Clinical paperClinical characteristics and outcomes after extracorporeal cardiopulmonary resuscitation in out-of-hospital cardiac arrest patients with an initial asystole rhythm☆
Introduction
The benefit of extracorporeal cardiopulmonary resuscitation (ECPR) for out-of-hospital cardiac arrest (OHCA) has been reported.[1], [2], [3], [4] In particular, ECPR for patients with an initial shockable rhythm improves survival and neurological outcomes compared with conventional cardiopulmonary resuscitation (CCPR).[3], [4]
In current clinical practice, ECPR has also been introduced in patients with an initial non-shockable rhythm based on clinicians’ decisions. Some observational studies showed that OHCA patients with an initial non-shockable rhythm could be candidates for ECPR if presumed to have a reversible aetiology.[5], [6], [7], [8] Of the initial non-shockable rhythms, an initial pulseless electrical activity (PEA) rhythm could be assumed to be a reversible aetiology, but on the other hand, in the case of an initial asystole rhythm, most clinicians would consider the aetiology irreversible and would not initiate ECPR. However, some cases of patients with an initial asystole rhythm with favourable neurological outcomes after ECPR have been reported, and details of those patients remain unknown.9
The purpose of this study was to describe the characteristics of cases whose initial cardiac rhythm was asystole in whom ECPR was introduced by the clinicians and discuss the clinical indications for ECPR in such patients.
Section snippets
SAVE-J II study
The SAVE-J II study was conducted as a retrospective, multicentre, registry study of OHCA patients resuscitated with ECPR, involving 36 participating institutions in Japan.9 The study design and data collection methods of the SAVE-J II study were described in a previous report.9 The SAVE-J II study included consecutive patients with OHCA aged ≥18 years who were admitted to the emergency department with OHCA between January 1, 2013 and December 31, 2018 and received ECPR. ECPR was defined as
Data collection
The following patient data were collected from SAVE- J II: age, sex, location of cardiac arrest, incidence of witnessed cardiac arrest and bystander CPR, ROSC before/after hospital arrival, temperature on arrival, cardiac rhythm on hospital arrival, pupil diameter on arrival, signs of life including agonal respiration or light reflex,13 arterial gas analysis data on arrival (pH, K, lactate), estimated low-flow time, cause of cardiac arrest, and costs of hospitalization. Shockable rhythm was
Results
A total of 2,157 patients were registered in the SAVE-J II study database. Of these, 1,943 patients were excluded because their initial cardiac rhythm was not asystole (1,331 had initial shockable rhythm, 583 had initial PEA rhythm, and 29 had initial unknown rhythm). Furthermore, two patients were excluded because VA-ECMO was introduced after ICU admission, and ten patients were excluded because they achieved ROSC at ECMO initiation. Thus, 202 eligible patients were included in the analysis (
Comparisons of the resuscitation criteria between favourable (CPC 1 or 2) and unfavourable neurological outcome patients with hypothermia (temperature < 32 °C) on hospital arrival
Fulfilment of the resuscitation criteria (pH > 6.7 and Lac < 140 mg/dL and K < 7.0 mEq/L) was significantly higher in the favourable outcome group than in the unfavourable outcome group (100.0% vs 37.5%, p = 0.007) (Table 3).
Comparisons of the requirements between favourable (CPC 1 or 2) and unfavourable neurological outcome patients with non-hypothermia (temperature ≥ 32 °C) on hospital arrival
Fulfilment of the requirements (1, witness; 2, bystander CPR; 3, SOLs or pupil < 5 mm) was significantly higher in the favourable outcome group than in the unfavourable outcome group (75.0% vs 12.7%, p = 0.009) (Table 4).
Discussion
The current study investigated the outcomes of ECPR for 202 patients with an initial asystole rhythm according to the largest ECPR registry data of OHCA in Japan. A favourable neurological outcome at hospital discharge was observed in 12 cases. Temperature and cardiac rhythm on hospital arrival were principal factors related to neurological outcome on statistical comparisons between the favourable and unfavourable outcome groups. In addition, detailed analysis showed that, among patients with
Conclusion
The current study described a total of 202 ECPR cases with an initial asystole rhythm, including 12 patients with favourable neurological outcomes. The application of ECPR to initial asystole rhythm is limited. However, limited prospective trials are needed, because some patients with hypothermia or less severe brain injury have favorable neurological outcomes.
Conflicts of interests
Toru Hifumi is currently receiving a grant from Asahi Kasei Japan. The remaining authors have disclosed that they do not have any potential conflicts of interest.
CRediT authorship contribution statement
Kasumi Shirasaki: Investigation, Writing – original draft. Toru Hifumi: Conceptualization, Investigation, Supervision. Masahiro Goto: Investigation, Supervision. Kijong Shin: Investigation, Supervision. Katsuhiro Horie: Investigation, Supervision. Shutaro Isokawa: Investigation, Supervision. Akihiko Inoue: Supervision. Tetsuya Sakamoto: Supervision. Yasuhiro Kuroda: Supervision. Ryosuke Imai: Supervision, Formal analysis. Norio Otani: .
Acknowledgements
No funding was obtained for the present work.
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This work was performed at St. Luke’s International Hospital, Tokyo, Japan.
- 1
The members of the The SAVE-J II study group Investigation Supervision are listed in Appendix 1 at the end of the article.