Background: Research on nurses early in the COVID-19 pandemic shows elevated severity of trauma-related stress, depression, anxiety, and poorer well-being than before the pandemic. Fewer studies examined nurses’ experiences three years into the pandemic and the relationships of the experiences that predict increased post-traumatic stress severity.

Objectives: This study evaluates the relationships among peritraumatic distress, moral distress, resilience, and post-traumatic stress severity as its primary objective. The study also examined the relationships of depression, anxiety, sleep quality, and nurses’ perceived work environment to post-traumatic stress as its secondary objective. The overall goal is to understand targets for intervention on the path to the development of post-traumatic stress that could potentially reduce the impact of crises on nurses.

Methods: This study evaluates the interrelationships of these variables using a concurrent triangulation mixed methods framework. Nurses participated in multiple surveys, and a subset of these nurses participated in semi-structured interviews. A structural equation model (SEM) examined the relationships of the primary outcomes, and multiple regression analyses investigate the independent predictive ability of the variables on post-traumatic stress. The interviews utilized a descriptive phenomenological methodology to describe the lived experiences of traumatic stress during the pandemic for these nurses.

Results: In the SEM, moral distress partially complementarily mediated the direct positive effect of peritraumatic distress on post-traumatic stress and negatively moderated the direct negative effect of resilience on post-traumatic stress. A multiple regression with all variables excluding resilience and sleep quality (not significant at p < .20) accounted for 62.6% of the variability in post-traumatic stress symptom severity. The interviews revealed that nurses exist in three interrelated worlds: their “Internal World” (emotions and personal well-being), their ‘Hospital World” (coworkers, leadership, environment, etc.) and the “Outside World” (the public, social media, current events, etc.).

Conclusion: Nurses require support for their mental health at work and outside the hospital during a crisis, and hospital policies must consider all three. Reduction in peritraumatic stress and moral distress and support for nurse resilience are some of the most critical areas to focus on to reduce the post-traumatic stress severity in nurses during a long-term crisis.