was 4-hour survival.
Results of this study showed that4-hour survival
was significantly improved in pigs with ECMO
(82%) compared to those without ECMO (31%,
p = 0.003). After four hours, nine pigs with ECMO
were suitable for decannulation.
The study concluded that ECMO-facilitated coronary reperfusion significantly improved 4-hour
survival compared with reperfusion facilitated by
CPR alone. ECMO support enabled cardiac recovery and hemodynamic stability within four hours.
These results support the idea that, although coronary reperfusion is a necessary condition for achieving ROSC, after prolonged ( 45 minutes) CPR the
metabolic ischemic substrate requires circulatory
support to improve outcomes.
Human Clinical Studies
In 2016, according to the Extracorporeal Life Support Organization (ELSO), survival to discharge
following ECPR for cardiac arrest that’s refractory to conventional CPR was 29% in their registry database of 2,885 adults. 16 Published studies
have reported widely varying results. Most of the
experience is from cohorts outside of the U.S.,
mainly in Asia. 17–22
Several studies of patients unresponsive to CPR
who received ECMO (and PCI when indicated)
found worse outcomes with OHCA vs. in-hospital
cardiac arrest (IHCA). One study analyzed data for
86 patients with OHCA or in-hospital cardiac arrest
(IHCA) unresponsive to CPR who received ECMO
(and PCI when indicated). Survival to day 30 was
29% overall, 17% (7/42) for OHCA vs. 41% (18/44)
for IHCA, and 37% (17/46) for patients presenting
with v tach/v fib vs. 20% (8/40) for patients with
non-shockable rhythms. 17
Compared with patients who didn’t survive to
day 30, survivors had a significantly shorter time
interval from collapse to the initiation of ECMO
( 54 minutes [34–74 minutes] vs. 40 minutes [ 25–
51 minutes], p = 0.002) and a higher rate of intra-arrest PCI (70% vs. 88%; p = 0.04).
A second study retrospectively described a cohort
of 230 patients who had received ECPR during a
period of five years ( 31 patients with OHCA and
199 with IHCA). 19
No significant differences were observed between
OHCA and IHCA in rate of survival to discharge
( 38.7% vs. 31.2%, p > 0.05) or functionally favor-
able outcome ( 25.8% vs. 25.1%, p > 0.05).
Duration of ischemia (collapse to ECPR) was a
key issue for survival. The authors attributed the
high survival rate in patients with OHCA compared
to previous studies17, 18, 23, 24 to a well-organized and
rapid-response EMT system, efficiency in handling
patient transportation and resuscitation, and an
equipped cart in the ED rather than in the ICU,
shortening the duration of ischemia.
In Australia, 26 patients with refractory prolonged cardiac arrest were treated with the CHEER
protocol (mechanical CPR, hypothermia, ECMO
and early reperfusion) during a period of 32
months. Of 15 patients with IHCA, all had ROSC
The Maquet CARDIOHELP System is a small miniaturized, highly mobile ECMO unit that can be deployed easily
around different areas and locations for emergent support.