Clinical paperDelayed neurologic improvement and long-term survival of patients with poor neurologic status after out-of-hospital cardiac arrest: A retrospective cohort study in Japan
Introduction
Out-of-hospital cardiac arrest (OHCA) is a major cause of death worldwide.1 Although the overall survival rate for OHCA remains low (5–10%),2 long-term survival in patients with good neurologic outcomes after OHCA has often been studied.3, 4 Andrew et al. reported that patients could have good neurologic outcomes after OHCA, with a five-year survival of 81.4%.3 In another study, survival and good neurologic outcomes after hospital discharge in patients resuscitated after ventricular fibrillation and treated with percutaneous coronary intervention were 99% and 92%, respectively.4 In patients with good neurologic outcomes after OHCA, long-term survival has been investigated, indicating good outcomes.
Although growing attention has been directed to post-resuscitation care,5 a considerable proportion of successfully resuscitated cardiac arrest survivors remain comatose or experience unfavorable neurologic recovery due to hypoxic brain damage.6 Prognostic predictions are widely performed in post-resuscitation care to assess the probability of awakening in patients resuscitated after OHCA and make decisions about withholding or withdrawing life-sustaining treatments (WLST).7, 8 However, accurate neurologic prognostication is challenging, especially in the early post-resuscitation period, and there remains no standardized timing for prognosis assessment.7 The accuracy and timing of neurologic prognostication are of the utmost importance to avoid premature WLST. The practice of WLST varies greatly between countries.8 In European and North American countries, the majority of OHCA survivors have favorable neurologic status, probably due to active WLST.8 Meanwhile, physicians in Asia are less likely than Western physicians to perform WLST.8, 9 Consequently, many patients in many Asian countries are discharged with poor neurologic status after resuscitation from OHCA.
In real-world clinical settings, unexpected recovery in long-term comatose patients may occur. However, the incidence of such awakening and the characteristics of those patients who would show delayed recovery have not been fully elucidated. Kim et al. reported that two patients (4.1%) with Cerebral Performance Category (CPC) 3 at discharge eventually improved to CPC 2 at the 6-month follow-up in Korea.10 Although their cohort was minimally affected by WLST, the number of patients included was limited because it was a single-center study. Additionally, two studies from Germany reported patients awakening from coma after cardiac arrest.11, 12 Howell et al. retrospectively investigated 113 patients with anoxic-ischemic encephalopathy in a single neurorehabilitation center and found that seven patients (6.2%) achieved a good functional outcome.11 Another retrospective single-center study reported that two patients (3.1%) with poor neurologic status improved during follow-up.12 In a recent paper from the US, Xiao et al. reported that five patients (11%) with poor neurologic status at hospital discharge after cardiac arrest recovered to follow commands during follow up period.13 However, these results reported from Germany and US are strongly affected by WLST.11, 12, 13
To the best of our knowledge, neurologic improvement and long-term survival of patients with poor neurologic status after OHCA, especially with minimal impact of WLST, have been scarcely investigated. We hypothesized that some patients with poor neurologic status at discharge from tertiary emergency hospital may recover to good neurologic status after a long period. This study aimed to assess the occurrence of neurologic improvements and long-term survival probability in patients with poor neurologic status, defined by CPC 3 or 4, after resuscitation from OHCA in Japan, where WLST rarely occurs.
Section snippets
Study design
This retrospective cohort study included all patients admitted to the Hokkaido University Hospital and Sapporo City General Hospital, which are tertiary emergency hospitals that provide emergency and intensive care to patients with OHCA. This study was approved by the Institutional Ethics Committee of Hokkaido University Hospital and Sapporo City General Hospital (No. 020-405). The ethical board waived the need for informed consent owing to its retrospective design.
Setting
All patients admitted to the
Results
During the study period, 1,012 patients were resuscitated after OHCA and admitted to tertiary emergency hospitals. Among the 447 patients who survived to discharge, 239 met our criteria and were included in the final analysis (Fig. 1). Among the patients excluded, in-hospital death occurred in 565 patients. Of these patients, three died after WLST for neurologic reasons, and 105 died due to brain death. Among those patients with brain death, 8 patients chose to donate their organs. Baseline
Discussion
Our results showed delayed neurologic improvement to favorable neurologic status, CPC 1 or 2, in nine (3.6%) of 239 patients with CPC 3 or 4 at discharge from the tertiary emergency hospitals after OHCA. No neurologic improvement in patients was observed after 6 months from cardiac arrest. The median survival time of patients with CPC 3 or 4 at discharge from tertiary emergency hospitals was approximately one year. As the cohort in this study includes patients with all etiologies for OHCA and
Conclusions
Delayed neurologic improvement occurred in patients with discharge CPC 3 or 4 at tertiary emergency hospitals, and the improvement rate was higher in CPC 3 than in CPC 4 patients. Although we demonstrated that the percentage of patients who achieved favorable outcomes was 3.6% and the timing of improvement was within 6 months after cardiac arrest, factors for potential neurologic recovery remain unclear. Further study will be needed to clarify the factors associated with delayed neurologic
Ethics approval and consent to participate
This study was approved by the Institutional Ethics Committee of Hokkaido University Hospital and Sapporo City General Hospital. The ethical board waived the need for informed consent owing to its retrospective design. The study was conducted in accordance with the principles laid down in the Declaration of Helsinki.
Consent for publication
Not applicable.
Funding
None.
Conflicts of interests
No conflicts of interest to declare.
CRediT authorship contribution statement
Mariko Hayamizu: Conceptualization, Data curation, Formal analysis, Writing – original draft. Akira Kodate: Conceptualization, Data curation, Formal analysis. Hisako Sageshima: Conceptualization, Writing - review & editing. Takumi Tsuchida: Writing - review & editing. Yoshinori Honma: Writing - review & editing. Asumi Mizugaki: Writing - review & editing. Tomonao Yoshida: Writing - review & editing. Tomoyo Saito: Writing - review & editing. Kenichi Katabami: Writing - review & editing. Takeshi
Acknowledgements
We would like to thank Editage (www.editage.com) for English language editing.
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