Comparison of extracorporeal and conventional cardiopulmonary resuscitation: A meta-analysis of 2 260 patients with cardiac arrest

Differences in outcomes of patients with out-of-hospital cardiac arrest treated with extracorporeal cardiopulmonary resuscitation between day-time and night-time

Although patients who underwent night-time resuscitation for out-of-hospital cardiac arrest (OHCA) had worse clinical outcomes than those who underwent day-time resuscitation, the differences between the outcomes of patients with OHCA who underwent extracorporeal cardiopulmonary resuscitation (ECPR) in the day-time and night-time remain unclear. We analyzed data from the Study of Advanced Life Support for Ventricular Fibrillation with Extracorporeal Circulation in Japan. Patients were categorized according to whether they received treatment during the day-time or night-time. The primary outcomes were survival to hospital discharge and favorable neurological outcome at discharge, and the secondary outcomes were estimated low-flow time, implementation time of ECPR, and complications due to ECPR. A multivariate logistic regression model adjusted for confounders was used for comparison. Among the 1644 patients, the night-time patients had a significantly longer ECMO implementation time and estimated low-flow time than the day-time patients, along with a significantly higher number of complications than the day-time patients. However, the survival and neurologically favorable survival rates did not differ significantly between the groups. Thus, although patients who underwent ECPR at night had an increased risk of longer implementation time and complications, their clinical outcomes did not differ from those who underwent day-time ECPR.

Impact of Lactate Clearance on Clinical and Neurological Outcomes of Patients With Out-of-Hospital Cardiac Arrest Treated With Extracorporeal Cardiopulmonary Resuscitation: A Secondary Data Analysis

OBJECTIVES

Serial evaluations of lactate concentration may be more useful in predicting outcomes in patients with out-of-hospital cardiac arrest (OHCA) than a single measurement. This study aimed to evaluate the impact of lactate clearance (LC) on clinical and neurologic outcomes in patients with OHCA who underwent extracorporeal cardiopulmonary resuscitation (ECPR).

DESIGN

Retrospective multicenter observational study.

SETTING

Patients with OHCA receiving ECPR at 36 hospitals in Japan between January 1, 2013, and December 31, 2018.

PATIENTS

This study evaluated 1227 patients, with lactate initial assessed upon emergency department admission and lactate second measured subsequently. To adjust for the disparity in the time between lactate measurements, the modified 6-hour LC was defined as follows: ([lactate initial -lactate second ]/lactate initial ) × 100 × (6/the duration between the initial and second measurements [hr]). The patients were divided into four groups according to the modified 6-hour LC with an equivalent number of patients among LC quartiles: Q1 (LC < 18.8), Q2 (18.8 < LC < 59.9), Q3 (60.0 < LC < 101.2), and Q4 (101.2 < LC).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The 30-day survival rates increased as the 6-hour LC increased (Q1, 21.2%; Q2, 36.8%; Q3, 41.4%; Q4, 53.6%; p for trend < 0.001). In the multivariate analysis, the modified 6-hour LC was significantly associated with a 30-day survival rate (adjusted odds ratio [AOR], 1.003; 95% CI, 1.001-1.005; p < 0.001) and favorable neurologic outcome (AOR, 1.002; 95% CI, 1.000-1.004; p = 0.027).

CONCLUSIONS

In patients with OHCA who underwent ECPR, an increase in the modified 6-hour LC was associated with favorable clinical and neurologic outcome. Thus, LC can be a criterion to assess whether ECPR should be continued.

Extracorporeal cardiopulmonary resuscitation versus conventional cardiopulmonary resuscitation in adults with cardiac arrest: a comparative meta-analysis and trial sequential analysis

BACKGROUND

Although outcomes of patients after cardiac arrest remain poor, studies have suggested that extracorporeal cardiopulmonary resuscitation (ECPR) might improve survival and neurological outcomes. We aimed to investigate any potential benefits of using ECPR over conventional cardiopulmonary resuscitation (CCPR) in patients with out-of-hospital cardiac arrest (OHCA) and in-hospital cardiac arrest (IHCA).

METHODS

In this systematic review and meta-analysis, we searched MEDLINE via PubMed, Embase, and Scopus from Jan 1, 2000, to April 1, 2023, for randomised controlled trials and propensity-score matched studies. We included studies comparing ECPR with CCPR in adults (aged ≥18 years) with OHCA and IHCA. We extracted data from published reports using a prespecified data extraction form. We did random-effects (Mantel-Haenszel) meta-analyses and rated the certainty of evidence using the Grading of Recommendations, Assessments, Developments, and Evaluations (GRADE) approach. We rated the risk of bias of randomised controlled trials using the Cochrane risk-of-bias 2.0 tool, and that of observational studies using the Newcastle-Ottawa Scale. The primary outcome was in-hospital mortality. Secondary outcomes included complications during extracorporeal membrane oxygenation, short-term (from hospital discharge to 30 days after cardiac arrest) and long-term (≥90 days after cardiac arrest) survival with favourable neurological outcomes (defined as cerebral performance category scores 1 or 2), and survival at 30 days, 3 months, 6 months, and 1 year after cardiac arrest. We also did trial sequential analyses to evaluate the required information sizes in the meta-analyses to detect clinically relevant reductions in mortality.

FINDINGS

We included 11 studies (4595 patients receiving ECPR and 4597 patients receiving CCPR) in the meta-analysis. ECPR was associated with a significant reduction in overall in-hospital mortality (OR 0·67, 95% CI 0·51-0·87; p=0·0034; high certainty), without evidence of publication bias (pegger=0·19); the trial sequential analysis was concordant with the meta-analysis. When considering IHCA only, in-hospital mortality was lower in patients receiving ECPR than in those receiving CCPR (0·42, 0·25-0·70; p=0·0009), whereas when considering OHCA only, no differences were found (0·76, 0·54-1·07; p=0·12). Centre volume (ie, the number of ECPR runs done per year in each centre) was associated with reductions in odds of mortality (regression coefficient per doubling of centre volume -0·17, 95% CI -0·32 to -0·017; p=0·030). ECPR was also associated with an increased rate of short-term (OR 1·65, 95% CI 1·02-2·68; p=0·042; moderate certainty) and long-term (2·04, 1·41-2·94; p=0·0001; high certainty) survival with favourable neurological outcomes. Additionally, patients receiving ECPR had increased survival at 30-day (OR 1·45, 95% CI 1·08-1·96; p=0·015), 3-month (3·98, 1·12-14·16; p=0·033), 6-month (1·87, 1·36-2·57; p=0·0001), and 1-year (1·72, 1·52-1·95; p<0·0001) follow-ups.

INTERPRETATION

Compared with CCPR, ECPR reduced in-hospital mortality and improved long-term neurological outcomes and post-arrest survival, particularly in patients with IHCA. These findings suggest that ECPR could be considered for eligible patients with IHCA, although further research into patients with OHCA is warranted.

FUNDING

None.

Potential role for extracorporeal membrane oxygenation cardiopulmonary resuscitation (E-CPR) during in-hospital cardiac arrest in Australia: A nested cohort study

Objective

This study aims to evaluate the characteristics and outcomes of patients who fulfilled extracorporeal membrane oxygenation cardiopulmonary resuscitation (E-CPR) selection criteria during in-hospital cardiac arrest (IHCA).

Design

This is a nested cohort study.

Setting

Code blue data were collected across seven hospitals in Australia between July 2017 and August 2018.

Participants

Participants who fulfilled E-CPR selection criteria during IHCA were included.

Main outcome measures

Return of spontaneous circulation and survival and functional outcome at hospital discharge. Functional outcome was measured using the modified Rankin scale, with scores dichotomised into good and poor functional outcome.

Results

Twenty-three (23/144; 16%) patients fulfilled E-CPR selection criteria during IHCA, and 11/23 (47.8%) had a poor outcome. Patients with a poor outcome were more likely to have a non-shockable rhythm (81.8% vs. 16.7%; p = 0.002), and a longer duration of CPR (median 12.5 [5.5, 39.5] vs. 1.5 [0.3, 2.5] minutes; p < 0.001) compared to those with a good outcome. The majority of patients (18/19 [94.7%]) achieved sustained return of spontaneous circulation within 15 minutes of CPR. All five patients who had CPR >15 minutes had a poor outcome.

Conclusion

Approximately one in six IHCA patients fulfilled E-CPR selection criteria during IHCA, half of whom had a poor outcome. Non-shockable rhythm and longer duration of CPR were associated with poor outcome. Patients who had CPR for >15 minutes and a poor outcome may have benefited from E-CPR. The feasibility, effectiveness and risks of commencing E-CPR earlier in IHCA and among those with non-shockable rhythms requires further investigation.

Clinician Perspectives on Cannulation for Extracorporeal Cardiopulmonary Resuscitation: A Mixed Methods Analysis

Out-of-hospital cardiac arrest is a leading cause of mortality with survival rates of less than 10%. In selected patients, survival may be improved via timely application of extracorporeal cardiopulmonary resuscitation (ECPR). However, ECPR is a complex and resource intensive intervention with a high risk of complications that impair widespread clinical adoption. This study employed a mixed approach of qualitative interview analysis embedded with quantitative data collection to uncover the major hurdles faced by clinicians during ECPR initiation. We conducted semi-structured interviews with eight ECPR intensive care specialists with 2-10 years of experience working at a large, tertiary ECPR center in Australia. Clinicians identified dilation as the most time-consuming step, followed by draping, and decision-making during extracorporeal membrane oxygenation patient selection. The most challenging step was the decision-making for patient selection, followed by dilation and imaging. These findings uncovered key barriers to ECPR, and identified priority areas for further research and clinical training. Major logistical hindrances will require well-defined protocols and improved clinical training. Engineering innovations in the identified areas may improve the delivery of ECPR, making it simpler and faster to deliver.

Analyzing willingness for extracorporeal cardiopulmonary resuscitation in refractory ventricular fibrillation

Extracorporeal cardiopulmonary resuscitation (ECPR) for refractory ventricular fibrillation/ventricular tachycardia in out-of-hospital cardiac arrest has recently been recommended for selected patients with favorable prognostic features. We aimed to identify factors affecting the willingness of emergency physicians to implement extracorporeal cardiopulmonary resuscitation (ECPR). We conducted a factorial survey with nine experimental vignettes by combining three different scene time intervals and transportation time intervals. Emergency physicians reported willingness to implement ECPR (1-100 points). Respondent characteristics that could affect the willingness were studied. Multilevel analysis of vignettes and respondent factors was conducted using a mixed-effects regression model. We obtained 486 vignette responses from 54 emergency physicians. In the case of longer scene time intervals, there was a significant difference in the willingness scores at 9 and 12 min transportation time intervals. When the pre-hospital time interval was > 40 min, emergency physicians demonstrated lower willingness to implement ECPR. Clinical experience of 15-19 years showed a significant favorable effect on willingness to implement extracorporeal membrane oxygenation (ECMO). However, the mean willingness scores of EPs for ECMO implementation were more than 75 across all vignettes. In ECPR, the prehospital time interval is an important factor, and the willingness of emergency physicians to implement ECMO could be mutually affected by scene time intervals, transportation time intervals, and total prehospital time.

Extracorporeal cardiopulmonary resuscitation in adults and children: A review of literature, published guidelines and pediatric single-center program building experience

Extracorporeal cardiopulmonary resuscitation (ECPR) is an adjunct supportive therapy to conventional cardiopulmonary resuscitation (CCPR) employing veno-arterial extracorporeal membrane oxygenation (VA-ECMO) in the setting of refractory cardiac arrest. Its use has seen a significant increase in the past decade, providing hope for good functional recovery to patients with cardiac arrest refractory to conventional resuscitation maneuvers. This review paper aims to summarize key findings from the ECPR literature available to date as well as the recommendations for ECPR set forth by leading national and international resuscitation societies. Additionally, we describe the successful pediatric ECPR program at Texas Children's Hospital, highlighting the logistical, technical and educational features of the program.

Predictors of Favorable Neurologic Outcomes in a Territory-First Extracorporeal Cardiopulmonary Resuscitation Program

Extracorporeal cardiopulmonary resuscitation (ECPR) is an advanced resuscitation method that has been associated with better outcomes after cardiac arrest compared with conventional cardiopulmonary resuscitation. This is a retrospective analysis of all patients who received ECPR for cardiac arrest in Hong Kong's first ECPR program from 2012 to 2020. The primary outcome was favorable neurologic outcome at 3 months. A new risk prediction model was developed and its performance was compared with published risk scores. One-hundred two patients received ECPR and 19 (18.6%) patients survived with favorable neurologic outcome. Having a shockable rhythm was the strongest predictor of favorable neurologic outcome in multivariate analysis (odds ratio, 9.64; 95% confidence interval [CI], 1.49 to 62.30; P = 0.017). We developed a simple model with three parameters for the prediction of favorable neurologic outcomes - presence of shockable rhythm, mean arterial pressure after extracorporeal membrane oxygenation, and the Acute Physiology And Chronic Health Evaluation IV score, with an area under receiver operating characteristic curve of 0.85 (95% CI, 0.77 to 0.94). In Hong Kong's first ECPR program, 18.6% patients survived with favorable neurologic outcomes, and having a shockable rhythm at presentation was the strongest predictor. Risk scores are useful in predicting important patient outcomes and should be included in clinical decision-making for patients who received ECPR.

Impact of left ventricular unloading using a peripheral Impella®-pump in eCPR patients

BACKGROUND

Extracorporeal cardiopulmonary resuscitation (eCPR) is a rapidly growing treatment strategy due to increasing survival rates in selected patients. Additional left ventricular mechanical unloading, using a transfemoral micro-axial blood pump (Impella® Denver, Massachusetts, USA), might improve patients' outcomes. In this regard, we sought to investigate patients who suffered OHCA (out-of hospital cardiac arrest) or IHCA (in-hospital cardiac arrest) with subsequent eCPR via VA-ECMO (veno-arterial extracorporeal membrane oxygenation) and concomitant Impella® implantation based on survival and feasibility of ECMO weaning.

METHODS

From January 2016 until December 2020, 108 patients underwent eCPR at our institution. Data prior to eCPR and early outcome parameters were analyzed comparing patients who were supported with an additional Impella® (2.5 or CP) (ECMO+Impella®, n = 18) and patients without additional (ECMO, n = 90) support during V-A ECMO therapy. The primary endpoint was in-hospital mortality; secondary endpoints were, among others: ECMO explantation, need for hemodialysis, stroke, and need for blood transfusions.

RESULTS

Low-flow time was significantly lower in the ECMO+Impella group (60 min vs. 55 min, p = .01). All-cause mortality was significantly lower in the ECMO+Impella® group (82% vs. 56%, p = .01). The time of circulatory support was shorter in the ECMO cohort (2.0 ± 1.73 vs. 4.76 ± 2.88 p = .05). ECMO decannulation was significantly more feasible in patients with ECMO+Impella® (72% vs. 32%, p = .01). Patients treated with additional Impella® showed significantly more acute kidney injury with the need for dialysis (72% vs. 18%, p ≤ .01).

CONCLUSION

Concomitant Impella® support might positively influence survival and ECMO weaning in eCPR patients. Treatment-associated complications such as the need for dialysis were more common in this highly selected patient group. Further studies with larger numbers are necessary to evaluate the clinical relevance of concomitant LV-unloading in eCPR patients using an Impella® device.

Ethics of ECPR research

The design of emergency medicine trials can raise several ethical concerns - risks may be greater, and randomisation may have to occur before consent. Research in emergency medicine is thus an illuminating context to explore the interplay between risk and randomisation, and the consequences for consent. Using a currently running trial, we describe possible concerns, considerations, and solutions to reconcile the conflicting interests of scientific inquiry, ethical principles, and clinical reality in emergency medicine research.

Analysis of Nosocomial Infection and Risk Factors in Patients with ECMO Treatment

Objective

To investigate the drug resistance of nosocomial infection-related pathogens in patients who underwent extracorporeal membrane oxygenation (ECMO), analyzing the nosocomial infection-related risk factors.

Methods

The medical records of 56 patients who received ECMO support treatment in the First Affiliated Hospital with Nanjing Medical University from January 2013 to December 2019 were selected. The nosocomial infection, pathogen distribution and drug resistance, and the influencing factors of nosocomial infection were analyzed. The predictive value of independent risk factors for nosocomial infection after ECMO was analyzed using the receiver operating characteristic (ROC) curve.

Results

A total of 56 patients receiving ECMO treatment were included. The nosocomial infection rate was 28.57%, and the prevalence infection rate was 44.64%. Lower respiratory tract infection was the main infection site. Among these infectious patients, 53 strains of pathogens were detected. The results showed that the gram-negative bacteria were mainly Acinetobacter baumannii and Klebsiella pneumonia. Moreover, the drug resistance rate of Acinetobacter baumannii to most of the antibiotics was more than 65%, among which the drug resistance rate to carbapenems was 80%. The results of risk factors of nosocomial infection after ECMO were analyzed by univariate analysis, showing that ECMO treatment time, hospitalization time, antibacterial drug use time, ventilator use time, catheter intubation time and central venous intubation time were statistically significant (all p < 0.001). Multivariate analysis identified that ECMO treatment time was an independent risk factor. As showed by ROC curve, ECMO treatment time had a high predictive value for postoperative nosocomial infection. ECMO treatment times of more than 4.5 days were associated with an increased risk of nosocomial infection.

Conclusion

The nosocomial infection rate after ECMO was relatively high, and the main pathogens are Gram-negative bacteria. The selection of antibiotics should be based on the results of pathogen drug sensitivity.

Application of extracorporeal cardiopulmonary resuscitation in adult patients with refractory cardiac arrest

Background

The aim of this study was to summarize the clinical experience of extracorporeal cardiopulmonary resuscitation (ECPR) in the treatment of adult patients with refractory cardiac arrest.

Methods

The clinical data of 12 cases of adult patients with cardiac arrest hospitalized between June 2015 and September 2019 who were unable to achieve return of spontaneous circulation effectively with conventional cardiopulmonary resuscitation (CCPR) and were treated with ECPR technology were retrospectively analyzed. The group included six males and six females aged between 18 and 69 years. All the patients underwent veno-arterial extracorporeal membrane oxygenation (V-A ECMO) support with the adoption of femoral artery and vein catheterization.

Results

The duration of cardiopulmonary resuscitation (CPR) for the 12 patients was 32-125 min, and the ECMO duration was 2-190 h. Four patients were successfully weaned from ECMO and survived until hospital discharge. The other eight patients died in hospital; hemodynamic collapse (four patients) in the early stage of ECMO and severe neurological complications (three patients) were the main causes of death.

Conclusions

Single-center data showed that ECPR provided a new rescue alternative for some patients with reversible refractory cardiac arrest. We have demonstrated that the success rate of treatment could be improved by selecting suitable patients and reducing the CPR duration as much as possible.

Long-term neurologically intact survival after extracorporeal cardiopulmonary resuscitation for in-hospital or out-of-hospital cardiac arrest: A systematic review and meta-analysis

Background

Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) has been used as extracorporeal cardiopulmonary resuscitation (ECPR) to support further resuscitation efforts in patients with cardiac arrest, yet its clinical effectiveness remains uncertain.

Objectives

This study reviews the role of ECPR in contemporary resuscitation care compared to no ECPR and/or standard care, e.g. conventional CPR, and quantitatively summarize the rates of long-term neurologically intact survival after adult in-hospital cardiac arrest (IHCA) or out-of-hospital cardiac arrest (OHCA).

Methods

We searched the following databases on January 31 st, 2020: CENTRAL, MEDLINE, Embase, and Web of Science. We followed PRISMA guidelines and used PICO format to summarize the research questions. Risk of bias was assessed using the ROBINS-I tool. Pooled risk ratios (RRs) for each outcome of interest were calculated. Quality of evidence was evaluated according to GRADE guidelines.

Results

Six cohort studies were included, totaling 1750 patients. Of these, 530 (30.3%) received the intervention, and 91 (17.2%) survived with long-term neurologically intact survival. ECPR compared to no ECPR is likely associated with improved long-term neurologically intact survival after cardiac arrest in any setting (risk ratio [RR] 3.11, 95% confidence interval [CI] 2.06–4.69; p < 0.00001) (GRADE: Very low quality). Similar results were found for long-term neurologically intact survival after IHCA (RR 3.21, 95% CI 1.74–5.94; p < 0.0002) (GRADE: Very low quality) and OHCA (RR 3.11, 95% CI 1.50–6.47; p < 0.002) (GRADE: Very low quality). Long-term time frames for neurologically intact survival (three months to two years) were combined into a single category, defined a priori as a Glasgow-Pittsburgh cerebral performance category (CPC) of 1 or 2.

Conclusions

VA-ECMO used as ECPR is likely associated with improved long-term neurologically intact survival after cardiac arrest. Future evidence from randomized trials is very likely to have an important impact on the estimated effect of this intervention and will further define optimal clinical practice. Review registration: PROSPERO CRD42020171945.

The 'Weekend Effect' in adult patients who receive extracorporeal cardiopulmonary resuscitation after in- and out-of-hospital cardiac arrest

Aim

This study investigates the potentially adverse association between extracorporeal cardiopulmonary resuscitation (ECPR) after cardiac arrest on weekends versus weekdays.

Methods

Single-centre, retrospective, stratified (weekday versus weekend) analysis of 318 patients who underwent in-hospital ECPR after out-of-hospital and in-hospital cardiac arrest (OHCA/IHCA) between 01/2008 and 12/2018. Weekend was defined as the period between Friday 17:00 and Monday 06:59.

Results

Seventy-three patients (23%) received ECPR during the weekend and 245 arrests (77%) occurred during the weekday. Whereas survival to discharge did not differ between both groups, long-term survival was significantly lower in the weekend group (p = 0.002). In the multivariate analysis, independent risk factors associated with hospital mortality were no flow time (OR 1.014; 95% CI 1.004–1.023) and serum lactate prior ECPR (OR 1.011; 95% CI 1.006–1.012), whereas each unit serum haemoglobin above average had a protective effect on in-hospital mortality (OR 0.87; 95% CI 0.79–0.96). New onset kidney failure requiring renal replacement therapy occurred more often in the weekend group (30.1% versus 18.4%; p = 0.04). One third of patients experienced complications regardless ECPR was initiated at weekdays or weekends.

Conclusion

Extracorporeal cardiopulmonary resuscitation at weekends adversely seems to impact long-term survival regardless timing (dayshift/nightshift). Duration of CPR and serum lactate prior ECPR were demonstrated as independent risk factors for in-hospital mortality. As ECPR at weekends could not be shown to be an independent outcome predictor a thorough analysis of clinical events subsequent to this intervention is warranted to understand long-term consequences of ECPR initiation after cardiac arrest.

Neurological outcome after extracorporeal cardiopulmonary resuscitation for in-hospital cardiac arrest: a systematic review and meta-analysis

BACKGROUND

In-hospital cardiac arrest (IHCA) is a major adverse event with a high mortality rate if not treated appropriately. Extracorporeal cardiopulmonary resuscitation (ECPR), as adjunct to conventional cardiopulmonary resuscitation (CCPR), is a promising technique for IHCA treatment. Evidence pertaining to neurological outcomes after ECPR is still scarce.

METHODS

We performed a comprehensive systematic search of all studies up to December 20, 2019. Our primary outcome was neurological outcome after ECPR at any moment after hospital discharge, defined by the Cerebral Performance Category (CPC) score. A score of 1 or 2 was defined as favourable outcome. Our secondary outcome was post-discharge mortality. A fixed-effects meta-analysis was performed.

RESULTS

Our search yielded 1215 results, of which 19 studies were included in this systematic review. The average survival rate was 30% (95% CI 28-33%, I2 = 0%, p = 0.24). In the surviving patients, the pooled percentage of favourable neurological outcome was 84% (95% CI 80-88%, I2 = 24%, p = 0.90).

CONCLUSION

ECPR as treatment for in-hospital cardiac arrest is associated with a large proportion of patients with good neurological outcome. The large proportion of favourable outcome could potentially be explained by the selection of patients for treatment using ECPR. Moreover, survival is higher than described in the conventional CPR literature. As indications for ECPR might extend to older or more fragile patient populations in the future, research should focus on increasing survival, while maintaining optimal neurological outcome.

Extracorporeal cardiopulmonary resuscitation for in- and out-of-hospital cardiac arrest: systematic review and meta-analysis of propensity score-matched cohort studies

INTRODUCTION

In this systematic review and meta-analysis of propensity score-matched cohort studies, we quantitatively summarize whether venoarterial extracorporeal membrane oxygenation (VA-ECMO) used as extracorporeal cardiopulmonary resuscitation (ECPR), compared with conventional cardiopulmonary resuscitation (CCPR), is associated with improved rates of 30-day and long-term favorable neurological outcomes and survival in patients resuscitated from in- and out-of-hospital cardiac arrest.

METHODS

We searched MEDLINE via PubMed, Embase, Scopus, and Google Scholar for eligible studies on January 14, 2019. All searches were limited to studies published between January 2000 and January 2019. Two investigators independently evaluated the quality (or certainty) of evidence according to GRADE guidelines. Pooled results are presented as relative risks (RRs) with 95% confidence intervals (CIs).

RESULTS

Six cohort studies using propensity score-matched analysis were included, totaling 1108 matched patients. Pooled analyses showed that ECPR was likely associated with improved 30-day and long-term favorable neurological outcome in adults compared to CCPR for in- and out-of-hospital cardiac arrest (RR = 2.02, 95% CI = 1.29-3.16; I2 = 20%, P = 0.002; very low-quality evidence) and (RR = 2.86, 95% CI = 1.64-5.01; I2 = 0%, P = 0.0002; moderate-quality evidence), respectively. When we analyzed in- and out-of-hospital cardiac arrest separately, ECPR was likely associated with improved 30-day favorable neurological outcome compared to CCPR for in-hospital cardiac arrest (RR = 2.18, 95% CI = 1.24-3.81; I2 = 9%, P = 0.006; very low-quality evidence), but not for out-of-hospital cardiac arrest (RR = 2.61, 95% CI = 0.56-12.20; I2 = 59%, P = 0.22; very low-quality evidence). ECPR was also likely associated with improved long-term favorable neurological outcome compared to CCPR for in-hospital cardiac arrest (RR = 2.50, 95% CI = 1.33-4.71; I2 = 0%, P = 0.005; moderate-quality evidence) and out-of-hospital cardiac arrest (RR = 4.64, 95% CI = 1.41-15.25; I2 = 0%, P = 0.01; moderate-quality evidence).

CONCLUSIONS

Our analysis suggests that VA-ECMO used as ECPR may improve long-term favorable neurological outcomes and survival when compared to the best standard of care in a selected patient population. Therefore, it is imperative for well-designed randomized clinical trials to obtain a higher level of scientific evidence to ensure optimal outcomes for cardiac arrest patients.

In-Depth Extracorporeal Cardiopulmonary Resuscitation in Adult Out-of-Hospital Cardiac Arrest

The use of extracorporeal cardiopulmonary resuscitation (E‐CPR) for the treatment of patients with out‐of‐hospital cardiac arrest who do not respond to conventional cardiopulmonary resuscitation CPR) has increased significantly in the past 10 years, in response to case reports and observational studies reporting encouraging results. However, no randomized controlled trials comparing E‐CPR with conventional CPR have been published to date. The evidence from systematic reviews of the available observational studies is conflicting. The inclusion criteria for published E‐CPR studies are variable, but most commonly include witnessed arrest, immediate bystander CPR, an initial shockable rhythm, and an estimated time from CPR start to establishment of E‐CPR (low‐flow time) of <60 minutes. A shorter low‐flow time has been consistently associated with improved survival. In an effort to reduce low‐flow times, commencement of E‐CPR in the prehospital setting has been reported and is currently under investigation. The provision of an E‐CPR service, whether hospital based or prehospital, carries considerable cost and technical challenges. Despite increased adoption, many questions remain as to which patients will derive the most benefit from E‐CPR, when and where to implement E‐CPR, optimal post‐arrest E‐CPR care, and whether this complex invasive intervention is cost‐effective. Results of ongoing trials are awaited to determine whether E‐CPR improves survival when compared with conventional CPR.

Patient and Institutional Characteristics Influence the Decision to Use Extracorporeal Cardiopulmonary Resuscitation for In-Hospital Cardiac Arrest

BACKGROUND

Outcomes from extracorporeal cardiopulmonary resuscitation (ECPR) are felt to be influenced by selective use, but the characteristics of those receiving ECPR are undefined. We demonstrate the relationship between individual patient and hospital characteristics and the probability of ECPR use.

METHODS AND RESULTS

We performed an observational analysis of adult inpatient cardiac arrests in the United States from 2000 to 2018 reported to the American Heart Association's Get With The Guidelines—Resuscitation registry restricted to hospitals that provided ECPR. We calculated case mix adjusted relative risk (RR) of receiving ECPR for individual characteristics. From 2000 to 2018, 129 736 patients had a cardiac arrest (128 654 conventional cardiopulmonary resuscitation and 1082 ECPR) in 224 hospitals that offered ECPR. ECPR use was associated with younger age (RR, 1.5 for <40 vs. 40–59 years; 95% CI, 1.2–1.8), no pre‐existing comorbidities (RR, 1.4; 95% CI, 1.1–1.8) or cardiac‐specific comorbidities (congestive heart failure [RR, 1.3; 95% CI, 1.2–1.5], prior myocardial infarction [RR, 1.4; 95% CI, 1.2–1.6], or current myocardial infarction [RR, 1.5; 95% CI, 1.3–1.8]), and in locations of procedural areas at the times of cardiac arrest (RR, 12.0; 95% CI, 9.5–15.1). ECPR decreased after hours (3–11 pm [RR, 0.8; 95% CI, 0.7–1.0] and 11 pm–7 am [RR, 0.6; 95% CI, 0.5–0.7]) and on weekends (RR, 0.7; 95% CI, 0.6–0.9).

CONCLUSIONS

Less than 1% of in‐hospital cardiac arrest patients are treated with ECPR. ECPR use is influenced by patient age, comorbidities, and hospital system factors. Randomized controlled trials are needed to better define the patients in whom ECPR may provide a benefit.

CPR and ECMO: The Next Frontier

Cardiopulmonary resuscitation (CPR) is a first-line therapy for sudden cardiac arrest, while extracorporeal membrane oxygenation (ECMO) has traditionally been used as a means of countering circulatory failure. However, new advances dictate that CPR and ECMO could be complementary for support after cardiac arrest. This review details the emerging science, technology, and clinical application that are enabling the new paradigm of these iconic circulatory support modalities in the setting of cardiac arrest.

Extracorporeal Membrane Oxygenation for Cardiac Indications in Adults: A Health Technology Assessment

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) is a rescue therapy used to stabilize patients with hemodynamic compromise such as refractory cardiogenic shock or cardiac arrest. When used for cardiac arrest, ECMO is also known as extracorporeal cardiopulmonary resuscitation (ECPR). We conducted a health technology assessment of venoarterial ECMO for adults (aged ≥ 18 years) with cardiac arrest refractory to conventional cardiopulmonary resuscitation (CPR) or with cardiogenic shock refractory to conventional medical management (i.e., drugs, mechanical support such as intra-aortic balloon pump and temporary ventricular assist devices). Our assessment included an evaluation of effectiveness, safety, cost-effectiveness, the budget impact of publicly funding ECMO for these indications, and patient preferences and values.

METHODS

We performed a systematic literature search of the clinical evidence. We assessed the risk of bias of each included study using the Risk of Bias in Systematic Reviews (ROBIS) tool for systematic reviews and the Risk of Bias Among Nonrandomized Trials (ROBINS-I) tool for observational studies, and the quality of the body of evidence according to the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) Working Group criteria. We performed a systematic economic literature search and conducted a cost-effectiveness analysis with a lifetime horizon from a public payer perspective. We also analyzed the budget impact of publicly funding ECMO in Ontario for patients with refractory cardiogenic shock or cardiac arrest. To contextualize the potential value of ECMO for cardiac indications, we spoke with patients and caregivers with direct experience with the procedure.

RESULTS

We included one systematic review (with 13 observational studies) and two additional observational studies in the clinical review. Compared with traditional CPR for patients with refractory cardiac arrest, ECPR was associated with significantly improved 30-day survival (pooled risk ratio [RR] 1.54; 95% CI 1.03 to 2.30) (GRADE: Very Low) and significantly improved long-term survival (pooled RR 2.17; 95% CI 1.37 to 3.44) (GRADE: Low). Overall, ECPR was associated with significantly improved 30-day favourable neurological outcome in patients with refractory cardiac arrest compared with traditional CPR; pooled RR 2.02 (95% CI 1.29 to 3.16) (GRADE: Very Low). For patients with cardiogenic shock, ECMO was associated with a significant improvement in 30-day survival compared with intra-aortic balloon pump (pooled RR 2.11; 95% CI 1.23 to 3.61) (GRADE: Very Low). Compared with temporary percutaneous ventricular assist devices, ECMO was not associated with improved survival (pooled risk ratio 0.94; 95% CI 0.67 to 1.30) (GRADE: Very Low).We estimated the incremental cost-effectiveness ratio of ECPR compared with conventional CPR is $18,722 and $28,792 per life-year gained (LYG) for in-hospital and out-of-hospital cardiac arrest, respectively. We estimated the probability of ECPR being cost-effective versus conventional CPR is 93% and 60% at a willingness-to-pay of $50,000 per LYG for in-hospital and out-of-hospital cardiac arrest, respectively. We estimate that publicly funding ECMO in Ontario over the next 5 years would result in additional total costs of $1,673,811 for cardiogenic shock (treating 314 people), $2,195,517 for in-hospital cardiac arrest (treating 126 people), and $3,762,117 for out-of-hospital cardiac arrest (treating 247 people).The eight patients and family members with whom we spoke had limited ability to assess the impact of ECMO or report their impressions because of their critical medical situations when they encountered the procedure. All had been in hospital with acute hemodynamic instability. In the decision to receive the procedure, participants generally relied on the expertise and judgment of physicians.

CONCLUSIONS

For adults treated for refractory cardiac arrest, ECPR may improve survival and likely improves long-term neurological outcomes compared with conventional cardiopulmonary resuscitation. For patients treated for cardiogenic shock, ECMO may improve 30-day survival compared with intra-aortic balloon pump, but there is considerable uncertainty.For adults with refractory cardiac arrest, ECPR may be cost-effective compared with conventional CPR. We estimate that publicly funding ECMO for people with cardiac arrest and cardiogenic shock in Ontario over the next 5 years would cost about $845,000 to $2.2 million per year.People with experience of ECMO for cardiac indications viewed it as a life-saving device and expressed gratitude that it was available and able to help stabilize their acute medical condition.

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.

Prolonged cardiopulmonary resuscitation and low flow state are not contraindications for extracorporeal support

Outcomes of out-of-hospital cardiac arrest are poor irrespective of the patient age group and circumstances. Survival to discharge after out-of-hospital arrest in children is less than 10%. Use of extracorporeal cardiopulmonary resuscitation is increasing and has been shown to improve outcomes in some situations. However, the candidacy for such augmentation is based on patient selection, institutional practices, and availability of an extracorporeal membrane oxygenation center. Often, duration of resuscitation, low flow state, presenting pH, and circumstances of arrest dictate candidacy for extracorporeal membrane oxygenation. We present a case of extremely prolonged resuscitation for out-of-hospital arrest in a pediatric patient, and we describe the use of mechanical compression device and transition to extracorporeal membrane oxygenation. We present the case outcome as well as brief discussion about controversies in extracorporeal cardiopulmonary resuscitation. We hope the case provides an opportunity for further discussion regarding opportunities to improve selection, use of extracorporeal cardiopulmonary resuscitation, and impact outcomes.

Amiloride Alleviates Neurological Deficits Following Transient Global Ischemia and Engagement of Central IL-6 and TNF-α Signal

BACKGROUND

Central pro-inflammatory cytokine (PIC) signal is involved in neurological deficits after transient global ischemia induced by cardiac arrest (CA). The present study was to examine if blocking acid sensing ion channels (ASICs) using amiloride in the Central Nervous System can alleviate neurological deficits after the induction of CA and further examine the participation of PIC signal in the hippocampus for the effects of amiloride.

METHODS

CA was induced by asphyxia and then cardiopulmonary resuscitation was performed in rats. Western blot analysis and ELISA were used to determine the protein expression of ASIC subunit ASIC1 in the hippocampus, and the levels of PICs. As noted, it is unlikely that this procedure is clinically used although amiloride and other pharmacological agents were given into the brain in this study.

RESULTS

CA increased ASIC1 in the hippocampus of rats in comparison with control animals. This was associated with the increase in IL-1β, IL-6 and TNF-α together with Caspase-3 and Caspase-9. The administration of amiloride into the lateral ventricle attenuated the upregulation of Caspase-3/Caspase-9 and this further alleviated neurological severity score and brain edema. Inhibition of central IL-6 and TNF-α also decreased ASIC1 in the hippocampus of CA rats.

CONCLUSION

Transient global ischemia induced by CA amplifies ASIC1a in the hippocampus likely via PIC signal. Amiloride administered into the Central Nervous System plays a neuroprotective role in the process of global ischemia. Thus, targeting ASICs (i.e., ASIC1a) is suggested for the treatment and improvement of CA-evoked global cerebral ischemia.

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.

A systematic literature review and meta-analysis of the effectiveness of extracorporeal-CPR versus conventional-CPR for adult patients in cardiac arrest

Introduction

The probability of surviving a cardiac arrest remains low. International resuscitation guidelines state that extracorporeal cardiopulmonary resuscitation (ECPR) may have a role in selected patients suffering refractory cardiac arrest. Identifying these patients is challenging. This project systematically reviewed the evidence comparing the outcomes of ECPR over conventional-CPR (CCPR), before examining resuscitation-specific parameters to assess which patients might benefit from ECPR.

Method

Literature searches of studies comparing ECPR to CCPR and the clinical parameters of survivors of ECPR were performed. The primary outcome examined was survival at hospital discharge or 30 days. A secondary analysis examined the resuscitation parameters that may be associated with survival in patients who receive ECPR (no-flow and low-flow intervals, bystander-CPR, initial shockable cardiac rhythm, and witnessed cardiac arrest).

Results

Seventeen of 948 examined studies were included. ECPR demonstrated improved survival (OR 0.40 (0.27-0.60)) and a better neurological outcome (OR 0.10 (0.04-0.27)) over CCPR during literature review and meta-analysis. Characteristics that were associated with improved survival in patients receiving ECPR included an initial shockable rhythm and a shorter low-flow time. Shorter no-flow, the presence of bystander-CPR and witnessed arrests were not characteristics that were associated with improved survival following meta-analysis, although the quality of input data was low. All data were non-randomised, and hence the potential for bias is high.

Conclusion

ECPR is a sophisticated treatment option which may improve outcomes in a selected patient population in refractory cardiac arrest. Further comparative research is needed clarify the role of this potential resuscitative therapy.

Predictors of survival and neurologic outcome for adults with extracorporeal cardiopulmonary resuscitation: A systemic review and meta-analysis

BACKGROUND

This systemic review aimed to explore the predictors of discharge and neurologic outcome of adult extracorporeal cardiopulmonary resuscitation (ECPR) to provide references for patient selection.

METHODS

Electronically searching of the Pubmed, Embase, Cochrane Library, and manual retrieval were done for clinical trials about predictors for adult ECPR which were published between January 2000 and January 2018 and included predictors for discharge and neurologic outcome. The literature was screened according to inclusion and exclusion criteria, the baseline information and interested outcomes were extracted. Two reviewers assessed the methodologic quality of the included studies and the quality of evidence for summary estimates independently. Pooled mean difference (MD) or odds ratio (OR) and 95% confidence interval (CI) were calculated by Review Manager Software 5.3. At last the quality of evidence for summary estimates was appraised according to Grading of Recommendations Assessment, Development, and Evaluation rating system.

RESULTS

In 16 studies, 1162 patients were enrolled. Out-of-hospital cardiac arrest (CA) (OR 0.58, 95% CI 0.36-0.93, P = .02), in-hospital CA (OR 1.73, 95% CI 1.08-2.77, P = .02), witnessed CA (OR 5.2, 95% CI 1.18-22.88, P = .01), bystander cardiopulmonary resuscitation (CPR) (OR 7.35, 95% CI 2.32-23.25, P < .01), initial shockable rhythm (OR 2.29, 95% CI 1.53-3.42, P < .01), 1st recorded nonshockable rhythm (OR 0.44, 95% CI 0.29-0.66, P < .01), CPR duration (MD -13.84 minutes, 95% CI -21 to -6.69, P < .0001), arrest-to-extracorporeal membrane oxygenation (ECMO) (MD -17.88 minutes, 95% CI -23.59 to -12.17, P < .01), PH (MD 0.14, 95% CI 0.08-0.21, P < .01), lactate (MD -3.66 mmol/L, 95% CI -7.15 to -0.17, P = .04), and percutaneous coronary intervention (PCI) (OR 1.63, 95% CI 1.02-2.58, P = .04)were identified as the survival predictors of ECPR. Shockable rhythm (OR 2.33, 95% CI 1.20-4.52, P = .01) and CPR duration (MD -9.85 minutes, 95% CI -15.71 to -3.99, P = .001) were identified as the neurologic outcome predictors of ECPR.

CONCLUSION

Current evidence showed that in-hospital CA, witnessed CA, bystander CPR, initial shockable rhythm, shorter CPR duration and arrest-to-ECMO duration, higher baseline PH, lower baseline lactate and PCI were favourable survival predictors of adult ECPR, and shockable rhythm and shorter CPR duration were good neurological outcome predictors of adult ECPR.

Perioperative Extracorporeal Cardiopulmonary Resuscitation: The Defibrillator of the 21st Century?: A Case Report

Veno-arterial-extracorporeal membrane oxygenation (ECMO) for cardiopulmonary resuscitation (ECMO-CPR) has been recommended by new resuscitation guidelines in the United Kingdom. Our recently established yet unfunded ECMO-CPR service has thus far treated 6 patients, with 3 making a good recovery. One patient suffered a catastrophic perioperative complication through glycine absorption and we are in no doubt that she would not have survived without ECMO. We argue for a pragmatic approach to funding of ECMO-CPR because observational evidence suggests superiority over traditional resuscitation and there exists major methodological and ethical barriers to randomized controlled studies. We also call for high-quality observational evidence in the perioperative setting.

Pre-hospital extra-corporeal cardiopulmonary resuscitation

Survival from out-of-hospital cardiac arrest (OHCA) has remained low despite advances in resuscitation science. Hospital-based extra-corporeal cardiopulmonary resuscitation (ECPR) is a novel use of an established technology that provides greater blood flow and oxygen delivery during cardiac arrest than closed chest compressions. Hospital-based ECPR is currently offered to selected OHCA patients in specialized centres. The interval between collapse and restoration of circulation is inversely associated with good clinical outcomes after ECPR. Pre-hospital delivery of ECPR concurrent with conventional resuscitation is one approach to shortening this interval and improving outcomes after OHCA. This article examines the background and rationale for pre-hospital ECPR; summarises the findings of a literature search for published evidence; and considers candidate selection, logistics, and complications for this complex intervention.

Extracorporeal Cardiopulmonary Resuscitation for Refractory Out-of-Hospital Cardiac Arrest: The State of the Evidence and Framework for Application

Out-of-hospital cardiac arrest (OHCA) affects 134 per 100,000 citizens annually. Extracorporeal cardiopulmonary resuscitation (ECPR), providing mechanical circulatory support, may improve the likelihood of survival among those with refractory OHCA. Compared with in-hospital ECPR candidates, those in the out-of-hospital setting tend to be sudden unexpected arrests in younger and healthier patients. The aims of this review were to summarize, and identify the limitations of, the evidence evaluating ECPR for OHCA, and to provide an approach for ECPR program application. Although there are many descriptions of ECPR-treated cohorts, we identified a paucity of robust data showing ECPR effectiveness compared with conventional resuscitation. However, it is highly likely that ECPR, provided after a prolonged attempt with conventional resuscitation, does benefit select patient populations compared with conventional resuscitation alone. Although reliable data showing the optimal patient selection criteria for ECPR are lacking, most implementations sought young previously healthy patients with rapid high-quality cardiopulmonary resuscitation. Carefully planned development of ECPR programs, in high-performing emergency medical systems at experienced extracorporeal membrane oxygenation centres, may be reasonable as part of systematic efforts to determine ECPR effectiveness and globally improve care. Protocol evaluation requires regional-level assessment, examining the incremental benefit of survival compared with standard care, while accounting for resource utilization.

Cardiac Support: Emphasis on Venoarterial ECMO

Major advances have been made in mechanical circulatory support in recent years. Venoarterial (VA) extracorporeal membrane oxygenation (ECMO) provides both pulmonary and circulatory support for critically ill patients with hemodynamic compromise, serving as a bridge to recovery or definitive therapy in the form of transplant or a durable ventricular assist device. In the past, VA ECMO support was used in cases of cardiogenic shock or failure to wean from cardiopulmonary bypass; however, the technology is now being applied to an ever-expanding list of conditions, including massive pulmonary embolism, cardiac arrest, drug overdose, and hypothermia.

Coverage of Journals from Mainland China in the Field of Emergency Medicine by Major International Biomedicine Databases

Objective

We aimed to explore the visibility of emergency medicine (EM) journals in mainland China based on the coverage by major indexing and abstracting information agencies and services.

Methodology

We first searched each journal by entering its title in Google's search engine, and then entered its home page to collect associated information, like publication cycle, journal language, publisher, editorial board, authors, and journal website. Second, to collect the inclusion information, totally ten databases were selected on the basis that they were considered as representative sources within the biomedicine. We adopted two forms for searching every journal: searching for every Chinese EM journal title (both English title and Chinese ‘ping yin’ title), and searching for the word ‘China’ from the fields provided for publisher of sources or for country of publication of sources indexed.

Results

Currently, in Mainland China, there were 13 EM journals, 12 in Chinese and one in English. Among them, both Science Citation Index Expanded (SCIE) and BIOSIS Previews (BP) did not include any EM journals; both MEDLINE and Abstract Journals (AJ) included only one, respectively; Scopus, EMBASE, Index Copernicus (IC), and Japan Science and Technology Agency (JST) indexed two journals, respectively; Western Pacific Region Index Medicus (WPRIM) included four journals, and Chemical Abstracts (CA) included six journals.

Conclusion

Only a few Chinese EM journals are indexed or abstracted in the international databases. More work should be done to achieve higher visibility of EM journals. (Hong Kong j.emerg.med. 2015;22:41-45)