Fatigue among pediatric critical care nurses threatens staff and patient safety. Psychological capital (PsyCap), characterized by hope, optimism, resilience, and self-efficacy, may improve professional quality of life (ProQOL) and mitigate workplace stressors.

This study examined the mediating role of psychological capital in the relationship between ProQOL and fatigue among nurses working in pediatric intensive care units.

Using multi-center, cross-sectional study, a sample of 208 pediatric nurses was recruited from three university hospitals between July and September 2025. Participants completed validated self-report measures assessing PsyCap, fatigue (using the OFER-15 scale), and ProQOL (using the ProQOL-5).

Participants reported moderate levels of fatigue and moderate scores across ProQOL domains (compassion satisfaction, burnout, secondary traumatic stress). PsyCap demonstrated a strong negative correlation with overall fatigue (r = −0.92), burnout (r = −0.80), and secondary traumatic stress (r = −0.90), and a strong positive correlation with compassion satisfaction (r = 0.81). Mediation analysis, controlling for work experience and weekly hours, revealed that PsyCap served as a significant partial mediator.

Psychological capital mediated the association between ProQOL and fatigue. These findings suggest that interventions aimed at strengthening PsyCap may help reduce fatigue and improve well-being, although the cross-sectional design limits causal inference and the strong correlations require replication.

Psychological capital represents a promising target for evidence-based interventions. Developing structured programs, such as resilience training, mentorship, and workshops to build hope, self-efficacy, optimism, and resilience, could mitigate fatigue and enhance the professional quality of life for pediatric critical care nurses.