Intensive care unit nurses' perceptions of night-work-related chronic fatigue and cognitive function: a cross-sectional survey.

INTRODUCTION: Night work disrupts circadian physiology and sleep, with documented consequences for the health and performance of nurses. In the intensive care unit (ICU), where sustained attention, rapid responses, and precision are essential to patient safety, night-work-related cognitive impairment is of particular concern for both patient and staff safety. This study examined how ICU nurses perceive the impact of night work on their cognitive functions. METHODS: A cross-sectional survey was conducted using a non-probability convenience sample of 50 nurses in the one ICU in Croatia. An questionnaire based on a Croatian adaptation of the Creighton Competency Evaluation Instrument 2.0 assessed 23 clinical-competency items and 7 statements on the perceived cognitive impact of night work. Responses were analyzed descriptively and compared across sociodemographic groups using Mann-Whitney U and Kruskal-Wallis tests, with Benjamini-Hochberg false discovery rate (FDR) correction applied within each demographic-variable family, in SPSS 26.0 and Python. RESULTS: Item means ranged from 3.34 to 4.86. Respondents agreed most strongly that night work can cause chronic fatigue (M = 4.86, SD = 0.35) and reduce attention (M = 4.38, SD = 0.73), weaken short-term (M = 4.26, SD = 0.94) and working memory (M = 4.22, SD = 0.79), and impair complex tasks and decision-making. Eight nominally significant subgroup comparisons emerged at raw p < 0.05 (e.g., chronic fatigue by age, H(3) = 10.02, p = 0.018; attention by sex, U = 204.00, p = 0.018), but none survived FDR correction (adjusted p ranging from 0.31 to 0.55); a post-hoc power analysis indicated the study was adequately powered only to detect large subgroup differences (minimum detectable effect at 80% power: d = 1.24 for the sex comparison). DISCUSSION: These self-reported findings suggest that ICU nurses perceive night work as a potential threat to cognitive functions relevant to safe care, particularly through fatigue-related mechanisms, and underscore the need for organizational fatigue-management strategies that protect both patient safety and staff well-being, while subgroup differences by sex, age, and length of service should be treated as hypothesis-generating rather than confirmed given the sample size and multiple-comparisons correction applied.