Objectives This study sought to investigate nurses’ knowledge, attitudes and practices, and analyse the influencing factors for subsyndromal delirium (SSD).Design A descriptive cross-sectional survey.Setting E-questionnaires were distributed to intensive care unit (ICU) nurses from 20 tertiary-grade, A-class hospitals in Henan Province, China.Participants A total of 740 ICU nurses participated in the questionnaire survey.Main outcome measures Each dimension score is converted to a percentage scale. A score of ≤60% on each dimension of the questionnaire was considered a negative score,