Shorter Interval from Witnessed Out-Of-Hospital Cardiac Arrest to Reaching the Target Temperature Could Improve Neurological Outcomes After Extracorporeal Cardiopulmonary Resuscitation with Target Temperature Management: A Retrospective Analysis of a Japanese Nationwide Multicenter Observational Registry

How effective is extracorporeal life support for patients with out-of-hospital cardiac arrest initiated at the emergency department? A systematic review and meta-analysis

BACKGROUND

Extracorporeal cardiopulmonary resuscitation (ECPR) is commonly initiated for adults experiencing cardiac arrest within the cardiac catheterization lab or the intensive care unit. However, the potential benefit of ECPR for these patients in the emergency department (ED) remains undocumented. This study aims to assess the benefit of ECPR initiated in the ED for patients with out-of-hospital cardiac arrest (OHCA).

METHODS

We conducted a systematic review and meta-analysis of studies comparing ECPR initiated in the ED versus conventional CPR. Relevant articles were identified by searching several databases including PubMed, EMBASE, Web of Science, and Cochrane collaborations up to July 31, 2022. Pooled estimates were calculated using the inverse variance heterogeneity method, while heterogeneity was evaluated using Q and I2 statistics. The risk of bias in included studies was evaluated using validated bias assessment tools. The primary outcome was a favorable neurological outcome at hospital discharge, and the secondary outcome was survival to hospital discharge or 30-day survival. Sensitivity analyses were performed to explore the benefits of ED-initiated ECPR in studies utilizing propensity score (PPS) analysis. Publication bias was assessed using Doi plots and the Luis Furuya-Kanamori (LFK) index.

RESULTS

The meta-analysis included a total of eight studies comprising 51,173 patients. ED-initiated ECPR may not be associated with a significant increase in favorable neurological outcomes (odds ratio [OR] 1.43, 95% confidence interval [CI] 0.30-6.70, I2 = 96%). However, this intervention may be linked to improved survival to hospital discharge (OR 3.34, 95% CI 2.23-5.01, I2 = 17%). Notably, when analyzing only PPS data, ED-initiated ECPR demonstrated efficacy for both favorable neurological outcomes (OR 1.89, 95% CI 1.26-2.83, I2 = 21%) and survival to hospital discharge (OR 3.37, 95% CI 1.52-7.49, I2 = 57%). Publication bias was detected for primary (LFK index 2.50) and secondary (LFK index 2.14) outcomes.

CONCLUSION

The results of this study indicate that ED-initiated ECPR may not offer significant benefits in terms of favorable neurological outcomes for OHCA patients. However, it may be associated with increased survival to hospital discharge. Future studies should prioritize randomized trials with larger sample sizes and strive for homogeneity in patient populations to obtain more robust evidence in this area.

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.

Hypothermia may reduce mortality and improve neurologic outcomes in adult patients treated with VA-ECMO: A systematic review and meta-analysis

BACKGROUND

VA-ECMO can greatly reduce mortality in critically ill patients, and hypothermia attenuates the deleterious effects of ischemia-reperfusion injury. We aimed to study the effects of hypothermia on mortality and neurological outcomes in VA-ECMO patients.

METHODS

A systematic search of the PubMed, Embase, Web of Science, and Cochrane Library databases was performed from the earliest available date to 31 December 2022. The primary outcome was discharge or 28-day mortality and favorable neurological outcomes in VA-ECMO patients, and the secondary outcome was bleeding risk in VA-ECMO patients. The results are presented as odds ratios (ORs) and 95% confidence intervals (CIs). Based on the heterogeneity assessed by the I2 statistic, meta-analyses were performed using random or fixed-effects models. GRADE methodology was used to rate the certainty in the findings.

RESULTS

A total of 27 articles (3782 patients) were included. Hypothermia (33-35 °C) lasting at least 24 h can significantly reduce discharge or 28-day mortality (OR, 0.45; 95% CI, 0.33-0.63; I2 = 41%) and significantly improve favorable neurological outcomes (OR, 2.08; 95% CI, 1.66-2.61; I2 = 3%) in VA-ECMO patients. Additionally, there was no risk associated with bleeding (OR, 1.15; 95% CI, 0.86-1.53; I2 = 12%). In our subgroup analysis according to in-hospital or out-of-hospital cardiac arrest, hypothermia reduced short-term mortality in both VA-ECMO-assisted in-hospital (OR, 0.30; 95% CI, 0.11-0.86; I2 = 0.0%) and out-of-hospital cardiac arrest (OR, 0.41; 95% CI, 0.25-0.69; I2 = 52.3%). Out-of-hospital cardiac arrest patients assisted by VA-ECMO for favorable neurological outcomes were consistent with the conclusions of this paper (OR, 2.10; 95% CI, 1.63-2.72; I2 = 0.5%).

CONCLUSIONS

Our results show that mild hypothermia (33-35 °C) lasting at least 24 h can greatly reduce short-term mortality and significantly improve favorable short-term neurologic outcomes in VA-ECMO-assisted patients without bleeding-related risks. As the grade assessment indicated that the certainty of the evidence was relatively low, hypothermia as a strategy for VA-ECMO-assisted patient care may need to be treated with caution.

Are serial neuron-specific enolase levels associated with neurologic outcome of ECPR patients: A retrospective multicenter observational study

AIM OF THE STUDY

This study aims to evaluate whether neuron-specific enolase (NSE) level at 48 h after extracorporeal cardiopulmonary resuscitation (ECPR) is associated with neurologic outcomes at 6 months after hospital discharge.

METHODS

This was a retrospective, multicenter, observational study of adult patients who received ECPR between May 2010 and December 2016. In the two hospitals involved in this study, NSE measurements were a routine part of the protocol for patients who received ECPR. Serial NSE levels were measured in all patients with ECPR. NSE levels were measured 24, 48, and 72 h after ECPR. The primary outcome was Cerebral Performance Categories (CPC) scale at 6 months after hospital discharge according to NSE levels at 48 h after ECPR.

RESULTS

At follow-up 6 months after hospital discharge, favorable neurologic outcomes of CPC 1 or 2 were observed in 9 (36.0%) of the 25 patients, and poor neurologic outcomes of CPC 3, 4, or 5 were observed in 16 (64%) patients. NSE levels at 24 h in the favorable and poor neurologic outcome groups were 58.3 (52.5-73.2) μg/L and 64.2 (37.9-89.8) μg/L, respectively (p = 0.95). NSE levels at 48 h in the favorable and poor neurologic outcome groups were 52.1 (22.3-64.9) μg/L and 302.0 (62.8-360.2) μg/L, respectively (p = 0.01). NSE levels at 72 h were 37.2 (12.5-53.2) μg/L and 240.9 (75.3-370.0) μg/L, respectively (p < 0.01). In receiver operating characteristic (ROC) curve analysis, as the predictor of poor outcome, the optimal cut-off value for NSE level at 48 h was 140.5 μg/L, and the area under the curve (AUC) was 0.844 (p < 0.01). The optimal cut-off NSE level at 72 h was 53.2 μg/L, and the AUC was 0.897 (p < 0.01).

CONCLUSIONS

NSE level at 72 h displayed the highest association with neurologic outcome after ECPR, and NSE level at 48 h was also associated with neurologic outcome after ECPR.

Extracorporeal cardiopulmonary resuscitation for cardiac arrest: An updated systematic review

OBJECTIVES

To provide an updated systematic review on the use of extracorporeal cardiopulmonary resuscitation (ECPR) compared with manual or mechanical cardiopulmonary resuscitation during cardiac arrest.

METHODS

This was an update of a systematic review published in 2018. OVID Medline, Embase, and the Cochrane Central Register of Controlled Trials were searched for randomized trials and observational studies between January 1, 2018, and June 21, 2022. The population included adults and children with out-of-hospital or in-hospital cardiac arrest. Two investigators reviewed studies for relevance, extracted data, and assessed bias. The certainty of evidence was evaluated using GRADE.

RESULTS

The search identified 3 trials, 27 observational studies, and 6 cost-effectiveness studies. All trials included adults with out-of-hospital cardiac arrest and were terminated before enrolling the intended number of subjects. One trial found a benefit of ECPR in survival and favorable neurological status, whereas two trials found no statistically significant differences in outcomes. There were 23 observational studies in adults with out-of-hospital cardiac arrest or in combination with in-hospital cardiac arrest, and 4 observational studies in children with in-hospital cardiac arrest. Results of individual studies were inconsistent, although many studies favored ECPR. The risk of bias was intermediate for trials and critical for observational studies. The certainty of evidence was very low to low. Study heterogeneity precluded meta-analyses. The cost-effectiveness varied depending on the setting and the analysis assumptions.

CONCLUSIONS

Recent randomized trials suggest potential benefit of ECPR, but the certainty of evidence remains low. It is unclear which patients might benefit from ECPR.

Extracorporeal cardiopulmonary resuscitation with temperature management could improve the neurological outcomes of out-of-hospital cardiac arrest: a retrospective analysis of a nationwide multicenter observational study in Japan

Background

Target temperature management (TTM) is an effective component of treating out-of-hospital cardiac arrest (OHCA) after return of spontaneous circulation in conventional cardiopulmonary resuscitation. However, therapeutic hypothermia (32–34 °C TTM) is not recommended based on the results of recent studies. Extracorporeal cardiopulmonary resuscitation (ECPR) with veno-arterial extracorporeal membrane oxygenation is another promising therapy for OHCA, but few studies have examined the effectiveness of ECPR with TTM. Therefore, we hypothesized that ECPR with TTM could have the effectiveness to improve the neurological outcomes for adults following witnessed OHCA, in comparison to ECPR without TTM.

Methods

We performed retrospective subanalyses of the Japanese Association for Acute Medicine OHCA registry. We focused on adults who underwent ECPR for witnessed OHCA. We performed univariate (the Mann–Whitney U test and Fisher’s exact test), multivariable (logistic regression analyses), and propensity score analyses (the inverse probability of the treatment-weighting method) with to compare the neurological outcomes between patients with or without TTM, among all eligible patients, patients with a cardiogenic cause, and patients divided into subgroups according to the interval from collapse to pump start (ICPS) (> 30, > 45, or > 60 min).

Results

We analyzed data for 977 patients. Among 471 patients treated with TTM, the target temperature was therapeutic hypothermia in 70%, and the median interval from collapse to target temperature was 249 min. Propensity score analysis showed a positive association between TTM and favorable neurological outcomes in all patients (odds ratio 1.546 [95% confidence interval 1.046–2.286], P = 0.029), and in patients with ICPS of > 30 or > 45 min, but not in those with ICPS of > 60 min. The propensity score analysis also showed a positive association between TTM and favorable neurological outcomes in patients with a cardiogenic cause (odds ratio 1.655 [95% confidence interval 1.096–2.500], P = 0.017), including in all ICPS subgroups (> 30, > 45, and > 60 min).

Conclusion

Within patients who underwent ECPR following OHCA, ECPR with TTM could show the potential of improvement in the neurological outcomes, compared to ECPR without TTM.

Contemporary targeted temperature management: Clinical evidence and controversies

Advancements in cardiac arrest and post-cardiac arrest care have led to improved survival to hospital discharge. While survival to hospital discharge is an important clinical outcome, neurologic recovery is also a priority. With the advancement of targeted temperature management (TTM), the American Heart Association guidelines for post-cardiac arrest care recommend TTM in patients who remain comatose after return of spontaneous circulation (ROSC). Recently, the TTM2 randomized controlled trial found no significant difference in neurologic function and mortality at 6-months between traditional hypothermia to 33°C versus 37.5°C. While TTM has been evaluated for decades, current literature suggests that the use of TTM to 33° when compared to a protocol of targeted normothermia does not result in improved outcomes. Instead, perhaps active avoidance of fever may be most beneficial. Extracorporeal cardiopulmonary resuscitation and membrane oxygenation can provide a means of both hemodynamic support and TTM after ROSC. This review aims to describe the pathophysiology, physiologic aspects, clinical trial evidence, changes in post-cardiac arrest care, potential risks, as well as controversies of TTM.

Outcomes of patients with refractory out-of-hospital cardiac arrest transported to an ECMO centre compared with transport to non-ECMO centres

Objective: To compare the outcomes of patients with refractory out-of-hospital cardiac arrest (OHCA) transported to a hospital that provides extracorporeal membrane oxygenation (ECMO) during cardiopulmonary resuscitation (ECPR) with patients transported to hospitals without ECPR capability. Design, setting: Retrospective review of patient care records in a pre-hospital and hospital setting. Participants: Adult patients with OHCA who left the scene and arrived with cardiopulmonary resuscitation in progress at 16 hospitals in Melbourne, Australia, between January 2016 and December 2019. Intervention: For selected patients transported to the ECPR centre, initiation of ECMO. Main outcome measures: Survival to hospital discharge and 12-month quality of life. Results: There were 223 eligible patients during the study period. Of 49 patients transported to the ECPR centre, 23 were commenced on ECMO. Of these, survival to hospital with good neurological recovery (Cerebral Performance Category [CPC] score 1/2) occurred in 4/23 patients. Four other patients developed return of spontaneous circulation in the ECPR centre before cannulation of whom one survived, giving overall good functional outcome at 12 months survival of 5/49 (10.2%). There were 174 patients transported to the 15 non-ECPR centres and 3/174 (2%) had good functional outcome at 12 months. After adjustment for baseline differences, the odds ratio for good neurological outcome after transport to an ECPR centre compared with a non-ECPR centre was 4.63 (95% CI, 0.97-22.11; P = 0.055). Conclusion: The survival rate of patients with refractory OHCA transported to an ECPR centre remains low. Outcomes in larger cities might be improved with shorter scene times and additional ECPR centres that would provide for earlier initiation of ECMO.