Abstract
BACKGROUND: Intensive Care Unit (ICU) nurses are at high risk for compassion fatigue and moral distress. Grounded in the Conservation of Resources Theory, this study proposes that compassion fatigue depletes emotional resources, thereby intensifying moral distress. However, the specific pathway and key components driving this relationship remain unclear. OBJECTIVE: To investigate the nonlinear relationship between compassion fatigue and moral distress among ICU nurses and to identify core symptoms of compassion fatigue that most significantly influence moral distress. METHODS: A nationwide cross-sectional online survey was conducted from July to December 2023, recruiting 645 ICU nurses from China. Compassion fatigue and moral distress were assessed using the Professional Quality of Life Scale and the Moral Distress Scale-Revised, respectively. The dose-response relationship was analyzed using restricted cubic splines, with moral distress as the outcome and compassion fatigue as the predictor, and network analysis with in silico interventions was applied to identify key compassion fatigue symptoms affecting moral distress. RESULTS: A significant nonlinear relationship was identified of compassion fatigue on moral distress (nonlinear F = 10.02, p < 0.01; adjusted model R² = 0.161), with moral distress increasing sharply at moderate compassion fatigue levels before plateauing. Network analysis and in silico simulations revealed three core compassion fatigue symptoms with the strongest influence on moral distress: “feeling trapped in the helping system” (a burnout symptom), “difficulty remembering important work aspects” (a secondary traumatic stress symptom), and “being a very sensitive person” (a secondary traumatic stress-related trait). Adjusting these symptoms led to significant changes in moral distress levels. CONCLUSION: This study confirms a nonlinear relationship of compassion fatigue on moral distress and identifies actionable targets for intervention. Addressing specific compassion fatigue symptoms can disrupt the resource loss spiral, offering a strategic approach to enhancing ICU nurse well-being and care quality. CLINICAL TRIAL NUMBER: Not applicable. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12912-025-04196-1.