Title (1)	A multicomponent family support intervention in intensive care units: study protocol for a multicenter cluster-randomized trial (FICUS Trial)
Trial registration (2a and 2b).	ClinicalTrials.gov, NCT05280691, and the Swiss National Clinical Trials Portal (SNCTP), SNCTP000004842
Protocol version (3)	Version 1.0, 25. October 2021
Funding (4)	The study is funded by the Swiss National Science Fund (SNSF, grant no. 33IC30_198778/1).
Author details (5a)	Rahel Naef: Institute for Implementation Science in Health Care, Faculty of Medicine, University of Zurich and Center of Clinical Nursing Science, University Hospital Zurich, Universitätsstrasse 84, CH-8006 Zurich, Switzerland. Miodrag Filipovic: Surgical Intensive Care Unit, Rescue and Pain Medicine, Intensive Care, Division of Anesthesiology, Cantonal Hospital of St. Gallen, Rorschacher Strasse 95, CH-9007 St. Gallen, Switzerland. Marie-Madlen Jeitziner: Department of Intensive Care Medicine, University Hospital Bern, Inselspital, University of Bern, Freiburgstrasse 10, 3010 Bern, Switzerland. Stefanie von Felten: Department of Biostatistics, Epidemiology, Biostatistics, and Prevention Institute, Faculty of Medicine, University of Zurich, Hirschengraben 84, 8001 Zurich, Switzerland. Judith Safford: Patient representative, no affiliation Marco Riguzzi: Institute for Implementation Science in Health Care, Faculty of Medicine, University of Zurich and Center of Clinical Nursing Science, University Hospital Zurich, Universitätsstrasse 84, 8006 Zurich, Switzerland. Michael Rufer: Department of Psychiatry, Psychotherapy, and Psychosomatics, Psychiatric University Hospital Zurich, University of Zurich and Center for Psychiatry and Psychotherapy, Psychiatric Hospital Zugersee, Triaplus AG, Widenstrasse 55, 6317 Oberwil-Zug, Switzerland.
Name and contact information of the trial sponsor (5b)	Rahel Naef, PhD, RN Institute for Implementation Science in Health Care, Faculty of Medicine, University of Zurich and Center of Clinical Nursing Science, University Hospital Zurich, Universitätsstrasse 84, CH-8006 Zurich, Switzerland. E-Mail: rahel.naef@uzh.ch Phone: +41 44 634 37 49
Role of sponsor (5c)	The sponsor-investigator acts as the coordinating investigator of the trial and has a primary role regarding study design; collection, management, analysis, and interpretation of the data; and writing of the report. She has ultimate authority over these activities. The funder (Swiss National Science Fund) has no role in the development of the study design; collection, analysis, or interpretation of the data; writing of the manuscript; or decision to submit the manuscript for publication.