<p>Interview guide.</p>

Introduction
In Japan, end-of-life care in intensive care units (ICU) remains inconsistent and often suboptimal, contributing to variability in the quality of dying and death. This study aimed to develop a culturally appropriate nurse-led intervention program to improve the quality of dying and death in Japanese ICU.
Methods
Using a structured framework for intervention development, we conducted a systematic and scoping review to identify modifiable factors and effective strategies for end-of-life care in ICUs. Eight evidence-based strategies were synthesized into four core components: symptom management, multidisciplinary bedside conferences, family conferences, and end-of-life care. A preliminary intervention program was developed and evaluated through expert interviews and web-based surveys to assess its clarity, feasibility, and alignment with the Japanese healthcare system.
Results
Based on expert feedback, revisions were made to enhance the clarity, feasibility, and alignment with the Japanese healthcare system. Key improvements included initiating symptom management early upon ICU admission, allowing flexible scheduling of conferences, and incorporating structured tools and frameworks commonly used in Japan. Additionally, a ladder-based system was introduced to tailor the intervention intensity according to the patients’ clinical conditions.
Conclusion
The final nurse-led intervention program was designed to facilitate more consistent delivery of end-of-life care in the ICU regardless of individual providers’ knowledge or attitudes. This study demonstrates a rigorous and culturally adapted intervention development process that may serve as a model for improving end-of-life care in ICU in Japan and other healthcare systems.