Improving access to extracorporeal membrane oxygenation for out of hospital cardiac arrest: pre-hospital ECPR and alternate delivery strategies

Assessing feasibility of proposed extracorporeal cardiopulmonary resuscitation programmes for out-of-hospital cardiac arrest in Scotland via geospatial modelling

BACKGROUND

Extracorporeal cardiopulmonary resuscitation (ECPR) can improve survival for refractory out-of-hospital cardiac arrest (OHCA). We sought to assess the feasibility of a proposed ECPR programme in Scotland, considering both in-hospital and pre-hospital implementation scenarios.

METHODS

We included treated OHCAs in Scotland aged 16-70 between August 2018 and March 2022. We defined those clinically eligible for ECPR as patients where the initial rhythm was ventricular fibrillation, ventricular tachycardia, or pulseless electrical activity, and where pre-hospital return of spontaneous circulation was not achieved. We computed the call-to-ECPR access time interval as the amount of time from emergency medical service (EMS) call reception to either arrival at an ECPR-ready hospital or arrival of a pre-hospital ECPR crew. We determined the number of patients that had access to ECPR within 45 min, and estimated the number of additional survivors as a result.

RESULTS

A total of 6,639 OHCAs were included in the geospatial modelling, 1,406 of which were eligible for ECPR. Depending on the implementation scenario, 52.9-112.6 (13.8-29.4%) OHCAs per year had a call-to-ECPR access time within 45 min, with pre-hospital implementation scenarios having greater and earlier access to ECPR for OHCA patients. We further estimated that an ECPR programme in Scotland would yield 11.8-28.2 additional survivors per year, with the pre-hospital implementation scenarios yielding higher numbers.

CONCLUSION

An ECPR programme for OHCA in Scotland could provide access to ECPR to a modest number of eligible OHCA patients, with pre-hospital ECPR implementation scenarios yielding higher access to ECPR and higher numbers of additional survivors.

[Open questions with respect to extracorporeal circulatory support 2024]

The use of extracorporeal circulatory support, both for cardiogenic shock and during resuscitation, still presents many unanswered questions. The inclusion and exclusion criteria for such a resource-intensive treatment must be clearly defined, considering that these criteria are directly associated with the type and location of treatment. For example, it is worth questioning the viability of an extracorporeal resuscitation program in areas where it is impossible to achieve low-flow times under 60 min due to local limitations. Additionally, the best approach for further treatment, including whether it is necessary to regularly relieve the left ventricle, must be explored. To find answers to some of these questions, large-scale, multicenter, randomized studies and registers must be performed. Until then this treatment must be carefully considered before use.

Prehospital Ground and Helicopter-Based Extracorporeal Cardiopulmonary Resuscitation (ECPR) Reduce Barriers to ECPR: A GIS Model

INTRODUCTION

Evidence suggests that Extracorporeal Cardiopulmonary Resuscitation (ECPR) can improve survival rates for nontraumatic out-of-hospital cardiac arrest (OHCA). However, when ECPR is indicated over 50% of potential candidates are unable to qualify in the current hospital-based system due to geographic limitations. This study employs a Geographic Information System (GIS) model to estimate the number of ECPR eligible patients within the United States in the current hospital-based system, a prehospital ECPR ground-based system, and a prehospital ECPR Helicopter Emergency Medical Services (HEMS)-based system.

METHODS

We constructed a GIS model to estimate ground and helicopter transport times. Time-dependent rates of ECPR eligibility were derived from the Resuscitation Outcome Consortium (ROC) database, while the Cardiac Arrest Registry to Enhance Survival (CARES) registry determined the number of OHCA patients meeting ECPR criteria within designated transportation times. Emergency Medical Services (EMS) response time, ECPR candidacy determination time, and on-scene time were modeled based on data from the EROCA trial. The combined model was used to estimate the total ECPR eligibility in each system.

RESULTS

The CARES registry recorded 736,066 OHCA patients from 2013 to 2021. After applying clinical criteria, 24,661 (3.4%) ECPR-indicated OHCA were identified. When considering overall ECPR eligibility within 45 min from OHCA to initiation, only 11.76% of OHCA where ECPR was indicated were eligible in the current hospital-based system. The prehospital ECPR HEMS-based system exhibited a four-fold increase in ECPR eligibility (49.3%), while the prehospital ground-based system showed a more than two-fold increase (28.4%).

CONCLUSIONS

The study demonstrates a two-fold increase in ECPR eligibility for a prehospital ECPR ground-based system and a four-fold increase for a prehospital ECPR HEMS-based system compared to the current hospital-based ECPR system. This novel GIS model can inform future ECPR implementation strategies, optimizing systems of care.

Cost-effectiveness analysis of an ambulance service-operated specialised cardiac vehicle with mobile extracorporeal cardiopulmonary resuscitation capacity for out-of-hospital cardiac arrests in Queensland, Australia

OBJECTIVE

Extracorporeal CPR (E-CPR) has been primarily limited to the in-hospital setting. A few systems around the world have implemented pre-hospital mobile E-CPR in the form of a dedicated cardiac vehicle fitted with specialised equipment and clinicians required for the performance of E-CPR on-scene. However, evidence of the outcomes and cost-effectiveness of mobile E-CPR remain to be established. We evaluated the cost-effectiveness of a hypothetical mobile E-CPR vehicle operated by Queensland Ambulance Service in the state of Queensland, Australia.

METHODS

We adapted our published mathematical model to estimate the cost-effectiveness of pre-hospital mobile E-CPR relative to current practice. In the model, a specialised cardiac vehicle with mobile E-CPR capability is deployed to selected OHCA patients, with eligible candidates receiving pre-hospital E-CPR in-field and rapid transport to the closest appropriate centre for in-hospital E-CPR. For comparison, non-candidates receive standard ACLS from a conventional ambulance response. Cost-effectiveness was expressed as Australian dollars ($, 2021 value) per quality-adjusted life year (QALY) gained.

RESULTS

Pre-hospital mobile E-CPR improves outcomes compared to current practice at a cost of $27 323 per QALY gained. The cost-effectiveness of pre-hospital mobile E-CPR is sensitive to the assumption around the number of patients who are the targets of the vehicle, with higher patient volume resulting in improved cost-effectiveness.

CONCLUSIONS

Pre-hospital E-CPR may be cost-effective. Successful implementation of a pre-hospital E-CPR programme requires substantial planning, training, logistics and operational adjustments.

Novel and innovative resuscitation systems in Japan

Aim

Out-of-hospital cardiac arrest (OHCA) is a life-threatening emergency that requires rapid and efficient intervention. Recently, several novel approaches have emerged and have been incorporated into resuscitation systems in some local areas of Japan. This review describes innovative resuscitation systems and highlights their strengths.

Main text

First, we discuss the deployment of a physician-staffed ambulance, in which emergency physicians offer advanced resuscitation to patients with OHCA on site. In addition, we describe the experimental practice of extracorporeal membrane oxygenation (ECPR) in a prehospital setting. Second, we describe a physician-staffed helicopter, wherein a medical team provides advanced resuscitation at the scene. We also explain their initiative to provide early ECPR, even in remote areas. Finally, we provide an overview of the "hybrid ER" system which is a "one-fits-all" resuscitation bay equipped with computed tomography and fluoroscopy equipment. This system is expected to help swiftly identify and rule out irreversible causes of cardiac arrest, such as massive subarachnoid hemorrhage, and implement ECPR without delay.

Conclusion

Although these revolutionary approaches may improve the outcomes of patients with OHCA, evidence of their effectiveness remains limited. In addition, it is crucial to ensure cost-effectiveness and sustainability. We will continue to work diligently to assess the effectiveness of these systems and focus on the development of cost-effective and sustainable systems.

Extracorporeal cardiopulmonary resuscitation for refractory cardiac arrest in Australia: a narrative review

Extracorporeal cardiopulmonary resuscitation (ECPR) in patients with prolonged or refractory out-of-hospital cardiac arrest (OHCA) is likely to be beneficial when used as part of a well developed emergency service system. ECPR is technically challenging to initiate and resource-intensive, but it has been found to be cost-effective in hospital-based ECPR programs. ECPR expansion within Australia has thus far been reactive and does not provide broad coverage or equity of access for patients. Newer delivery strategies that improve access to ECPR for patients with OHCA are being trialled, including networked hospital-based ECPR and pre-hospital ECPR programs. The efficacy, scalability, sustainability and cost-effectiveness of these programs need to be assessed. There is a need for national collaboration to determine the most cost-effective delivery strategies for ECPR provision along with its place in the OHCA survival chain.

Expedited transport versus continued on-scene resuscitation for refractory out-of-hospital cardiac arrest: A systematic review and meta-analysis

Background

The benefit of rapid transport from the scene to definitive in-hospital care versus extended on-scene resuscitation in out-of-Hospital Cardiac Arrest (OHCA) is uncertain.

Aim

To assess the use of expedited transport from the scene of OHCA compared with more extended on-scene resuscitation of out-of-hospital cardiac arrest in adults.

Methods

A systematic search of the literature was conducted using MEDLINE, Embase, and SCOPUS. Randomised control trials (RCTs) and observational studies were included. Studies reporting transport timing for OHCA patients with outcome data on survival were identified and reviewed. Two investigators assessed studies identified by screening for relevance and assessed bias using the ROBINS-I tool. Studies with non-dichotomous timing data or an absence of comparator group(s) were excluded. Outcomes of interest included survival and favourable neurological outcome. Survival to discharge and favourable neurological outcome were meta-analysed using a random-effects model.

Results

Nine studies (eight cohort studies, one RCT) met eligibility criteria and were considered suitable for meta-analysis. On pooled analysis, expedited (or earlier) transfer was not predictive of survival to discharge (odds ratio [OR] 1.16, 95% confidence interval [CI] 0.53 to 2.53, I2 = 99%, p = 0. 65) or favorable neurological outcome (OR 1.06, 95% CI 0.48 to 2.37, I2 = 99%, p = 0.85). The certainty of evidence across studies was assessed as very low with a moderate risk of bias. Region of publication was noted to be a major contributor to the significant heterogeneity observed amongst included studies.

Conclusions

There is inconclusive evidence to support or refute the use of expedited transport of refractory OHCA.

Benefits, key protocol components, and considerations for successful implementation of extracorporeal cardiopulmonary resuscitation: a review of the recent literature

The application of venoarterial extracorporeal membrane oxygenation (ECMO) in patients unresponsive to conventional cardiopulmonary resuscitation (CPR) has significantly increased in recent years. To date, three published randomized trials have investigated the use of extracorporeal CPR (ECPR) in adults with refractory out-of-hospital cardiac arrest. Although these trials reported inconsistent results, they suggest that ECPR may have a significant survival benefit over conventional CPR in selected patients only when performed with strict protocol adherence in experienced emergency medical services-hospital systems. Several studies suggest that identifying suitable ECPR candidates and reducing the time from cardiac arrest to ECMO initiation are key to successful outcomes. Prehospital ECPR or the rendezvous approach may allow more patients to receive ECPR within acceptable timeframes than ECPR initiation on arrival at a capable hospital. ECPR is only one part of the system of care for resuscitation of cardiac arrest victims. Optimizing the chain of survival is critical to improving outcomes of patients receiving ECPR. Further studies are needed to find the optimal strategy for the use of ECPR.

ECPR Survivor Estimates: A Simulation-Based Approach to Comparing ECPR Delivery Strategies

Objective: The number of out-of-hospital cardiac arrest (OHCA) patients who may benefit from prehospital extracorporeal cardiopulmonary resuscitation (ECPR) is yet to be elucidated. Patient eligibility is determined both by case characteristics and physical proximity to an ECPR service. We applied accessibility principles to historical cardiac arrest data, to identify the number of patients who would have been eligible for prehospital ECPR in Sydney, Australia, and the potential survival benefit had prehospital ECPR been available.Methods: The New South Wales cardiac arrest registry between January 2017 to June 2021 included 39,387 cardiac arrests. We retrospectively defined two groups: 1) possible ECPR eligible arrests that would have triggered activation of a team, and 2) ECPR eligible arrests, those arrests that met ECPR inclusion criteria and remained refractory. Transport accessibility modeling was used to ascertain the number of arrests that would have been served by a hypothetical prehospital service and the potential survival benefit.Results: There were 699 arrests screened as possibly ECPR eligible in the Sydney metropolitan area, 488 of whom were subsequently confirmed as ECPR eligible refractory OHCA. Of these, 38% (n = 185) received intra-arrest transfer to hospital, with 37% (n = 180) arriving within 60 min. Using spatial and transport modeling, a prehospital team located at an optimal location could establish 437 (90%) patients onto ECMO within 60 min, with an estimated survival of 48% (IQR 38-57). Based on existing survival curves, compared to conventional CPR, an optimally located prehospital ECPR service has the potential to save one additional life for every 3.0 patients.Conclusions: A significant number of historical OHCA patients could have benefited from prehospital ECPR, with a potential survival benefit above conventional CPR.