Over the past two decades, the rapid advancement of critical care medicine has significantly reduced short-term mortality among critically ill patients. However, a growing number of intensive care unit (ICU) survivors experience persistent physical, cognitive, and psychological impairments after hospital discharge, a syndrome termed post-intensive care syndrome (PICS). Although PICS has gained increasing attention in recent years, existing studies still have multiple limitations. Given the continuously increasing number of ICU survivors in China and the marked heterogeneity in critical care delivery models across different regions and healthcare institutions, there is an urgent need for large-scale multicenter observational studies to systematically characterize the epidemiological features, multidimensional functional impairment profiles, and clinical impact of PICS in Chinese patients, thereby providing an evidence-based foundation for the development of a scientific post-ICU continuum of care.

This multi-center observational study aims to characterize the epidemiological profile and multidimensional functional impairments of Post-Intensive Care Syndrome (PICS) in ICU survivors across China. The study will enroll approximately 800 eligible participants from four participating high-dependency units (HDUs) between January 2018 and January 2026. Data on physical, cognitive, and psychological function will be collected using validated assessment tools including the MRC score, ICU Mobility Scale, CPAx, MMSE, S5Q, PHQ-9, GAD-7, PSQI, Barthel Index, and EQ-5D-5L. The primary outcomes include the incidence of PICS and comorbidity patterns across multiple functional domains. The secondary outcomes encompass functional status, quality of life, and risk factors for PICS.

Inclusion Criteria:

• Age ≥18 years
• First admission to ICU, with ICU length of stay ≥ 48 hours before transfer to HDU
• Complete the PICS assessment within 7 days after HDU admission
• Complete clinical data available (demographics, ICU-related information)
• Signed informed consent obtained from participants or legal guardians

Exclusion Criteria:

• Prior ICU admission
• Terminal illness or estimated life expectancy <6 months
• Participants or family members refuse to complete questionnaires

This study is a multi-center, retrospective, observational cohort study that will enroll patients from four participating high-dependency units (HDUs) across China. Patients transferred from general hospital ICUs to the participating HDUs between January 2018 and January 2026 will be screened. Data will be sourced from medical records, nursing records, rehabilitation assessment records, and follow-up documentation from routine clinical care. The anticipated total sample size is 800 participants.