The role of contributing factors, triggers, and prodromal symptoms in the etiological classification of out-of-hospital cardiac arrest; A scoping review

Sedigheh Shaeri; Julie Considine; Katie N. Dainty; Theresa Mariero Olasveengen; Laurie J. Morrison

doi:10.1371/journal.pone.0327651

Peer Review History

Original SubmissionJanuary 11, 2025
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Thank you for stating the following financial disclosure: [The primary author received 2019-2020 Graduate student funding from Institute of Health Policy, Management, and Evaluation and Graduate Student Endowment Funding from faculty of medicine, University of Toronto.]. Please state what role the funders took in the study. If the funders had no role, please state: ""The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript."" If this statement is not correct you must amend it as needed. Please include this amended Role of Funder statement in your cover letter; we will change the online submission form on your behalf. [Note: HTML markup is below. Please do not edit.] Reviewers' comments: Reviewer's Responses to Questions Comments to the Author 1. Is the manuscript technically sound, and do the data support the conclusions? Reviewer #1: Yes Reviewer #2: Yes ******** 2. Has the statistical analysis been performed appropriately and rigorously? -->?> Reviewer #1: Yes Reviewer #2: Yes ****** 3. Have the authors made all data underlying the findings in their manuscript fully available??> The PLOS Data policy Reviewer #1: Yes Reviewer #2: Yes ****** 4. Is the manuscript presented in an intelligible fashion and written in standard English??> Reviewer #1: Yes Reviewer #2: Yes ****** Reviewer #1: The manuscript is organized, methodologically sound, and relevant to emergency medicine and cardiac arrest classification. Overall Assessment of the Manuscript This manuscript presents a well-organized and methodologically robust scoping review of the factors, triggers, and early symptoms contributing to the etiological classification of out-of-hospital cardiac arrest (OHCA). The research is timely and essential, addressing a vital gap in understanding OHCA etiology, with significant implications for clinical practice and future research. Below is a comprehensive critique that evaluates the content, clarity, methodology, and adherence to PRISMA-ScR guidelines. Areas for Improvement 1. Justification for Scoping Review Approach (Minor Issue) Though the study utilizes a scoping review methodology, the rationale for selecting this approach could be articulated more effectively. Incorporate a brief statement in the introduction that clarifies why a scoping review (as opposed to a systematic review) was the most suitable choice. 2. Transparency in Protocol Registration (Moderate Issue) The manuscript notes that the protocol is registered with the Open Science Framework (OSF) but does not include a registration number or direct link. Add the OSF link for increased transparency. 3. Missing Detailed Search Strategy (Moderate Issue) The search strategy is summarized but lacks comprehensive detail, such as Boolean operators, MeSH terms, and gray literature inclusion. Please Provide a complete search strategy in an accompanying appendix. 4. Justification for Excluding Critical Appraisal (Moderate Issue) The manuscript does not explain why a formal quality assessment is excluded. Although PRISMA-ScR does not require such an assessment, a brief justification is essential. please Include a one-sentence rationale in the methods section. 5. Limitations Section Needs Expansion (Major Issue) The limitations section is brief and does not discuss potential biases (e.g., selection bias, exclusion of non-English studies, reliance on EMS data). Please expand the limitations to include: ◦ Potential selection bias due to language restrictions. ◦ Inherent limitations of EMS data (e.g., misclassification of OHCA etiology). ◦ Absence of a formal quality appraisal as a potential limitation. ◦ Future research is necessary to validate findings with prospective cohort studies. Reviewer #2: Thank you for the opportunity to review this well-conducted scoping review. This is a systematic review aimed at identifying additional contributing factors, triggers, and symptoms of out-of-hospital cardiac arrest (OHCA) to supplement the existing Utstein criteria with further classification parameters. Overall, this systematic review has been conducted with sound scientific methodology. However, it appears that a substantial number of studies have already examined the relationship between COVID-19 and OHCA. I find it difficult to understand why COVID-19 is considered such a significant influencing factor in OHCA, and I would appreciate clarification from the authors on this matter. The included studies in this systematic review seem to be heavily focused on COVID-19, which I would like to comment on and critically question. Apart from this, the paper is coherently written, and this work represents a valuable contribution to the scientific understanding of OHCA and the development of more suitable quick alerts for identifying its etiology. ****** what does this mean? ). If published, this will include your full peer review and any attached files. If you choose “no”, your identity will remain anonymous but your review may still be made public. Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy Reviewer #1: Yes: Assistant Professor of Nursing, Department of Prehospital Emergency Medicine, Asadabad School of Medical Sciences, Asadabad, Iran. Email: A.khazaei91@gmail.com, ORCID ID: 0000-0002-8063-3419 Reviewer #2: Yes: Joachim Riße ******** [NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. 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Revision 1
6 Jun 2025 Author Response Journal requirements and reviewers’ comments Journal requirements 1-Thank you for stating the following financial disclosure: [The primary author received 2019-2020 Graduate student funding from Institute of Health Policy, Management, and Evaluation and Graduate Student Endowment Funding from faculty of medicine, University of Toronto.]. Please state what role the funders took in the study. If the funders had no role, please state: ""The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript."" If this statement is not correct you must amend it as needed. Please include this amended Role of Funder statement in your cover letter; we will change the online submission form on your behalf. The authors’ response: We declare that “The funders had no role in study design, data collection and analysis, decision to publish, or preparation of this manuscript” 2- "We note that your Data Availability Statement is currently as follows: [All relevant data are within the manuscript and its Supporting Information files.] Please confirm at this time whether or not your submission contains all raw data required to replicate the results of your study. Authors must share the “minimal data set” for their submission. PLOS defines the minimal data set to consist of the data required to replicate all study findings reported in the article, as well as related metadata and methods (https://journals.plos.org/plosone/s/data-availability#loc-minimal-data-set-definition). For example, authors should submit the following data: - The values behind the means, standard deviations and other measures reported; - The values used to build graphs; - The points extracted from images for analysis. Authors' response: This is a scoping review to map current published articles. No meta-analysis has been conducted. Minimal data set of this scoping review, including a summary of included studies is available within the manuscript and S3-6 Appendices with relevant citations. The result of descriptive analysis (number and percentage) is available in Table 2 . No mean and standard deviation have been measured. There is no graph in this submission. No points have been extracted from images for analysis. Reviewer #1 The manuscript is organized, methodologically sound, and relevant to emergency medicine and cardiac arrest classification. Overall Assessment of the Manuscript: This manuscript presents a well-organized and methodologically robust scoping review of the factors, triggers, and early symptoms contributing to the etiological classification of out-of-hospital cardiac arrest (OHCA). The research is timely and essential, addressing a vital gap in understanding OHCA etiology, with significant implications for clinical practice and future research. Below is a comprehensive critique that evaluates the content, clarity, methodology, and adherence to PRISMA-ScR guidelines. Areas for Improvement 1. Justification for Scoping Review Approach (Minor Issue) Though the study utilizes a scoping review methodology, the rationale for selecting this approach could be articulated more effectively. Incorporate a brief statement in the introduction that clarifies why a scoping review (as opposed to a systematic review) was the most suitable choice Authors' response: The justification for scoping review is included in the introduction (Line# 85-87). We selected the scoping review because it was anticipated studies with diverse methodology (mostly observational or reflective) and limited number of publications. The purpose of this review was to map current evidence to identify the contributing factors, triggers, and prodromal symptoms of OHCA that may contribute to etiological classification of cardiac arrest. Since no systematic or scoping review has been conducted before, the scoping review was deemed to be the best option to map evidence and identify scientific evidence to address the study’s objective. 2. Transparency in Protocol Registration (Moderate Issue) The manuscript notes that the protocol is registered with the Open Science Framework (OSF) but does not include a registration number or direct link. Add the OSF link for increased transparency. Authors' response: The OSF provides DOI, which is specific to this scoping review and directly links to the registration (Line # 100 and S1 Appendix). The registration number OSF.IO/K5ZDP was added to line #99. 3. Missing Detailed Search Strategy (Moderate Issue) The search strategy is summarized but lacks comprehensive detail, such as Boolean operators, MeSH terms, and gray literature inclusion. Please Provide a complete search strategy in an accompanying appendix. Authors' response: Search strategy is available in S2 Appendix, including the chosen mesh terms and Boolean to search all three electronic databases, including Medline, Embase, and EBM-Cochrane databases. We didn’t search gray literature, and this was noted as limitation of this scoping review (line#401). According to scoping review methodology, searching gray literature is not mandatory to conduct a scoping review [1]. We strongly preferred to map scientific evidence from published peer-reviewed studies for this scoping review to provide a rational knowledge synthesis and a firm foundation upon which to justify further research. 4. Justification for Excluding Critical Appraisal (Moderate Issue) The manuscript does not explain why a formal quality assessment is excluded. Although PRISMA-ScR does not require such an assessment, a brief justification is essential. please Include a one-sentence rationale in the methods section. Authors' response: Critical appraisal is not mandatory for conducting a scoping review because the purpose of scoping review is to provide a comprehensive evidence map or an overview of current evidence regardless of the quality of evidence [1-3]. This was explained and cited in Line # 142. One sentence has been added to the limitation. (line#416-417) 5. Limitations Section Needs Expansion (Major Issue) The limitations section is brief and does not discuss potential biases (e.g., selection bias, exclusion of non-English studies, reliance on EMS data). Please expand the limitations to include:◦ Potential selection bias due to language restrictions.◦ Inherent limitations of EMS data (e.g., misclassification of OHCA etiology).◦ Absence of a formal quality appraisal as a potential limitation.◦ Future research is necessary to validate findings with prospective cohort studies. Thanks for comments, suggestions, and encouragement Authors' response: We excluded the non-English literature according to our protocol and defined eligibility criteria (Table 1; Page#7) due to difficulty of translation or having someone with relevant expertise to translate the scientific text in foreign languages. This was already noted as the limitation of this study (Line# 401-402) and slightly revised. We added one sentence to the limitation (line # 415-416) pertaining to the potential etiological misclassification of included studies. The purpose of this scoping review was not to evaluate the etiological misclassification. A prior scoping review highlighted a three-time discrepancy between initial etiological classification of OHCA based on EMS documentation using Utstein etiological classification and confirmed etiologies documented in medical charts or autopsy reports [4].This current scoping review was conducted to understand the role of contributing factors, triggers, and prodromal symptoms, which may help refine the etiological classifications. The finding of this review may strengthen the finding of previous scoping review on the potential etiological misclassification. We included studies with observational, case-crossover, and time series that provide scientific evidence regarding the contributing factors, triggers, and prodromal symptoms of OHCA. The design of selected studies is available in S3-S6 Appendices. Future research would be suggested to integrate findings of this scoping review with real-life data. (Line#424) Reviewer #2 Thank you for the opportunity to review this well-conducted scoping review. This is a systematic review aimed at identifying additional contributing factors, triggers, and symptoms of out-of-hospital cardiac arrest (OHCA) to supplement the existing Utstein criteria with further classification parameters. Overall, this systematic review has been conducted with sound scientific methodology. However, it appears that a substantial number of studies have already examined the relationship between COVID-19 and OHCA. I find it difficult to understand why COVID-19 is considered such a significant influencing factor in OHCA, and I would appreciate clarification from the authors on this matter. The included studies in this systematic review seem to be heavily focused on COVID-19, which I would like to comment on and critically question. Apart from this, the paper is coherently written, and this work represents a valuable contribution to the scientific understanding of OHCA and the development of more suitable quick alerts for identifying its etiology. Thank you for your supportive comments. Authors' response: Observational studies of COVID-19 pandemic and etiological classification of OHCA were targeted in the search as an example of a circumstance or contributing factor affecting the etiological classification of OHCA. The covid-19 pandemic as a contributing factor increased the likelihood of respiratory or medical cause to OHCA. One sentence has been added to clarify this section. (Line# 177) Attachments Attachment Submitted filename: PONE-D-24-59166, Rebuttal Letter-Jan-2025.docx Attachment Submitted filename: PONE-D-25-01818 Response to reviewers.docx https://doi.org/10.1371/journal.pone.0327651.r002
Decision Letter - Nik Hisamuddin Nik Ab. Rahman, Editor The role of contributing factors, triggers, and prodromal symptoms in the etiological classification of out-of-hospital cardiac arrest; A Scoping Review PONE-D-25-01818R1 Dear SEDIGHEH SHAERI, We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements. Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication. An invoice will be generated when your article is formally accepted. Please note, if your institution has a publishing partnership with PLOS and your article meets the relevant criteria, all or part of your publication costs will be covered. Please make sure your user information is up-to-date by logging into Editorial Manager at Editorial Manager® and clicking the ‘Update My Information' link at the top of the page. If you have any questions relating to publication charges, please contact our Author Billing department directly at authorbilling@plos.org. If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org. Kind regards, Nik Hisamuddin Nik Ab. Rahman Academic Editor PLOS ONE Additional Editor Comments (optional): Reviewers' comments: https://doi.org/10.1371/journal.pone.0327651.r003
Formally Accepted
Acceptance Letter - Nik Hisamuddin Nik Ab. Rahman, Editor PONE-D-25-01818R1 PLOS ONE Dear Dr. SHAERI, I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now being handed over to our production team. At this stage, our production department will prepare your paper for publication. This includes ensuring the following: * All references, tables, and figures are properly cited * All relevant supporting information is included in the manuscript submission, * There are no issues that prevent the paper from being properly typeset You will receive further instructions from the production team, including instructions on how to review your proof when it is ready. Please keep in mind that we are working through a large volume of accepted articles, so please give us a few days to review your paper and let you know the next and final steps. Lastly, if your institution or institutions have a press office, please let them know about your upcoming paper now to help maximize its impact. If they'll be preparing press materials, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org. If we can help with anything else, please email us at customercare@plos.org. Thank you for submitting your work to PLOS ONE and supporting open access. Kind regards, PLOS ONE Editorial Office Staff on behalf of Professor Dr Nik Hisamuddin Nik Ab. Rahman Academic Editor PLOS ONE https://doi.org/10.1371/journal.pone.0327651.r004

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