Does therapeutic hypothermia benefit adult cardiac arrest patients presenting with non-shockable initial rhythms?: A systematic review and meta-analysis of randomized and non-randomized studies

Intracerebroventricular infusion of secretoneurin inhibits neuronal NLRP3-Apoptosis pathway and preserves learning and memory after cerebral ischemia

Transient global cerebral ischemia (GCI) results in delayed neuronal death, primarily apoptosis, in the hippocampal CA1 subregion, which leads to severe cognitive deficits. While therapeutic hypothermia is an approved treatment for patients following cardiac arrest, it is associated with various adverse effects. Secretoneurin (SN) is an evolutionarily conserved neuropeptide generated in the brain, adrenal medulla and other endocrine tissues. In this study, SN was infused into the rat brain by intracerebroventricular injection 1 day after GCI, and we demonstrated that SN could significantly preserve spatial learning and memory in the Barnes maze tasks examined on days 14-17 after GCI. To further investigate underlying pathways involved, we demonstrated that, on day 5 after GCI, SN could significantly inhibit GCI-induced expression levels of Apoptosis Inducing Factor (AIF) and cleaved-PARP1, as well as neuronal apoptosis and synaptic loss in the hippocampal CA1 region. Additionally, SN could attenuate GCI-induced activation of both caspase-1 and caspase-3, and the levels of pro-inflammatory cytokines IL-1β and IL-18 in the CA1 region. Mechanically, we observed that treatment with SN effectively inhibited NLRP3 protein elevation and the bindings of NLRP3-ASC and ASC-caspase-1 in hippocampal neurons after GCI. In summary, our data indicate that SN could effectively attenuate NLRP3 inflammasome formation, as well as the activation of caspase-1 and -3, the production of pro-inflammatory cytokines, and ultimately the neuronal apoptotic loss induced by GCI. Potential neuronal pyroptosis, or caspase-1-dependent cell death, could also be involved in ischemic neuronal death, which needs further investigation.

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.

Ten rules for optimizing ventilatory settings and targets in post-cardiac arrest patients

Cardiac arrest (CA) is a major cause of morbidity and mortality frequently associated with neurological and systemic involvement. Supportive therapeutic strategies such as mechanical ventilation, hemodynamic settings, and temperature management have been implemented in the last decade in post-CA patients, aiming at protecting both the brain and the lungs and preventing systemic complications. A lung-protective ventilator strategy is currently the standard of care among critically ill patients since it demonstrated beneficial effects on mortality, ventilator-free days, and other clinical outcomes. The role of protective and personalized mechanical ventilation setting in patients without acute respiratory distress syndrome and after CA is becoming more evident. The individual effect of different parameters of lung-protective ventilation, including mechanical power as well as the optimal oxygen and carbon dioxide targets, on clinical outcomes is a matter of debate in post-CA patients. The management of hemodynamics and temperature in post-CA patients represents critical steps for obtaining clinical improvement. The aim of this review is to summarize and discuss current evidence on how to optimize mechanical ventilation in post-CA patients. We will provide ten tips and key insights to apply a lung-protective ventilator strategy in post-CA patients, considering the interplay between the lungs and other systems and organs, including the brain.

Ventilatory settings in the initial 72 h and their association with outcome in out-of-hospital cardiac arrest patients: a preplanned secondary analysis of the targeted hypothermia versus targeted normothermia after out-of-hospital cardiac arrest (TTM2) trial

PURPOSE

The optimal ventilatory settings in patients after cardiac arrest and their association with outcome remain unclear. The aim of this study was to describe the ventilatory settings applied in the first 72 h of mechanical ventilation in patients after out-of-hospital cardiac arrest and their association with 6-month outcomes.

METHODS

Preplanned sub-analysis of the Target Temperature Management-2 trial. Clinical outcomes were mortality and functional status (assessed by the Modified Rankin Scale) 6 months after randomization.

RESULTS

A total of 1848 patients were included (mean age 64 [Standard Deviation, SD = 14] years). At 6 months, 950 (51%) patients were alive and 898 (49%) were dead. Median tidal volume (V_T) was 7 (Interquartile range, IQR = 6.2-8.5) mL per Predicted Body Weight (PBW), positive end expiratory pressure (PEEP) was 7 (IQR = 5-9) cmH₂0, plateau pressure was 20 cmH₂0 (IQR = 17-23), driving pressure was 12 cmH₂0 (IQR = 10-15), mechanical power 16.2 J/min (IQR = 12.1-21.8), ventilatory ratio was 1.27 (IQR = 1.04-1.6), and respiratory rate was 17 breaths/minute (IQR = 14-20). Median partial pressure of oxygen was 87 mmHg (IQR = 75-105), and partial pressure of carbon dioxide was 40.5 mmHg (IQR = 36-45.7). Respiratory rate, driving pressure, and mechanical power were independently associated with 6-month mortality (omnibus p-values for their non-linear trajectories: p < 0.0001, p = 0.026, and p = 0.029, respectively). Respiratory rate and driving pressure were also independently associated with poor neurological outcome (odds ratio, OR = 1.035, 95% confidence interval, CI = 1.003-1.068, p = 0.030, and OR = 1.005, 95% CI = 1.001-1.036, p = 0.048). A composite formula calculated as [(4*driving pressure) + respiratory rate] was independently associated with mortality and poor neurological outcome.

CONCLUSIONS

Protective ventilation strategies are commonly applied in patients after cardiac arrest. Ventilator settings in the first 72 h after hospital admission, in particular driving pressure and respiratory rate, may influence 6-month outcomes.

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.

Targeted Temperature Management in Unconscious Survivors of Postcardiac Arrest: A Systematic Review and Meta-analysis of Randomized Controlled Trials

Background

Targeted temperature management (TTM) is a vital element of postresuscitation management after cardiac arrest. Though international guidelines recommend TTM, the supporting evidence is of low certainty.

Aims and objectives

To estimate the effect of TTM strategy on mortality and neurological outcomes in postcardiac arrest survivors.

Materials and methods

Randomized controlled trials (RCTs) published in English evaluating the use of TTM in adult comatose survivors of cardiac arrest were included. Studies were categorized into two groups, based on hypothermia vs normothermia. The main outcome was death due to any origin. The secondary outcome measures evaluated neurological outcome and complications associated with TTM. Outcomes were analyzed by calculating Odds Ratio (OR) of a worse outcome. ORs with 95% CIs in a forest plot were used to show the results of random-effects meta-analyses.

Results

On pooled analysis of 11 RCTs, no difference was observed in death due to any origin rates in the hypothermia compared to the normothermia group (OR; 0.88, 95% CI: 0.39–1.16). Overall, no difference in poor neurological outcome was observed between the two groups (OR; 0.86, 95% CI: 0.66–1.12). Trial sequencing analysis for mortality and poor neurological outcome showed that number to achieve power to predict futility has been achieved in both the parameters.

Conclusions

This meta-analysis showed that hypothermia compared to normothermia TTM strategies does not improve survival or neurologic outcomes.

How to cite this article

Mishra SB, Patnaik R, Rath A, Samal S, Dash A, Nayak B. Targeted Temperature Management in Unconscious Survivors of Postcardiac Arrest: A Systematic Review and Meta-analysis of Randomized Controlled Trials. Indian J Crit Care Med 2022;26(4):506–513.

Ventilation management and outcomes in out-of-hospital cardiac arrest: a protocol for a preplanned secondary analysis of the TTM2 trial

INTRODUCTION

Mechanical ventilation is a fundamental component in the management of patients post cardiac arrest. However, the ventilator settings and the gas-exchange targets used after cardiac arrest may not be optimal to minimise post-anoxic secondary brain injury. Therefore, questions remain regarding the best ventilator management in such patients.

METHODS AND ANALYSIS

This is a preplanned analysis of the international randomised controlled trial, targeted hypothermia versus targeted normothermia after out-of-hospital cardiac arrest (OHCA)-target temperature management 2 (TTM2). The primary objective is to describe ventilatory settings and gas exchange in patients who required invasive mechanical ventilation and included in the TTM2 trial. Secondary objectives include evaluating the association of ventilator settings and gas-exchange values with 6 months mortality and neurological outcome. Adult patients after an OHCA who were included in the TTM2 trial and who received invasive mechanical ventilation will be eligible for this analysis. Data collected in the TTM2 trial that will be analysed include patients' prehospital characteristics, clinical examination, ventilator settings and arterial blood gases recorded at hospital and intensive care unit (ICU) admission and daily during ICU stay.

ETHICS AND DISSEMINATION

The TTM2 study has been approved by the regional ethics committee at Lund University and by all relevant ethics boards in participating countries. No further ethical committee approval is required for this secondary analysis. Data will be disseminated to the scientific community by abstracts and by original articles submitted to peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT02908308.

Hypoxic postconditioning-induced neuroprotection increases neuronal autophagy via activation of the SIRT1/FoxO1 signaling pathway in rats with global cerebral ischemia

Hypoxic postconditioning (HPC) has been reported to be a beneficial and promising treatment for global cerebral ischemia (GCI). However, its neuroprotective mechanism remains unclear. The aim of the present study was to determine whether the protective effects of HPC in a rat model of GCI were due to the upregulation of autophagy via the silent information regulator transcript-1 (SIRT1)/Forkhead box protein 1 (FoxO1) pathway. Morris water maze test revealed that HPC attenuated cognitive damage in GCI rats. HPC also significantly increased the levels of the autophagy-related protein LC3-II, SIRT1 and FoxO1 compared with those in the GCI group. However, the HPC-induced LC3-II upregulation was blocked by the SIRT1 inhibitor EX527. These results suggested that the beneficial effects of HPC on GCI rats were due to the upregulation of ischemiainduced autophagy and involved the SIRT1/FoxO1 signaling pathway.

Post-cardiac arrest care and targeted temperature management: A consensus of scientific statement from the Taiwan Society of Emergency & Critical Care Medicine, Taiwan Society of Critical Care Medicine and Taiwan Society of Emergency Medicine

BACKGROUND

Post-cardiac arrest care is critically important in bringing cardiac arrest patients to functional recovery after the detrimental event. More high quality studies are published and evidence is accumulated for the post-cardiac arrest care in the recent years. It is still a challenge for the clinicians to integrate these scientific data into the real clinical practice for such a complicated intensive care involving many different disciplines.

METHODS

With the cooperation of the experienced experts from all disciplines relevant to post-cardiac arrest care, the consensus of the scientific statement was generated and supported by three major scientific groups for emergency and critical care in post-cardiac arrest care.

RESULTS

High quality post-cardiac arrest care, including targeted temperature management, early evaluation of possible acute coronary event and intensive care for hemodynamic and respiratory care are inevitably needed to get full recovery for cardiac arrest. Management of these critical issues were reviewed and proposed in the consensus CONCLUSION: The goal of the statement is to provide help for the clinical physician to achieve better quality and evidence-based care in post-cardiac arrest period.

Effects of prenatal photobiomodulation treatment on neonatal hypoxic ischemia in rat offspring

Neonatal hypoxic-ischemic (HI) injury is a severe complication often leading to neonatal death and long-term neurobehavioral deficits in children. Currently, the only treatment option available for neonatal HI injury is therapeutic hypothermia. However, the necessary specialized equipment, possible adverse side effects, and limited effectiveness of this therapy creates an urgent need for the development of new HI treatment methods. Photobiomodulation (PBM) has been shown to be neuroprotective against multiple brain disorders in animal models, as well as limited human studies. However, the effects of PBM treatment on neonatal HI injury remain unclear. Methods: Two-minutes PBM (808 nm continuous wave laser, 8 mW/cm² on neonatal brain) was applied three times weekly on the abdomen of pregnant rats from gestation day 1 (GD1) to GD21. After neonatal right common carotid artery ligation, cortex- and hippocampus-related behavioral deficits due to HI insult were measured using a battery of behavioral tests. The effects of HI insult and PBM pretreatment on infarct size; synaptic, dendritic, and white matter damage; neuronal degeneration; apoptosis; mitochondrial function; mitochondrial fragmentation; oxidative stress; and gliosis were then assessed. Results: Prenatal PBM treatment significantly improved the survival rate of neonatal rats and decreased infarct size after HI insult. Behavioral tests revealed that prenatal PBM treatment significantly alleviated cortex-related motor deficits and hippocampus-related memory and learning dysfunction. In addition, mitochondrial function and integrity were protected in HI animals treated with PBM. Additional studies revealed that prenatal PBM treatment significantly alleviated HI-induced neuroinflammation, oxidative stress, and myeloid cell/astrocyte activation. Conclusion: Prenatal PBM treatment exerts neuroprotective effects on neonatal HI rats. Underlying mechanisms for this neuroprotection may include preservation of mitochondrial function, reduction of inflammation, and decreased oxidative stress. Our findings support the possible use of PBM treatment in high-risk pregnancies to alleviate or prevent HI-induced brain injury in the perinatal period.

Therapeutic hypothermia for cardiac arrest due to non-shockable rhythm: A protocol for systematic review and meta-analysis

BACKGROUND

The effectiveness of therapeutic hypothermia (TH) for patients following cardiac arrest with non-shockable rhythm is debated. We plan to conduct a systematic review and meta-analysis with all available randomized controlled trials (RCTs) to explore the efficacy and safety of TH in in this population.

METHODS

PubMed, EMBASE and Cochrane Library will be searched to identify RCTs published from inception through December 2020 without language restriction. Patients following cardiac arrest due to non-shockable rhythm will be included. The primary outcome is the hospital mortality. The secondary outcome is the favorable neurological outcome. The pooled effects will be analyzed as mean differences using the inverse-variance method for continuous data or as risk ratios using the Mantel-Haenszel method for dichotomous data. Subgroup and sensitivity analyses will be conducted. The Egger's test and/or the funnel plot will be used to test the publication bias. The grades of recommendation assessment, development, and evaluation (GRADE) methodology will be used to assess the quality of evidence. The trial sequential analysis will be used to test whether the meta-analysis is conclusive.

RESULTS

The RCTs on the effectiveness of TH for patients following cardiac arrest with non-shockable rhythm will be systematically reviewed and advance evidence will be provided.

CONCLUSION

Advanced evidence of TH for cardiac arrest due to non-shockable rhythm will be provided for physicians.

PROSPERO REGISTRATION NUMBER

CRD42020161823.

[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.

G-protein-coupled estrogen receptor activation upregulates interleukin-1 receptor antagonist in the hippocampus after global cerebral ischemia: implications for neuronal self-defense

BACKGROUND

G-protein-coupled estrogen receptor (GPER/GPR30) is a novel membrane-associated estrogen receptor that can induce rapid kinase signaling in various cells. Activation of GPER can prevent hippocampal neuronal cell death following transient global cerebral ischemia (GCI), although the mechanisms remain unclear. In the current study, we sought to address whether GPER activation exerts potent anti-inflammatory effects in the rat hippocampus after GCI as a potential mechanism to limit neuronal cell death.

METHODS

GCI was induced by four-vessel occlusion in ovariectomized female SD rats. Specific agonist G1 or antagonist G36 of GPER was administrated using minipump, and antisense oligonucleotide (AS) of interleukin-1β receptor antagonist (IL1RA) was administrated using brain infusion kit. Protein expression of IL1RA, NF-κB-P65, phosphorylation of CREB (p-CREB), Bcl2, cleaved caspase 3, and microglial markers Iba1, CD11b, as well as inflammasome components NLRP3, ASC, cleaved caspase 1, and Cle-IL1β in the hippocampal CA1 region were investigated by immunofluorescent staining and Western blot analysis. The Duolink II in situ proximity ligation assay (PLA) was performed to detect the interaction between NLRP3 and ASC. Immunofluorescent staining for NeuN and TUNEL analysis were used to analyze neuronal survival and apoptosis, respectively. We performed Barnes maze and Novel object tests to compare the cognitive function of the rats.

RESULTS

The results showed that G1 attenuated GCI-induced elevation of Iba1 and CD11b in the hippocampal CA1 region at 14 days of reperfusion, and this effect was blocked by G36. G1 treatment also markedly decreased expression of the NLRP3-ASC-caspase 1 inflammasome and IL1β activation, as well as downstream NF-κB signaling, the effects reversed by G36 administration. Intriguingly, G1 caused a robust elevation in neurons of a well-known endogenous anti-inflammatory factor IL1RA, which was reversed by G36 treatment. G1 also enhanced p-CREB level in the hippocampus, a transcription factor known to enhance expression of IL1RA. Finally, in vivo IL1RA-AS abolished the anti-inflammatory, neuroprotective, and anti-apoptotic effects of G1 after GCI and reversed the cognitive-enhancing effects of G1 at 14 days after GCI.

CONCLUSIONS

Taken together, the current results suggest that GPER preserves cognitive function following GCI in part by exerting anti-inflammatory effects and enhancing the defense mechanism of neurons by upregulating IL1RA.

Association Between Therapeutic Hypothermia and Outcomes in Patients with Non-shockable Out-of-Hospital Cardiac Arrest Developed After Emergency Medical Service Arrival (SOS-KANTO 2012 Analysis Report)

BACKGROUND/OBJECTIVE

The outcomes of patients with non-shockable out-of-hospital cardiac arrest (non-shockable OHCA) are poorer than those of patients with shockable out-of-hospital cardiac arrest (shockable OHCA). In this retrospective study, we selected patients from the SOS-KANTO 2012 study with non-shockable OHCA that developed after emergency medical service (EMS) arrival and analyzed the effect of therapeutic hypothermia (TH) on non-shockable OHCA patients.

METHODS

Of 16,452 patients who have definitive data on the 3-month outcome in the SOS-KANTO 2012 study, we selected 241 patients who met the following criteria: age ≥ 18 years, normal spontaneous respiration or palpable pulse upon emergency medical services arrival, no ventricular fibrillation or pulseless ventricular tachycardia before hospital arrival, and achievement of spontaneous circulation without cardiopulmonary bypass. Patients were divided into two groups based on the presence or absence of TH and were analyzed.

RESULTS

Of the 241 patients, 49 underwent TH. Univariate analysis showed that the 1-/3-month survival rates and favorable 3-month cerebral function outcome rates in the TH group were significantly better than the non-TH group (46% vs 19%, respectively, P < 0.001, 35% vs 12%, respectively, P < 0.001, 20% vs 7%, respectively, P = 0.01). Multivariate logistic regression analysis showed that TH was a significant, independent prognostic factor for cerebral function outcome.

CONCLUSIONS

In this study, TH was an independent prognostic factor for the 3-month cerebral function outcome. Even in patients with non-shockable OHCA, TH may improve outcome if the interval from the onset of cardiopulmonary arrest is relatively short, and adequate cardiopulmonary resuscitation is initiated immediately after onset.

Contemporary Management of Out-of-hospital Cardiac Arrest in the Cardiac Catheterisation Laboratory: Current Status and Future Directions

Out-of-hospital cardiac arrest (OHCA) is an important cause of mortality and morbidity in developed countries and remains an important public health burden. A primary cardiac aetiology is common in OHCA patients, and so patients are increasingly brought to specialist cardiac centres for consideration of coronary angiography, percutaneous coronary intervention and mechanical circulatory support. This article focuses on the management of OHCA in the cardiac catheterisation laboratory. In particular, it addresses conveyance of the OHCA patient direct to a specialist centre, the role of targeted temperature management, pharmacological considerations, provision of early coronary angiography and mechanical circulatory support.

Photobiomodulation preconditioning prevents cognitive impairment in a neonatal rat model of hypoxia-ischemia

Neonatal hypoxia-ischemia (HI) injury caused by oxygen deprivation is the most common cause of mortality and severe neurologic deficits in neonates. The present work evaluated the preventative effect of photobiomodulation (PBM) preconditioning, and its underlying mechanism of action on brain damage in an HI model in neonatal rats. According to the optimal time response of ATP levels in brain samples removed from normal rats, a PBM preconditioning (PBM-P) regimen (808 nm CW laser, 1 cm2 spot, 100 mW/cm2 , 12 J/cm2 ) was delivered to the scalp 6 hours before HI. PBM-P significantly attenuated cognitive impairment, volume shrinkage in the brain, neuron loss, dendritic and synaptic injury after HI. Further mechanistic investigation found that PBM-P could restore HI-induced mitochondrial dynamics and inhibit mitochondrial fragmentation, followed by a robust suppression of cytochrome c release, and prevention of neuronal apoptosis by inhibition of caspase activation. Our work suggests that PBM-P can attenuate HI-induced brain injury by maintaining mitochondrial dynamics and inhibiting the mitochondrial apoptotic pathway.

Targeted Temperature Management and Postcardiac arrest Care

Despite recent advances, care of the post-cardiac arrest patient remains a challenge. In this article, the authors discuss an approach to the initial care of post-cardiac arrest patients with particular focus on targeted temperature management (TTM). The article starts with history, physiologic rationale, and the major randomized controlled trials that have shaped guidelines for post-cardiac arrest care. It also reviews controversial topics, including TTM for nonshockable rhythms, TTM dose, and surface versus endovascular cooling. The article concludes with a brief review of other key aspects of post-arrest care: coronary angiography, hemodynamic optimization, ventilator management, and prognostication.

Initial arterial pH as a predictor of neurologic outcome after out-of-hospital cardiac arrest: A propensity-adjusted analysis

BACKGROUND

Lower pH after out-of-hospital cardiac arrest (OHCA) has been associated with worsening neurologic outcome, with <7.2 identified as an "unfavorable resuscitation feature" in consensus treatment algorithms despite conflicting data. This study aimed to describe the relationship between decremental post-resuscitation pH and neurologic outcomes after OHCA.

METHODS

Consecutive OHCA patients treated with targeted temperature management (TTM) at multiple US centers from 2008 to 2017 were evaluated. Poor neurologic outcome at hospital discharge was defined as cerebral performance category ≥3. The exposure was initial arterial pH after return of spontaneous circulation (ROSC) analyzed in decremental 0.05 thresholds. Potential confounders (demographics, history, resuscitation characteristics, initial studies) were defined a priori and controlled for via ATT-weighting on the inverse propensity score plus direct adjustment for the linear propensity score.

RESULTS

Of 723 patients, 589 (80%) experienced poor neurologic outcome at hospital discharge. After propensity-adjustment with excellent covariate balance, the adjusted odds ratios for poor neurologic outcome by pH threshold were: ≤7.3: 2.0 (1.0-4.0); ≤7.25: 1.9 (1.2-3.1); ≤7.2: 2.1 (1.3-3.3); ≤7.15: 1.9 (1.2-3.1); ≤7.1: 2.4 (1.4-4.1); ≤7.05: 3.1 (1.5-6.3); ≤7.0: 4.5 (1.8-12).

CONCLUSIONS

No increased hazard of progressively poor neurologic outcomes was observed in resuscitated OHCA patients treated with TTM until the initial post-ROSC arterial pH was at least ≤7.1. This threshold is more acidic than in current guidelines, suggesting the possibility that post-arrest pH may be utilized presently as an inappropriately-pessimistic prognosticator.

Photobiomodulation for Global Cerebral Ischemia: Targeting Mitochondrial Dynamics and Functions

Hypothermia is currently the only approved therapy for global cerebral ischemia (GCI) after cardiac arrest; however, it unfortunately has multiple adverse effects. As a noninvasive procedure, photobiomodulation (PBM) therapy has emerged as a potential novel treatment for brain injury. PBM involves the use of low-level laser light therapy to influence cell behavior. In this study, we evaluated the therapeutic effects of PBM treatment with an 808-nm diode laser initiated 6 h after GCI. It was noted that PBM dose-dependently protected against GCI-induced neuronal death in the vulnerable hippocampal CA1 subregion. Functional assessments demonstrated that PBM markedly preserved both short-term (a week) and long-term (6 months) spatial learning and memory function following GCI. Further mechanistic studies revealed that PBM post-treatment (a) preserved healthy mitochondrial dynamics and suppressed substantial mitochondrial fragmentation of CA1 neurons, by reducing the detrimental Drp1 GTPase activity and its interactions with adaptor proteins Mff and Fis1 and by balancing mitochondrial targeting fission and fusion protein levels; (b) reduced mitochondrial oxidative damage and excessive mitophagy and restored mitochondrial overall health status and preserved mitochondrial function; and (c) suppressed mitochondria-dependent apoptosome formation/caspase-3/9 apoptosis-processing activities. Additionally, we validated, in an in vitro ischemia model, that cytochrome c oxidase served as a key PBM target for mitochondrial function preservation and neuroprotection. Our findings suggest that PBM serves as a promising therapeutic strategy for the functional recovery after GCI, with mechanisms involving PBM's preservation on mitochondrial dynamics and functions and the inhibition of delayed apoptotic neuronal death in GCI.

Targeted Temperature Management After Cardiac Arrest: Systematic Review and Meta-analyses

BACKGROUND

Targeted temperature management (TTM) with therapeutic hypothermia is an integral component of postarrest care for survivors. However, recent randomized controlled trials (RCTs) have failed to demonstrate the benefit of TTM on clinical outcomes. We sought to determine if the pooled data from available RCTs support the use of prehospital and/or in-hospital TTM after cardiac arrest.

METHODS

A comprehensive search of SCOPUS, Elsevier's abstract and citation database of peer-reviewed literature, from 1966 to November 2016 was performed using predefined criteria. Therapeutic hypothermia was defined as any strategy that aimed to cool post-cardiac arrest survivors to a temperature ≤34°C. Normothermia was temperature of ≥36°C. We compared mortality and neurologic outcomes in patients by categorizing the studies into 2 groups: (1) hypothermia versus normothermia and (2) prehospital hypothermia versus in-hospital hypothermia using standard meta-analytic methods. A random effects modeling was utilized to estimate comparative risk ratios (RR) and 95% confidence intervals (CIs).

RESULTS

The hypothermia and normothermia strategies were compared in 5 RCTs with 1389 patients, whereas prehospital hypothermia and in-hospital hypothermia were compared in 6 RCTs with 3393 patients. We observed no difference in mortality (RR, 0.88; 95% CI, 0.73-1.05) or neurologic outcomes (RR, 1.26; 95% CI, 0.92-1.72) between the hypothermia and normothermia strategies. Similarly, no difference was observed in mortality (RR, 1.00; 95% CI, 0.97-1.03) or neurologic outcome (RR, 0.96; 95% CI, 0.85-1.08) between the prehospital hypothermia versus in-hospital hypothermia strategies.

CONCLUSIONS

Our results suggest that TTM with therapeutic hypothermia may not improve mortality or neurologic outcomes in postarrest survivors. Using therapeutic hypothermia as a standard of care strategy of postarrest care in survivors may need to be reevaluated.

Critical Care of the Post-Cardiac Arrest Patient

The post-cardiac arrest syndrome is a highly inflammatory state characterized by organ dysfunction, systemic ischemia and reperfusion injury, and persistent precipitating pathology. Early critical care should focus on identifying and treating arrest etiology and minimizing further injury to the brain and other organs by optimizing perfusion, oxygenation, ventilation, and temperature. Patients should be treated with targeted temperature management, although the exact temperature goal is not clear. No earlier than 72 hours after rewarming, prognostication using a multimodal approach should inform discussions with families regarding likely neurologic outcome.

Association between lymphocyte count and neurological outcomes in post-cardiac arrest patients treated with mild therapeutic hypothermia

Aim

To examine lymphocyte counts as a predictive prognostic marker in patients with coma after cardiac arrest.

Methods

We retrospectively evaluated patients with coma after cardiac arrest admitted to the intensive care unit of Shiga University of Medical Science (Otsu, Japan). Lymphocyte counts were measured for 6 days from admission. Neurological outcome was assessed as favorable or unfavorable using cerebral performance categories. Associations between lymphocyte count and prognosis were investigated using multivariate logistic regression analysis and receiver operating characteristic curves.

Results

Forty‐six patients were assessed from February 2012 to December 2016. Survivors had significantly higher lymphocyte counts than non‐survivors on days 2 and 5. Multivariate analysis showed that lymphocyte count was not associated with 90‐day mortality. Patients with favorable neurological outcome at discharge had significantly higher lymphocyte counts on days 2–6 than patients with unfavorable outcomes. Multivariate logistic regression analysis, including possible confounders, showed that lymphocyte counts on days 2–4 and 6 were associated with neurological outcome (day 2: odds ratio [OR] = 0.75, 95% confidence interval [CI] = 0.58–0.97, P = 0.029; day 3: OR = 0.68, 95% CI = 0.47–0.98, P = 0.04; day 4: OR = 0.4, 95% CI = 0.16–1.00, P = 0.05; day 6: OR = 0.69, 95% CI = 0.48–0.99, P = 0.046). Receiver operating characteristic curve analysis indicated high accuracy for predicting neurological outcome for each lymphocyte count on days 2–6 using the area under the curve, day 4 values being most accurate (day 2: 0.776, day 3: 0.787, day 4: 0.909, day 5: 0.774, day 6: 0.839).

Conclusion

Lymphocyte counts on days 2–4 and 6 after cardiac arrest are associated with neurological outcome; counts on day 4 most accurately predict neurological outcome.

Comparison of temperature measurements in esophagus and urinary bladder in comatose patients after cardiac arrest undergoing mild therapeutic hypothermia

BACKGROUND

Mild therapeutic hypothermia (MTH) is a recommended method of treatment for comatose out-of-hospital cardiac arrest (OHCA) survivors. However, the proper site of temperature measurement in MTH is still not defined. The aim of this study was to compare temperature measurements in the esophagus and urinary bladder in comatose post-OHCA patients treated with MTH.

METHODS

This temperature comparison protocol was a part of a prospective, observational, multicenter cohort study. The study population included 36 unconscious patients after resuscitation for OHCA. The patient's core temperature was independently measured every hour during MTH in the urinary bladder and in the esophagus.

RESULTS

The mean temperature was lower in the esophagus (differences during induction phase: 1.04 ± 0.92°C, p < 0.0001; stabilization phase: 0.54 ± 0.39°C, p < 0.0001; rewarming phase: 0.40 ± 0.47°C, p < 0.0001). Nevertheless, a strong correlation between both sites was found (R2 = 0.83, p < 0.001). The decrease in temperature observed in the esophagus during the induction phase was faster when compared with the urinary bladder (1.09 ± 0.71°C/h vs. 0.83 ± 0.41°C/h; p = 0.002). As a consequence, time to reach temperature < 34.0°C was longer when temperature was measured in the urinary bladder (the difference between medians of the time 1.0 [0-1.5] h, p < 0.001).

CONCLUSIONS

Urinary bladder temperature measurements may lag behind temperature changes measured in the esophagus. Monitoring temperature simultaneously in the esophagus and in the urinary bladder is an accessible and reliable combination, although esophageal measurements seem to better reflect the dynamics of temperature changes, thus it seems to be more appropriate for MTH control. ClinicalTrials.gov Identifier: NCT02611934.

Targeted Temperature Management and Multimodality Monitoring of Comatose Patients After Cardiac Arrest

Out-of-hospital cardiac arrest (CA) remains a leading cause of sudden morbidity and mortality; however, outcomes have continued to improve in the era of targeted temperature management (TTM). In this review, we highlight the clinical use of TTM, and provide an updated summary of multimodality monitoring possible in a modern ICU. TTM is neuroprotective for survivors of CA by inhibiting multiple pathophysiologic processes caused by anoxic brain injury, with a final common pathway of neuronal death. Current guidelines recommend the use of TTM for out-of-hospital CA survivors who present with a shockable rhythm. Further studies are being completed to determine the optimal timing, depth and duration of hypothermia to optimize patient outcomes. Although a multidisciplinary approach is necessary in the CA population, neurologists and neurointensivists are central in selecting TTM candidates and guiding patient care and prognostic evaluation. Established prognostic tools include clinal exam, SSEP, EEG and MR imaging, while functional MRI and invasive monitoring is not validated to improve outcomes in CA or aid in prognosis. We recommend that an evidence-based TTM and prognostication algorithm be locally implemented, based on each institution's resources and limitations. Given the high incidence of CA and difficulty in predicting outcomes, further study is urgently needed to determine the utility of more recent multimodality devices and studies.

Photobiomodulation Therapy Attenuates Hypoxic-Ischemic Injury in a Neonatal Rat Model

Photobiomodulation (PBM) has been demonstrated as a neuroprotective strategy, but its effect on perinatal hypoxic-ischemic encephalopathy is still unknown. The current study was designed to shed light on the potential beneficial effect of PBM on neonatal brain injury induced by hypoxia ischemia (HI) in a rat model. Postnatal rats were subjected to hypoxic-ischemic insult, followed by a 7-day PBM treatment via a continuous wave diode laser with a wavelength of 808 nm. We demonstrated that PBM treatment significantly reduced HI-induced brain lesion in both the cortex and hippocampal CA1 subregions. Molecular studies indicated that PBM treatment profoundly restored mitochondrial dynamics by suppressing HI-induced mitochondrial fragmentation. Further investigation of mitochondrial function revealed that PBM treatment remarkably attenuated mitochondrial membrane collapse, accompanied with enhanced ATP synthesis in neonatal HI rats. In addition, PBM treatment led to robust inhibition of oxidative damage, manifested by significant reduction in the productions of 4-HNE, P-H2AX (S139), malondialdehyde (MDA), as well as protein carbonyls. Finally, PBM treatment suppressed the activation of mitochondria-dependent neuronal apoptosis in HI rats, as evidenced by decreased pro-apoptotic cascade 3/9 and TUNEL-positive neurons. Taken together, our findings demonstrated that PBM treatment contributed to a robust neuroprotection via the attenuation of mitochondrial dysfunction, oxidative stress, and final neuronal apoptosis in the neonatal HI brain.

From Mitochondrial Function to Neuroprotection-an Emerging Role for Methylene Blue

Methylene blue (MB) is a well-established drug with a long history of use, owing to its diverse range of use and its minimal side effect profile. MB has been used classically for the treatment of malaria, methemoglobinemia, and carbon monoxide poisoning, as well as a histological dye. Its role in the mitochondria, however, has elicited much of its renewed interest in recent years. MB can reroute electrons in the mitochondrial electron transfer chain directly from NADH to cytochrome c, increasing the activity of complex IV and effectively promoting mitochondrial activity while mitigating oxidative stress. In addition to its beneficial effect on mitochondrial protection, MB is also known to have robust effects in mitigating neuroinflammation. Mitochondrial dysfunction has been identified as a seemingly unifying pathological phenomenon across a wide range of neurodegenerative disorders, which thus positions methylene blue as a promising therapeutic. In both in vitro and in vivo studies, MB has shown impressive efficacy in mitigating neurodegeneration and the accompanying behavioral phenotypes in animal models for such conditions as stroke, global cerebral ischemia, Alzheimer's disease, Parkinson's disease, and traumatic brain injury. This review summarizes recent work establishing MB as a promising candidate for neuroprotection, with particular emphasis on the contribution of mitochondrial function to neural health. Furthermore, this review will briefly examine the link between MB, neurogenesis, and improved cognition in respect to age-related cognitive decline.

Targeted Temperature Management for Improved Outcomes: Are We There Yet?

Therapeutic hypothermia, also referred to as targeted temperature management, has been a component of the postcardiac arrest treatment guidelines since 2010. Although almost a decade has passed since its inclusion in the postarrest guidelines, many unanswered questions remain regarding selection of the appropriate patient population, optimal target temperature, ideal window of time in which to initiate therapy after arrest, most efficient, safe, and accurate equipment choice for inducing and maintaining hypothermia, most effective duration of treatment, and rate of cooling or rewarming. On a national and international level, critical care nurses are in a unique position to participate in research that will define targeted temperature management protocols and practices. Nurses are also ideal for standardizing the targeted temperature management policy and protocol locally and nationally based on current available evidence. This review aims to serve 2 purposes: first, to provide a broad update on the current clarifications and limitations per research findings on target temperature management therapy; second, to explain how critical care nurses can use this updated information to improve outcomes for their patients with cardiac arrest.

Therapeutic temperature management (TTM): post-resuscitation care for adult cardiac arrest, with recommendations from the National TTM Workgroup

Therapeutic temperature management (TTM) was strongly recommended by the 2015 International Liaison Committee on Resuscitation as a component of post-resuscitation care. It has been known to be effective in improving the survival rate and neurologic functional outcome of patients after cardiac arrest. In an effort to increase local adoption of TTM as a standard of post-resuscitation care, this paper discusses and makes recommendations on the treatment for local providers.

Temperature management for out-of-hospital cardiac arrest

More than 300,000 Americans suffer a cardiac arrest outside of the hospital each year and even among those who are successfully resuscitated and survive to hospital admission, outcomes remain poor. Temperature management (previously known as therapeutic hypothermia) is the only intervention that has been reproducibly demonstrated to ameliorate the neurologic injury that follows cardiac arrest. The results of a recent large randomized controlled trial have highlighted the uncertainty about temperature management strategies following cardiac arrest. This article reviews the issues and recommendations.

Targeted temperature management in the ICU: Guidelines from a French expert panel

Over the recent period, the use of induced hypothermia has gained an increasing interest for critically ill patients, in particular in brain-injured patients. The term "targeted temperature management" (TTM) has now emerged as the most appropriate when referring to interventions used to reach and maintain a specific level temperature for each individual. TTM may be used to prevent fever, to maintain normothermia, or to lower core temperature. This treatment is widely used in intensive care units, mostly as a primary neuroprotective method. Indications are, however, associated with variable levels of evidence based on inhomogeneous or even contradictory literature. Our aim was to conduct a systematic analysis of the published data in order to provide guidelines. We present herein recommendations for the use of TTM in adult and paediatric critically ill patients developed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) method. These guidelines were conducted by a group of experts from the French Intensive Care Society (Société de réanimation de langue française [SRLF]) and the French Society of Anesthesia and Intensive Care Medicine (Société francaise d'anesthésie réanimation [SFAR]) with the participation of the French Emergency Medicine Association (Société française de médecine d'urgence [SFMU]), the French Group for Pediatric Intensive Care and Emergencies (Groupe francophone de réanimation et urgences pédiatriques [GFRUP]), the French National Association of Neuro-Anesthesiology and Critical Care (Association nationale de neuro-anesthésie réanimation française [ANARLF]), and the French Neurovascular Society (Société française neurovasculaire [SFNV]). Fifteen experts and two coordinators agreed to consider questions concerning TTM and its practical implementation in five clinical situations: cardiac arrest, traumatic brain injury, stroke, other brain injuries, and shock. This resulted in 30 recommendations: 3 recommendations were strong (Grade 1), 13 were weak (Grade 2), and 14 were experts' opinions. After two rounds of rating and various amendments, a strong agreement from voting participants was obtained for all 30 (100%) recommendations, which are exposed in the present article.

Targeted temperature management in the ICU: guidelines from a French expert panel

Over the recent period, the use of induced hypothermia has gained an increasing interest for critically ill patients, in particular in brain-injured patients. The term “targeted temperature management” (TTM) has now emerged as the most appropriate when referring to interventions used to reach and maintain a specific level temperature for each individual. TTM may be used to prevent fever, to maintain normothermia, or to lower core temperature. This treatment is widely used in intensive care units, mostly as a primary neuroprotective method. Indications are, however, associated with variable levels of evidence based on inhomogeneous or even contradictory literature. Our aim was to conduct a systematic analysis of the published data in order to provide guidelines. We present herein recommendations for the use of TTM in adult and paediatric critically ill patients developed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) method. These guidelines were conducted by a group of experts from the French Intensive Care Society (Société de Réanimation de Langue Française [SRLF]) and the French Society of Anesthesia and Intensive Care Medicine (Société Francaise d’Anesthésie Réanimation [SFAR]) with the participation of the French Emergency Medicine Association (Société Française de Médecine d’Urgence [SFMU]), the French Group for Pediatric Intensive Care and Emergencies (Groupe Francophone de Réanimation et Urgences Pédiatriques [GFRUP]), the French National Association of Neuro-Anesthesiology and Critical Care (Association Nationale de Neuro-Anesthésie Réanimation Française [ANARLF]), and the French Neurovascular Society (Société Française Neurovasculaire [SFNV]). Fifteen experts and two coordinators agreed to consider questions concerning TTM and its practical implementation in five clinical situations: cardiac arrest, traumatic brain injury, stroke, other brain injuries, and shock. This resulted in 30 recommendations: 3 recommendations were strong (Grade 1), 13 were weak (Grade 2), and 14 were experts’ opinions. After two rounds of rating and various amendments, a strong agreement from voting participants was obtained for all 30 (100%) recommendations, which are exposed in the present article.

Observed survival benefit of mild therapeutic hypothermia reanalysing the Circulation Improving Resuscitation Care trial

BACKGROUND

Mild therapeutic hypothermia is argued being beneficial for outcome after cardiac arrest.

MATERIALS AND METHODS

Retrospective analysis of Circulation Improving Resuscitation Care (CIRC) trial data to assess if therapeutic cooling to 33 ± 1 °C core temperature had an association with survival. Of 4231 adult, out-of-hospital cardiac arrests of presumed cardiac origin initially enrolled, eligibility criteria for therapeutic hypothermia were met by 1812. Logistic regression was undertaken in a stepwise fashion to account for the impact on outcome of each significant difference and for the variable of interest between the groups.

RESULTS

Out-of- and in-hospital cooled were 263 (15%), only after admission cooled were 230 (13%) and not cooled were 357 (20%) patients. The group cooled out of- and in hospital had 98 (37%) survivors as compared to the groups cooled in hospital only [80 (35%)] and of those not cooled [68 (19%)]. After adjusting for known covariates (sex, age, witnessed cardiac arrest, no- and low-flow time, shockable initial rhythm, random allocation, bystander cardiopulmonary resuscitation and percutaneous coronary intervention), the odds ratio for survival comparing no cooling to out-of- plus in-hospital cooling was 0·53 [95% confidence interval (CI): 0·46-0·61, P < 0·001], and comparing to in-hospital cooling only was 0·67 (95% CI: 0·50-0·89, P = 0·006).

CONCLUSION

Mild therapeutic hypothermia initiated out of hospital and/or in hospital was associated with improved survival within this secondary analysis of the CIRC cohort compared to no therapeutic hypothermia.

C-GRApH: A Validated Scoring System for Early Stratification of Neurologic Outcome After Out-of-Hospital Cardiac Arrest Treated With Targeted Temperature Management

Background

Out‐of‐hospital cardiac arrest (OHCA) results in significant morbidity and mortality, primarily from neurologic injury. Predicting neurologic outcome early post‐OHCA remains difficult in patients receiving targeted temperature management.

Methods and Results

Retrospective analysis was performed on consecutive OHCA patients receiving targeted temperature management (32–34°C) for 24 hours at a tertiary‐care center from 2008 to 2012 (development cohort, n=122). The primary outcome was favorable neurologic outcome at hospital discharge, defined as cerebral performance category 1 to 2 (poor 3–5). Patient demographics, pre‐OHCA diagnoses, and initial laboratory studies post‐resuscitation were compared between favorable and poor neurologic outcomes with multivariable logistic regression used to develop a simple scoring system (C‐GRApH). The C‐GRApH score ranges 0 to 5 using equally weighted variables: (C): coronary artery disease, known pre‐OHCA; (G): glucose ≥200 mg/dL; (R): rhythm of arrest not ventricular tachycardia/fibrillation; (A): age >45; (pH): arterial pH ≤7.0. A validation cohort (n=344) included subsequent patients from the initial site (n=72) and an external quaternary‐care health system (n=272) from 2012 to 2014. The c‐statistic for predicting neurologic outcome was 0.82 (0.74–0.90, P<0.001) in the development cohort and 0.81 (0.76–0.87, P<0.001) in the validation cohort. When subdivided by C‐GRApH score, similar rates of favorable neurologic outcome were seen in both cohorts, 70% each for low (0–1, n=60), 22% versus 19% for medium (2–3, n=307), and 0% versus 2% for high (4–5, n=99) C‐GRApH scores in the development and validation cohorts, respectively.

Conclusions

C‐GRApH stratifies neurologic outcomes following OHCA in patients receiving targeted temperature management (32–34°C) using objective data available at hospital presentation, identifying patient subsets with disproportionally favorable (C‐GRApH ≤1) and poor (C‐GRApH ≥4) prognoses.

Combination Treatment with Methylene Blue and Hypothermia in Global Cerebral Ischemia

Therapeutic hypothermia (TH) is the most potent therapeutic strategy for global cerebral ischemia (GCI), usually induced by cardiac arrest. TH has been shown both to suppress the delayed neuronal cell death in the vulnerable hippocampal CA1 subregion and to improve neurological outcomes in experimental animals after GCI. However, given the multiple adverse effects resulting from TH, application of such a therapy is typically limited. In recent years, methylene blue (MB) has emerged as a potential therapeutic drug for the treatment of neurodegenerative diseases. In this study, we investigated the beneficial effects of mild TH combined with MB treatment after GCI. We report that both the neuronal survival in the hippocampal CA1 region and the hippocampus-dependent spatial learning and memory in the combined treatment animals were enhanced compared to those in the single treatment animals. Mechanistic studies revealed that combined TH and MB treatment significantly attenuated mitochondrial dysfunction induced by GCI in the hippocampus CA1 region. The combined treatment also markedly suppressed GCI-induced reactive gliosis and inflammation and reduced oxidative stress while enhancing the antioxidant capacity of hippocampal CA1 neurons. Finally, combining TH and MB synergistically attenuated the intrinsic cytochrome c/caspase-3 apoptotic pathway induced by GCI. Our results suggest that TH and MB act synergistically to protect the ischemic brain and suppress cognitive impairment caused by GCI.

Therapeutic Hypothermia After Resuscitation From a Non-Shockable Rhythm Improves Outcomes in a Regionalized System of Cardiac Arrest Care

OBJECTIVE

Therapeutic hypothermia (TH) improves neurologic outcome in patients resuscitated from ventricular fibrillation. The purpose of this study was to evaluate TH effects on neurologic outcome in patients resuscitated from a non-shockable out-of-hospital cardiac arrest rhythm.

DESIGN AND SETTING

This is a retrospective cohort study of data reported to a registry in an emergency medical system in a large metropolitan region. Patients achieving field return of spontaneous circulation are transported to designated hospitals with TH protocols.

PATIENTS

Patients with an initial non-shockable rhythm were identified. Patients were excluded if awake in the Emergency Department or if TH was withheld due to preexisting coma or death prior to initiation. The decision to initiate TH was determined by the treating physician.

MEASUREMENTS

The primary outcome was survival with good neurologic outcome defined by a cerebral performance category of 1 or 2.

MAIN RESULTS

Of the 2772 patients treated for cardiac arrest during the study period, there were 1713 patients resuscitated from cardiac arrest with an initial non-shockable rhythm and 1432 patients met inclusion criteria. The median age was 69 years [IQR 59-82]; 802 (56%) male. TH was induced in 596 (42%) patients. Survival with good neurologic outcome was 14% in the group receiving TH, compared with 5% in those not treated with TH (risk difference = 8%, 95% CI 5-12%). The adjusted OR for a CPC 1 or 2 with TH was 2.9 (95% CI 1.9-4.4).

CONCLUSION

Analyzing the data collected from the registry of the standard practice in a large metropolitan region, TH is associated with improved neurologic outcome in patients resuscitated from initial non-shockable rhythms in a regionalized system for post-resuscitation care.

The Outcomes of Targeted Temperature Management After Cardiac Arrest at Emergency Department: A Real-World Experience in a Developing Country

Targeted temperature management (TTM) is indicated for comatose survivors of cardiac arrest to improve outcomes. However, the benefit of TTM was verified by rigid controlled clinical trials. This study aimed at evaluating its effects in real-world practices. A prospective observational study was done at the emergency department of tertiary care, Thammasat Hospital, from March 2012 until October 2015. We included all who did not obey verbal commands after being resuscitated from cardiac arrest regardless of initial cardiac rhythm. We excluded patients with traumatic arrest, uncontrolled bleeding, younger than 15 years old, and of poor neurological status (Glasgow coma scale below 14) before cardiac arrest. Primary and secondary outcomes were survival to hospital discharge and favorable neurological outcome (Cerebral Performance Categories 1 or 2 within 30 days). We used the logistic regression model to estimate the propensity score (PS) that will be used as a weight in the analysis. To analyze outcomes, the PS was introduced as a factor in the final logistic regression model in conjunction with other factors. A total of 192 cases, 61 and 131 patients, were enrolled in TTM and non-TTM groups, respectively. Characteristics believed to be related to initiation of TTM: gender, age, cardiac etiology, out-of-hospital cardiac arrest, witness arrest, collapse time, initial rhythm, received defibrillation, and advanced airway insertion, were included in multivariable analysis and estimated PS. After adjusted regression analysis with PS, the TTM group had a better result in survival to hospital discharge (34.43% vs. 12.21%; adjusted incidence risk ratio (IRR), 2.95; 95% confidence interval (CI), 1.49-5.84; p = 0.002). For neurological outcome, the TTM group had a higher number of favorable neurological outcomes (24.59% vs. 6.87%; IRR, 3.96; 95% CI, 1.67-9.36; p = 0.002). In real-world practices without a strictly controlled environment, TTM can improve survival and favorable neurological outcome in postcardiac arrest patients regardless of initial rhythm.

The Role of Targeted Temperature Management in Adult Patients Resuscitated from Nonshockable Cardiac Arrests: An Updated Systematic Review and Meta-Analysis

Routine targeted temperature management is recommended for comatose adult patients with return of spontaneous circulation after cardiac arrest. However, the role of targeted temperature management in patients resuscitated from nonshockable cardiac arrests remains uncertain. We conducted an updated systematic review and meta-analysis to evaluate the effects of targeted temperature management in this population. Medline, EMBASE, and Cochrane databases were systematically reviewed for studies published between January 2005 and March 2016, in which targeted temperature management was compared with standard care or normothermia for adult patients resuscitated from nonshockable cardiac arrests. A total of 25 trials that included 5715 patients were identified from 10985 relevant papers. Pooled data showed that targeted temperature management not only associated with improved short-term survival (RR = 1.42, 95% CI: 1.28-1.57) and neurological function (RR = 1.63, 95% CI: 1.39-1.91) but also associated with improved long-term survival (RR = 1.64, 95% CI: 1.27-2.12) and neurological recovery (RR = 1.42, 95% CI: 1.07-1.90) in observational cohort studies. However, more frequent infectious complications were reported in hypothermia-treated patients (RR = 1.46, 95% CI: 1.26-1.70) and the quality of the evidence ranged from moderate to very low.

Association Between Therapeutic Hypothermia and Survival After In-Hospital Cardiac Arrest

IMPORTANCE

Therapeutic hypothermia is used for patients following both out-of-hospital and in-hospital cardiac arrest. However, randomized trials on its efficacy for the in-hospital setting do not exist, and comparative effectiveness data are limited.

OBJECTIVE

To evaluate the association between therapeutic hypothermia and survival after in-hospital cardiac arrest.

DESIGN, SETTING, AND PATIENTS

In this cohort study, within the national Get With the Guidelines-Resuscitation registry, 26 183 patients successfully resuscitated from an in-hospital cardiac arrest between March 1, 2002, and December 31, 2014, and either treated or not treated with hypothermia at 355 US hospitals were identified. Follow-up ended February 4, 2015.

EXPOSURE

Induction of therapeutic hypothermia.

MAIN OUTCOMES AND MEASURES

The primary outcome was survival to hospital discharge. The secondary outcome was favorable neurological survival, defined as a Cerebral Performance Category score of 1 or 2 (ie, without severe neurological disability). Comparisons were performed using a matched propensity score analysis and examined for all cardiac arrests and separately for nonshockable (asystole and pulseless electrical activity) and shockable (ventricular fibrillation and pulseless ventricular tachycardia) cardiac arrests.

RESULTS

Overall, 1568 of 26 183 patients with in-hospital cardiac arrest (6.0%) were treated with therapeutic hypothermia; 1524 of these patients (mean [SD] age, 61.6 [16.2] years; 58.5% male) were matched by propensity score to 3714 non-hypothermia-treated patients (mean [SD] age, 62.2 [17.5] years; 57.1% male). After adjustment, therapeutic hypothermia was associated with lower in-hospital survival (27.4% vs 29.2%; relative risk [RR], 0.88 [95% CI, 0.80 to 0.97]; risk difference, -3.6% [95% CI, -6.3% to -0.9%]; P = .01), and this association was similar (interaction P = .74) for nonshockable cardiac arrest rhythms (22.2% vs 24.5%; RR, 0.87 [95% CI, 0.76 to 0.99]; risk difference, -3.2% [95% CI, -6.2% to -0.3%]) and shockable cardiac arrest rhythms (41.3% vs 44.1%; RR, 0.90 [95% CI, 0.77 to 1.05]; risk difference, -4.6% [95% CI, -10.9% to 1.7%]). Therapeutic hypothermia was also associated with lower rates of favorable neurological survival for the overall cohort (hypothermia-treated group, 17.0% [246 of 1443 patients]; non-hypothermia-treated group, 20.5% [725 of 3529 patients]; RR, 0.79 [95% CI, 0.69 to 0.90]; risk difference, -4.4% [95% CI, -6.8% to -2.0%]; P < .001) and for both rhythm types (interaction P = .88).

CONCLUSIONS AND RELEVANCE

Among patients with in-hospital cardiac arrest, use of therapeutic hypothermia compared with usual care was associated with a lower likelihood of survival to hospital discharge and a lower likelihood of favorable neurological survival. These observational findings warrant a randomized clinical trial to assess efficacy of therapeutic hypothermia for in-hospital cardiac arrest.

Glibenclamide Is Comparable to Target Temperature Management in Improving Survival and Neurological Outcome After Asphyxial Cardiac Arrest in Rats

Background

We previously have shown that glibenclamide (GBC), a sulfonylurea receptor 1–transient receptor potential M4 (SUR1‐TRPM4) channel inhibitor, improves survival and neurological outcome after asphyxial cardiac arrest and cardiopulmonary resuscitation (ACA/CPR). Here, we further compare the efficacy of GBC with target temperature management (TTM) and determine whether the efficacy of GBC is affected by TTM.

Methods and Results

Male Sprague‐Dawley rats (n=213) subjected to 10‐minute ACA/CPR were randomized to 4 groups after return of spontaneous circulation (ROSC): normothermia control (NT); GBC; TTM; and TTM+GBC. Survival, neurodeficit scores, histological injury, as well as the expressions of SUR1 and TRPM4 were evaluated. The 7‐day survival rate was 34.4% (11 of 32) in the NT group, 65% (13 of 20) in the GBC group, 50% (10 of 20) in the TTM group, and 70% (14 of 20) in the TTM+GBC group. Rats that received either GBC, TTM alone, or in combination showed less neurological deficit than NT control at 24, 48, and 72 hours and 7 days after ROSC. Moreover, TTM or GBC ameliorated neuronal degeneration and glial activation in the hippocampal CA1 region with similar efficacy, whereas the combination of them had a trend toward better effect. The subunits of SUR1‐TRPM4 heterodimers were both strongly upregulated after ACA/CPR and expressed in multiple types of brain cells, but partly suppressed by TTM.

Conclusions

GBC is comparable to TTM in improving survival and neurological outcome after ACA/CPR. When GBC is given along with TTM, less histological injury tended to be achieved.

Predictors of death among cardiac arrest patients after therapeutic hypothermia: A non-tertiary care center's initial experience

INTRODUCTION AND OBJECTIVES

Therapeutic hypothermia (TH) is recommended for patients with return of spontaneous circulation (ROSC) after cardiac arrest (CA). There is still uncertainty about management, target temperature and duration of TH. In the present study we aim to describe the initial experience of a non-tertiary care center with TH after CA and to determine predictors of mortality.

METHODS

During the period 2011-2014, out of 2279 patients hospitalized in the intensive care unit, 82 had a diagnosis of CA with ROSC. We determined predictors of mortality and neurological outcome in comatose patients with ROSC after CA treated by TH.

RESULTS

A total of 15 patients were included, mean age 47.3±14 years, 10 (67.0%) male. CA occurred out-of-hospital (n=11; 73.3%) or in-hospital (n=4; 26.7%), in initial shockable (n=10; 66.7%) or non-shockable (n=5, 33.3%) rhythm. The mean time from CA to ROSC (CA-ROSC) was 44.7±36.5 min. All patients met the 24-hour TH target temperature of 33°C. The mean neuron-specific enolase (NSE) level was 93.7±109.0 μg/l. Seven patients (46.7%) were discharged with good cerebral performance and eight (53.3%) died. Patients who survived had lower median age (p=0.032), shorter CA-ROSC (p=0.048), lower NSE levels (p=0.020) and initial ventricular fibrillation rhythm (p=NS).

CONCLUSIONS

The effectiveness of TH appears to be related to younger age, shockable initial rhythm and shorter CA-ROSC time. This results indicates some lines of inquiry that should be developed in appropriate prospective studies. The role of biomarkers as predictors of prognosis is an open question, with NSE potentially playing an important role.