Extracorporeal Cardiopulmonary Resuscitation with Therapeutic Hypothermia for Prolonged Refractory In-hospital Cardiac Arrest

A Systematic Review with Meta-Analysis Investigating the Impact of Targeted Perfusion Parameters during Extracorporeal Cardiopulmonary Resuscitation in Out-of-Hospital and Inhospital Cardiac Arrest

Evidence regarding perfusion conditions during extracorporeal cardiopulmonary resuscitation (ECPR) is rare. Therefore, we investigated the impact of perfusion parameters on neurologic outcome and survival in patients with in- or out-of-hospital cardiac arrest (IHCA; OHCA) treated with ECPR. We performed a systematic review with meta-analysis. The focus was set on perfusion parameters and their impact on survival and a goal neurological outcome using the cerebral performance category score of 1-2. We conducted random- and mixed-effects meta-analyses and computed pooled estimates and 95% confidence intervals (CI). We included a total of n = 1,282 ECPR (100%) patients from 20 ECPR studies. The target values of flow and mean arterial pressure (MAP) were frequently available. We transferred flow and MAP target values to high, medium, and low categories. The meta-analysis could not demonstrate a single effect of flow or MAP on outcome variables. In a second mixed-effects model, the combined occurrence of targeted flow and MAP as medium and high showed a significant effect on survival (OHCA: 52%, 95% CI: 29%, 74%; IHCA: 60%, 95% CI: 35%, 85%) and on neurological outcomes (OHCA: 53%, 95% CI: 27%, 78%; IHCA: 62%, 95% CI: 38%, 86%). Random-effects analysis showed also that IHCA led to a significant 11% (p = 0.006; 95% CI: 3%, 18%) improvement in survival and 12% (p = .005; 95% CI: 4%, 21%) improvement in neurological outcomes compared to OHCA. A combination of medium flow and high MAP showed advantages in survival and for neurological outcomes. We also identified improved outcomes for IHCA.

Survival and Factors Associated with Survival with Extracorporeal Life Support During Cardiac Arrest: A Systematic Review and Meta-Analysis

The survival rate after cardiac arrest (CA) remains low. The utilization of extracorporeal life support is proposed to improve management. However, this resource-intensive tool is associated with complications and must be used in selected patients. We performed a meta-analysis to determine predictive factors of survival. Among the 81 studies included, involving 9256 patients, survival was 26.2% at discharge and 20.4% with a good neurologic outcome. Meta-regressions identified an association between survival at discharge and lower lactate values, intrahospital CA, and lower cardio pulmonary resuscitation (CPR) duration. After adjustment for age, intrahospital CA, and mean CPR duration, an initial shockable rhythm was the only remaining factor associated with survival to discharge (β = 0.02, 95% CI: 0.007-0.02; p = 0.0004).

Impact of therapeutic hypothermia on bleeding events in adult patients treated with extracorporeal life support peri-cardiac arrest

PURPOSE

Whether therapeutic hypothermia (TH) adds to the risk of bleeding in patients on extracorporeal life support (ECLS) peri-cardiac arrest remains unknown.

MATERIAL AND METHODS

Single center retrospective study on patients receiving veno-arterial ECLS peri-cardiac arrest ± TH at 32-34 °C (January 2009-December 2015).

PRIMARY OUTCOME

major bleeding (including intracerebral hemorrhage, ICH) < 72 h of cardiac arrest. Logistic regression and marginal structural models were used to analyze associations with major bleeding.

RESULTS

Of 66 patients receiving ECLS, 36 were treated with TH. Major bleeding occurred in 14 patients (39%) treated with ECLS+TH and in 17 patients (57%) with ECLS alone. ICH was reported in 3 (8%) and one patient (3%), respectively. There was no difference in mortality, but lung injury occurred more often in ECLS+TH. A platelet count <60 × 10⁹/L but not TH was associated with major bleeding (including ICH). The estimated causal risk ratio of TH on the occurrence of major bleeding (including ICH) at 72 h post cardiac arrest was 0.95 (95%CI 0.62-1.45).

CONCLUSIONS

Bleeding complications were common in our study. However, TH (32-34 °C) was not associated with an increased risk of major bleeding in patients on ECLS peri-cardiac arrest.

Outcomes of Veno-Arterial Extracorporeal Membrane Oxygenation for In-Hospital Cardiac Arrest

Veno-arterial extracorporeal membrane oxygenation (VA ECMO) is increasingly used in cardiac arrest. Currently, public registries report the outcomes of cardiac arrest regardless of the setting (out-of-hospital versus in-hospital). Meanwhile, in-hospital cardiac arrest represents a more favorable setting for ECMO-assisted cardiopulmonary resuscitation than out-of-hospital cardiac arrest. Survival to discharge varies, but looks promising overall, ranging from 18.9 to 65%, with the bulk of the studies reporting survival to discharge between 30% and 50%, with about one-third to half of the patients discharged with no or minimal neurologic deficit. Based on the reported outcomes, in-hospital cardiac arrests can become a next focus for studies on successful implementation of VA ECMO.

Extracorporeal Cardiopulmonary Resuscitation for Out-of-Hospital Cardiac Arrest in Adult Patients

Extracorporeal cardiopulmonary resuscitation (ECPR) followed by targeted temperature management has been demonstrated to significantly improve the outcomes of out-of-hospital cardiac arrest (OHCA) in adult patients. Although recent narrative and systematic reviews on extracorporeal life support in the emergency department are available in the literature, they are focused on the efficacy of ECPR, and no comprehensively summarized review on ECPR for OHCA in adult patients is available. In this review, we aimed to clarify the prevalence, pathophysiology, predictors, management, and details of the complications of ECPR for OHCA, all of which have not been reviewed in previous literature, with the aim of facilitating understanding among acute care physicians. The leading countries in the field of ECPR are those in East Asia followed by those in Europe and the United States. ECPR may reduce the risks of reperfusion injury and deterioration to secondary brain injury. Unlike conventional cardiopulmonary resuscitation, however, no clear prognostic markers have been identified for ECPR for OHCA. Bleeding was identified as the most common complication of ECPR in patients with OHCA. Future studies should combine ECPR with intra-aortic balloon pump, extracorporeal membrane oxygenation flow, target blood pressure, and seizure management in ECPR.

Associations of therapeutic hypothermia with clinical outcomes in patients receiving ECPR after cardiac arrest: systematic review with meta-analysis

BACKGROUND

Therapeutic hypothermia has been recommended for eligible patients after cardiac arrest (CA) in order to improve outcomes. Up to now, several comparative observational studies have evaluated the combined use of extracorporeal cardiopulmonary resuscitation (ECPR) and therapeutic hypothermia in adult patients with CA. However, the effects of therapeutic hypothermia in adult CA patients receiving ECPR are inconsistent.

METHODS

Relevant studies in English databases (PubMed, ISI web of science, OVID, and Embase) were systematically searched up to September 2019. Odds ratios (ORs) from eligible studies were extracted and pooled to summarize the associations of therapeutic hypothermia with favorable neurological outcomes and survival in adult CA patients receiving ECPR.

RESULTS

13 articles were included in the present meta-analysis study. There were nine studies with a total of 806 cases reporting the association of therapeutic hypothermia with neurological outcomes in CA patients receiving ECPR. Pooling analysis suggested that therapeutic hypothermia was significantly associated with favorable neurological outcomes in overall (N = 9, OR = 3.507, 95%CI = 2.194-5.607, P < 0.001, fixed-effects model) and in all subgroups according to control type, regions, sample size, CA location, ORs obtained methods, follow-up period, and modified Newcastle Ottawa Scale (mNOS) scores. There were nine studies with a total of 806 cases assessing the association of therapeutic hypothermia with survival in CA patients receiving ECPR. After pooling the ORs, therapeutic hypothermia was found to be significantly associated with survival in overall (N = 9, OR = 2.540, 95%CI = 1.245-5.180, P = 0.010, random-effects model) and in some subgroups. Publication bias was found when evaluating the association of therapeutic hypothermia with neurological outcomes in CA patients receiving ECPR. Additional trim-and-fill analysis estimated four "missing" studies, which adjusted the effect size to 2.800 (95%CI = 1.842-4.526, P < 0.001, fixed-effects model) for neurological outcomes.

CONCLUSIONS

Therapeutic hypothermia may be associated with favorable neurological outcomes and survival in adult CA patients undergoing ECPR. However, the result should be treated carefully because it is a synthesis of low-level evidence and other limitations exist in present study. It is necessary to perform randomized controlled trials to validate our result before considering the result in clinical practices.