Systematic reviews were conducted by ILCOR task force members with expertise in systematic reviews and the content area following standardized procedures.² The methodology was based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses³ and the approach proposed by the Grading of Recommendations Assessment, Development and Evaluation (GRADE) Working Group.⁴ The overall process was coordinated by the Scientific Advisory Committee of ILCOR and guided by the task force Scientific Advisory Committee representatives.

In brief, each ILCOR task force identified and prioritized questions to be addressed by using the PICOST (population, intervention, comparator, outcome, study design, time frame) format.⁵ A detailed search for relevant publications was performed on MEDLINE, Embase, and Cochrane Library databases, with identified publications screened for further evaluation. Two systematic reviewers conducted a risk-of-bias assessment for each relevant study by using Cochrane and GRADE criteria for randomized controlled trials,⁶ Quality Assessment of Diagnostic Accuracy Studies, version 2, for studies of diagnostic accuracy,⁷ and GRADE criteria for observational and interventional studies informing therapy or prognosis questions.⁴ In addition to assessing scientific bias, the Cochrane risk-of-bias tool also considers both the source of funding and potential conflicts of interest of authors of the study. The reviewers created evidence profile tables containing information on all study outcomes. Using the GRADE approach,⁸ the certainty of evidence (ie, confidence in the estimate of the effect) was categorized as high, moderate, low, or very low on the basis of the study methodologies. The certainty of evidence was upgraded for a dose-response or large effect, and downgraded for bias, inconsistency, indirectness, imprecision, or publication bias (Tables 1 and 2).⁹ Any unresolved disparity between reviewer assessments was resolved through discussions and consensus with the task force representative of the Scientific Advisory Committee and, if disagreement remained, by the larger task force.

The ILCOR task forces reviewed, discussed, and debated the studies and systematic review analyses, drafting a consensus on science statement and a written summary of identified evidence and evidence certainty for each outcome. When there was consensus, the task force developed consensus treatment recommendations, labeled as strong or weak and either for or against a therapy, prognostic tool, or diagnostic test, noting the certainty of the evidence. In addition, each topic summary included the PICOST question and a justification and evidence-to-decision framework section, capturing the values and preferences considered by the task force as well as a list of knowledge gaps. Public input was sought for the draft CoSTR statements.¹⁰ The task forces considered all public comments when finalizing the CoSTR statements. A task force insights approach was used rather than a formal CoSTR when there were insufficient data to support a recommendation. All CoSTR statements from 2021 to 2025 underwent peer review by at least 5 subject matter experts and were endorsed by the ILCOR board before publication.

The purpose of a scoping review is to provide an overview of the extent, range, and nature of research activity; to clarify key concepts; to identify gaps; or to identify topics for future systematic reviews.¹¹ One difference between scoping reviews and systematic reviews is that scoping reviews attempt to provide an overview of a broad topic with a large and diverse body of literature, and to produce a summary of the studies, but not a magnitude of effect. Systematic reviews address a narrow, more clearly focused research question. Scoping reviews are helpful in examining emerging areas of research, clarifying key concepts, and identifying gaps in knowledge. Additionally, scoping reviews do not include formal evaluation of the certainty of evidence or risk of bias and are not assessed according to GRADE recommendations. Due to these differences, unlike the treatment recommendations that can arise from a systematic review, scoping reviews cannot result in CoSTR without an additional systematic review. Scoping reviews can, however, result in the development of good practice statements. Although ILCOR does not create or alter treatment recommendations without a systematic review, if the topic of a scoping review is thought to be of particular interest to the resuscitation community, good practice statements are often made. Good practice statements represent expert opinion informed by the very limited evidence available.¹²

The methodology for conducting a scoping review was based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews.^3,13,14 Each task force identified questions to be reviewed, presented in the PICOST or population, concept, context format. MEDLINE, Embase, and Cochrane databases were searched to identify relevant publications, with additional databases searched where appropriate. Those performing the scoping reviews extracted data to create summary tables. The task force then reviewed the studies and the evidence tables, developing a consensus narrative summary of the evidence and an overview of the task force insights including knowledge gaps and research priorities. Each topic narrative summary and overview of task force insights (including why the topic was reviewed, narrative evidence summary, and a narrative report of the task force discussions), as well as the complete scoping review, were posted on the ILCOR website for public review and input,¹³ with final versions included in the appendix and summarized in the body of the relevant task force CoSTR publication. When ILCOR task forces believed there was a need to make a clinical recommendation after performing a scoping review or evidence update (because no treatment recommendations can be made without a full systematic review under ILCOR policy), task forces were permitted to make expert consensus-based good practice statements. These statements were designed to reflect what experts in the resuscitation science community believe are the current best practices when sufficient data are not yet available to support such conclusions. In such cases, ILCOR expects that such statements can be replaced with formal treatment recommendations through the CoSTR process in the future as more research becomes available.

ILCOR evidence updates involve a systematic way of searching the literature and updating an overview of the evidence available on a particular PICOST topic of interest for ILCOR.¹⁵ The evidence updates may be done to evaluate the existence of new research related to an already commissioned PICOST or may be done as preliminary work related to a newly developed PICOST topic. The evidence update reviewers used PubMed to conduct searches of English language publications indexed in the MEDLINE database. When the search strategies from previous reviews were available, these were repeated. Searching beyond the MEDLINE database was optional and at the discretion of the reviewer. Reviewers identified relevant new studies, guidelines, and systematic reviews, and completed an evidence update worksheet, which included the research question, the search strategy, and a table summarizing any new evidence.¹³ After review by the ILCOR Science Advisory Committee Chair, the evidence update worksheet was included in the relevant 2025 CoSTR task force publication appendix and cited within the body of the manuscript. As mentioned, a good practice statement could be added by an ILCOR task force after an evidence update was performed.

An internal AHA evidence evaluation process was used to support recommendation updates or the development of new recommendations if applicable. These reviews are specifically conducted when current ILCOR evidence synthesis outputs (eg, systematic review, scoping review, or evidence update) are not available. Evidence reviewers followed a standard operating procedure for evidence review developed by the AHA ECC Committee based on systematic review methodology and supported by designated information specialists with expertise in systematic literature review methodology.^4,15 The process was designed to provide a comprehensive synthesis of all available evidence on a topic to support the development of specific guidelines. It was designed to ensure rigor and feasibility, providing guidance and support for writing group members to conduct the searches and evidence synthesis for submission to the writing group chair and section authors.

Where possible, evidence reviews were conducted by 2 independent reviewers assigned by the writing group chair. Reviewers defined the elements of a PICOST research question if the clinical area under review allowed for this. The determination of these elements was set a priori to guide the development of the search strategy in collaboration with the AHA librarians, to assist in the development of inclusion and exclusion criteria for article selection, and to guide data abstraction when relevant articles were identified. If the PICOST approach was not relevant for a particular area, reviewers defined the clinical area of interest, the specific terms used to define that area, and as many of the elements of the PICOST as possible. Reviewers codeveloped search strategies with the AHA librarians. Depending on the topic area and availability of published data, literature searches were limited to randomized clinical trials, or expanded to include nonrandomized trials, observational studies, or case studies. Literature searching included the following online databases: MEDLINE, PubMed, Embase, and the Cochrane Library. For guideline updates, searches were limited to the time period following the last search date reported in the prior version of the guideline. In the case of a new guideline or full revision, no time limits on searches were imposed, unless the writing group determined that a different time frame was appropriate. The 2 reviewers then independently reviewed citations for inclusion, and evaluated included studies for risk of bias using the Robins-I tool for nonrandomized studies¹⁶ and the Cochrane risk-of-bias tool for randomized control trial designs.⁶ Disagreements in study selection, risk-of-bias evaluation, and data abstraction were resolved through consensus building between the 2 reviewers. When consensus could not be reached, a third reviewer was used to resolve the disagreement.

The output from this process, including data abstracted from each study relevant to the PICOST question, was documented in a standardized evidence review form, and then returned to the writing group chair for distribution to the members. Reviewers used their review of the literature, with risk-of-bias assessments considered, to propose a summary of the evidence and to suggest either no change to prior recommendations, to suggest modifications to existing recommendations, or to draft entirely new recommendations. The results of these reviews by the Writing Groups were under embargo and therefore were not posted for public comment.

One opportunity to enhance and streamline the 2025 guideline process has been the ability to integrate external systematic reviews and guidelines into the AHA guideline process. This can be in the form of adopting existing recommendations or developing recommendations based on the available evidence synthesis termed adolopment. An adolopment evaluation process was used when a writing group identified a need for guidance on a particular topic, but existing guidelines or systematic reviews from external organizations, not directly affiliated with ECC, already provided valuable, high-quality information.¹⁷ Instead of creating new guidelines, adolopment allowed writing groups to leverage this information, provided the external guideline fit specific criteria. When a writing group identified the need for adolopment of external publications, there was first an initial comprehensive search of existing AHA guidelines (eg, AHA/American College of Cardiology, AHA/American Stroke Association) to ensure no conflicts existed between the adopted adolopment and current AHA recommendations. The writing group then presented their justification for adolopment along with their AHA guideline search results to the Science Subcommittee leadership [Chair (MD), Vice Chair (JB) and Immediate Past Chair (ARP)] and the AHA Vice President Science and Innovation (CS) for approval. Once approved, the writing group conducted a thorough assessment of the external guideline’s methodology to ensure rigor. Key elements such as the search strategy, inclusion/exclusion criteria, data extraction, bias assessments, GRADE evidence profile tables, and meta-analyses were evaluated. Writing groups were permitted to incorporate guidelines from other organizations, even if their development process was less rigorous (eg, did not use multiple databases), provided their evidence review process was transparent. These requests were evaluated on a case-by-case basis, with input from Science Subcommittee leadership and AHA staff. Alternatively, writing groups could choose to conduct an evidence review that included these external guidelines and their recommendations, using them as part of the broader body of evidence to inform recommendations. With this approach, rather than adolopment of external guidelines, external guidelines could be used to contribute to the overall evidence base for guideline development by the writing groups.

Each of the 2025 Guidelines articles was submitted for blinded peer review to 5 to 10 subject matter experts nominated by the AHA and AAP, as appropriate. Subject matter expert reviewers were required to disclose relationships with industry and any other potential conflicts of interest, and all disclosures were reviewed by AHA staff. Peer reviewer feedback was provided for guidelines in draft format and again in final format. AHA Policy requires that official positions and guidelines of the AHA must be reviewed and approved by the Board of Directors and/or its Executive Committee. Upon completion of peer review, these guidelines were reviewed and edited for publication by the AHA Science Advisory and Coordinating Committee and the AHA Executive Committee following the standard review process for all official AHA documents with legal, communications and science staff to ensure risk mitigation and accurate alignment with AHA mission. To maintain the highest level of methodological rigor and transparency, the 2025 AHA/ECC Guidelines were developed consistent with the domains of the Appraisal of Guidelines for Research & Evaluation II Instrument³⁵ and a description is provided in an online supplement.

• Ashish R. Panchal, MD, PhD, Chair
• Jason A. Bartos, MD, PhD, Vice Chair
• Myra H. Wykoff, MD
• Ian R. Drennan, ACP, PhD
• Melissa Mahgoub, PhD
• Stephen M. Schexnayder, MD
• Amber J. Rodriguez, PhD
• Comilla Sasson, MD, PhD
• Jaylen I. Wright, PhD
• Steven C. Brooks, MD
• Dianne L. Atkins, MD
• Marina Del Rios, MD, MS.