International facets of the ‘chain of survival’ for out-of-hospital and in-hospital cardiac arrest – A scoping review

Background: The “chain of survival” was first systematically addressed in 1991, and its sequence still forms the cornerstone of current resuscitation guidelines. The term “chain of survival” is widely used around the world in literature, education, and awareness campaigns, but growing heterogeneity in the components of the chain has led to confusion. It is unclear which of these emerging chains is most suitable, or if adaptations are needed in particular contexts to depict key actions of resuscitation in the 21st century. This scoping review provides an overview of the variety of chains of survival described. Objectives: To identify published facets of the chain of survival, to assess views and strategies about adapting the chain, and to identify reports on how the chain of survival affects teaching, implementation, or patient outcomes. Methods, eligibility criteria, and sources of evidence: A scoping review as part of the continuous evidence evaluation process of the International Liaison Committee on Resuscitation (ILCOR) was conducted. MEDLINE(R) ALL (Ovid), Embase (Ovid), APA PsycINFO (Ovid), CINAHL (Ebscohost), ERIC (Ebscohost), Web of Science (Clarivate), Scopus (Elsevier), and Cochrane Library (Wiley Online) were searched. All publications in all languages describing chains of survival were eligible, without time restrictions. Due to the heterogeneity and publication types of the relevant studies, we did not pursue a systematic review or meta-analysis. Results: A primary search yielded 1713 studies and after screening we included 43 publications. Modified versions of the chain of survival for specific contexts were found (e.g., in-hospital cardiac arrest or paediatric resuscitation). There were also numerous versions with minor adaptations of the existing chain. Three publications suggested an impact of the use of the chain of survival on patient outcomes. No educational or implementation outcomes were reported. Conclusion: There is a vast heterogeneity of chain of survival concepts published. Future research is warranted, especially into the concept's importance concerning educational, implementation, and clinical outcomes.