Background: In the US out-of-hospital cardiac arrest (OHCA) has an estimated survival rate of <10% overall, but slightly better survival rates with shockable rhythms of approximately 30% [2]. A small proportion of these patients will have refractory VF/VT OHCA not treatable by standard ACLS guidelines. One possible modality for these patients is extracorporeal membrane oxygenation (ECMO, followed by immediate coronary angiography and percutaneous coronary intervention (PCI). How would this ECMO-facilitated resuscitation strategy fair when applied in a US metropolitan community?
Paper: Bartos JA et al. The Minnesota Mobile Extracorporeal Cardiopulmonary Resuscitation Consortium for Treatment of Out-of-Hospital Refractor Ventricular Fibrillation: Program Description, Performance and Outcomes. Lancet 2020 [Link is HERE]
Clinical Question: Can a community ECMO program improve survival with good neurological outcome in patients with refractory VF/VT OHCA?
What They Did:
- Observational cohort study of consecutive patients prospectively enrolled in the Minnesota Mobile Resuscitation Consortium’s ECMO-facilitated resuscitation program
- Program components:
- 24/7 Mobile ECMO cannulation teams
- 4 dedicated ECMO cannulation team rapid response vehicles
- 3 community ECMO initiation hospitals with ED ECMO cannulation sites
- 24/7 cardiac catheterization laboratories
- Single, centralized ECMO ICU
Image from Main Article [Link is HERE]
- Patients meeting ≥2 resuscitation discontinuation criteria were declared dead:
- etCO2 ≤10mmHg
- PaO2 ≤50mmHg or O2 saturation ≤85%
- Lactic acid ≥18mmol/L
MMRC Program Performance Metrics and Benchmarks
Outcomes:
- Primary: Survival with good neurological outcome (CPC 1 or 2)
-
Secondary:
- 3 month functionally favorable survival
- ECMO cannulation rate
- Safety
Inclusion:
- Adults aged 18 to 75 years
- VF/VT OHCA
- No ROSC following 3 shocks
- Automated cardiopulmonary resuscitation with a LUCAS device
- Estimated transfer time of <30min
Exclusion:
- Nursing home residents
- Known DNR orders
- Significant bleeding
- Known terminal illness
- <1-year life expectancy
Results:
- 151 patients with VF/VT OHCA
- 97/151 (64%) were refractory VF/VT OHCA
- 60 refractory VF/VT OHCA + 3 primary PEA patients out of 97 were included in the analysis
- 58 (97%) met criteria and were treated by the mobile ECMO service
- 13/58 (22%) had ≥2 resuscitation discontinuation criteria on arrival and were pronounced dead
- 45/58 (78%) received full resuscitation efforts (ECMO cannulation and CCL angiography/PCI)
- Mean age = 57 +/- 1.8 years
-
EMS Agency
- Accuracy of EMS agency patient selection was 58/63 (92%)
- Despite a benchmark of <15min, paramedics were on-scene at a mean of 22.0 +/- 8.9min prior to transport (>15min in 66% of cases)
- Mean time from 911 call to patient arrival at 3 ECMO Initiation Hospitals was 46.9 +/- 12.3min
-
Mobile ECMO Cannulation Team
- Mean response time was 14.9 +/- 5.7min (71% of cases had response times <15min)
- Mean time from ECMO-eligible patient arrival to ECMO initiation was 14.4 +/- 6.1min (63% received ECMO in <15min)
- All ECMO cannulations were successful without complications (45/45 patients)
-
CCL
- Patients taken to CCL within 2h of 911 call in 21/45 (47%) of cases with a mean time of 121 +/- 56min
- Coronary angiography was performed in 45/58 (78%) of patients
- 29/45 (64%) had severe CAD
- 22/29 (85%) received PCI
-
Timing of ECMO-Facilitated Resuscitation Cases (Of the 58 patients…)
- 27/58 (47%) had survival to hospital discharge
- 25/58 (43%) were both discharged from the hospital and alive at 3 months with CPC 1 or 2
- Of the patients discharged from the hospital, 100% were alive at 3 months with CPC 1 or 2 (25/58, 43%; 95% CI 31 to 56%)
- Mean CPC score was 1.6 +/- 0.7 and 1.3 +/- 0.7 at hospital discharge and at 3 months
Strengths:
- 1st community-wide ECMO-facilitated resuscitation program in the US
- Adhered to the STROBE guidelines for observational studies
- Funding source (Helmsely Charitable Trust) had no role in study design, collection, analysis of data, interpretation of data, or the writing/editing of the manuscript
- This cohort of patients was identified and studied separately than the group in the ARREST trial, conducted within the same system [3]
Limitations:
- Each healthcare system will have unique aspects that will require modification of this program in order to be successful
- Small patient cohort size makes it impossible to show meaningful subgroup comparisons
- Early evaluation may not reflect longer term issues include skill maintenance of the teams
- A cost analysis of having a program like this was not discussed
Discussion:
- All patients received therapeutic hypothermia (goal temp of 34C)
- Important to point out that each component of care is crucial and significantly contributes to survival.It is not just ECMO that makes the difference
- Selection of a modest number of well-trained mobile ECMO cannulation team members assures high quality performance, high patient volume, and sill maintenance
- A lack of community experience necessitated rigorous education/training programs in addition to the capability to monitor performance required
- Authors Comments on Benchmarks and Goals:
- Mean duration of CPR only decreased by 5 to 8 min compared to prior cohort studies
- Paramedic scene time longer than 15 min
- Time from arrest to coronary angiography was longer than benchmarked
- Reducing CPR time and time to CCL remains a priority in these patients to ensure survival with good neurological outcomes
Author Conclusion: “This first, community-wide ECMO-facilitated resuscitation program in the US demonstrated 100% successful cannulation, 43% functionally favorable survival rates at hospital discharge and 3 months, as well as safety. The program provides a potential model of this approach for other communities.”
Clinical Take Home Point: These authors should be commended for demonstrating what an ECMO-facilitated resuscitation program can look like when rolled out into a metropolitan community. The description of systems issues may help facilitate discussions in other communities. They demonstrated safety, and most importantly the ability to achieve functionally favorable survival rates (i.e. 43%) at hospital discharge and 3 months, in patients with refractory VF/VT arrest, a traditionally difficult population to treat.
References:
- Bartos JA et al. The Minnesota Mobile Extracorporeal Cardiopulmonary Resuscitation Consortium for Treatment of Out-of-Hospital Refractor Ventricular Fibrillation: Program Description, Performance and Outcomes. Lancet 2020 [Link is HERE]
- Zive DM et al. Survival and Variability Over Time from Out of Hospital Cardiac Arrest Across Large Geographically Diverse Communities Participating in the Resuscitation Outcomes Consortium. Resuscitation 2018. PMID: 30053457
- Yannopoulos D et al. Advanced reperfusion strategies for patients with out-of-hospital cardiac arrest and refractory ventricular fibrillation (ARREST): a phase 2, single center, open-label, randomized controlled trial. Lancet 2020 (LINK is HERE)
For More Thoughts on This Topic Checkout:
- Critical Care Now: It Takes a Village – A Community Approach to ECPR for OHCA (Part 1)
Post Peer Reviewed By: Zaf Qasim, MD (Twitter: @ResusOne)
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