality rates were 34% (135 of 394) and 37% (146 of 395), respectively, HR 0.92 (0.73-1.16) p = 0.46. For device-based fever prevention for a total of 36 compared to 72 h, 1-year mortality rates were 35% (139 of 393) and 36% (142 of 396), respectively, HR 0.98 (0.78-1.24) p = 0.89. There was no sign of interaction between the interventions, and accordingly, no combination of randomizations indicated differentiated treatment effects.

CONCLUSIONS

There was no difference in 1-year mortality rates for a low compared to high blood pressure target, a liberal compared to restrictive oxygenation target, or a longer compared to shorter duration of device-based fever prevention after cardiac arrest. No combination of the interventions affected these findings. Trial registration ClinicalTrials.gov NCT03141099, Registered 30 April 2017.

Effects of Hypothermia vs Normothermia on Societal Participation and Cognitive Function at 6 Months in Survivors After Out-of-Hospital Cardiac Arrest: A Predefined Analysis of the TTM2 Randomized Clinical Trial

Importance

The Targeted Hypothermia vs Targeted Normothermia After Out-of-Hospital Cardiac Arrest (TTM2) trial reported no difference in mortality or poor functional outcome at 6 months after out-of-hospital cardiac arrest (OHCA). This predefined exploratory analysis provides more detailed estimation of brain dysfunction for the comparison of the 2 intervention regimens.

Objectives

To investigate the effects of targeted hypothermia vs targeted normothermia on functional outcome with focus on societal participation and cognitive function in survivors 6 months after OHCA.

Design, Setting, and Participants

This study is a predefined analysis of an international multicenter, randomized clinical trial that took place from November 2017 to January 2020 and included participants at 61 hospitals in 14 countries. A structured follow-up for survivors performed at 6 months was by masked outcome assessors. The last follow-up took place in October 2020. Participants included 1861 adult (older than 18 years) patients with OHCA who were comatose at hospital admission. At 6 months, 939 of 1861 were alive and invited to a follow-up, of which 103 of 939 declined or were missing.

Interventions

Randomization 1:1 to temperature control with targeted hypothermia at 33 °C or targeted normothermia and early treatment of fever (37.8 °C or higher).

Main outcomes and measures

Functional outcome focusing on societal participation assessed by the Glasgow Outcome Scale Extended ([GOSE] 1 to 8) and cognitive function assessed by the Montreal Cognitive Assessment ([MoCA] 0 to 30) and the Symbol Digit Modalities Test ([SDMT] z scores). Higher scores represent better outcomes.

Results

At 6 months, 836 of 939 survivors with a mean age of 60 (SD, 13) (range, 18 to 88) years (700 of 836 male [84%]) participated in the follow-up. There were no differences between the 2 intervention groups in functional outcome focusing on societal participation (GOSE score, odds ratio, 0.91; 95% CI, 0.71-1.17; P = .46) or in cognitive function by MoCA (mean difference, 0.36; 95% CI,-0.33 to 1.05; P = .37) and SDMT (mean difference, 0.06; 95% CI,-0.16 to 0.27; P = .62). Limitations in societal participation (GOSE score less than 7) were common regardless of intervention (hypothermia, 178 of 415 [43%]; normothermia, 168 of 419 [40%]). Cognitive impairment was identified in 353 of 599 survivors (59%).

Conclusions

In this predefined analysis of comatose patients after OHCA, hypothermia did not lead to better functional outcome assessed with a focus on societal participation and cognitive function than management with normothermia. At 6 months, many survivors had not regained their pre-arrest activities and roles, and mild cognitive dysfunction was common.

Trial Registration

ClinicalTrials.gov Identifier: NCT02908308.

Epidemiology and outcome predictors in 450 patients with hanging-induced cardiac arrest: a retrospective study

Background

Cardiac arrest is the most life-threatening complication of attempted suicide by hanging. However, data are scarce on its characteristics and outcome predictors.

Methods

This retrospective observational multicentre study in 31 hospitals included consecutive adults admitted after cardiac arrest induced by suicidal hanging. Factors associated with in-hospital mortality were identified by multivariate logistic regression with multiple imputations for missing data and adjusted to the temporal trends over the study period.

Results

Of 450 patients (350 men, median age, 43 [34-52] years), 305 (68%) had a psychiatric history, and 31 (6.9%) attempted hanging while hospitalized. The median time from unhanging to cardiopulmonary resuscitation was 0 [0-5] min, and the median time to return of spontaneous circulation (ROSC) was 20 [10-30] min. Seventy-nine (18%) patients survived to hospital discharge. Three variables were independently associated with higher in-hospital mortality: time from collapse or unhanging to ROSC>20 min (odds ratio [OR], 4.71; 95% confidence intervals [95%CIs], 2.02-10.96; p = 0.0004); glycaemia >1.4 g/L at admission (OR, 6.38; 95%CI, 2.60-15.66; p < 0.0001); and lactate >3.5 mmol/L at admission (OR, 6.08; 95%CI, 1.71-21.06; p = 0.005). A Glasgow Coma Scale (GCS) score of >5 at admission was associated with lower in-hospital mortality (OR, 0.009; 95%CI, 0.02-0.37; p = 0.0009).

Conclusion

In patients with hanging-induced cardiac arrest, time from collapse or unhanging to return of spontaneous circulation, glycaemia, arterial lactate, and coma depth at admission were independently associated with survival to hospital discharge. Knowledge of these risk factors may help guide treatment decisions in these patients at high risk of hospital mortality.

Changes in Practice of Controlled Hypothermia after Cardiac Arrest in the Past 20 Years: A Critical Care Perspective

For 20 years, induced hypothermia and targeted temperature management have been recommended to mitigate brain injury and increase survival after cardiac arrest. On the basis of animal research and small clinical trials, the International Liaison Committee on Resuscitation strongly advocated hypothermia at 32-34 °C for 12-24 hours for comatose patients with out-of-hospital cardiac arrest with initial rhythm of ventricular fibrillation or nonperfusing ventricular tachycardia. The intervention was implemented worldwide. In the past decade, hypothermia and targeted temperature management have been investigated in larger clinical randomized trials focusing on target temperature depth, target temperature duration, prehospital versus in-hospital initiation, nonshockable rhythms, and in-hospital cardiac arrest. Systematic reviews suggest little or no effect of delivering the intervention on the basis of the summary of evidence, and the International Liaison Committee on Resuscitation today recommends only to treat fever and keep body temperature below 37.5 °C (weak recommendation, low-certainty evidence). Here we describe the evolution of temperature management for patients with cardiac arrest during the past 20 years and how the accrued evidence has influenced not only the recommendations but also the guideline process. We also discuss possible paths forward in this field, bringing up both whether fever management is at all beneficial for patients with cardiac arrest and which knowledge gaps future clinical trials in temperature management should address.

Serum potassium changes during hypothermia and rewarming: a case series and hypothesis on the mechanism

Introduction

Hypokalemia is known to occur in association with therapeutically induced hypothermia and is usually managed by the administration of potassium (K+).

Methods

We reviewed data from 74 patients who underwent a therapeutic hypothermia protocol at our medical institution.

Results

In four patients in whom data on serum K+ and temperature were available, a strong positive correlation between serum K+ and body temperature was found. Based on the close positive relationship between serum K+ and total body temperature, we hypothesize that serum K+ decreases during hypothermia owing to decreased activity of temperature-dependent K+ exit channels that under normal conditions are sufficiently active to match cellular K+ intake via sodium/K+/adenosine triphosphatase. Upon rewarming, reactivation of these channels results in a rapid increase in serum K+ as a result of K+ exit down its concentration gradient.

Conclusion

Administration of K+ during hypothermia should be done cautiously and avoided during rewarming to avoid potentially life-threatening hyperkalemia. K+ exit via temperature-dependent K+ channels provides a logical explanation for the rebound hyperkalemia. K+ exit channels may play a bigger role than previously appreciated in the regulation of serum K+ during normal and pathophysiological conditions.

Duration of Device-Based Fever Prevention after Cardiac Arrest

BACKGROUND

Guidelines recommend active fever prevention for 72 hours after cardiac arrest. Data from randomized clinical trials of this intervention have been lacking.

METHODS

We randomly assigned comatose patients who had been resuscitated after an out-of-hospital cardiac arrest of presumed cardiac cause to device-based temperature control targeting 36°C for 24 hours followed by targeting of 37°C for either 12 or 48 hours (for total intervention times of 36 and 72 hours, respectively) or until the patient regained consciousness. The primary outcome was a composite of death from any cause or hospital discharge with a Cerebral Performance Category of 3 or 4 (range, 1 to 5, with higher scores indicating more severe disability; a category of 3 or 4 indicates severe cerebral disability or coma) within 90 days after randomization. Secondary outcomes included death from any cause and the Montreal Cognitive Assessment score (range, 0 to 30, with higher scores indicating better cognitive ability) at 3 months.

RESULTS

A total of 393 patients were randomly assigned to temperature control for 36 hours, and 396 patients were assigned to temperature control for 72 hours. At 90 days after randomization, a primary end-point event had occurred in 127 of 393 patients (32.3%) in the 36-hour group and in 133 of 396 patients (33.6%) in the 72-hour group (hazard ratio, 0.99; 95% confidence interval, 0.77 to 1.26; P = 0.70) and mortality was 29.5% in the 36-hour group and 30.3% in the 72-hour group. At 3 months, the median Montreal Cognitive Assessment score was 26 (interquartile range, 24 to 29) and 27 (interquartile range, 24 to 28), respectively. There was no significant between-group difference in the incidence of adverse events.

CONCLUSIONS

Active device-based fever prevention for 36 or 72 hours after cardiac arrest did not result in significantly different percentages of patients dying or having severe disability or coma. (Funded by the Novo Nordisk Foundation; BOX ClinicalTrials.gov number, NCT03141099.).

Centre for Statistical and Methodological Excellence (CESAME): A Consortium Initiative for Improving Methodology in Randomised Clinical Trials

When conducting randomised clinical trials, the choice of methodology and statistical analyses will influence the results. If the planned methodology is not of optimal quality and predefined in detail, there is a risk of biased trial results and interpretation. Even though clinical trial methodology is already at a very high standard, there are many trials that deliver biased results due to the implementation of inadequate methodology, poor data quality and erroneous or biased analyses. To increase the internal and external validity of randomised clinical trial results, several international institutions within clinical intervention research have formed The Centre for Statistical and Methodological Excellence (CESAME). Based on international consensus, the CESAME initiative will develop recommendations for the proper methodological planning, conduct and analysis of clinical intervention research. CESAME aims to increase the validity of randomised clinical trial results which will ultimately benefit patients worldwide across medical specialities. The work of CESAME will be performed within 3 closely interconnected pillars: (1) planning randomised clinical trials; (2) conducting randomised clinical trials; and (3) analysing randomised clinical trials.

Temperature control after cardiac arrest

Most of the patients who die after cardiac arrest do so because of hypoxic-ischemic brain injury (HIBI). Experimental evidence shows that temperature control targeted at hypothermia mitigates HIBI. In 2002, one randomized trial and one quasi-randomized trial showed that temperature control targeted at 32-34 °C improved neurological outcome and mortality in patients who are comatose after cardiac arrest. However, following the publication of these trials, other studies have questioned the neuroprotective effects of hypothermia. In 2021, the largest study conducted so far on temperature control (the TTM-2 trial) including 1900 adults comatose after resuscitation showed no effect of temperature control targeted at 33 °C compared with normothermia or fever control. A systematic review of 32 trials published between 2001 and 2021 concluded that temperature control with a target of 32-34 °C compared with fever prevention did not result in an improvement in survival (RR 1.08; 95% CI 0.89-1.30) or favorable functional outcome (RR 1.21; 95% CI 0.91-1.61) at 90-180 days after resuscitation. There was substantial heterogeneity across the trials, and the certainty of the evidence was low. Based on these results, the International Liaison Committee on Resuscitation currently recommends monitoring core temperature and actively preventing fever (37.7 °C) for at least 72 h in patients who are comatose after resuscitation from cardiac arrest. Future studies are needed to identify potential patient subgroups who may benefit from temperature control aimed at hypothermia. There are no trials comparing normothermia or fever control with no temperature control after cardiac arrest.

Hypothermic versus Normothermic Temperature Control after Cardiac Arrest

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

The neurovascular unit and systemic biology in stroke - implications for translation and treatment

Ischaemic stroke is a leading cause of disability and death for which no acute treatments exist beyond recanalization. The development of novel therapies has been repeatedly hindered by translational failures that have changed the way we think about tissue damage after stroke. What was initially a neuron-centric view has been replaced with the concept of the neurovascular unit (NVU), which encompasses neuronal, glial and vascular compartments, and the biphasic nature of neural-glial-vascular signalling. However, it is now clear that the brain is not the private niche it was traditionally thought to be and that the NVU interacts bidirectionally with systemic biology, such as systemic metabolism, the peripheral immune system and the gut microbiota. Furthermore, these interactions are profoundly modified by internal and external factors, such as ageing, temperature and day-night cycles. In this Review, we propose an extension of the concept of the NVU to include its dynamic interactions with systemic biology. We anticipate that this integrated view will lead to the identification of novel mechanisms of stroke pathophysiology, potentially explain previous translational failures, and improve stroke care by identifying new biomarkers of and treatment targets in stroke.

Temperature Management in the ICU

OBJECTIVE

Temperature abnormalities are recognized as a marker of human disease, and the therapeutic value of temperature is an attractive treatment target. The objective of this synthetic review is to summarize and critically appraise evidence for active temperature management in critically ill patients.

DATA SOURCES

We searched MEDLINE for publications relevant to body temperature management (including targeted temperature management and antipyretic therapy) in cardiac arrest, acute ischemic and hemorrhagic stroke, traumatic brain injury, and sepsis. Bibliographies of included articles were also searched to identify additional relevant studies.

STUDY SELECTION

English-language systematic reviews, meta-analyses, randomized trials, observational studies, and nonhuman data were reviewed, with a focus on the most recent randomized control trial evidence.

DATA EXTRACTION

Data regarding study methodology, patient population, temperature management strategy, and clinical outcomes were qualitatively assessed.

DATA SYNTHESIS

Temperature management is common in critically ill patients, and multiple large trials have been conducted to elucidate temperature targets, management strategies, and timing. The strongest data concerning the use of therapeutic hypothermia exist in comatose survivors of cardiac arrest, and recent trials suggest that appropriate postarrest temperature targets between 33°C and 37.5°C are reasonable. Targeted temperature management in other critical illnesses, including acute stroke, traumatic brain injury, and sepsis, has not shown benefit in large clinical trials. Likewise, trials of pharmacologic antipyretic therapy have not demonstrated improved outcomes, although national guidelines do recommend treatment of fever in patients with stroke and traumatic brain injury based on observational evidence associating fever with worse outcomes.

CONCLUSIONS

Body temperature management in critically ill patients remains an appealing therapy for several illnesses, and additional studies are needed to clarify management strategies and therapeutic pathways.

Paracetamol-Induced Hypothermia in Rodents: A Review on Pharmacodynamics

Paracetamol can induce hypothermia in humans and rodents. The study’s aim is to review the mechanisms of paracetamol-induced hypothermia in rodents or the results issued from in vitro studies on the same species’ tissues (in doses that do not produce hepatic impairment) using the latest developments published in scientific journals over the last 15 years. Available human studies are also analysed. An extensive search in PubMed databases exploring the hypothermic response to paracetamol was conducted. 4669 articles about paracetamol’s effects on body temperature in mice or rats were found. After applying additional filters, 20 articles were selected for review, with 9 of them presented in tabular forms. The analysis of these articles found that the hypothermic effect of paracetamol is due to the inhibition of a cyclooxygenase-1 variant, is potentiated by endothelin receptor antagonists, and can be mediated through GABAA receptors and possibly through transient receptor potential cation channel subfamily A member 1 via N-acetyl-p-benzoquinone imine in the central nervous system. Human studies confirm the in vivo and in vitro experiments in rodents regarding the presence of a hypothermic effect after high, non-toxic doses of paracetamol. Further research is required to understand the mechanisms behind paracetamol’s hypothermic effect in humans.

Percutaneous Coronary Intervention After Return of Spontaneous Circulation Reduces the In-Hospital Mortality in Patients with Acute Myocardial Infarction Complicated by Cardiac Arrest

Background and Objective

The role of percutaneous coronary intervention (PCI) after return of spontaneous circulation (ROSC) in patients with acute myocardial infarction (AMI) complicated by cardiac arrest (CA) is controversial. This study aimed to evaluate the effects of PCI on the in-hospital mortality after ROSC in patients with AMI complicated by CA.

Methods

The clinical data of 66 consecutive patients with ROSC after CA caused by AMI from January 2006 to December 2015 at the First Affiliated Hospital of Sun Yat-sen University were collected. Among these patients, 21 underwent urgent PCI. We analyzed the clinical characteristics of the patients during hospitalization.

Results

The patients who underwent PCI had a higher rate of ST-segment elevation, and their initial recorded heart rhythms were more likely to have a shockable rhythm. Further, they had a high PCI success rate of 100%. The in-hospital mortality in the patients who did not undergo PCI was significantly higher than that in the patients who underwent PCI (68.9% vs 9.5%, P<0.05). Multivariate logistic regression analysis showed that cardiogenic shock (odds ratio [OR], 3.537; 95% CI, 1.047–11.945; P=0.042) and Glasgow Coma Scale score of ≤8 after ROSC (OR, 14.992; 95% CI, 2.815–79.843; P=0.002) were the independent risk factors for in-hospital mortality among the patients. Meanwhile, PCI was a protective factor against in-hospital mortality (OR, 0.063; 95% CI, 0.012–0.318; P=0.001). After propensity matching analysis, the results still showed that PCI (OR, 0.226; 95% CI, 0.028–1.814; P=0.0162) was a protective factor for in-hospital death.

Conclusion

The patients with ROSC after CA caused by AMI who underwent PCI had a lower in-hospital mortality than those who did not undergo PCI.

Outcomes of Venoarterial Extracorporeal Membrane Oxygenation for Cardiac Arrest in Adult Patients in the United States

Background

Factors associated with poor prognosis following receipt of extracorporeal membrane oxygenation (ECMO) in adults with cardiac arrest remain unclear. We aimed to identify predictors of mortality in adults with cardiac arrest receiving ECMO in a nationally representative sample.

Methods and Results

The US Healthcare Cost and Utilization Project's National Inpatient Sample was used to identify 782 adults hospitalized with cardiac arrest who received ECMO between 2006 and 2014. The primary outcome of interest was all‐cause in‐hospital mortality. Factors associated with mortality were analyzed using multivariable logistic regression. The overall in‐hospital mortality rate was 60.4% (n=472). Patients who died were older and more often men, of non‐White race, and with lower household income than those surviving to discharge. In the risk‐adjusted analysis, independent predictors of mortality included older age, male sex, lower annual income, absence of ventricular arrhythmia, absence of percutaneous coronary intervention, and presence of therapeutic hypothermia.

Conclusions

Demographic and therapeutic factors are independently associated with mortality in patients with cardiac arrest receiving ECMO. Identification of which patients with cardiac arrest may receive the utmost benefit from ECMO may aid with decision‐making regarding its implementation. Larger‐scale studies are warranted to assess the appropriate candidates for ECMO in cardiac arrest.

Regulation of STAT3 and its role in cardioprotection by conditioning: focus on non-genomic roles targeting mitochondrial function

Ischemia–reperfusion injury (IRI) is one of the biggest challenges for cardiovascular researchers given the huge death toll caused by myocardial ischemic disease. Cardioprotective conditioning strategies, namely pre- and post-conditioning maneuvers, represent the most important strategies for stimulating pro-survival pathways essential to preserve cardiac health. Conditioning maneuvers have proved to be fundamental for the knowledge of the molecular basis of both IRI and cardioprotection. Among this evidence, the importance of signal transducer and activator of transcription 3 (STAT3) emerged. STAT3 is not only a transcription factor but also exhibits non-genomic pro-survival functions preserving mitochondrial function from IRI. Indeed, STAT3 is emerging as an influencer of mitochondrial function to explain the cardioprotection phenomena. Studying cardioprotection, STAT3 proved to be crucial as an element of the survivor activating factor enhancement (SAFE) pathway, which converges on mitochondria and influences their function by cross-talking with other cardioprotective pathways. Clearly there are still some functional properties of STAT3 to be discovered. Therefore, in this review, we highlight the evidence that places STAT3 as a promoter of the metabolic network. In particular, we focus on the possible interactions of STAT3 with processes aimed at maintaining mitochondrial functions, including the regulation of the electron transport chain, the production of reactive oxygen species, the homeostasis of Ca²⁺ and the inhibition of opening of mitochondrial permeability transition pore. Then we consider the role of STAT3 and the parallels between STA3/STAT5 in cardioprotection by conditioning, giving emphasis to the human heart and confounders.

Mild Hypothermia Therapy Lowers the Inflammatory Level and Apoptosis Rate of Myocardial Cells of Rats with Myocardial Ischemia-Reperfusion Injury via the NLRP3 Inflammasome Pathway

Objective

To explore the protective effects and mechanism of mild hypothermia treatment in the treatment of myocardial ischemia-reperfusion injury. Material and Methods. A total of 20 Sprague-Dawley (SD) rats were assigned to 4 groups: the blank control group, sham operation group, ischemia reperfusion group, and mild hypothermia therapy group (each n = 5). Some indexes were detected. In addition, myocardial cell models of oxygen-glucose deprivation/reoxygenation injury (OGD) were established. The expression of mRNA IL-6 and TNF-α and the key enzyme levels of apoptosis (cleaved-Caspase-3) and the NLRP3 inflammasome/p53 signaling pathway in the models were determined.

Results

The expression of serum IL-6 and TNF-α in the mild hypothermia therapy group was significantly lower than that in the ischemia reperfusion group. The mild hypothermia therapy group also showed a significantly lower TUNEL cell count and NLRP3 and p53 phosphorylation levels than the ischemia reperfusion group (all p < 0.05). The in vitro mild hypothermia + OGD group also showed significantly lower mRNA expression of IL-6 and TNF-α and levels of cleaved Caspase-3, NLRP3, and phosphorylated p53 protein than the OGD group (all p < 0.05).

Conclusion

In conclusion, mild hypothermia therapy can inhibit the apoptosis and myocardial inflammation of cells induced by MI/R injury in rats and inhibiting the activity of the NLRP3 inflammasome pathway and p53 signaling pathway may be the mechanism.

Pharmacological Approach for Neuroprotection After Cardiac Arrest-A Narrative Review of Current Therapies and Future Neuroprotective Cocktail

Cardiac arrest (CA) results in global ischemia-reperfusion injury damaging tissues in the whole body. The landscape of therapeutic interventions in resuscitation medicine has evolved from focusing solely on achieving return of circulation to now exploring options to mitigate brain injury and preserve brain function after CA. CA pathology includes mitochondrial damage and endoplasmic reticulum stress response, increased generation of reactive oxygen species, neuroinflammation, and neuronal excitotoxic death. Current non-pharmacologic therapies, such as therapeutic hypothermia and extracorporeal cardiopulmonary resuscitation, have shown benefits in protecting against ischemic brain injury and improving neurological outcomes post-CA, yet their application is difficult to institute ubiquitously. The current preclinical pharmacopeia to address CA and the resulting brain injury utilizes drugs that often target singular pathways and have been difficult to translate from the bench to the clinic. Furthermore, the limited combination therapies that have been attempted have shown mixed effects in conferring neuroprotection and improving survival post-CA. The global scale of CA damage and its resultant brain injury necessitates the future of CA interventions to simultaneously target multiple pathways and alleviate the hemodynamic, mitochondrial, metabolic, oxidative, and inflammatory processes in the brain. This narrative review seeks to highlight the current field of post-CA neuroprotective pharmaceutical therapies, both singular and combination, and discuss the use of an extensive multi-drug cocktail therapy as a novel approach to treat CA-mediated dysregulation of multiple pathways, enhancing survival, and neuroprotection.

Circadian Biology and Stroke

Circadian biology modulates almost all aspects of mammalian physiology, disease, and response to therapies. Emerging data suggest that circadian biology may significantly affect the mechanisms of susceptibility, injury, recovery, and the response to therapy in stroke. In this review/perspective, we survey the accumulating literature and attempt to connect molecular, cellular, and physiological pathways in circadian biology to clinical consequences in stroke. Accounting for the complex and multifactorial effects of circadian rhythm may improve translational opportunities for stroke diagnostics and therapeutics.

Prognostic value of 'late' electroencephalography recordings in patients with cardiopulmonal resuscitation after cardiac arrest

Background

Electroencephalography (EEG) significantly contributes to the neuroprognostication after resuscitation from cardiac arrest. Recent studies suggest that the prognostic value of EEG is highest for continuous recording within the first days after cardiac arrest. Early continuous EEG, however, is not available in all hospitals. In this observational study, we sought to evaluate the predictive value of a ‘late’ EEG recording 5–14 days after cardiac arrest without sedatives.

Methods

We retrospectively analyzed EEG data in consecutive adult patients treated at the medical intensive care units (ICU) of the Charité—Universitätsmedizin Berlin. Outcome was assessed as cerebral performance category (CPC) at discharge from ICU, with an unfavorable outcome being defined as CPC 4 and 5.

Results

In 187 patients, a ‘late’ EEG recording was performed. Of these patients, 127 were without continuous administration of sedative agents for at least 24 h before the EEG recording. In this patient group, a continuously suppressed background activity < 10 µV predicted an unfavorable outcome with a sensitivity of 31% (95% confidence interval (CI) 20–45) and a specificity of 99% (95% CI 91–100). In patients with suppressed background activity and generalized periodic discharges, sensitivity was 15% (95% CI 7–27) and specificity was 100% (95% CI 94–100). GPDs on unsuppressed background activity were associated with a sensitivity of 42% (95% CI 29–46) and a specificity of 92% (95% CI 82–97).

Conclusions

A ‘late’ EEG performed 5 to 14 days after resuscitation from cardiac arrest can aide in prognosticating functional outcome. A suppressed EEG background activity in this time period indicates poor outcome.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00415-021-10549-y.

Changes in temperature management and outcome after out-of-hospital cardiac arrest in United Kingdom intensive care units following publication of the targeted temperature management trial

AIM

To investigate how the publication of the targeted temperature management (TTM) trial in December 2013 affected the trends in temperature management and outcome following admission to UK intensive care units (ICUs) after out-of-hospital cardiac arrest (OHCA).

METHODS

We used a national ICU database of 1,181,405 consecutive admissions to 235 adult ICUs. OHCA admissions mechanically ventilated in the first 24 h in the ICU were divided into a pre-TTM trial cohort of patients admitted before publication of the TTM trial (January 2010-December 2013) and post-TTM cohort of patients admitted after TTM trial publication (January 2014-December 2017). The primary outcome variables were lowest temperature in the first 24 h in ICU and survival to hospital discharge.

RESULTS

The lowest temperature recorded in the first-24 h of admission was significantly higher in the post-TTM cohort (n = 18,106) than in the pre-TTM cohort (n = 12,162) (mean 34.7 (±1.6) versus 33.6 °C (±1.8); absolute difference 1.12 °C (95% CI 1.08-1.16). The post-TTM cohort had a greater prevalence of fever (>38.0 °C) (24.8% vs 14.7%; (odds ratio (OR) 1.91 (95% CI 1.80-2.03); p < 0.001)) and higher unadjusted in-hospital mortality (63.7% vs 61.6%). In a multilevel model, accounting for time trend and including site as a random effect, neither the step change in acute hospital mortality following publication of the TTM trial result (OR 1.04, 95% CI 0.95-1.15; p = 0.37), nor the change in slope (from OR 1.00 per year, 95% CI 0.97-1.04, to 1.04 per year, 95% CI 1.02-1.07; p = 0.059), was statistically significant. Adjusted analyses were limited by the models' dependence on temperature and temperature-related variables.

CONCLUSIONS

The lowest temperature recorded in the first-24 h of admission in OHCA patients was higher in the post-TTM cohort compared with the pre-TTM cohort. There has been an increase in the proportion of patients with fever (>38 °C) in the first 24 h. Although crude mortality was slightly higher in the post-TTM cohort, an analysis accounting for time trend and variation between critical care units, found no significant change associated with the TTM publication.

Treatment Effects of Interleukin-6 Receptor Antibodies for Modulating the Systemic Inflammatory Response After Out-of-Hospital Cardiac Arrest (The IMICA Trial): A Double-Blinded, Placebo-Controlled, Single-Center, Randomized, Clinical Trial

Supplemental Digital Content is available in the text.

Patients experiencing out-of-hospital cardiac arrest who remain comatose after initial resuscitation are at high risk of morbidity and mortality attributable to the ensuing post–cardiac arrest syndrome. Systemic inflammation constitutes a major component of post–cardiac arrest syndrome, and IL-6 (interleukin-6) levels are associated with post–cardiac arrest syndrome severity. The IL-6 receptor antagonist tocilizumab could potentially dampen inflammation in post–cardiac arrest syndrome. The objective of the present trial was to determine the efficacy of tocilizumab to reduce systemic inflammation after out-of-hospital cardiac arrest of a presumed cardiac cause and thereby potentially mitigate organ injury.

Adjuvant therapeutic potential of moderate hypothermia for glioblastoma

PURPOSE

Glioblastoma is the most common malignant brain tumor, currently treated by surgery followed by concomitant radiotherapy and temozolomide-based chemotherapy. Despite these treatments, median survival is only 15 months as a result of tumor recurrence in the resection margins. Here, we propose therapeutic hypothermia - known to have neuroprotective effects - as an adjuvant treatment to maintain residual glioblastoma cells in a dormant state, and thus prevent tumor recurrence.

METHODS

In vitro experiments were performed on healthy tissue with primary human astrocytes, and four human glioblastoma cell lines: A172, U251, U87, and T98G. We explored the adjuvant potential of moderate hypothermia (28 °C) by studying the reversibility of its inhibitory effects on cell proliferation and comparing them to currently used temozolomide.

RESULTS

Moderate hypothermia reduced healthy cell growth, but also inhibited glioblastoma cell proliferation even after rewarming. Indeed, hypothermic preconditioning duration strongly enhanced inhibitory effects from 35% after 3 days to 100% after 30 days. In contrast, moderate (28 °C) and severe (23 °C) preconditioning induced similar results. Finally, moderate hypothermia had more uniform inhibitory effects than temozolomide, which reduced proliferation by between 15% and 95%, and also potentiated the effects of the latter.

CONCLUSION

Moderate hypothermia shows promise as an adjuvant therapy for glioblastoma through its inhibition of cell proliferation beyond direct conditioning and potentiation of the effects of chemotherapy. If in vivo preclinical results corroborate our findings, therapeutic hypothermia applied at the resection margins could probably inhibit tumor growth, delay tumor recurrence and reduce inter-patient variability.

Review of Hypothermia Protocol and Timing of the Echocardiogram

Targeted temperature management, also known as therapeutic hypothermia (TH), is recommended for out-of-hospital cardiac arrest (OHCA). Both internal or external methods of cooling can be applied. Individuals resuscitated from OHCA frequently develop postarrest myocardial dysfunction resulting in decreased cardiac output and left ventricular systolic function. This dysfunction is usually transient and improves with spontaneous recovery over time. Echocardiogram (ECHO) can be a vital tool for the assessment and management of these patients. This manuscript reviewed methods available for TH after OHCA and reviews role of ECHO in the diagnosis and prognosis in this setting.

Intravascular Targeted Temperature Management: One Hospital's Experience

Sudden cardiac arrest (SCA) is one of the leading causes of death in adults around the world. And in some patients, SCA is followed by a return of spontaneous circulation (ROSC) and remain unresponsive. International guidelines recommend therapeutic hypothermia within 4 hours of ROSC for patients' survival. A medium-sized tertiary teaching hospital in the Midwestern United States was not achieving the recommendations of therapeutic hypothermia therapy. A root cause analysis identified multiple factors contributed to therapy delay. In March 2019, this hospital embarked on a 6-month trial of an intravascular targeted temperature management (ITTM) system to meet the recommendations. Donabedian's model guided the trial and included patients who suffered an SCA, with ROSC and remained unresponsive. Descriptive analysis was completed to compare the patients before and after the trial. The trial included interprofessional education of the ITTM system, policies, orders, and new process for initiating the therapy. A total of nine patients were included in the trial and with an average time to target temperature was 3.28 hours compared with 8.81 hours before the trial. The trial demonstrated ITTM was successful in meeting the recommendations. Paired with the promising research on the system's effectiveness, we have demonstrated that intravascular cooling can be implemented to reach the international recommendations. These reductions in treatment delays may prompt improved outcomes for individuals in the post-SCA population.

Assessing the impact of resuscitation residents on the treatment of cardiopulmonary resuscitation patients

BACKGROUND

The management of cardiac arrest patients receiving cardiopulmonary resuscitation (CPR) is an essential aspect of emergency medicine (EM) training. At our institution, we have a 1-month Resuscitation Rotation designed to augment resident training in managing critical patients. The objective of this study is to compare 30-day mortality between cardiac arrest patients with resuscitation resident (RR) involvement versus patients without. Our secondary outcome is to determine if RR involvement altered rates of initiating targeted temperature management (TTM).

METHODS

This study was conducted at a single site tertiary care Level-1 trauma center with an Emergency Department (ED) census of nearly 130,000 visits per year. Data was collected from 01/01/2015 to 01/01/2018 using electronic medical records via query. Patients admitted with cardiac arrest were separated into two groups, one with RR involvement and one without. Initial rhythm of ventricular fibrillation/tachycardia (VFIB/VTACH), 30-day mortality, history of coronary artery disease (CAD), and initiation of TTM were compared. Statistical analysis was performed.

RESULTS

Out of 885 patient encounters, 91 (10.28%) had RR participation. There was no statistical difference in 30-day mortality between patients with RR involvement compared to those without (71.42% vs 66.36%; P = 0.3613). However, TTM was initiated more in the RR group (20.70% vs 8.86%; P = 0.0025). Patients who received TTM also had a lower 30-day mortality compared to those without TTM (52.94% vs 70.87%; P = 0.0020). Patients who were older and had no history of CAD were also noted to have a statistically significant higher 30-day mortality. All other variables were not statistically significant.

CONCLUSION

Resuscitation resident involvement with the care of cardiac arrest patients had no impact in 30-day mortality. However, the involvement of RR was associated with a statistically significant increase in the initiation of TTM. One limitation is that RR participated in 10.28% of the cases analyzed herein, thus the two arms are unbalanced in size. Future work may investigate if the increase in TTM in the RR involved cases may portend improved rates of neurologically intact survival or more rapid achievement of goal temperatures.

COVID-19 cardiac arrest management: A review for emergency clinicians

INTRODUCTION

A great deal of literature has recently discussed the evaluation and management of the coronavirus disease of 2019 (COVID-19) patient in the emergency department (ED) setting, but there remains a dearth of literature providing guidance on cardiac arrest management in this population.

OBJECTIVE

This narrative review outlines the underlying pathophysiology of patients with COVID-19 and discusses approaches to cardiac arrest management in the ED based on the current literature as well as extrapolations from experience with other pathogens.

DISCUSSION

Patients with COVID-19 may experience cardiovascular manifestations that place them at risk for acute myocardial injury, arrhythmias, and cardiac arrest. The mortality for these critically ill patients is high and increases with age and comorbidities. While providing resuscitative interventions and performing procedures on these patients, healthcare providers must adhere to strict infection control measures and prioritize their own safety through the appropriate use of personal protective equipment. A novel approach must be implemented in combination with national guidelines. The changes in these guidelines emphasize early placement of an advanced airway to limit nosocomial viral transmission and encourage healthcare providers to determine the effectiveness of their efforts prior to placing staff at risk for exposure.

CONCLUSIONS

While treatment priorities and goals are identical to pre-pandemic approaches, the management of COVID-19 patients in cardiac arrest has distinct differences from cardiac arrest patients without COVID-19. We provide a review of the current literature on the changes in cardiac arrest management as well as details outlining team composition.

A pilot protocol and review of triple neuroprotection with targeted hypothermia, controlled induced hypertension, and barbiturate infusion during emergency carotid endarterectomy for acute stroke after failed tPA or beyond 24-hour window of opportunity

An alternative to tissue plasminogen activator (tPA) failure has been a daunting challenge in ischemic stroke management. As tPA is time-dependent, delays can occur in definitive treatment while passively waiting to observe a clinical response to intravenous thrombolysis. Until today, uncertainty exists in the management strategy of wake-up stroke patients or those presenting beyond the therapeutic tPA window. Clinical dilemmas in these situations can prolong the transitional period of inertia, resulting in an adverse neurological outcome. We propose and review an innovative approach called triple neuro-protection (TNP), which encompasses three technical domains-targeted hypothermia, systemic induced hypertension, and barbiturates infusion, to protect the brain during carotid endarterectomy after failed tPA and/or beyond the 24-hour therapeutic mechanical thrombectomy window. This proposal assimilates discussion on the clinical evidence of the individual domains of TNP with our own clinical experience with TNP. Our first TNP was successfully employed in a 55-year-old man in 2015 while performing emergency carotid endarterectomy after he was referred to us 72 hours post tPA failure. The patient had a successful clinical outcome despite being in therapeutic inertia with 90–99% ipsilateral carotid stenosis and contralateral occlusion on presentation. In the last five years, we have safely used TNP in 25 selected cases with favourable clinical outcomes.

Interleukin-6 Receptor Antibodies for Modulating the Systemic Inflammatory Response after Out-of-Hospital Cardiac Arrest (IMICA): study protocol for a double-blinded, placebo-controlled, single-center, randomized clinical trial

Background

Resuscitated out-of-hospital cardiac arrest (OHCA) patients who remain comatose at admission are at high risk of morbidity and mortality. This has been attributed to the post-cardiac arrest syndrome (PCAS) which encompasses multiple interacting components, including systemic inflammation. Elevated levels of circulating interleukin-6 (IL-6), a pro-inflammatory cytokine, is associated with worse outcomes in OHCA patients, including higher vasopressor requirements and higher mortality rates. In this study, we aim to reduce systemic inflammation after OHCA by administering a single infusion of tocilizumab, an IL-6 receptor antibody approved for use for other indications.

Methods

Investigator-initiated, double-blinded, placebo-controlled, single-center, randomized clinical trial in comatose OHCA patients admitted to an intensive cardiac care unit. Brief inclusion criteria: OHCA of presumed cardiac cause, persistent unconsciousness, age ≥ 18 years. Intervention: 80 patients will be randomized in a 1:1 ratio to a single 1-h intravenous infusion of either tocilizumab or placebo (NaCl). During the study period, patients will receive standard of care, including sedation and targeted temperature management of 36 ° for at least 24 h, vasopressors and/or inotropes as/if needed, prophylactic antibiotics, and any additional treatment at the discretion of the treating physician. Blood samples are drawn for measurements of biomarkers included in the primary and secondary endpoints during the initial 72 h. Primary endpoint: reduction in C-reactive protein (CRP). Secondary endpoints (abbreviated): cytokine levels, markers of brain, cardiac, kidney and liver damage, hemodynamic and hemostatic function, adverse events, and follow-up assessment of cerebral function and mortality.

Discussion

We hypothesize that reducing the effect of circulating IL-6 by administering an IL-6 receptor antibody will mitigate the systemic inflammatory response and thereby modify the severity of PCAS, in turn leading to lessened vasopressor use, more normal hemodynamics, and better organ function. This will be assessed by primarily focusing on hemodynamics and biomarkers of organ damage during the initial 72 h.

In addition, pro-inflammatory and anti-inflammatory cytokines will be measured to assess if cytokine patterns are modulated by IL-6 receptor blockage.

Trial registration

ClinicalTrials.gov Identifier: NCT03863015; submitted February 22, 2019, first posted March 5, 2019.

EudraCT: 2018-002686-19; date study was authorized to proceed: November 7, 2018.

Neurocritical Management of Traumatic Acute Subdural Hematomas

Acute subdural hematoma (ASDH) has been a major part of traumatic brain injury. Intracranial hypertension may be followed by ASDH and brain edema. Regardless of the complicated pathophysiology of ASDH, the extent of primary brain injury underlying the ASDH is the most important factor affecting outcome. Ongoing intracranial pressure (ICP) increasing lead to cerebral perfusion pressure (CPP) decrease and cerebral blood flow (CBF) decreasing occurred by CPP decrease. In additionally, disruption of cerebral autoregulation, vasospasm, decreasing of metabolic demand may lead to CBF decreasing. Various protocols for ICP lowering were introduced in neuro-trauma field. Usage of anti-epileptic drugs (AEDs) for ASDH patients have controversy. AEDs may reduce the risk of early seizure (<7 days), but, does not for late-onset epilepsy. Usage of anticoagulants/antiplatelets is increasing due to life-long medical disease conditions in aging populations. It makes a difficulty to decide the proper management. Tranexamic acid may use to reducing bleeding and reduce ASDH related death rate. Decompressive craniectomy for ASDH can reduce patient's death rate. However, it may be accompanied with surgical risks due to big operation and additional cranioplasty afterwards. If the craniotomy is a sufficient management for the ASDH, endoscopic surgery will be good alternative to a conventional larger craniotomy to evacuate the hematoma. The management plan for the ASDH should be individualized based on age, neurologic status, radiologic findings, and the patient's conditions.

Timing of inducing therapeutic hypothermia in patients successfully resuscitated after out-of-hospital cardiac arrest

Background:

Therapeutic hypothermia can improve neurological status in cardiac arrest survivors.

Objectives:

We investigated the association between the timing of inducing therapeutic hypothermia and neurological outcomes in patients who experienced out-of-hospital cardiac arrest.

Methods:

We evaluated data from 116 patients who were comatose after return of spontaneous circulation and those who received therapeutic hypothermia between January 2013 and April 2017. The primary endpoint was good neurological outcomes during index hospitalization, defined as a cerebral performance category score of 1 or 2. Therapeutic hypothermia timing was defined as the duration from the return of spontaneous circulation to hypothermia initiation. We analyzed the effect of early hypothermia induction on neurological results.

Results:

In total, 112 patients were enrolled. The median duration to hypothermia initiation was 284 min (25th–75th percentile, 171–418 min). Eighty-two (69.5%) patients underwent hypothermia within 6 h, and 30 (25.4%) had good neurological outcomes. The rates of good neurological outcomes by hypothermia initiation time quartile (shortest to longest) were 28.3%, 34.5%, 14.8%, and 28.6% (p = 0.401). The good neurologic outcomes did not differ between hypothermia patients within 6 h or after (26.5% vs 26.7%, p = 0.986). Short low-flow time and bystander resuscitation were associated with good neurological outcomes (p = 0.044, confidence interval: 0.027–0.955), but the timing of hypothermia initiation was not (p = 0.602, confidence interval: 0.622–1.317).

Conclusion:

A shorter low-flow time was associated with good neurological outcomes in out-of-hospital cardiac arrest patients who experienced hypothermia. However, inducing hypothermia sooner, even within 6 h, did not improve the neurological outcomes. Thus, as current guidelines recommend, initiating hypothermia within 6 h of recovery of spontaneous circulation is reasonable.

A Case of Severe QTc Prolongation During Targeted Temperature Management - What Can We Learn?

BACKGROUND QTc prolongation during targeted temperature management (TTM) post cardiac arrest is a known effect of hypothermia, but its significance is unclear. Several studies suggest that temporary prolongation during TTM is not prognostic and does not potentiate fatal arrhythmias; however, there are limited cases of patients presenting with QTc intervals >700 milliseconds. CASE REPORT We describe a case in which a 57-year-old woman with diabetes, hypertension, and atrial fibrillation presented with concern for stroke. The hospital course was complicated by cardiac arrest requiring TTM, which was stopped early due to significant QTc prolongation of 746 milliseconds. CONCLUSIONS TTM is beneficial post resuscitation for good neurological outcomes, but it also has known adverse cardiac effects such as QTc prolongation. The significance of QTc prolongation during TTM is unclear as several studies have shown no increased incidence of malignant arrhythmias. One case report in the literature describes the incidence of torsades de pointes due to QTc prolongation during TTM. Further study and guidelines regarding electrocardiogram monitoring are needed to determine the importance of QTc prolongation during TTM.

Outcomes and Utilization of Therapeutic Hypothermia in Post-Cardiac Arrest Patients in Teaching Versus Non-Teaching Hospitals: Retrospective Study of the Nationwide Inpatient Sample Database (2016)

Background Using therapeutic hypothermia (TH) reduces the core body temperature of survivors of cardiac arrest to minimize the neurological damage caused by severe hypoxia. The TH protocol is initiated following return of spontaneous circulation (ROSC) in non-responsive patients. Clinical trials examining this technique have shown significant improvement in neurological function among survivors of cardiac arrests. Though there is strong evidence to support TH use to improve the neurologic outcomes in shockable and nonshockable rhythms, predictors of TH utilization are not well-characterized. Our study tried to evaluate TH utilization, as well as the effect of the teaching status of hospitals, on outcomes, including mortality, length of stay, and total hospitalization charges. Method We conducted a retrospective analysis of the Healthcare Cost and Utilization Project - Nationwide Inpatient Sample (HCUP-NIS) database. Patients with an admitting diagnosis of cardiac arrest, as identified by the corresponding International Classification of Disease, 10th Revision (ICD-10) code for the year 2016 were analyzed. In addition, we identified TH using the ICD-10 procedure code. A weighted descriptive analysis was performed to generate national estimates. Groups of patients admitted to teaching hospitals were compared to those admitted in non-teaching hospitals. Patients were stratified by age, sex, race, and demographic and clinical data, including the Charlson Comorbidity Index (CCI), for these two groups, and statistical analysis was done for the primary outcome, in-hospital mortality, as well as the secondary outcomes, including length of stay (LOS) and total hospitalization charges. Fisher's exact test was used to compare proportions and student's t-test for continuous variables. Statistical analysis was completed by linear regression analysis. Results A total of 13,780 patients met the inclusion criteria for cardiac arrest admission. The number of patients with cardiac arrest admitted to a teaching hospital was 9285. A total of 670 patients received TH, with 495 admissions to teaching hospitals. The population of females in the hypothermia group was 270. The mean age of patients received TH was 59.4 years. In patients who received TH, 65% were Caucasians followed by Hispanics (16%), with no significant statistical racial differences in groups (p=0.30). The majority of patients with TH in both groups (teaching vs. non-teaching admissions) had Medicare (58.8% vs 49.5%; p=0.75). Hospitals in the southern region had the most admissions in both groups (45.7% and 31.3%), with the northeast region having the least non-teaching hospital admissions (8.5%) and approximately similar teaching hospital admissions in other regions (~22%) (p=0.27). The total number of deaths in this group was 510, out of which 370 were in a teaching hospital. After adjusting for age, sex, race, income, the CCI, hospital location, and bed size, mortality was not significantly different between these two groups (p=0.797). We found increased LOS in patients admitted to teaching hospitals (p=0.021). With a p-value of 0.097, there were no differences in total hospitalization charges in both groups. Conclusion There were no significant differences in mortality or total hospitalization charge between patients admitted with cardiac arrest to a teaching hospital and received TH as compared to a non-teaching hospital although patients admitted to teaching hospitals stayed longer.

Therapeutic hypothermia for pediatric refractory status epilepticus May Ameliorate post-status epilepticus epilepsy

BACKGROUND

To compare the clinical characteristics and outcomes of pediatric patients with refractory status epilepticus (RSE) and super-refractory status epilepticus (SRSE) who received therapeutic hypothermia (TH) plus anticonvulsants or anticonvulsants alone.

METHODS

Two-medical referral centers, retrospective cohort study. Pediatric Intensive Care Unit (PICU) at Taoyuan Chang Gung Children's hospital and Kaohsiung Chang Gung Memorial Hospital. We reviewed the medical records of 23 patients with RSE/SRSE who were admitted to PICU from January 2014 to December 2017. Of these, 11 patients received TH (TH group) and 12 patients did not (control group).

RESULTS

The selective endpoints were RSE/SRSE duration, length of PICU stay, and Glasgow Outcome Scale (GOS) score. We applied TH using the Artic Sun® temperature management system (target temperature, 34-35 °C; duration, 48-72 h). Of the 11 patients who received TH, 7 had febrile infection-related epilepsy syndrome (FIRSE), one had Dravet syndrome, and three had traumatic brain injury. The TH group had significantly shortern seizure durations than did the control group (hrs; median (IQR) 24(40) vs. 96(90), p < 0.05). Two patients in the TH group died of pulmonary embolism and extreme brain edema. The length of PICU stay was similar between the groups (days; median (IQR) 30(42) v.s 30.5(30.25)). The TH group had significantly better long-term outcomes than did the control group (GOS score, median (IQR) 4(2) v.s 3 (0.75), p = 0.01∗). The TH group had a significantly lower incidence of later chronic refractory epilepsy than did the control group (TH v.s non-TH, 5/11 (45%) v.s. 12/12(100%), p < 0.01).

CONCLUSIONS

TH effectively reduced the seizure burden in patients with RSE/SRSE. Our findings support that for patients with RSE/SRSE, TH shortens the seizure duration, ultimately reducing the occurrence of post-status epilepticus epilepsy and improving patients' long-term survival.

Safety of Triple Neuroprotection with Targeted Hypothermia, Controlled Induced Hypertension, and Barbiturate Infusion during Emergency Carotid Endarterectomy for Acute Stroke after Missing the 24 Hours Window Opportunity

BACKGROUND

The aim of this study is to establish the initial safety of triple neuroprotection (TNP) in an acute stroke setting in patients presenting outside the window for systemic tissue plasminogen activator (tPA).

METHODS

Over 12,000 patients were referred to our vascular services with carotid artery disease, of whom 832 had carotid intervention with a stroke rate of 0.72%. Of these, 25 patients presented (3%), between March 2015 and 2019, with acute dense stroke. These patients had either failed tPA or passed the recommended timing for acute stroke intervention. Fifteen (60%) had hemi-neglect with evidence of acute infarct on magnetic resonance imaging of the brain and a Rankin score of 4 or 5. Ninety-six percent had an 80-99% stenosis on the symptomatic side. Mean ABCD3-I score was 11.35. All patients underwent emergency carotid endarterectomy (CEA) with therapeutically induced hypothermia (32-34°C), targeted hypertension (systolic blood pressure 180-200 mm Hg), and brain suppression with barbiturate.

RESULTS

There were no cases of myocardial infarction, death, cranial nerve injury, wound hematoma, or procedural bleeding. Mean hospital stay was 8.4 (±9.5) days. All cases had resolution of neurological symptoms, except 3 who had failed previous thrombolysis. Eighty percent had a postoperative Rankin score of 0 on discharge and 88% of patients were discharged home with 3 requiring rehabilitation.

CONCLUSIONS

Positive neurological outcomes and no serious adverse events were observed using TNP during emergency CEA in patients with acute brain injury. We recommend TNP for patients who are at an increased risk of stroke perioperatively, or who have already suffered from an acute stroke beyond the recommended window of 24 hr. Certainly, the positive outcomes are not likely reproducible outside of high-volume units and patients requiring this surgery should be transferred to experienced surgeons in appropriate tertiary referral centers.

Frequency of Medical Reversal Among Published Randomized Controlled Trials Assessing Cardiopulmonary Resuscitation (CPR)

OBJECTIVE

To characterize what proportion of all randomized controlled trials (RCTs) among patients experiencing cardiac arrest find that an established practice is ineffective or harmful, that is, a medical reversal.

METHODS

We reviewed a database of all published RCTs of cardiac arrest patient populations between 1995 and 2014. Articles were classified on the basis of whether they tested a new or existing therapy and whether results were positive or negative. A reversal was defined as a negative RCT of an established practice. Further review and categorization were performed to confirm that reversals were supported by subsequent systematic review, as well as to identify the type of medical practice studied in each reversal. This study was conducted from October 2017 to June 17, 2019.

RESULTS

We reviewed 92 original articles, 76 of which could be conclusively categorized. Of these, 18 (24%) articles examined a new medical practice, whereas 58 (76%) tested an established practice. A total of 18 (24%) studies had positive findings, whereas 58 (76%) reached a negative conclusion. Of the 58 articles testing existing standard of care, 44 (76%) reversed that practice, whereas 14 (24%) reaffirmed it.

CONCLUSION

Reversal of cardiopulmonary resuscitation practices is widespread. This investigation sheds new light on low-value practices and patterns of medical research and suggests that novel resuscitation practices have low pretest probability and should be empirically tested with rigorous trials before implementation.

[Therapeutic Hypothermia in a Cardiac Arrest: Complicated Questions and Unsolved Problems]

The article aims to review the main trials, meta-analyses and guidelines regarding to various practical aspects and unsolved questions of an appliance of the therapeutic hypothermia in out-of-hospital and in-hospital cardiac arrest.

Pediatric Drowning: A Standard Operating Procedure to Aid the Prehospital Management of Pediatric Cardiac Arrest Resulting From Submersion

OBJECTIVES

Drowning is one of the leading causes of death in children. Resuscitating a child following submersion is a high-pressure situation, and standard operating procedures can reduce error. Currently, the Resuscitation Council UK guidance does not include a standard operating procedure on pediatric drowning. The objective of this project was to design a standard operating procedure to improve outcomes of drowned children.

METHODS

A literature review on the management of pediatric drowning was conducted. Relevant publications were used to develop a standard operating procedure for management of pediatric drowning.

RESULTS

A concise standard operating procedure was developed for resuscitation following pediatric submersion. Specific recommendations include the following: the Heimlich maneuver should not be used in this context; however, prolonged resuscitation and therapeutic hypothermia are recommended.

CONCLUSIONS

This standard operating procedure is a potentially useful adjunct to the Resuscitation Council UK guidance and should be considered for incorporation into its next iteration.

Update of the organoprotective properties of xenon and argon: from bench to beside

The growth of the elderly population has led to an increase in patients with myocardial infarction and stroke (Wajngarten and Silva, Eur Cardiol 14: 111–115, 2019). Patients receiving treatment for ST-segment-elevation myocardial infarction (STEMI) highly profit from early reperfusion therapy under 3 h from the onset of symptoms. However, mortality from STEMI remains high due to the increase in age and comorbidities (Menees et al., N Engl J Med 369: 901–909, 2013). These factors also account for patients with acute ischaemic stroke. Reperfusion therapy has been established as the gold standard within the first 4 to 5 h after onset of symptoms (Powers et al., Stroke 49: e46-e110, 2018). Nonetheless, not all patients are eligible for reperfusion therapy. The same is true for traumatic brain injury patients. Due to the complexity of acute myocardial and central nervous injury (CNS), finding organ protective substances to improve the function of remote myocardium and the ischaemic penumbra of the brain is urgent. This narrative review focuses on the noble gases argon and xenon and their possible cardiac, renal and neuroprotectant properties in the elderly high-risk (surgical) population. The article will provide an overview of the latest experimental and clinical studies. It is beyond the scope of this review to give a detailed summary of the mechanistic understanding of organ protection by xenon and argon.

Moderate Hypothermia Modifies Coronary Hemodynamics and Endothelium-Dependent Vasodilation in a Porcine Model of Temperature Management

Background Hypothermia has been associated with therapeutic benefits including reduced mortality and better neurologic outcomes in survivors of cardiac arrest. However, undesirable side effects have been reported in patients undergoing coronary interventions. Using a large animal model of temperature management, we aimed to describe how temperature interferes with the coronary vasculature. Methods and Results Coronary hemodynamics and endothelial function were studied in 12 pigs at various core temperatures. Left circumflex coronary artery was challenged with intracoronary nitroglycerin, bradykinin, and adenosine at normothermia (38°C) and mild hypothermia (34°C), followed by either rewarming (38°C; n=6) or moderate hypothermia (MoHT; 32°C, n=6). Invasive coronary hemodynamics by Doppler wire revealed a slower coronary blood velocity at 32°C in the MoHT protocol (normothermia 20.2±11.2 cm/s versus mild hypothermia 18.7±4.3 cm/s versus MoHT 11.3±5.3 cm/s, P=0.007). MoHT time point was also associated with high values of hyperemic microvascular resistance (>3 mm Hg/cm per second) (normothermia 2.0±0.6 mm Hg/cm per second versus mild hypothermia 2.0±0.8 mm Hg/cm per second versus MoHT 3.4±1.6 mm Hg/cm per second, P=0.273). Assessment of coronary vasodilation by quantitative coronary analysis showed increased endothelium-dependent (bradykinin) vasodilation at 32°C when compared with normothermia (normothermia 6.96% change versus mild hypothermia 9.01% change versus MoHT 25.42% change, P=0.044). Results from coronary reactivity in vitro were in agreement with angiography data and established that endothelium-dependent relaxation in MoHT completely relies on NO production. Conclusions In this porcine model of temperature management, 34°C hypothermia and rewarming (38°C) did not affect coronary hemodynamics or endothelial function. However, 32°C hypothermia altered coronary vasculature physiology by slowing coronary blood flow, increasing microvascular resistance, and exacerbating endothelium-dependent vasodilatory response.