Shared Decision-Making with a Surrogate for Life-Sustaining Treatment of Critically Ill Patients: A Scoping Review Protocol (Preprint)

BACKGROUND Shared decision-making (SDM) is a collaborative process that incorporates patients’ values and preferences into healthcare decisions. In ICUs, critically ill patients often lack decision-making capacity, requiring surrogates to make complex choices regarding life-sustaining treatment (LST). While SDM is essential in supporting surrogates and ensuring patient-centered care, evidence on its application in this context remains unclear. OBJECTIVE This scoping review aims to clarify the extent and type of evidence on SDM involving surrogates for LST of critically ill patients. METHODS This scoping review will follow the JBI methodology and the PRISMA-ScR reporting guidelines. Studies will be included if they examine shared decision-making involving surrogates of adult critically ill patients regarding life-sustaining treatment decisions in ICU settings. SDM is defined using four criteria: participation of both healthcare professionals and surrogates; mutual information sharing; consensus-building; and agreement on treatment based on the patient's values and preferences. A comprehensive search will be conducted across PubMed, CINAHL, PsycInfo, CENTRAL, and Ichushi-Web for English and Japanese studies published from 2016 to 2025. Eligible study designs include quantitative, qualitative, and mixed-methods research. Title and abstract screening and full-text selection will be conducted independently by two reviewers using Rayyan. Data will be extracted on study characteristics, SDM definitions, participant roles, and key findings. Results will be mapped descriptively and presented in tables and narrative summaries to identify gaps and inform future research. RESULTS As of June 13, 2025, the literature search has been completed. A total of 2,899 citations were identified through the specified database searches, of which 527 duplicates were removed. Title and abstract screening is currently in progress, and full-text review is expected to be completed by September 2025. CONCLUSIONS This scoping review will be the first to systematically map evidence on SDM with surrogates for LST in critically ill patients. By synthesizing diverse studies, it will clarify healthcare professionals’ roles, identify interventions, and highlight challenges surrogates face. The findings will inform future interventions and policies, and advance patient- and family-centered care in critical care.