This study aims to evaluate the feasibility, usability, and clinical effectiveness of a digital rehabilitation platform in adult patients discharged from the intensive care unit (ICU). Adult patients aged 19 years or older who stayed in the ICU for more than 48 hours and are capable of using a smartphone will be enrolled from two tertiary hospitals in South Korea.

Participants will receive individualized rehabilitation programs using a digital rehabilitation platform ("Tuntun Rehabilitation Assistant") based on their functional status. Rehabilitation will be conducted once daily for up to 30 minutes per session. Physical and cognitive function outcomes will be assessed at baseline, two weeks after intervention initiation, at hospital discharge, and during follow-up when applicable.

This prospective cohort study will investigate changes in physical function, mobility, cognitive status, and quality of life, as well as platform usage and safety-related events, to determine the clinical usefulness of digital rehabilitation for ICU survivors.

This is a prospective cohort clinical study designed to evaluate the feasibility, usability, and clinical effectiveness of a digital rehabilitation platform in adult patients discharged from the intensive care unit (ICU).

Study Population Eligible participants are adult patients aged 19 years or older who were admitted to the ICU for more than 48 hours at Seoul Asan Medical Center or Seoul National University Bundang Hospital. Participants must own a smartphone, be capable of operating a digital platform, and provide voluntary informed consent.

Study Design and Sample Size This is a multicenter prospective cohort study. Approximately 40 participants will be recruited from Seoul Asan Medical Center and 30 participants from Seoul National University Bundang Hospital.

Intervention Participants will receive individualized rehabilitation interventions using the digital rehabilitation platform "Tuntun Rehabilitation Assistant." At enrollment, overall physical function will be assessed, and an appropriate rehabilitation program will be prescribed accordingly. The intervention will be administered once daily, with each session lasting no more than 30 minutes.

During the first five sessions, a researcher will visit the patient's hospital room to assist with the intervention. Afterward, participants will continue the rehabilitation independently using the digital platform.

Outcome Assessments Assessments will be conducted at baseline, two weeks after intervention initiation, and at hospital discharge. For participants who remain hospitalized for more than four weeks after the two-week assessment, an additional evaluation will be performed four weeks after the two-week assessment.

Participants discharged after completing in-hospital assessments will continue using the digital rehabilitation platform at home until their outpatient follow-up visit one month after discharge, at which time an additional evaluation will be conducted.

Data Collection Patient characteristics, outcome measures, and intervention-related data will be collected, including physical function, mobility, cognitive status, quality of life, platform usage, adherence, and safety-related events.

Inclusion Criteria:

• Age 19 years or older.
• Admission to the intensive care unit (ICU) for more than 48 hours.
• Hospitalization at Asan Medical Center or Seoul National University Bundang Hospital.
• Discharge from the ICU at the time of enrollment.
• Ownership of a smartphone and ability to operate a digital rehabilitation platform.
• Ability to understand the study procedures and provide voluntary written informed consent.

Exclusion Criteria:

• Medical conditions that contraindicate participation in rehabilitation exercise, as determined by the attending physician.
• Severe cognitive impairment or communication difficulties that interfere with understanding or following study instructions.
• Unstable medical conditions requiring ongoing intensive medical treatment.
• Inability to use a smartphone or digital platform independently.
• Refusal to participate or withdrawal of informed consent.

All individual patient data (IPD) used in this study will be handled in compliance with domestic privacy protection laws and relevant regulations. The privacy of study participants will be strictly safeguarded, and their personal information will not be used for purposes other than the study. When sharing data, only de-identified data that has been approved by the researchers after adequate request will be provided, and privacy protection and security will be prioritized throughout the process.