ECMO in refractory out of hospital VFib cardiac arrest

Yannopoulos D, Bartos J, Raveendran G, Walser E, et al published a trial in the Lancet   about therapy in patients with out of hospital  refractory ventricular fibrillation cardiac arrest. 

WHAT

Phase 2, single-center, open-label, pragmatic, randomized clinical trial.  

WHERE

University of Minnesota Medical Center (MN, USA)

PATIENTS

Adult patients (aged 18-75) with out of hospital cardiac arrest, an initial rhythm of ventricular fibrillation or ventricular tachycardia, no return of spontaneous circulation (ROSC) after three defibrillations, a body size that fit the Lund CPR Assist system, and an estimated transfer time to the emergency department of less than 30 minutes.

EXCLUSIONS

DNR orders, trauma or burns, drowning, overdose, pregnancy, nursing home resident, unavailability of the cath lab, contraindications to angiography, contract allergy, and active GI or internal bleeding. 

INTERVENTION

Patients were randomly assigned to early ECMO-facilitated resuscitation (veno-arterial extracorporeal membrane oxygenation, Patients were brought straight to the cath lab by EMS and placed on ECMO) or standard ACLS treatment on hospital arrival.

RESULTS

  • Between Aug 8, 2019, and June 14, 2020, 36 patients were assessed for inclusion.
  • 30 patients enrolled(15 in each arm)
  • The mean age was 59 years (range 36–73), and 25 (83%) of 30 patients were men.
  • Survival to hospital discharge was observed in one (7%) of 15 patients (95% credible interval 1·6–30·2) in the standard ACLS treatment group versus six (43%) of 14 patients (21·3–67·7) in the early ECMO-facilitated resuscitation group (risk difference 36·2%, 3·7–59·2; posterior probability of ECMO superiority 0·9861).
  • Study was terminated early as posterior probability of ECMO superiority exceeded the prespecified monitoring boundary.

LIMITATIONS

  • A very small single-center study
  • ECMO was performed in the cath lab and so every patient in the ECMO group received an immediate angiogram.
  • Exclusion criteria of non availability of cath lab may have excluded few eligible patients.

BOTTOM LINE

ECMO may be a therapy of future in refractory  ventricular fibrillation arrest.  Further large study needs to be done,  to confirm the findings of the small study.  As exciting as this may sound,  due to significant technical capabilities requirements,  it will be a long time before this therapy may become standard of care.  Furthermore,  if a large trial proves  that ECMO improve survival in such patients,  will such therapy be possible at the site of arrest,  outside the hospital. 

 In the interim,  a trial of ECMO in  patients of cardiac arrest  inside the hospital is  urgently needed. 

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