Postcardiac arrest syndrome: from immediate resuscitation to long-term outcome

Stearic acid methyl ester affords neuroprotection and improves functional outcomes after cardiac arrest

Cardiac arrest causes neuronal damage and functional impairments that can result in learning/memory dysfunction after ischemia. We previously identified a saturated fatty acid (stearic acid methyl ester, SAME) that was released from the superior cervical ganglion (sympathetic ganglion). The function of stearic acid methyl ester is currently unknown. Here, we show that SAME can inhibit the detrimental effects of global cerebral ischemia (i.e. cardiac arrest). Treatment with SAME in the presence of asphyxial cardiac arrest (ACA) revived learning and working memory deficits. Similarly, SAME-treated hippocampal slices after oxygen-glucose deprivation inhibited neuronal cell death. Moreover, SAME afforded neuroprotection against ACA in the CA1 region of the hippocampus, reduced ionized calcium-binding adapter molecule 1 expression and inflammatory cytokines/chemokines, with restoration in mitochondria respiration. Altogether, we describe a unique and uncharted role of saturated fatty acids in the brain that may have important implications against cerebral ischemia.

Experiences of family members of patients treated with targeted temperature management post cardiac arrest: a qualitative systematic review protocol

OBJECTIVE

The objective of this review is to evaluate the experiences of family members of patients who receive targeted temperature management following the return of spontaneous circulation after a cardiac arrest.

INTRODUCTION

Since 2002, targeted temperature management has become an international standard of care for the preservation of neurological status for patients following a cardiac arrest and who remain comatose. During this process, survivors are placed into a mild hypothermic state with their body temperature maintained at 32°C to 36°C for a minimum of 24 hours. It is during this time that family members experience the uncertainty of whether their loved one will survive, or if any negative long-term sequelae will be experienced. While much is known about the physical application and management of targeted temperature management, less is known about the psychosocial aspects of this treatment.

INCLUSION CRITERIA

This review will consider qualitative studies that address the experiences of family members of adult patients who have received targeted temperature management following a cardiac arrest.

METHODS

CINAHL, ProQuest Nursing and Allied Health Source, PsycINFO, PubMed (MEDLINE), Scopus, Sociological Abstracts, and Web of Science will be searched for relevant studies. Studies published in English and French from 2002 onward will be considered. Two reviewers will independently appraise studies and extract qualitative data using the JBI standardized critical appraisal and extraction instruments. Findings from the review will be categorized according to similarity in meaning, and categories subjected to a meta-aggregation to produce a single comprehensive set of synthesized findings.

SYSTEMATIC REVIEW REGISTRATION NUMBER

PROSPERO CRD42020142942.

Postarrest Interventions that Save Lives

Patients resuscitated from cardiac arrest require complex management. An organized approach to early postarrest care can improve patient outcomes. Priorities include completing a focused diagnostic work-up to identify and reverse the inciting cause of arrest, stabilizing cardiorespiratory instability to prevent rearrest, minimizing secondary brain injury, evaluating the risk and benefits of transfer to a specialty care center, and avoiding early neurologic prognostication.

Management of temperature control in post-cardiac arrest care: an expert report

Targeted temperature management (TTM) through induced hypothermia (between 32-36 ^oC) is currently regarded as a first-line treatment during the management of post-cardiac arrest patients admitted to the Intensive Care Unit (ICU). The aim of TTM is to afford neuroprotection and reduce secondary neurological damage caused by anoxia. Despite the large body of evidence on its benefits, the TTM is still little used in Spain. There are controversial issues referred to its implementation, such as the optimal target body temperature, timing, duration and the rewarming process. The present study reviews the best available scientific evidence and the current recommendations contained in the international guidelines. In addition, the study focuses on the practical implementation of TTM in post-cardiac arrest patients in general and cardiological ICUs, with a discussion of the implementation strategies, protocols, management of complications and assessment of the neurological prognosis.

Plasma Adenylate Levels are Elevated in Cardiopulmonary Arrest Patients and May Predict Mortality

Cerebral and cardiac dysfunction cause morbidity and mortality in postcardiac arrest syndrome (PCAS) patients. Predicting clinical outcome is necessary to provide the optimal level of life support for these patients. In this pilot study, we examined whether plasma ATP and adenylate levels have value in predicting clinical outcome in PCAS patients. In total, 15 patients who experienced cardiac arrest outside the hospital setting and who could be reanimated were enrolled in this study. Healthy volunteers (n = 8) served as controls. Of the 15 PCAS patients, 8 died within 4 days after resuscitation. Of the 7 survivors, 2 lapsed into vegetative states, 1 survived with moderate disabilities, and 4 showed good recoveries. Arterial blood samples were drawn immediately after successful resuscitation and return of spontaneous circulation (ROSC). The concentrations of ATP and other adenylates in plasma were assessed with high-performance liquid chromatography. PCAS patients had significantly higher ATP levels than healthy controls. Plasma ATP levels correlated with lactate levels, Acute Physiology and Chronic Health Evaluation II scores, and the time it took to ROSC (time-to-ROSC). Plasma adenylate levels in patients who died after resuscitation were significantly higher than in survivors. Based on our results and receiver-operating characteristic curve analysis, we conclude that plasma adenylate levels may help predict outcome in PCAS patients.

Does the Uniform Determination of Death Act Need to Be Revised?

Prompted by concerns raised by the rise in litigations, which challenge the legal status of brain death (BD), Lewis and colleagues recently proposed a revision of the Uniform Determination of Death Act (UDDA). The revision consists of (i) narrowing down the definition of BD to the loss of specific brain functions, namely those functions that can be assessed on bedside neurological examination; (ii) requiring that the determination of BD must be in accordance with the specific guidelines designated in the revision; and (iii) eliminating the necessity for obtaining consent prior to performing the tests for BD determination. By analyzing Lewis and colleagues' revision, this article shows that this revision is fraught with difficulties. Therefore, this article also proposes two approaches for an ethical revision of the UDDA; the first is in accordance with scientific realism and Christian anthropology, while the second is grounded in trust and respect for persons. If the UDDA is to be revised, then it should be based on sound ethical principles in order to resolve the ongoing BD controversies and rebuild public trust.

Summary

This article critically examines the recent revision of the Uniform Determination of Death Act (UDDA) advanced by Lewis and colleagues. The revision only further reinforces the status quo of brain death without taking into account the root cause of the litigations and controversies about the declaration of death by neurological criteria. In view of this deficiency, this article offers two approaches to revising the UDDA, both of which are founded on sound moral principles.

Adiponectin inhibits cardiac arrest/cardiopulmonary resuscitation‑induced apoptosis in brain by increasing autophagy involved in AdipoR1‑AMPK signaling

Emerging evidence suggests that both apoptosis and autophagy contribute to global cerebral ischemia‑reperfusion (GCIR)‑induced neuronal death, which results from cardiac arrest (CA). However, the mechanism of how GCIR may affect the balance between apoptosis and autophagy resulting from CA remains to be elucidated. Additionally, the role of adiponectin (APN) in reversing the apoptosis and autophagy induced by GCIR following cardiac arrest‑cardiopulmonary resuscitation (CA‑CPR) is unclear. Thus, the aim of the present study was to investigate how GCIR affect the apoptosis and autophagy in response to CA and to clarify whether APN may alter the apoptosis and autophagy of neuronal death in GCIR‑injured brain post‑CA‑CPR. Using normal controls (Sham group) and two experimental groups [CA‑CPR‑induced GCIR injury (PCAS) group and exogenous treatment with adiponectin post‑CA‑CPR (APN group)], it was demonstrated that both apoptosis and autophagy were observed simultaneously in the brain subjected to GCIR, but apoptosis appeared to be more apparent. Exogenous administration of APN significantly reduced the formation of malondialdehyde, a marker of oxidative stress and increased the expression of superoxide dismutase, an anti‑oxidative enzyme, resulting in the stimulation of autophagy, inhibition of apoptosis and reduced brain tissue injury (P<0.05 vs. PCAS). APN treatment increased the expression of APN receptor 1 (AdipR1) and the phosphorylation of AMP‑activated protein kinase (AMPK; Ser182) in brain tissues. In conclusion, GCIR induced apoptosis and inhibited autophagy, contributing to brain injury in CA‑CPR. By contrast, APN reduced the brain injury by reversing the changes of neuronal autophagy and apoptosis induced by GCIR. The possible mechanism might owe to its effects on the activation of AMPK after combining with AdipR1 on neurons, which suggests a novel intervention against GCIR injury in CA‑CPR conditions.

Acute mesenteric ischaemia in refractory shock on veno-arterial extracorporeal membrane oxygenation

BACKGROUND

Acute mesenteric ischaemia is a severe complication in critically ill patients, but has never been evaluated in patients on veno-arterial extracorporeal membrane oxygenation (V-A ECMO). This study was designed to determine the prevalence of mesenteric ischaemia in patients supported by V-A ECMO and to evaluate its risk factors, as well as to appreciate therapeutic modalities and outcome.

METHODS

In a retrospective single centre study (January 2013 to January 2017), all consecutive adult patients who underwent V-A ECMO were included, with exclusion of those dying in the first 24 hours. Diagnosis of mesenteric ischaemia was performed using digestive endoscopy, computed tomography scan or first-line laparotomy.

RESULTS

One hundred and fifty V-A ECMOs were implanted (65 for post-cardiotomy shock, 85 for acute cardiogenic shock, including 39 patients after refractory cardiac arrest). Overall, median age was 58 (48-69) years and mortality 56%. Acute mesenteric ischaemia was suspected in 38 patients, with a delay of four (2-7) days after ECMO implantation, and confirmed in 14 patients, that is, a prevalence of 9%. Exploratory laparotomy was performed in six out of 14 patients, the others being too unstable to undergo surgery. All patients with mesenteric ischaemia died. Independent risk factors for developing mesenteric ischaemia were renal replacement therapy (odds ratio (OR) 4.5, 95% confidence interval (CI) 1.3-15.7, p=0.02) and onset of a second shock within the first five days (OR 7.8, 95% CI 1.5-41.3, p=0.02). Conversely, early initiation of enteral nutrition was negatively associated with mesenteric ischaemia (OR 0.15, 95% CI 0.03-0.69, p=0.02).

CONCLUSIONS

Acute mesenteric ischaemia is a relatively frequent but dramatic complication among patients on V-A ECMO.

Prognostic value of the delta neutrophil index in pediatric cardiac arrest

The delta neutrophil index (DNI), which reflects the ratio of circulating immature neutrophils, has been reported to be highly predictive of mortality in systemic inflammation. We investigated the prognostic significance of DNI value for early mortality and neurologic outcomes after pediatric cardiac arrest (CA). We retrospectively analyzed the data of eligible patients (<19 years in age). Among 85 patients, 55 subjects (64.7%) survived and 36 (42.4%) showed good outcomes at 30 days after CA. Cox regression analysis revealed that the DNI values immediately after the return of spontaneous circulation, at 24 hours and 48 hours after CA, were related to an increased risk for death within 30 days after CA (P < 0.001). A DNI value of higher than 3.3% at 24 hours could significantly predict both 30-day mortality (hazard ratio: 11.8; P < 0.001) and neurologic outcomes (odds ratio: 8.04; P = 0.003). The C statistic for multivariable prediction models for 30-day mortality (incorporating DNI at 24 hours, compression time, and serum sodium level) was 0.799, and the area under the receiver operating characteristic curve of DNI at 24 hours for poor neurologic outcome was 0.871. Higher DNI was independently associated with 30-day mortality and poor neurologic outcomes after pediatric CA.

Acute respiratory failure and inflammatory response after out-of-hospital cardiac arrest: results of the Post-Cardiac Arrest Syndrome (PCAS) pilot study

BACKGROUND

Although the lungs are potentially highly susceptible to post-cardiac arrest syndrome injury, the issue of acute respiratory failure after out-of-hospital cardiac arrest has not been investigated. The objectives of this analysis were to determine the prevalence of acute respiratory failure after out-of-hospital cardiac arrest, its association with post-cardiac arrest syndrome inflammatory response and to clarify its importance for early mortality.

METHODS

The Post-Cardiac Arrest Syndrome (PCAS) pilot study was a prospective, observational, six-centre project (Poland 2, Denmark 1, Spain 1, Italy 1, UK 1), studying patients resuscitated after out-of-hospital cardiac arrest of cardiac origin. Primary outcomes were: (a) the profile of organ failure within the first 72 hours after out-of-hospital cardiac arrest; (b) in-hospital and short-term mortality, up to 30 days of follow-up. Respiratory failure was defined using a modified version of the Berlin acute respiratory distress syndrome definition. Inflammatory response was defined using leukocytes (white blood cells), platelet count and C-reactive protein concentration. All parameters were assessed every 24 hours, from admission until 72 hours of stay.

RESULTS

Overall, 148 patients (age 62.9±15.27 years; 27.7% women) were included. Acute respiratory failure was noted in between 50 (33.8%) and 75 (50.7%) patients over the first 72 hours. In-hospital and short-term mortality was 68 (46.9%) and 72 (48.6%), respectively. Inflammation was significantly associated with the risk of acute respiratory failure, with the highest cumulative odds ratio of 748 at 72 hours (C-reactive protein 1.035 (1.001-1.070); 0.043, white blood cells 1.086 (1.039-1.136); 0.001, platelets 1.004 (1.001-1.007); <0.005). Early acute respiratory failure was related to in-hospital mortality (3.172, 95% confidence interval 1.496-6.725; 0.002) and to short-term mortality (3.335 (1.815-6.129); 0.0001).

CONCLUSIONS

An inflammatory response is significantly associated with acute respiratory failure early after out-of-hospital cardiac arrest. Acute respiratory failure is associated with a worse early prognosis after out-of-hospital cardiac arrest.

Cannabinoid Receptor Agonist WIN55, 212-2 Adjusts Lipid Metabolism in a Rat Model of Cardiac Arrest

The objective of this study was to investigate the effects of pharmacologically induced hypothermia with WIN55, 212-2 (WIN)on postresuscitation myocardial function, microcirculation, and metabolism-specific lipids in a rat cardiac arrest (CA) model. Ventricular fibrillation was electrically induced and untreated for 6 minutes in 24 Sprague-Dawley rats weighing 450-550 g. Cardiopulmonary resuscitation including chest compression and mechanical ventilation was then initiated and continued for 8 minutes, followed by defibrillation. At 5 minutes after restoration of spontaneous circulation (ROSC), animals were randomized into four groups: (1) normothermia with vehicle (NT); (2) physical hypothermia with vehicle (PH); (3) WIN55, 212-2 with normothermia (WN); and (4) WIN55, 212-2 with hypothermia (WH). For groups of WN and WH, WIN was administered by continuous intravenous infusion with a syringe pump for 4 hours. PH started at 5 minutes after resuscitation. NT maintained core temperature at 37°C ± 0.2°C with the aid of a heating blanket. Hypothermia groups maintained temperature at 33°C ± 0.5°C for 4 hours after ROSC. There was a significant improvement in myocardial function as measured by ejection fraction, cardiac output, and myocardial performance index in animals treated with WH and PH beginning at 1 hour after start of infusion. In the WH and PH groups, buccal microcirculation was significantly improved compared with NT and WN. Plasma at pre-CA and ROSC 4 hours was harvested for lipid metabolism. The WH group appeared to be closer to baseline than the other groups in lipid metabolism. lysophosphatidylcholine (LPC) 18:2, free fatty acid (FFA) 22:6, and ceramide (CER) (24:0) changed significantly among the lipidomic data compared with NT (p < 0.05). Postresuscitation hypothermia improved myocardial function and microcirculation. WH-mediated lipid metabolism had the best metabolic outcome to bring back the animals to normal metabolism, which may be protective to improve outcomes of CA. LPC 18:2, FFA 22:6, and CER (24:0) may be important predictors of outcomes of CA.

A nationwide overview of 1-year mortality in cardiac arrest patients admitted to intensive care units in the Netherlands between 2010 and 2016

AIM

Worldwide, cardiac arrest (CA) remains a major cause of death. Most post-CA patients are admitted to the intensive care unit (ICU). The aim of this study is to describe mortality rates and possible changes in mortality rates in patients with CA admitted to the ICU in the Netherlands between 2010 and 2016.

METHODS

In this study, we included all adult CA patients registered in the National Intensive Care Evaluation (NICE) registry who were admitted to ICUs in the Netherlands between 2010 and 2016. The primary outcome was 1-year mortality which was analysed by Cox regression. The secondary outcomes were ICU mortality and hospital mortality. Hospital mortality was analysed by binary logistic regression analysis. Patients were stratified by whether they experienced in-hospital cardiac arrest (IHCA) or out-of-hospital cardiac arrest (OHCA). Finally, the outcome over calendar time was assessed for both groups.

RESULTS

We included 26,056 CA patients: 10,618 (40.8%) IHCA patients and 14,482 (55.6%) OHCA patients. The 1-year mortality rate was 57.5%: 59% for IHCA and 56.4% for OHCA, p < 0.01. This mortality rate remained stable between 2010 and 2016 for IHCA (p = 0.31) and declined for OHCA patients (p = 0.01). The hospital mortality rate was 50.3%: 50.5% for IHCA and 50.2% for OHCA, p = 0.66. This mortality rate remained stable between 2010-2016 for IHCA (p = 0.21) and decreased for OHCA patients (p < 0.01). An additional analysis with calendar year as a continuous variable showed a mortality decline of 1.56% per calendar year for 1-year mortality.

CONCLUSION

This nationwide registry cohort study reported a 57.5% 1-year mortality rate for CA patients admitted to the ICU between 2010 and 2016. We reported a decline in 1-year mortality for OHCA patients in these years.

Association between inflammation in acute phase and early onset pneumonia in patients with out-of-hospital cardiac arrest treated with extracorporeal cardiopulmonary resuscitation

BACKGROUND

Early onset pneumonia (EOP) in patients with cardiac arrest treated with targeted temperature management is a recently debated issue. We assessed the association between C-reactive protein (CRP) levels and development of EOP in patients treated with extracorporeal cardiopulmonary resuscitation (ECPR).

METHODS AND RESULTS

We reviewed the data of all patients admitted to our hospital after out-of-hospital cardiac arrest treated with ECPR between April 2006 and April 2019 who survived for at least 48 h. We collected demographic data, cardiac arrest characteristics, prophylactic antibiotic use, and neurologic outcomes. Diagnosis of EOP was made based on clinical, radiological, and microbiological criteria. The primary endpoint was the association between the incidence of EOP and CRP levels from day 1 to day 4. A total of 55 patients were included, of which 20 developed EOP. CRP levels on days 3 and 4 were significantly elevated in patients who developed EOP (13.1 [11.8-21.1] mg/dL versus 11.6 [7.4-15.2] mg/dL, P = 0.005; and 19.0 [16.9-27.1] mg/dL versus 14.7 [7.4-21.2] mg/dL, P = 0.019, respectively). In the multivariable logistic regression model, the CRP level on day 3 was significantly associated with the development of EOP (odds ratio 1.22; 95% confidence interval 1.06-1.41; P = 0.001).

CONCLUSIONS

Increased inflammation in acute phase was associated with development of EOP in patients treated with ECPR.

Resistin and Cardiac Arrest-A Prospective Study

The systemic response to ischemia-reperfusion that occurs after a cardiac arrest (CA) followed by the return of spontaneous circulation leads to endothelial toxicity and cytokine production, both responsible for the subsequent occurrence of severe cardiocirculatory dysfunction and early death. Resistin is emerging as a biomarker of proinflammatory status and myocardial ischemic injury and as a mediator of endothelial dysfunction. The study aimed to analyze the possible associations between several clinical and biological variables and the serum levels of resistin in CA survivors. Forty patients with out-of-hospital resuscitated CA, were enrolled in the study. Demographic, clinical and laboratory data (including serum resistin measurements at admission and at 6, 12, 24, 48 and 72 h) were recorded. For resistin, we calculated the area under the curve (AUC) using the trapezoidal method with measurements from 0 to 12 h, 0 to 24 h, 0 to 48 h and 0 to 72 h. Fifteen (37.5%) patients died in the first 72 h after CA. Cardiovascular comorbidities were present in 65% of patients. The majority of patients had post-CA shock (29 (72.5%)). Resistin serum levels rose in the first 12–24 h and decreased in the next 48–72 h. In univariate analysis, advanced age, longer duration of resuscitation, high sequential organ failure assessment score, high lactate levels, presence of cardiovascular comorbidities and the post-CA shock were associated with higher resistin levels. In multivariate analysis, post-CA shock or cardiovascular comorbidities were independently associated with higher AUCs for resistin for 0–12 h and 0–24 h. The only identified variable to independently predict higher AUCs for resistin for 0–48 h and 0–72 h was the presence of post-CA shock. Our data demonstrate strong independent correlation between high serum resistin levels, cardiac comorbidities and post-CA shock. The impact of the post-CA shock on serum concentration of resistin was greater than that of cardiac comorbidities.

Targeted Temperature Management for Cardiac Arrest with Nonshockable Rhythm

BACKGROUND

Moderate therapeutic hypothermia is currently recommended to improve neurologic outcomes in adults with persistent coma after resuscitated out-of-hospital cardiac arrest. However, the effectiveness of moderate therapeutic hypothermia in patients with nonshockable rhythms (asystole or pulseless electrical activity) is debated.

METHODS

We performed an open-label, randomized, controlled trial comparing moderate therapeutic hypothermia (33°C during the first 24 hours) with targeted normothermia (37°C) in patients with coma who had been admitted to the intensive care unit (ICU) after resuscitation from cardiac arrest with nonshockable rhythm. The primary outcome was survival with a favorable neurologic outcome, assessed on day 90 after randomization with the use of the Cerebral Performance Category (CPC) scale (which ranges from 1 to 5, with higher scores indicating greater disability). We defined a favorable neurologic outcome as a CPC score of 1 or 2. Outcome assessment was blinded. Mortality and safety were also assessed.

RESULTS

From January 2014 through January 2018, a total of 584 patients from 25 ICUs underwent randomization, and 581 were included in the analysis (3 patients withdrew consent). On day 90, a total of 29 of 284 patients (10.2%) in the hypothermia group were alive with a CPC score of 1 or 2, as compared with 17 of 297 (5.7%) in the normothermia group (difference, 4.5 percentage points; 95% confidence interval [CI], 0.1 to 8.9; P = 0.04). Mortality at 90 days did not differ significantly between the hypothermia group and the normothermia group (81.3% and 83.2%, respectively; difference, -1.9 percentage points; 95% CI, -8.0 to 4.3). The incidence of prespecified adverse events did not differ significantly between groups.

CONCLUSIONS

Among patients with coma who had been resuscitated from cardiac arrest with nonshockable rhythm, moderate therapeutic hypothermia at 33°C for 24 hours led to a higher percentage of patients who survived with a favorable neurologic outcome at day 90 than was observed with targeted normothermia. (Funded by the French Ministry of Health and others; HYPERION ClinicalTrials.gov number, NCT01994772.).

Fingolimod Plays Role in Attenuation of Myocardial Injury Related to Experimental Model of Cardiac Arrest and Extracorporeal Life Support Resuscitation

Background: Sudden cardiac arrest is a major global health concern, and survival of patients with ischemia–reperfusion injury is a leading cause of myocardial dysfunction. The mechanism of this phenomenon is not well understood because of the complex pathophysiological nature of the disease. Aim of the study was to investigate the cardioprotective role of fingolimod in an in vivo model of cardiac arrest and resuscitation. Methods: In this study, an in vivo rat model of cardiac arrest using extracorporeal membrane oxygenation resuscitation monitored by invasive hemodynamic measurement was developed. At the beginning of extracorporeal life support (ECLS), animals were randomly treated with fingolimod (Group A, n = 30) or saline (Group B, n = 30). Half of the animals in each group (Group A1 and B1, n = 15 each) were sacrificed after 1 h, and the remaining animals (Group A2 and B2) after 24 h of reperfusion. Blood and myocardial tissues were collected for analysis of cardiac features, inflammatory biomarkers, and cell signaling pathways. Results: Treatment with fingolimod resulted in activation of survival pathways resulting into reduced inflammation, myocardial oxidative stress and apoptosis of cardiomyocytes. This led to significant improvement in systolic and diastolic functions of the left ventricle and improved contractility index. Conclusions: Sphingosine1phosphate receptor activation with fingolimod improved cardiac function after cardiac arrest supported with ECLS. Present study findings strongly support a cardioprotective role of fingolimod through sphingosine-1-phosphate receptor activation during reperfusion after circulatory arrest.

Effects of regional body temperature variation during asphyxial cardiac arrest on mortality and brain damage in a rat model

To date, hypothermia has focused on improving rates of resuscitation to increase survival in patients sustaining cardiac arrest (CA). Towards this end, the role of body temperature in neuronal damage or death during CA needs to be determined. However, few studies have investigated the effect of regional temperature variation on survival rate and neurological outcomes. In this study, adult male rats (12 week-old) were used under the following four conditions: (i) whole-body normothermia (37 ± 0.5 °C) plus (+) no asphyxial CA, (ii) whole-body normothermia + CA, (iii) whole-body hypothermia (33 ± 0.5 °C)+CA, (iv) body hypothermia/brain normothermia + CA, and (v) brain hypothermia/body normothermia + CA. The survival rate after resuscitation was significantly elevated in groups exposed to whole-body hypothermia plus CA and body hypothermia/brain normothermia plus CA, but not in groups exposed to whole-body normothermia combined with CA and brain hypothermia/body normothermia plus CA. However, the group exposed to hypothermia/brain normothermia combined with CA exhibited higher neuroprotective effects against asphyxial CA injury, i.e. improved neurological deficit and neuronal death in the hippocampus compared with those involving whole-body normothermia combined with CA. In addition, neurological deficit and neuronal death in the group of rat exposed to brain hypothermia/body normothermia and CA were similar to those in the rats subjected to whole-body normothermia and CA. In brief, only brain hypothermia during CA was not associated with effective survival rate, neurological function or neuronal protection compared with those under body (but not brain) hypothermia during CA. Our present study suggests that regional temperature in patients during CA significantly affects the outcomes associated with survival rate and neurological recovery.

Initial serum cholesterol level as a potential marker for post cardiac arrest patient outcomes

AIM

Cholesterol and lipoproteins have many roles during systemic inflammation in critically ill patients. Many previous studies have reported that low levels of cholesterol are associated with poor outcomes in these patients. The aim of this study was to investigate the association of initial total cholesterol with predicting neurologic outcome of post-cardiac arrest patients.

METHODS

This was a retrospective observational study of out-of-hospital-cardiac arrest (OHCA) survivors who had serum cholesterol levels at admission. Multivariate regression analysis was performed to investigate total cholesterol and its association with neurologic outcome. Area under receiver operator characteristic curve (AUROC) was assessed and cut off values for predicting good or poor neurologic outcomes were analysed.

RESULTS

A total of 355 patients were analysed. Lower total cholesterol was significantly associated with poor neurologic outcome [OR: 0.99 (95% CI: 0.98-0.99), p < 0.01] in the multivariate analysis. Cholesterol was also useful to screening for poor neurologic outcome [AUROC: 0.70 (95%CI: 0.63-0.77)]. Patients with cholesterol lower than 71 mg/dL had poor neurologic outcome with a specificity of 100%.

CONCLUSIONS

Initial cholesterol level is an easily obtained biomarker that showed association with neurologic outcomes of post cardiac arrest patients.

Three-Dimensional Shapes and Cell Deformability of Rat Red Blood Cells during and after Asphyxial Cardiac Arrest

Changes in microcirculation are believed to perform an important role after cardiac arrest. In particular, rheological changes in red blood cells (RBCs) have been observed during and after ischemic-reperfusion injury. Employing three-dimensional laser interferometric microscopy, we investigated three-dimensional shapes and deformability of RBCs during and after asphyxial cardiac arrest in rats at the individual cell level. Rat cardiac arrest was induced by asphyxia. Five rats were maintained for 7 min of no-flow time, and then, cardiopulmonary resuscitation (CPR) was started. Blood samples were obtained before cardiac arrest, during CPR, and 60 min after return of spontaneous circulation (ROSC). Quantitative phase imaging (QPI) techniques based on laser interferometry were used to measure the three-dimensional refractive index (RI) tomograms of the RBC, from which structural and biochemical properties were retrieved. Dynamic membrane fluctuations in the cell membrane were also quantitatively and sensitively measured in order to investigate cell deformability. Mean corpuscular hemoglobin, mean cell volume, mean corpuscular hemoglobin concentration, and red blood cell distribution width remained unchanged during CPR and after ROSC compared with those before cardiac arrest. QPI results revealed that RBC membrane fluctuations, sphericity, and surface area did not change significantly during CPR or after ROSC compared with initial values. In conclusion, no three-dimensional shapes and cell deformability changes in RBCs were detected.

Hydrogen Inhalation is Superior to Mild Hypothermia for Improving Neurological Outcome and Survival in a Cardiac Arrest Model of Spontaneously Hypertensive Rat

BACKGROUND

Postcardiac arrest syndrome is the consequence of whole-body ischemia-reperfusion events that lead to multiple organ failure and eventually to death. Recent animal studies demonstrated that inhalation of hydrogen greatly mitigates postresuscitation myocardial dysfunction and brain injury. However, the influence of underlying heart disease on the efficacy of hydrogen is still unknown. In the present study, we investigated the effects of hydrogen inhalation on neurological outcome and survival in a cardiac arrest model of spontaneously hypertensive rat (SHR).

METHODS

Cardiopulmonary resuscitation was initiated after 4 min of untreated ventricular fibrillation in 40 SHRs. Immediately after successful resuscitation, animals were randomized to be ventilated with 98% oxygen and 2% nitrogen under normothermia (Ctrl), 2% nitrogen under hypothermia (TH), 2% hydrogen under normothermia (H2), or 2% hydrogen under hypothermia (H2+TH) for 2 h. Hypothermia was maintained at 33°C for 2 h. Animals were observed up to 96 h for assessment of survival and neurologic recovery.

RESULTS

No statistical differences in baseline measurements were observed among groups and all the animals were successfully resuscitated. Compared with Ctrl, serum cardiac troponin T measured at 5 h and myocardial damage score measured at 96 h after resuscitation were markedly reduced in H2, TH, and H2+TH groups. Compared with Ctrl and TH, astroglial protein S100 beta measured during the earlier postresuscitation period, and neurological deficit score and neuronal damage score measured at 96 h were considerably lower in both H2 and H2+TH groups. Ninety-six hours survival rates were significantly higher in the H2 (80.0%) and H2+TH (90.0%) groups than TH (30.0%) and to Ctrl (30.0%).

CONCLUSIONS

Hydrogen inhaling was superior to mild hypothermia for improving neurological outcome and survival in cardiac arrest and resuscitation model of systemic hypertension rats.

Increased Citrullinated Histone H3 Levels in the Early Post-Resuscitative Period Are Associated with Poor Neurologic Function in Cardiac Arrest Survivors-A Prospective Observational Study

The exact contribution of neutrophils to post-resuscitative brain damage is unknown. We aimed to investigate whether neutrophil extracellular trap (NET) formation in the early phase after return of spontaneous circulation (ROSC) may be associated with poor 30 day neurologic function in cardiac arrest survivors. This study prospectively included adult (≥18 years) out-of-hospital cardiac arrest (OHCA) survivors with cardiac origin, who were subjected to targeted temperature management. Plasma levels of specific (citrullinated histone H3, H3Cit) and putative (cell-free DNA (cfDNA) and nucleosomes) biomarkers of NET formation were assessed at 0 and 12 h after admission. The primary outcome was neurologic function on day 30 after admission, which was assessed using the five-point cerebral performance category (CPC) score, classifying patients into good (CPC 1–2) or poor (CPC 3–5) neurologic function. The main variable of interest was the effect of H3Cit level quintiles at 12 h on 30 day neurologic function, assessed by logistic regression. The first quintile was used as a baseline reference. Results are given as crude odds ratio (OR) with 95% confidence interval (95% CI). Sixty-two patients (79% male, median age: 57 years) were enrolled. The odds of poor neurologic function increased linearly, with 0 h levels of cfNDA (crude OR 1.8, 95% CI: 1.2–2.7, p = 0.007) and nucleosomes (crude OR 1.7, 95% CI: 1.0–2.2, p = 0.049), as well as with 12 h levels of cfDNA (crude OR 1.6, 95% CI: 1.1–2.4, p = 0.024), nucleosomes (crude OR 1.7, 95% CI: 1.1–2.5, p = 0.020), and H3Cit (crude OR 1.6, 95% CI: 1.1–2.3, p = 0.029). Patients in the fourth (7.9, 95% CI: 1.1–56, p = 0.039) and fifth (9.0, 95% CI: 1.3–63, p = 0.027) H3Cit quintile had significantly higher odds of poor 30 day neurologic function compared to patients in the first quintile. Increased plasma levels of H3Cit, 12 h after admission, are associated with poor 30 day neurologic function in adult OHCA survivors, which may suggest a contribution of NET formation to post-resuscitative brain damage and therefore provide a therapeutic target in the future.

Intrabronchial Catheter Resuscitation for Respiratory and Cardiorespiratory Arrest

INTRODUCTION

We sought to determine whether intrabronchial oxygenation would provide adequate gas exchange during both anesthesia induced apneic and cardiopulmonary arrest and cardiac massage (CPR).

METHODS

Ten pigs underwent general anesthesia with mechanical ventilation. Blood gases were measured in each animal at 4 min intervals for up to 28 min. An intrabronchial catheter (4 L/min O2) was inserted through an endotracheal tube after respirator cessation. Group A animals (6) were resuscitated with the catheter but without CPR. Group B animals (4) were rendered apneic and cardioplegic and resuscitated by CPR for 28 min using the intrabronchial device.

RESULTS

All group A animals were resuscitated and survived after 24 min of apnea. Mean pO2 decreased from 378 mmHg (95% confidence interval [CI], 288-468) to 292 mmHg (95% CI, 246-339), P = 0.009; pCO2 increased from 52 mmHg (95% CI, 43-61) to 137 mmHg (95% CI, 116-158), P < 0.0001; and pH decreased from 7.32 (7.29-7.36) to 6.98 (6.92-7.03), P < 0.0001. In a control animal bronchial catheter oxygen flow ceased at baseline and pO2 decreased from 268 to 30 mmHg by 20 min. In group B animals mean pO2 decreased from 426 mmHg (95% CI, 273-579) to 130 mmHg (95% CI, 92-168) after 28 min, P < 0.0001; pCO2 increased from 49 mmHg (95% CI, 41-58) to 73 mmHg (95% CI, 61-86), P = 0.03; and pH decreased from 7.34 (7.33-7.35) to 7.07 (6.98-7.16), P < 0.0001. In the control receiving intratracheal oxygen pO2 decreased from 324 to 88 mmHg after 16 minu of CPR.

CONCLUSIONS

Intrabronchial oxygenation provides sustained hyperoxemia during complete apnea and cardiac arrest with CPR.

Optimizing the Early Resuscitation After Out-of-Hospital Cardiac Arrest

Resuscitation after out-of-hospital cardiac arrest can be one of the most challenging scenarios in acute-care medicine. The devastating effects of postcardiac arrest syndrome carry a substantial morbidity and mortality that persist long after return of spontaneous circulation. Management of these patients requires the clinician to simultaneously address multiple emergent priorities including the resuscitation of the patient and the efficient diagnosis and management of the underlying etiology. This review provides a concise evidence-based overview of the core concepts involved in the early postcardiac arrest resuscitation. It will highlight the components of an effective management strategy including addressing hemodynamic, oxygenation, and ventilation goals as well as carefully considering cardiac catheterization and targeted temperature management. An organized approach is paramount to providing effective care to patients in this vulnerable time period.

Clinical Efficacy of Extracorporeal Cardiopulmonary Resuscitation for Adults with Cardiac Arrest: Meta-Analysis with Trial Sequential Analysis

Objective

This meta-analysis with trial sequential analysis (TSA) compared the clinical efficacy of extracorporeal cardiopulmonary resuscitation (ECPR) with conventional CPR (CCPR) for adult patients who experienced in-hospital cardiac arrest (IHCA) or out-of-hospital CA (OHCA).

Methods

A literature search was used to identify eligible publications (up to 30 July 2018) from PubMed, the Cochrane Library, the ISI Web of Knowledge, and Embase. Two investigators independently conducted the literature search, study selection, data extraction, and quality evaluation. Meta-analysis and TSA were used to analyze each outcome, and the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) was used to evaluate the level of evidence. The primary outcome was 30-day survival, and the secondary outcomes were 30-day neurologic outcome, 3-6 months' survival, 3-6 months' neurological outcome, 1-year survival, and 1-year neurological outcome.

Results

We identified 13 eligible observational studies for the final analysis. Pooled analyses showed that ECPR was associated with a significantly better 30-day survival (RR = 1.60, 95% CI = 1.25-2.06) and 30-day neurologic outcome (RR = 2.69, 95% CI = 1.63-4.46), and TSA confirmed these results. However, subgroup analysis of patients with OHCA indicated that ECPR and CCPR had similar effects on 30-day survival (RR = 1.18, 95% CI = 0.71-1.97), which was not confirmed by TSA. Analysis of OHCA patients indicated that ECPR provided a better 30-day neurological outcome (RR = 3.93, 95% CI = 1.00-15.50), but TSA did not support these results. Analysis of IHCA patients indicated that ECPR was associated with a better 30-day survival (RR 1.90, 95% CI 1.43-2.52) and 30-day neurologic outcome (RR 2.02, 95% CI 1.21-3.39), and TSA supported these results. Other subgroup analyses showed that the results were generally consistent, regardless of nation, propensity score matching, presumed etiology, whether the CA was witnessed or not, and study quality.

Conclusions

Relative to CCPR, ECPR improved the survival and neurological outcome of patients who had IHCA. Compared to IHCA patients, TSA could not confirm better survival and neurologic outcome of ECPR in OHCA patients, suggesting that further studies are needed.

Trial Registration

This trial was registered with PROSPERO (CRD42018100513) on 17 July 2018.

Real-time quantitative monitoring of cerebral blood flow by laser speckle contrast imaging after cardiac arrest with targeted temperature management

Brain injury is the main cause of mortality and morbidity after cardiac arrest (CA). Changes in cerebral blood flow (CBF) after reperfusion are associated with brain injury and recovery. To characterize the relative CBF (rCBF) after CA, 14 rats underwent 7 min asphyxia-CA and were randomly treated with 6 h post-resuscitation normothermic (36.5-37.5℃) or hypothermic- (32-34℃) targeted temperature management (TTM) (N = 7). rCBF was monitored by a laser speckle contrast imaging (LSCI) technique. Brain recovery was evaluated by neurologic deficit score (NDS) and quantitative EEG - information quantity (qEEG-IQ). There were regional differences in rCBF among veins of distinct cerebral areas and heterogeneous responses among the three components of the vascular system. Hypothermia immediately following return of spontaneous circulation led to a longer hyperemia duration (19.7 ± 1.8 vs. 12.7 ± 0.8 min, p < 0.01), a lower rCBF (0.73 ± 0.01 vs. 0.79 ± 0.01; p < 0.001) at the hypoperfusion phase, a better NDS (median [25th-75th], 74 [61-77] vs. 49 [40-77], p < 0.01), and a higher qEEG-IQ (0.94 ± 0.02 vs. 0.77 ± 0.02, p < 0.001) compared with normothermic TTM. High resolution LSCI technique demonstrated hypothermic TTM extends hyperemia duration, delays onset of hypoperfusion phase and lowered rCBF, which is associated with early restoration of electrophysiological recovery and improved functional outcome after CA.

Effect of serum albumin level on hospital outcomes in out-of-hospital cardiac arrest

Background:

Background: Serum albumin has been known as a strong predictive value of mortality in various disease conditions, severe burns, major surgeries, stroke, myocardial infarction, etc. But little is known for the effect of serum albumin level on out-of-hospital cardiac arrest patients.

Objectives:

This study aimed to investigate the effect of serum albumin level on the outcome of out of hospital cardiac arrest.

Methods:

This study was a prospective hospital-based patient cohort study, conducted during January to December 2014 at 27 emergency departments in Cardiac Arrest Pursuit Trial with Unique Registration and Epidemiologic Surveillance project. The albumin was measured immediately after arrival to the emergency department during cardiopulmonary resuscitation, and albumin was categorized into two groups, group < 3.5 g/dL group and ⩾ 3.5 g/dL group. The primary outcome was a good neurological recovery at discharge (cerebral performance category scale 1 or 2). Multivariable logistic regression was used for adjusting for confounders.

Results:

During the study period, 1616 out-of-hospital cardiac arrest patients with presumed cardiac etiology were enrolled, and the total of 1013 patients were analyzed in this study. A total 452 (44.6%) patients had serum albumin level less than 3.5 g/dL. The serum albumin ⩾ 3.5 g/dL group showed better neurological outcomes than the serum albumin < 3.5 g/dL group: 18.5% versus 4.0%, and ⩾ 3.5 g/dL group had higher survival discharge rates than the < 3.5 g/dL group: 23.9% versus 9.1% (p < 0.01). After adjusting for potential covariates, patients with serum albumin ⩾ 3.5 g/dL had a higher odds of good neurological recovery (adjusted odds ratio: 2.94 (95% confidence interval: [1.57, 5.49])), and higher survival to discharge (adjusted odds ratio: 1.74 (95% confidence interval: [1.10, 2.76])).

Conclusion:

Low serum albumin levels are associated with a worse neurologic outcome in patients with out-of-hospital cardiac arrest.

Hemodynamic efficiency of hemodialysis treatment with high cut-off membrane during the early period of post-resuscitation shock: The HYPERDIA trial

BACKGROUND

After resuscitation of cardiac arrest (CA), an acute circulatory failure occurs in about 50% of cases, which shares many characteristics with septic shock. Most frequently, supportive treatments are poorly efficient to prevent multiple organ failure and death. We evaluated whether an early plasma removal of inflammatory mediators using high cut-off continuous veno-venous hemodialysis (HCO-CVVHD) could improve hemodynamic status and outcome of these patients.

PATIENTS AND METHODS

We performed a randomized open-label trial. Patients with post-cardiac arrest shock (defined as requirement of norepinephrine or epinephrine infusion > 1 mg/h) were included. The experimental group received 2 distinct sessions of HCO-CVVHD during the first 48 h following ICU admission. The control group received continuous veno-venous hemofiltration (CVVH) with standard membranes if needed. The primary endpoint was the delay to shock resolution asssessed by the length of catecholamine infusion. Number of vasopressors-free days at day 28, arterial blood pressure measures every 6-hours, daily fluid balance and mortality (ICU and day-28) were evaluated as secondary endpoints.

RESULTS

35 patients were included: 17 (median age 68.4, 59% male) in the HCO-CVVHD group and 18 (median age 66.3, 83% male) in the control group. Baseline characteristics did not differ between the two groups. Day-28 mortality rate was 64.7% and 72.2% in the HCO-CVVHD and control group, respectively (p = 0.72). Probability of vasopressors discontinuation over time was similar in the two groups (p for logrank test = 0.67). Number of day-28 catecholamine-free days was 25.1 [0, 26.5] and 24.5 [0, 26.2] in the HCO-CVVHD and control group, respectively (p = 0.65). No difference was observed regarding the daily-dose of vasopressors, arterial pressure profile and fluid balance.

CONCLUSION

In cardiac arrest patients, HCO-CVVHD did not decrease the lenght of post-resuscitation shock and had no significant effect on hemodynamic profile.

REGISTRATION

NCT00780299.

ExtraCorporeal life support for Cardiac ARrest in patients with post cardiac arrest syndrome: The ECCAR study

BACKGROUND

Post cardiac arrest shock (PCAS) occurring after resuscitated cardiac arrest (CA) is a main cause of early death. Extracorporeal life support (ECLS) could be useful pending recovery from myocardial failure.

AIM

To describe our PCAS population, and the factors associated with initiation of ECLS.

METHODS

This analysis included 921 patients admitted to two intensive care units between 2005 and 2014 for CA and PCAS; 43 of these patients had ECLS initiated. Neurological and ECLS-related outcomes were gathered retrospectively.

RESULTS

The 43 patients treated with ECLS were predominantly (70%) young males with evidence of myocardial infarction on coronary angiography. ECLS was initiated in patients with severe cardiovascular dysfunction (median left ventricular ejection fraction 15% [interquartile range 10-25%]), a median of 9hours [interquartile range 6-16hours] after the CA. At 1 year, eight patients (19%) had survived without neurological disability. Blood lactate and coronary aetiology were associated with neurological outcomes. Logistic regression conducted using 878 controls with PCAS identified age>62 years, location of CA, use of a high dose of adrenaline (>3mg) and blood lactate and serum creatinine concentrations (>5mmol/L and>109μmol/L, respectively) as risk factors for initiation of ECLS.

CONCLUSIONS

ECLS, as a salvage therapy for PCAS, could be an acceptable alternative for highly-selected patients.

Repetitive anodal transcranial direct current stimulation improves neurological outcome and survival in a ventricular fibrillation cardiac arrest rat model

BACKGROUND

Transcranial direct current stimulation (tDCS) modulates neuronal activity and is a potential therapeutic tool for many neurological diseases. However, its beneficial effects on post cardiac arrest syndrome remains uncertain.

OBJECTIVE/HYPOTHESIS

We investigated the effects of repetitive anodal tDCS on neurological outcome and survival in a ventricular fibrillation (VF) cardiac arrest rat model.

METHODS

Cardiopulmonary resuscitation was initiated after 6 min of VF in 36 Sprague-Dawley rats. The animals were randomized into three groups immediately after resuscitation (n = 12 each): no-treatment control (NTC) group, targeted temperature management (TTM) group, and tDCS group. For tDCS, 1 mA anodal tDCS was applied on the dorsal scalp for 0.5 h. The stimulation was repeated for four sessions with 1-h resting interval under normothermia. Post-resuscitation hemodynamic, cerebral, and myocardial injuries, 96-h neurological outcome, and survival were evaluated.

RESULTS

Compared with the NTC group, post-resuscitation serum astroglial protein S100 beta and cardiac troponin T levels and 96-h neuronal and myocardial damage scores were markedly reduced in the tDCS and TTM groups. Myocardial ejection fraction, neurological deficit score, and 96-h survival rate were also significantly better for the tDCS and TTM groups. The period of post-resuscitation arrhythmia with hemodynamic instability was considerably shorter in the tDCS group, but no differences were observed in neurological outcome and survival between the tDCS and TTM groups.

CONCLUSIONS

In this cardiac arrest rat model, repeated anodal tDCS commenced after resuscitation improves 96-h neurological outcome and survival to an extent comparable to TTM by attenuating post-resuscitation cerebral and cardiac injuries.

The complement lectin pathway after cardiac arrest

The lectin pathway (LP) of the complement system may initiate inflammatory reactions when body tissue is altered. We aimed to investigate the levels of the LP proteins in out-of-hospital cardiac arrest patients, and to compare these with healthy individuals. Furthermore, we aimed to clarify whether the duration of targeted temperature management influenced LP protein levels, and we further examined whether LP proteins were associated with 30-day mortality. We included 82 patients resuscitated from out-of-hospital cardiac arrest. The patients were randomly assigned to 24 or 48 hours of targeted temperature management at 33 ± 1°C. Blood samples were obtained 22, 46 and 70 hours after target temperature was reached. Levels of the LP proteins (mannan-binding lectin [MBL], M-ficolin, H-ficolin, collectin liver 1 [CL-L1], MBL-associated serine protease 1 [MASP-1], MASP-2, MASP-3 and MBL-associated protein of 44 kDa [MAp44]) were measured using time-resolved immunofluorometric assays. Data from 82 gender matched healthy individuals were used for comparison. Levels of CL-L1, MASP-1, MASP-2 and MAp44 were significantly higher, whereas M-ficolin levels were significantly lower in cardiac arrest patients compared with healthy individuals. MASP-2, MASP-3 and M-ficolin levels changed significantly when comparing 24 and 48 hours of targeted temperature management. The LP protein levels were not different between 30-day survivors and non-survivors after cardiac arrest. The differences in LP protein levels between patients and healthy individuals may indicate that cardiac arrest patients have an activated LP. Overall, the LP protein levels were not influenced by the duration of targeted temperature management, and the levels were not associated with 30-day mortality.

The relationship between low survival and acute increase of tumor necrosis factor α expression in the lung in a rat model of asphyxial cardiac arrest

Cardiac arrest (CA) is sudden loss of heart function and abrupt stop in effective blood flow to the body. The patients who initially achieve return of spontaneous circulation (RoSC) after CA have low survival rate. It has been known that multiorgan dysfunctions after RoSC are associated with high morbidity and mortality. Most previous studies have focused on the heart and brain in RoSC after CA. Therefore, the aim of this research was to perform serological, physiological, and histopathology study in the lung and to determine whether or how pulmonary dysfunction is associated with low survival rate after CA. Experimental animals were divided into sham-operated group (n=14 at each point in time), which was not subjected to CA operation, and CA-operated group (n=14 at each point in time), which was subjected to CA. The rats in each group were sacrificed at 6 hours, 12 hours, 24 hours, and 2 days, respectively, after RoSC. Then, pathological changes of the lungs were analyzed by hematoxylin and eosin staining, Western blot and immunohistochemistry for tumor necrosis factor α (TNF-α). The survival rate after CA was decreased with time past. We found that histopathological score and TNF-α immunoreactivity were significantly increased in the lung after CA. These results indicate that inflammation triggered by ischemia-reperfusion damage after CA leads to pulmonary injury/dysfunctions and contributes to low survival rate. In addition, the finding of increase in TNF-α via inflammation in the lung after CA would be able to utilize therapeutic or diagnostic measures in the future.

Metformin Improves Neurologic Outcome Via AMP-Activated Protein Kinase-Mediated Autophagy Activation in a Rat Model of Cardiac Arrest and Resuscitation

BACKGROUND

Sudden cardiac arrest (CA) often results in severe injury to the brain, and neuroprotection after CA has proved to be difficult to achieve. Herein, we sought to investigate the effects of metformin pretreatment on brain injury secondary to CA and cardiopulmonary resuscitation.

METHODS AND RESULTS

Rats were subjected to 9-minute asphyxial CA after receiving daily metformin treatment for 2 weeks. Survival rate, neurologic deficit scores, neuronal loss, AMP-activated protein kinase (AMPK), and autophagy activation were assessed at indicated time points within the first 7 days after return of spontaneous circulation. Our results showed that metformin pretreatment elevated the 7-day survival rate from 55% to 85% and significantly reduced neurologic deficit scores. Moreover, metformin ameliorated CA-induced neuronal degeneration and glial activation in the hippocampal CA1 region, which was accompanied by augmented AMPK phosphorylation and autophagy activation in affected neuronal tissue. Inhibition of AMPK or autophagy with pharmacological inhibitors abolished metformin-afforded neuroprotection, and augmented autophagy induction by metformin treatment appeared downstream of AMPK activation.

CONCLUSIONS

Taken together, our data demonstrate, for the first time, that metformin confers neuroprotection against ischemic brain injury after CA/cardiopulmonary resuscitation by augmenting AMPK-dependent autophagy activation.

Prognostic value of adrenal gland volume after cardiac arrest: Association of CT-scan evaluation with shock and mortality

BACKGROUND

Adrenal gland volume is associated with survival in septic shock. As sepsis and post-cardiac arrest syndrome share many pathophysiological features, we assessed the association between adrenal gland volume measured by computerized tomography (CT)-scan and post-cardiac arrest shock and intensive care unit (ICU) mortality, in a large cohort of out-of-hospital cardiac arrest (OHCA) patients. We also investigated the association between adrenal hormonal function and both adrenal gland volume and outcomes.

PATIENTS AND METHODS

Prospective analysis of CT-scan performed at hospital admission in patients admitted after OHCA (2007-2012). A pair of blinded radiologist calculated manually adrenal gland volume. In a subgroup of patients, plasma cortisol was measured at admission and 60 min after a cosyntropin test. Factors associated with post-cardiac arrest shock and ICU mortality were identified using multivariate logistic regression.

RESULTS

Among 775 patients admitted during this period after OHCA, 138 patients were included: 72 patients (52.2%) developed a post-cardiac arrest shock, and 98 patients (71.1%) died. In univariate analysis, adrenal gland volume was not different between patients with and without post-cardiac arrest shock: 10.6 and 11.3 cm³, respectively (p = 0.9) and between patients discharged alive or dead: 10.2 and 11.8 cm³, respectively (p = 0.4). Multivariate analysis confirmed that total adrenal gland volume was associated neither with post-cardiac arrest shock nor mortality. Neither baseline cortisol level nor delta between baseline and after cosyntropin test cortisol levels were associated with adrenal volume, post-cardiac arrest shock onset or mortality.

CONCLUSION

After OHCA, adrenal gland volume is not associated with post-cardiac arrest shock onset or ICU mortality. Adrenal gland volume does not predict adrenal gland hormonal response.

Does the British Heart Foundation PocketCPR training application improve confidence in bystanders performing CPR?

OBJECTIVES

Out-of-hospital cardiac arrest has poor prognosis and patients rarely survive unless they receive immediate cardiopulmonary resuscitation from bystanders. In 2012, the British Heart Foundation launched its PocketCPR training application to simplify bystander cardiopulmonary resuscitation training and overcome barriers to resuscitation. This study investigates whether the British Heart Foundation PocketCPR training application improves the confidence of bystanders who perform cardiopulmonary resuscitation during simulated resuscitation attempts.

METHODS

This is a mixed method study using a randomised crossover trial with questionnaire analysis. One hundred and twenty participants were randomised to either perform two minutes of cardiopulmonary resuscitation on a resuscitation manikin using the British Heart Foundation PocketCPR application or perform cardiopulmonary resuscitation without instruction. Participants completed a questionnaire to capture their confidence before completing the opposite arm of the study. Each participant then completed a second questionnaire to allow for comparison of levels of confidence.

RESULTS

Participants in this study were more confident in their overall performance of cardio-pulmonary resuscitation using the British Heart Foundation PocketCPR training application compared to performing cardiopulmonary resuscitation without instruction (mean confidence score (0-100): 50.41 with PocketCPR and 43.92 without (p = 0.026)). They were also more confident that the number of chest compressions in this study was correct (mean: 60.39 with PocketCPR vs. 46.10 without (p < 0.001)), and in the delivery of cardiopulmonary resuscitation without having recent cardiopulmonary resuscitation training (mean: 48.67 with PocketCPR vs. 39.79 without (p < 0.002)).

CONCLUSION

The British Heart Foundation PocketCPR training application improved the confidence of bystanders performing cardiopulmonary resuscitation during simulated resuscitation attempts.

APACHE II Score Immediately after Cardiac Arrest as a Predictor of Good Neurological Outcome in Out-of-Hospital Cardiac Arrest Patients Receiving Targeted Temperature Management

Background

This study assessed the association between the initial Acute Physiology and Chronic Health Evaluation (APACHE) II score and good neurological outcome in comatose survivors of out-of-hospital cardiac arrest who received targeted temperature management (TTM).

Methods

Data from survivors of cardiac arrest who received TTM between January 2011 and June 2016 were retrospectively analyzed. The initial APACHE II score was determined using the data immediately collected after return of spontaneous circulation rather than within 24 hours after being admitted to the intensive care unit. Good neurological outcome, defined as Cerebral Performance Category 1 or 2 on day 28, was the primary outcome of this study.

Results

Among 143 survivors of cardiac arrest who received TTM, 62 (43.4%) survived, and 34 (23.8%) exhibited good neurological outcome on day 28. The initial APACHE II score was significantly lower in the patients with good neurological outcome than in those with poor neurological outcome (23.71 ± 4.39 vs. 27.62 ± 6.16, P = 0.001). The predictive ability of the initial APACHE II score for good neurological outcome, assessed using the area under the receiver operating characteristic curve, was 0.697 (95% confidence interval [CI], 0.599 to 0.795; P = 0.001). The initial APACHE II score was associated with good neurological outcome after adjusting for confounders (odds ratio, 0.878; 95% CI, 0.792 to 0.974; P = 0.014).

Conclusions

In the present study, the APACHE II score calculated in the immediate post-cardiac arrest period was associated with good neurological outcome. The initial APACHE II score might be useful for early identification of good neurological outcome.

Independent Predictors of 6-Month Mortality in Patients Successfully Resuscitated for Out-of-Hospital Cardiac Arrest: Observational Retrospective Single Center Study

Background

Mortality of admitted out-of-hospital cardiac arrest (OHCA) patients is decreasing. Our aim was to evaluate independent predictors of six-month mortality of successfully resuscitated OHCA patients.

Methods

We reviewed retrospectively the records of 119 OHCA patients, admitted in 2011 to 2013 (73.1% men, mean age 64 ± 13,5 years) and registered their clinical data, treatments, and predictors of 6-month mortality.

Results

Six-month mortality of admitted OHCA patients was 47.5% and was associated significantly with older age (67.7 ± 12.9 years versus 59.9 ± 13 years, p < 0.05), mechanical ventilation, longer time of resuscitation (24.6 ± 18.9 sec versus 8.9 ± 8.4 sec, p < 0.05), use of vasopressors (87.3% versus 62.5%, p < 0.05), and increased serum lactate (8.1 ± 3.9 mmol/l versus 4.5 ± 3.6 mmol/l, p < 0.05) but less likely with prior shockable rhythm (38% versus 73.2%, p < 0.05), percutaneous coronary intervention (27% versus 55.4%, p < 0.05), achieved target temperatures 32°-34°C of mild therapeutic hypothermia (47.6% versus 71.4%, p < 0.05), acute coronary syndromes (31.7% versus 51.8%, p < 0.05), and neurological recovery (4.8% versus 69.6%, p < 0.05) when compared to survivors. Neurological outcome was most significant early independent predictor of 6-month mortality (OR 50.47; 95% CI 6.74 to 377.68; p < 0.001).

Conclusions

Postcardiac arrest brain injury most significantly and independently predicted 6-month mortality in hospitalized OHCA patients.

Erythropoietin alleviates post-resuscitation myocardial dysfunction in rats potentially through increasing the expression of angiotensin II receptor type 2 in myocardial tissues

Activation of renin-angiotensin system (RAS) is one of the pathological mechanisms associated with myocardial ischemia-reperfusion injury following resuscitation. The present study aimed to determine whether erythropoietin (EPO) improves post‑resuscitation myocardial dysfunction and how it affects the renin‑angiotensin system. Sprague‑Dawley rats were randomly divided into sham, vehicle, epinephrine (EP), EPO and EP + EPO groups. Excluding the sham group, all groups underwent cardiopulmonary resuscitation (CPR) 4 min after asphyxia‑induced cardiac arrest (CA). EP and/or EPO was administrated by intravenous injection when CPR began. The results demonstrated that the vehicle group exhibited lower mean arterial pressure, left ventricular systolic pressure, maximal ascending rate of left ventricular pressure during left ventricular isovolumic contraction and maximal descending rate of left ventricular pressure during left ventricular isovolumic relaxation (+LVdP/dt max and ‑LVdP/dt max, respectively), and higher left ventricular end‑diastolic pressure, compared with the sham group following return of spontaneous circulation (ROSC). Few significant differences were observed concerning the myocardial function between the vehicle and EP groups; however, compared with the vehicle group, EPO reversed myocardial function indices following ROSC, excluding‑LVdP/dt max. Serum renin and angiotensin (Ang) II levels were measured by ELISA. The serum levels of renin and Ang II were significantly increased in the vehicle group compared with the sham group, which was also observed for the myocardial expression of renin and Ang II receptor type 1 (AT1R), as determined by reverse transcription‑quantitative polymerase chain reaction and western blotting. EPO alone did not significantly reduce the high serum levels of renin and Ang II post-resuscitation, but changed the protein levels of renin and AT1R expression in myocardial tissues. However, EPO enhanced the myocardial expression of Ang II receptor type 2 (AT2R) following ROSC. In conclusion, the present study confirmed that CA resuscitation activated the renin‑Ang II‑AT1R signaling pathway, which may contribute to myocardial dysfunction in rats. The present study confirmed that EPO treatment is beneficial for protecting cardiac function post‑resuscitation, and the roles of EPO in alleviating post‑resuscitation myocardial dysfunction may potentially be associated with enhanced myocardial expression of AT2R.

Accidental hypothermia

Accidental hypothermia causes profound changes to the body's physiology. After an initial burst of agitation (e.g., 36-37°C), vital functions will slow down with further cooling, until they vanish (e.g. <20-25°C). Thus, a deeply hypothermic person may appear dead, but may still be able to be resuscitated if treated correctly. The hospital use of minimally invasive rewarming for nonarrested, otherwise healthy patients with primary hypothermia and stable vital signs has the potential to substantially decrease morbidity and mortality for these patients. Extracorporeal life support (ECLS) has revolutionized the management of hypothermic cardiac arrest, with survival rates approaching 100%. Hypothermic patients with risk factors for imminent cardiac arrest (i.e., temperature <28°C, ventricular arrhythmia, systolic blood pressure <90 mmHg), and those who have already arrested, should be transferred directly to an ECLS center. Cardiac arrest patients should receive continuous cardiopulmonary resuscitation (CPR) during transfer. If prolonged transport is required or terrain is difficult, mechanic CPR can be helpful. Intermittent CPR may be appropriate in hypothermic arrest when continuous CPR is impossible. Modern postresuscitation care should be implemented following hypothermic arrest. Structured protocols should be in place to optimize prehospital triage, transport, and treatment as well as in-hospital management, including detailed criteria and protocols for the use of ECLS and postresuscitation care.

Changes in histopathology and tumor necrosis factor-α levels in the hearts of rats following asphyxial cardiac arrest

OBJECTIVE

Post cardiac arrest (CA) syndrome is associated with a low survival rate in patients who initially have return of spontaneous circulation (ROSC) after CA. The aim of this study was to examine the histopathology and inflammatory response in the heart during the post CA syndrome.

METHODS

We induced asphyxial CA in male Sprague-Dawley rats and determined the survival rate of these rats during the post resuscitation phase.

RESULTS

Survival of the rats decreased after CA: 66.7% at 6 hours, 36.7% at 1 day, and 6.7% at 2 days after ROSC following CA. The rats were sacrificed at 6 hours, 12 hours, 1 day, and 2 days after ROSC, and their heart tissues were examined. Histopathological scores increased at 12 hours post CA and afterwards, histopathological changes were not significant. In addition, levels of tumor necrosis factor-α immunoreactivity gradually increased after CA.

CONCLUSION

The survival rate of rats 2 days post CA was very low, even though histopathological and inflammatory changes in the heart were not pronounced in the early stage following CA.