Extracorporeal cardiopulmonary resuscitation among patients with out-of-hospital cardiac arrest

Abstract

Objective
Extracorporeal cardiopulmonary resuscitation (ECPR) may be considered as a rescue therapy for patients with refractory cardiac arrest. Identifying patients who might benefit from this potential life-saving procedure is crucial for implementation of ECPR. The objective of this study was to estimate the number of patients who fulfilled a hypothetical set of ECPR criteria and to evaluate the outcome of ECPR candidates treated with conventional cardiopulmonary resuscitation.

Methods
We performed an observational study using data from a prospective registry of consecutive adults (≥18 years) with non-traumatic out-of-hospital cardiac arrest in a tertiary hospital between January 2011 and December 2015. We developed a hypothetical set of ECPR criteria including age ≤75 years, witnessed cardiac arrest, no-flow time ≤5 minutes, low-flow time ≤30 minutes, refractory arrest at emergency department >10 minutes, and no exclusion criteria. The primary endpoint was the proportion of good neurologic outcome of ECPR-eligible patients.

Results
Of 568 out-of-hospital cardiac arrest cases, 60 cases (10.6%) fulfilled our ECPR criteria. ECPR was performed for 10 of 60 ECPR-eligible patients (16.7%). Three of the 10 patients with ECPR (30.0%), but only 2 of the other 50 patients without ECPR (4.0%) had a good neurologic outcome at 1 month.

Conclusion
ECPR implementation might be a rescue option for increasing the probability of survival in potentially hopeless but ECPR-eligible patients.

Full text

132 Copyright © 2016 The Korean Society of Emergency Medicine
Extracorporeal cardiopulmonary
resuscitation among patients with
out-of-hospital cardiac arrest
Dae-Hee Choi1, Youn-Jung Kim1, Seung Mok Ryoo1, Chang Hwan Sohn1,
Shin Ahn1, Dong-Woo Seo1, Ju Yong Lim2, Won Young Kim1
1 Department of Emergency Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul,
Korea
2 Department of Thoracic and Cardiovascular Surgery, Asan Medical Center, University of Ulsan College of
Medicine, Seoul, Korea
Objective Extracorporeal cardiopulmonary resuscitation (ECPR) may be considered as a rescue
therapy for patients with refractory cardiac arrest. Identifying patients who might benefit from
this potential life-saving procedure is crucial for implementation of ECPR. The objective of this
study was to estimate the number of patients who fulfilled a hypothetical set of ECPR criteria
and to evaluate the outcome of ECPR candidates treated with conventional cardiopulmonary re-
suscitation.
Methods We performed an observational study using data from a prospective registry of con-
secutive adults (≥18 years) with non-traumatic out-of-hospital cardiac arrest in a tertiary hos-
pital between January 2011 and December 2015. We developed a hypothetical set of ECPR crite-
ria including age ≤75 years, witnessed cardiac arrest, no-flow time ≤5 minutes, low-flow time
≤30 minutes, refractory arrest at emergency department >10 minutes, and no exclusion criteria.
The primary endpoint was the proportion of good neurologic outcome of ECPR-eligible patients.
Results Of 568 out-of-hospital cardiac arrest cases, 60 cases (10.6%) fulfilled our ECPR criteria.
ECPR was performed for 10 of 60 ECPR-eligible patients (16.7%). Three of the 10 patients with
ECPR (30.0%), but only 2 of the other 50 patients without ECPR (4.0%) had a good neurologic
outcome at 1 month.
Conclusion ECPR implementation might be a rescue option for increasing the probability of sur-
vival in potentially hopeless but ECPR-eligible patients.
Keywords Out-of-hospital cardiac arrest; Cardiopulmonary resuscitation; Extracorporeal mem-
brane oxygenation
Clin Exp Emerg Med 2016;3(3):132-138
http://dx.doi.org/10.15441/ceem.16.145
eISSN: 2383-4625
Original Article
Received: 6 May 2016
Revised: 31 May 2016
Accepted: 14 June 2016
Correspondence to: Won Young Kim
Department of Emergency Medicine,
Asan Medical Center, University of
Ulsan College of Medicine, 88 Olympic-
ro 43-gil, Songpa-gu, Seoul 05505,
Korea
E-mail: wonpia73@naver.com
How to cite this article:
Choi DH, Kim YJ, Ryoo SM, Sohn CH, Ahn S,
Seo DW, Lim JY, Kim WY. Extracorporeal
cardiopulmonary resuscitation among
patients with out-of-hospital cardiac arrest.
Clin Exp Emerg Med 2016;3(3):132-138.
This is an Open Access article distributed
under the terms of the Creative Commons
Attribution Non-Commercial License (http://
creativecommons.org/licenses/by-nc/4.0/).
What is already known
Extracorporeal cardiopulmonary resuscitation (ECPR) for cardiac arrest may be
considered as a rescue therapy for refractory cardiac arrest patients. Selection
of patients for ECPR is especially important for successful implementation of
ECPR strategy for out-of-hospital cardiac arrest patients.
What is new in the current study
We found 10% of out-of-hospital cardiac arrest patients were potential candi-
dates for ECPR and that 30% of patients with ECPR had a good neurological
outcome, whereas only 4% of those with conventional cardiopulmonary resus-
citation did.

133
Clin Exp Emerg Med 2016;3(3):132-138
Dae-Hee Choi, et al.
INTRODUCTION
Despite recent improvements in advanced life support, the re-
ported overall rate of survival to hospital discharge is 10.6% and
the rate of survival with good neurologic function is 8.3%.1 Ex-
tracorporeal cardiopulmonary resuscitation (ECPR) is the use of
venoarterial extracorporeal membrane oxygenation (ECMO) to
provide support after conventional cardiopulmonary resuscitation
(CPR) has failed to restore circulation. Studies have shown ECPR
to improve the survival rate among refractory cardiac arrest pa-
tients.2-8 Although there is insufficient evidence to recommend
the routine use of ECPR, ECPR may have a role as a rescue thera-
py in selected patients in whom the suspected etiology of cardiac
arrest is potentially reversible.
The implementation of ECPR requires a specially trained team
that may include physicians, surgeons, perfusionists, and skilled
nursing staff as well as specialized protocols, equipment, and
hospital resources.2,4 Therefore, selection of suitable patients is
one of the important factors for success.8 Observational studies
have shown that ECPR for cardiac arrest is associated with im-
proved survival when the cause of cardiac arrest is reversible (e.g.,
myocardial infarction, pulmonary embolism, severe hypothermia,
and poisoning); the comorbidity is low; it is a case of witnessed
cardiac arrest; the individual receives immediate high-quality
CPR; and ECPR is implemented early (e.g., within 1 hour of col-
lapse).3,7,9-14 However, there are several uncertainties in the ECPR
eligibility criteria. Moreover, the number of out-of-hospital cardi-
ac arrest (OHCA) patients who can be candidates for ECPR has
not been reported in South Korea.
The aim of this study was to estimate the number of patients
who fulfilled a hypothetical set of ECPR criteria and to evaluate
the outcome of ECPR candidates treated with conventional CPR.
METHODS
Study design and population
This retrospective cohort study used data from a prospective reg-
istry and was conducted at the emergency department (ED) of a
university-affiliated teaching hospital in Seoul, Korea, with an
annual census of approximately 100,000 visits, between January
1, 2011, and December 31, 2015. Before commencing the study,
the institutional review board of the hospital approved our study
and waived the requirement for informed consent because of its
retrospective design.
In this study, all consecutive adults (age ≥ 18 years) with non-
traumatic OHCA were included, and their electronic medical re-
cords were reviewed thoroughly by investigators. Emergency med-
ical service (EMS) providers in Korea are instructed to scoop and
run to the ED while performing CPR during ambulance transport
as soon as possible after performing 1 cycle of CPR. In the field,
EMS personnel are not legally allowed to declare death.
Despite the lack of a standardized ECPR strategy and hetero-
geneity in previous ECPR studies, some factors have been com-
monly suggested as the inclusion and exclusion criteria for re-
ceiving ECPR. Based on previous studies, we developed a hypo-
thetical set of ECPR eligibility criteria and applied the criteria to
our cohort to determine the number of OHCA patients who could
be candidates for ECPR. The ECPR eligibility criteria were age ≤ 75
years, witnessed cardiac arrest, bystander administration of CPR
or no-flow time ≤ 5 minutes, prehospital low-flow time ≤ 30 min-
utes and refractory arrest > 10 minutes of conventional CPR at
the ED, known absence of severe comorbidities that preclude ad-
mission to the intensive care unit, and absence of all exclusion
criteria. The exclusion criteria were do-not-resuscitate order, a
poor performance status or terminal illness that preceded the ar-
rest due to malignancy or neurologic disease, trauma, intracranial
hemorrhage, acute aortic dissection with pericardial effusion ob-
served by echocardiography, and achievement of sustained return
of spontaneous circulation within 10 minutes after ED arrival.
Data collection
Demographic data were obtained from EMS reports and medical
records. We extracted the following data: demographic character-
istics, cause of cardiac arrest, initial documented electrocardiogram
rhythm at the scene, bystander administration of CPR, prehospital
no-flow time, prehospital resuscitation time, and outcome includ-
ing achievement of sustained return of spontaneous circulation,
survival at 1 month after cardiac arrest, and good neurologic state
defined as Cerebral Performance Category 1 or 2 at 1 month after
cardiac arrest. Basic life support, advanced cardiovascular life sup-
port, and post-resuscitation care were performed in accordance
with the current Advanced Cardiac Life Support Guidelines of 2010.
Statistical analysis
Continuous variables are expressed as mean ±standard deviation
when normally distributed and median with interquartile range
when non-normally distributed. Categorical data are presented as
absolute numbers and percentages. Differences between means
were analyzed by the Student’s t-test or the Mann-Whitney U-
test. Differences between categorical variables were analyzed by
the χ2 test or the Fisher’s exact test, as appropriate. A 2-sided P-
value < 0.05 was considered statistically significant. All statistical
analyses were performed using PASW Statistics ver. 18.0 (SPSS
Inc., Chicago, IL, USA).

134 www.ceemjournal.org
Candidates for ECPR in OHCA patients
RESULTS
Between January 1, 2011, and December 31, 2015, 568 adults
with non-traumatic OHCA arrived in our ED (Fig. 1). Among these
patients, the majority was excluded owing to the following rea-
sons: age >75 years (n = 160, 28.2%), unwitnessed arrest (n= 167,
29.4%), no-flow time > 5 minutes (n = 65, 11.4%), prehospital
low-flow time > 30 minutes (n = 37, 6.5%), and other reasons
(n = 79, 13.9%). Finally, 60 patients (10.6%) met our ECPR crite-
ria. Of these 60 patients, ECPR was performed for 10 patients,
and conventional CPR was performed for the other 50 patients at
our ED.
The demographic and baseline characteristics of the OHCA pa-
tients and ECPR-eligible patients are summarized in Tables 1 and
2, respectively. The prehospital clinical factors including age, sex,
administration of CPR by bystanders, initial arrest rhythm, and
prehospital low-flow time were similar between the 2 groups.
However, ECPR patients were more likely to achieve sustained re-
turn of spontaneous circulation (90.0% vs. 30.0%, P = 0.001) and
demonstrate a good neurologic outcome at 1 month (30.0% vs.
4.0%, P = 0.03).
In all ECPR patients with good neurologic outcomes, the cardi-
ac arrest was witnessed and bystanders administered CPR (Table
3). The mean prehospital low-flow time was 16 minutes in pa-
tients with good neurologic outcomes. The mean time to implan-
tation of the ECMO set-up from ED arrival was 49 minutes in pa-
tients with good neurologic outcomes, and all these patients were
treated with therapeutic hypothermia at 33°C for 24 hours as well
Fig. 1. Patient flow diagram. OHCA, out-of-hospital cardiac arrest; ROSC, return of spontaneous circulation; ACLS, advanced cardiovascular life support;
ED, emergency department; ECPR, extracorporeal cardiopulmonary resuscitation.
60 Refractory cardiac arrest
≥ 10 minutes of ACLS in ED
(10.6%)
Exclusion no. 2
20 ROSC within 10 minutes
Exclusion no. 1
160 Age > 75 years
167 Unwitnessed
65 No-flow time > 5 minutes
37 Prehospital low-flow time > 30 minutes
59 Exclusion
34 Do-not-attempt-resuscitate state
19 Poor performance status or terminal illness
6 Intracranial hemorrhage
10 ECPR conducted
3 Good neurology
at 1 month
50 ECPR not conducted
2 Good neurology
at 1 month
568 Non-traumatic OHCA
Table 1. Demographic and clinical data of OHCA patients
Characteristics Total OHCA patients (n= 568)
Age (yr) 65.0 (51.3–77.0)
Male sex 369 (65.0)
Witnessed
By emergency medical service providers
By lay person
348 (61.3)
60 (10.6)
288 (50.7)
Bystander CPR 320 (56.3)
Initial rhythm at scene
Shockable
Unknown non-shockable
Pulseless electrical activity
Asystole
76 (13.4)
87 (15.3)
76 (13.4)
329 (57.9)
Prehospital no-flow time (min) 3.0 (0.0–8.0)
Prehospital low-flow time (min) 19.0 (14.0–25.0)
Etiology
Cardiogenic
Respiratory
Other medical condition
Asphyxia
Bleeding
Others
236 (41.5)
113 (19.9)
94 (16.5)
39 (6.8)
23 (4.0)
63 (11.1)
Resuscitation duration in ED 19.0 (8.0–30.0)
Sustained ROSC 258 (45.4)
Admission 158 (27.8)
Survival at 1 month 53 (9.3)
Neurologic outcome at 1 month
CPC 1
CPC 2
CPC 3
CPC 4
18 (34.0)
5 (9.4)
6 (11.3)
24 (45.3)
Values are expressed as median with interquartile range or number (%).
OHCA, out-of-hospital cardiac arrest; CPR, cardiopulmonary resuscitation; ED,
emergency department; ROSC, return of spontaneous circulation; CPC, Cerebral
Performance Category.

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Clin Exp Emerg Med 2016;3(3):132-138
Dae-Hee Choi, et al.
Table 2. Demographic and clinical data of patients who fulfilled the ECPR eligibility criteria
Total (n= 60) ECPR patients (n = 10) Non-ECPR patients (n = 50) P-value
Age (yr) 58.9 ±11.2 57.7±6.2 59.2 ±12.0 0.57
Male sex 45 (75.0) 7 (70.0) 38 (76.0) 0.70
Witnessed
By EMS providers
By layperson
11 (18.3)
49 (81.7)
4 (40.0)
6 (60.0)
7 (14.0)
43 (86.0)
0.07
Bystander CPR 49 (81.7) 8 (80.0) 41 (82.0) > 0.99
Initial shockable rhythm at scene 16 (26.7) 3 (30.0) 13 (26.0) > 0.99
Prehospital low-flow time (min) 18.0 ±8.1 13.9 ±9.8 18.8 ±7.6 0.08
Presumed cardiogenic etiology 38 (63.3) 9 (90.0) 29 (58.0) 0.08
Sustained ROSC
Therapeutic hypothermia
Percutaneous coronary intervention
24 (40.0)
16 (66.7)
7 (29.2)
9 (90.0)
6 (66.7)
5 (55.6)
15 (30.0)
10 (66.7)
2 (13.3)
0.001
> 0.99
0.06
Survival at 1 month 7 (11.7) 3 (30.0) 4 (8.0) 0.08
Good neurologic outcome at 1 month 5 (8.3) 3 (30.0) 2 (4.0) 0.03
Values are expressed as mean±standard deviation or number (%).
ECPR, extracorporeal cardiopulmonary resuscitation; EMS, emergency medical service; CPR, cardiopulmonary resuscitation; ED, emergency department; ROSC, return of
spontaneous circulation.
Table 3. Demographic and clinical data of ECPR patients who fulfilled
our ECPR eligibility criteria
Total
(n = 10)
Good neuro-
logic outcome
at 1 month
(n = 3)
Poor neuro-
logic outcome
at 1 month
(n = 7)
Age (yr) 57.7 ±6.2 55.7 ±5.7 58.1 ±6.8
Male sex 7 (70.0) 3 (100.0) 4 (57.1)
Witnessed
By EMS providers
By layperson
4 (40.0)
6 (60.0)
2 (66.7)
1 (33.3)
2 (28.6)
5 (71.4)
Bystander CPR 8 (80.0) 3 (100.0) 5 (71.4)
Initial shockable rhythm at scene 3 (30.0) 2 (66.7) 1 (14.3)
Prehospital low-flow time (min) 13.9 ±9.8 16.0 ±11.5 13.0 ±9.8
Presumed cardiogenic etiology 9 (90.0) 3 (100.0) 6 (85.7)
Time to ECPR from ED arrival 50.5 ±22.0 49.0±13.0 57.9 ±22.2
Therapeutic hypothermia 6 (60.0) 3 (100.0) 3 (42.9)
Percutaneous coronary intervention 5 (50.0) 3 (100.0) 2 (28.6)
Survival at 1 month 3 (30.0) 3 (100.0) 0 (0)
Neurologic outcome at 1 month
CPC 1
CPC 2
2 (66.7)
1 (33.3)
2 (66.7)
1 (33.3)
-
-
Values are expressed as mean±standard deviation or number (%).
ECPR, extracorporeal cardiopulmonary resuscitation; EMS, emergency medical
service; CPR, cardiopulmonary resuscitation; ED, emergency department; CPC,
Cerebral Performance Category.
Table 4. Demographic and clinical data of non-ECPR patients who ful-
filled our ECPR eligibility criteria
Total
(n = 50)
Good neuro-
logic outcome
at 1 month
(n = 2)
Poor neuro-
logic outcome
at 1 month
(n = 48)
Age (yr) 59.2±12.0 64.0±9.9 59.0 ±12.1
Male sex 38 (76.0) 2 (100.0) 36 (75.0)
Witnessed
By EMS providers
By layperson
6 (12.0)
43 (86.0)
1 (50.0)
1 (50.0)
5 (12.5)
42 (87.5)
Bystander CPR 41 (82.0) 2 (100.0) 39 (81.3)
Initial shockable rhythm at scene 13 (26.0) 2 (100.0) 11 (22.9)
Prehospital low-flow time (min) 18.8±7.6 22.0 ±4.2 18.6±7.7
Presumed cardiogenic etiology 29 (58.0) 2 (100.0) 27 (56.3)
ED resuscitation duration 32.1 ±14.0 27.0 ±19.8 32.3 ±14.0
Therapeutic hypothermia 10 (20.0) 1 (50.0) 9 (26.5)
Coronary angiography 2 (4.0) 2 (100.0) 0 (0)
Survival at 1 month 4 (8.0) 2 (100.0) 2 (4.2)
Values are expressed as mean±standard deviation or number (%).
ECPR, extracorporeal cardiopulmonary resuscitation; EMS, emergency medical
service; CPR, cardiopulmonary resuscitation; ED, emergency department.
as urgent percutaneous coronary intervention. The mean time to
ECPR from ED arrival in patients with poor neurologic outcomes
was prolonged to 58 minutes, and because of their hemodynamic
instability, therapeutic hypothermia and percutaneous coronary
intervention were performed selectively for 43% and 29% of the
patients, respectively. All patients who had received ECPR but
showed poor neurologic outcomes died within 1 month of ECPR.
All of the ECPR patients with poor neurologic outcomes died with-
in 1 month of ECPR. The demographic and clinical factors of pa-
tients who received conventional CPR are shown in Table 4. Al-
though the prehospital clinical factors were similar between ECPR-
eligible patients who underwent ECPR and those who underwent
conventional CPR, only 2 of 50 patients (4.0%) had good neuro-
logic outcome at 1 month without ECMO. Notably, witnessed ar-
rest, administration of CPR by a bystander at that time, and initial
shockable rhythm at the scene were reported in both the cases.

136 www.ceemjournal.org
Candidates for ECPR in OHCA patients
DISCUSSION
In this study, we aimed to estimate the number of patients who
could be candidates for ECPR therapy by using a hypothetical set
of ECPR criteria and to determine the outcomes of ECPR-eligible
patients treated with conventional resuscitation in order to esti-
mate the potential benefits of ECPR. Sixty of 568 patients (10.6%)
fulfilled the hypothetical set of criteria for ECPR. Among these 60
patients, ECPR was performed for 10 patients, and 3 patients
(30.0%) had a good neurologic outcome at 1 month. Although
the prehospital clinical factors were similar between ECPR and
conventional CPR patients, only 2 of the 50 patients who under-
went conventional CPR and fulfilled our ECPR criteria (4.0%) dem-
onstrated a good neurologic outcome at 1 month.
Several studies have reported favorable outcomes of ECPR for
in-hospital cardiac arrest.3,15-18 However, several recent studies have
reported conflicting experiences with ECPR in cases of OHCA.7,19,20
A recent meta-analysis reported that the rate of survival to dis-
charge was lower in patients with OHCA who had received ECPR
than that in patients with in-hospital cardiac arrest.21 However,
the beneficial effect of ECPR compared with conventional CPR in
OHCA patients was not clear for survival to discharge (relative
risk, 1.45; 95% confidence interval, 0.41 to 5.16). The effect of
ECPR on outcome in patients with OHCA may differ from those
in patients with in-hospital cardiac arrest owing to many influ-
encing factors that could be a reversible cause, such as no-flow
time, low-flow time, witnessed arrest, and the quality of bystand-
er CPR before ED arrival. Therefore, the selection of candidates for
ECPR is important for successful implementation of ECPR in pa-
tients with OHCA. Further, ECPR is a resource intense- and time-
dependent procedure. The decision to perform ECPR is made
discre etly in accordance with standardized protocols, not on a
case-by-case basis according to the attending staff, to allow for
rapid initiation.22
Most previous studies used the criteria of age < 75 years and
witnessed arrest for ECPR.23-25 However, inclusion of other criteria
such as CPR performed by bystander, initial shockable rhythm,
and resuscitation duration is still being debated, and the litera-
ture suggests that there is an inverse relationship between CPR
duration before ECPR and outcome. CPR provided for < 45 min-
utes before ECPR has been associated with a survival-to-discharge
rate of 57.1% compared with an 11.5% survival-to-discharge
rate when the ECPR duration exceeds 60 minutes.26,27 In another
study, a high mortality rate of 70% was observed when CPR ex-
ceeded 60 minutes. In our study, we selected prehospital low-flow
time < 30 minutes as a criterion for eligibility because we aimed
not to exceed 60 minutes of collapse-to-ECMO run time.
Recently, Grunau et al.28 reported that approximately 10% of
EMS-treated cases of OHCA fulfilled their hypothetical set of ECPR
criteria. The variables of ECPR criteria suggested by Grunau et al.
were similar to our criteria, except the age range; Grunau et al.
included younger patients ( < 60 years). According to them, their
ECPR-eligible cohort demonstrated better outcomes with good
neurologic outcomes of 35% in contrast to 8% in our cohort.
These differences might be attributable to the difference in the
EMS system as well as the age of patients. There are regional dif-
ferences in the EMS systems, and in Korea, EMS personnel rarely
perform procedures such as epinephrine administration and ad-
vanced airway insertion. Thus, regional ECPR programs should be
considered.
In our study, we found no difference in the prehospital vari-
ables between patients who received ECPR and those who re-
ceived conventional CPR. However, the proportion of patients
with good neurological outcomes at 1 month in the ECPR group
(30.0%) was more than 7-fold higher than that in the conven-
tional CPR group (4.0%). This result is consistent with the find-
ings of previous studies and corroborates evidence on the poten-
tial benefit of ECPR in selective OHCA patients.7,8,10,11,13,21,22,29
Interestingly, the duration between ED arrival and implantation
of ECMO was long; i.e., the mean time for patients with good neu-
rological outcomes was 49 minutes, whereas the mean time for
patients with poor neurological outcomes was 58 minutes. Despite
the prolonged low-flow time in our study patients, the outcome
was comparable to that of previous studies, which ranged between
10% and 30% in the rate of discharge with good neurological
outcomes.7,8,10,11,13,21,22,29 These results indicate that for some OHCA
patients who fulfill the ECPR criteria, termination of resuscitation
efforts may not be allowed in a prehospital setting and these pa-
tients may have to be transferred to a facility where EMS person-
nel can attempt to resuscitate patients by performing ECPR.21
The main limitations of our present study are its retrospective
design and the limited number of patients. First, because our cri-
teria for ECPR eligibility were based on data from previous stud-
ies, characteristics not represented in our set of criteria may also
be valuable for further identification of the ideal ECPR candidate.
Second, during the study period, there were no ECPR eligibility
criteria, and therefore, ECPR was performed in a case-by-case
manner. Third, the generalizability of our results is limited because
this study was conducted in a single tertiary medical center lo-
cated in an urban area in Seoul, Korea. Finally, owing to the small
number of patients who received ECPR (n = 10), the statistical pow-
er of our results was low.
In conclusion, approximately 11% of OHCA patients were eli-
gible for ECPR in our study. Among those patients, only 4% of

137
Clin Exp Emerg Med 2016;3(3):132-138
Dae-Hee Choi, et al.
patients (2/50) who did not receive ECPR survived with a good
neurological outcome. Therefore, ECPR implementation might be
a rescue option for increasing the probability of survival in poten-
tially hopeless ECPR-eligible patients.
CONFLICT OF INTEREST
No potential conflict of interest relevant to this article was re-
ported.
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