Evid-ECMO (Evidence for ECMO): Critical Analysis of the ECMO literature #1

Podcast: Play in new window | Download (Duration: 14:17 — 13.1MB)

Subscribe: RSS

Both of these articles are fantastic. We review these two articles and describe their impact on the ECMO World:

Article 1: Conventional CPR vs. ECPR for In-House Cardiac Arrest (CPS Chen Lancet Study)

Identification:

Title:  Cardiopulmonary resuscitation with assisted extracorporeal life-support versus conventional cardiopulmonary resuscitation in adults with in-hospital cardiac arrest: an observational study and propensity analysis

Authors: Chen, Lin, et al.

Location: National Taiwan University Hospital; Taipei, Taiwan

Source: Lancet 2008; 372: 554-61

ClinicalTrials.gov #: NCT00173615

Introduction:

Problem: Comparing ECPR to conventional CPR for in-hospital cardiac arrest. Prior studies that showed a  benefit of ECPR over conventional CPR may have had selection bias. Prior studies also included all causes of arrest whereas this study attempts to focus on arrest of cardiac origin.

Purpose:  Is ECPR superior to conventional CPR for in-hospital cardiac arrest of cardiac origin?

Significance:  Important paper for resuscitationists to consider when considering ECMO during CPR for in-house arrest.

Methods:

Study Type:  Prospective Observational with Propensity-Score analysis matching

• Single-Center
• 3 years
• 975 total patients; 172 patients: conventional CPR = 113; ECPR = 59

Subjects:  18-75 YOA; witnessed cardiac arrest of cardiac origin who underwent CPR for longer than 10 min. Matching based on propensity-score;

• CPR team: senior medical resident, junior residents, RT, several ICU RN’s. *residents were cannulating!

Primary End-Point: Survival to hospital discharge, with sub-analysis of neurologic outcomes.

Analysis: Intention to treat

Results/Conclusions: 

• Main conclusion:
  • Extracorporeal CPR had a short-term and long-term survival benefit over conventional CPR in patients with in-hospital cardiac arrest of cardiac origin.
  • Survival to Hospital discharge:
    • Unmatched: 28.8% ECPR vs. 12.3% conventional CPR
    • Matched: 32.6% ECPR vs. 17.4% conventional CPR

****THE BOTTOM LINE:  EDECMO Critical Assessment:

• Good study that showed a benefit of ECPR over conventional CPR for in-house arrest for short and long-term patient-oriented outcomes.
• Propensity matching method reasonably mitigated selection bias
• 3 patients in the ‘conventional CPR’ arm were later put on ECMO because of persistent shock > Is there an implied benefit of ECMO for the post-cardiac arrest syndrome?
• Criticisms/Confounders
  • Single-Center
  • Patients in the ECMO group had higher incidence of LVAD, intervention, and heart transplant.
  • first documented rhythm of VT/VF (49% ECPR vs. 32% CPR) was significantly higher in ECPR group; and asystole (22% ECPR vs. 27% CPR) was higher in the CPR group: ? selection bias?
  • Location of arrest/CPR may make a difference (Emergency Department vs. ICU/Operating room)
  • Failed conventional CPR was defined as CPR without ROSC at 30 minutes – is this timeframe too short.  What if conventional CPR were continued for 60 min?
  • No TTM or hypothermia in either group.

Article 2:  CPR vs. ECPR for Out-of-Hospital Cardiac Arrest (SAVE-J)

Identification:

Title:  Extracorporeal cardiopulmonary resuscitation versus conventional cardiopulmonary resuscitation in adults with out-of-hospital cardiac arrest: a prospective observational study

Authors: Sakamoto, Morimura, Nagao, Asai, Yokota, Nara, Hase, Tahara, Atsumi, SAVE-J Study Group

Location: Yokohoma City University Graduate School of Medicine, Yokohama, Kanagawa, Japan

Source:  Resuscitation 2014 Jun;85(6):762-8

Introduction:

Problem: Does ECPR improve patient-oriented outcomes after OHCA? Prior to this study, the effects of ECPR on long-term neurologic outcomes were unknown.

Purpose:  To determine whether ECPR is better than conventional CPR for short and long term neurologic recovery for patients who suffer OHCA

Significance:  Important paper for resuscitationists to consider when considering ECMO during CPR for OHCA.

Methods:

Study Type:  Prospective Observational;

• multi-center: 46 centers: 26 ECPR, 20 non-ECPR
• 3 years
• 454 patients: Conventional CPR = 194; ECPR = 260

Subjects: 20-75 YOA; VF/VT arrest; <45 total arrest time;

Primary End-Point: Rate of favorable outcomes (CPC 1 or 2) at 1 and 6 months after OHCA.

Analysis: Intention to treat

Results/Conclusions: 

• Main conclusion: In OHCA due to VF/VT, a treatment bundle of ECPR, TH (TTM?), and IABP was associated with improved neurologic outcomes at 1 and 6 months.
  • Intention-to-treat Analysis:
    • 1 month:
      • ECPR  = 12.3%
      • Non-ECPR = 1.5%
    • 6 months
      • ECPR = 11.2%
      • Non-ECPR = 2.6%
  • Per-protocol Analysis:
    • 1-month
      • ECPR = 13.7%
      • Non-ECPR = 1.9%
    • 6-month
      • ECPR = 12.4%
      • Non-ECPR = 3.1%

****THE BOTTOM LINE:  EDECMO Critical Assessment:

• Excellent multi center study a benefit of ECPR over conventional CPR for OHCA for short and long-term patient-oriented outcomes.
• Criticisms/Confounders:
  • Rate of use of TTM/TH and IABP were higher in ECPR group.
  • Choice of ECPR vs Non-ECPR was dependent on individual centers with each center doing one or the other but not both.  In other words, does the quality of care at an ECPR center trump the quality of care at a non-ECPR center and does that impose bias?