Trauma resulting from accidental injuries is one of the top ten leading causes of death among adolescents and adults worldwide. Although the COVID-19 pandemic has had a significant impact on global mortality rates, accidental injuries continue to be a major cause of death (World Health Organization, 2023, World Health Organization, 2024). In Taiwan, accidents ranked as one of the top ten leading causes of death in 2023. According to the statistics from the past decade, road traffic accidents are the primary cause of accidental injuries and rank among the top five causes of death for individuals aged 1–64 years (Ministry of Health and Welfare, 2014–2023). Trauma-related deaths account for approximately 10 % of the overall mortality rate, with chest trauma contributing to around 20–25 % of all trauma-related deaths, representing a high proportion of severe injuries (Ding et al., 2016, Abelsson et al., 2017, Narayanan et al., 2018, Almarhabi et al., 2023).

Road traffic accidents are the primary cause of thoracic trauma, with approximately 40 % of patients with multiple traumas presenting with concomitant thoracic injuries on hospital admission (McGuinness et al., 2023). Thoracic trauma can lead to respiratory dysfunction, decreased lung capacity and other complications. If not promptly detected or treated, it may result in respiratory failure or even death (Nyland et al., 2016, Narayanan et al., 2018, Kourouche et al., 2024). Therefore, nurses should conduct systematic trauma assessments to identify changes in patient conditions early, promptly notify physicians and implement appropriate interventions to reduce the risk of complications (Nyland et al., 2016, Schreiter et al., 2016). To enhance nurses' competency in thoracic trauma care, ongoing professional development and training have been shown to effectively improve patient outcomes (Ding et al., 2016, Donelan et al., 2020).

Since the 1970s, the American College of Surgeons has developed the Advanced Trauma Life Support (ATLS) course to provide physicians with systematic and comprehensive trauma training. Additionally, since 1986, the Emergency Nurses Association has developed the Trauma Nursing Core Course (TNCC) for practicing nurses and has expanded it to many countries around the world (Jeffries et al., 2023; Emergency Nurses Association, n.d.). The TNCC covers the pathophysiology of trauma across all body systems, trauma assessment skills, intervention timing, trauma management techniques and case discussions. These courses are regularly updated in accordance with advancements in practice (Ding et al., 2016, Lee and Battle, 2018, Gautreaux et al., 2019). Currently, diverse teaching strategies have been used in trauma education, such as classroom lectures combined with hands-on demonstrations (Finstad et al., 2020, Kaur et al., 2021, Chowdhury et al., 2022), simulations using standardized patients (Courteille et al., 2018) and high-fidelity simulations (Abelsson et al., 2017, Klunder-Rosser and Pennington, 2021, Knapp, 2023).

In Taiwan, in response to international trends in trauma care and the nation's specific healthcare needs, corresponding trauma training courses have been developed. These courses not only cover a broad range of trauma knowledge but also emphasize the systematic process of trauma management, skills training, teamwork and scenario-based learning, effectively improving trainees' trauma knowledge and competency. These courses typically range from one to two days. However, challenges, such as high training costs, limited participant enrollment per session, the requirement for personal expenses or leave time to attend and the lack of continuous training opportunities, may affect the effectiveness of trauma training (Harvey et al., 2019, Mulli et al., 2021, Bailey and Emory, 2022). Insufficient or infrequent trauma training may cause nurses to feel overwhelmed, which may compromise the quality of trauma care (Garvey et al., 2016, Chowdhury et al., 2022).

To efficiently manage emergency incidents, emergency room (ER) nurses must possess clinical reasoning skills to respond effectively to trauma patients. Failure to recognize changes in patient conditions or delays in interventions can lead to severe complications and increased mortality risk. Therefore, clinical reasoning should be a key focus in nurses' continuing education (Lee et al., 2021, Huang et al., 2023, Kow et al., 2024). According to Huang et al. (2023), clinical reasoning is "a continuous, interactive and dynamic process that requires ongoing adjustments and modifications based on clinical changes" that consists of four domains: "clinical cue recognition", "problem identification", "decision-making and action implementation" and "evaluation and reflection” (Huang et al., 2023, p.2–3). Recognizing clinical cues allow nurses to execute timely and appropriate interventions, improving patient outcomes. Continuous learning and practical application enhance nurses' clinical judgment and decision-making abilities, ultimately improving care quality. Integrating these four domains into thoracic trauma nursing courses may enhance emergency response capabilities and ensure timely, effective patient care.

Current trauma care training mainly combines in-person lectures with case discussions or simulations. Simulation-based teaching has been shown to be an effective alternative to traditional clinical courses, helping to reduce nurses’ learning and practice load (Garvey et al., 2016, Gautreaux et al., 2019). However, the complex nature of various body systems can place a high cognitive load on participants when learning the knowledge and management of chest trauma. In traditional in-person scenario-based training, the limited participation due to space constraints and time limitations makes it difficult for instructors to meet everyone's needs and provide immediate feedback to all learners (Garvey et al., 2016, Gautreaux et al., 2019). As educational models transition toward digitalization, pedagogical approaches with real-time feedback mechanisms can help learners identify and correct mistakes, reduce cognitive load and enhance learning outcomes. Therefore, if thoracic trauma care courses can be delivered through online digital learning methods, these constraints can be overcome. It will offer personalized and flexible learning opportunities to improve training opportunities and learning effectiveness (Cant and Cooper, 2017, Garvey et al., 2016, Killam and Luctkar-Flude, 2021).

In recent years, interactive video simulation training with real-time feedback has been widely applied in healthcare education, effectively enhancing knowledge acquisition and skill retention. This approach uses visual and interactive methods to deepen understanding of trauma cases and strengthen knowledge acquisition (Masha’al and Rababa, 2020; Killam and Luctkar, 2021; Wehling et al., 2021). Research shows that interactive videos facilitate cognitive retention through multimodal information transmission, encouraging critical thinking and improving clinical applications. Real-time feedback in simulation training allows learners to adjust their decision-making processes and actions, enhancing overall learning outcomes. Compared to traditional methods, decision-based branching simulations provide superior outcomes by guiding participants through clinical reasoning and decision-making processes logically and systematically (Masha’al and Rababa, 2020, Smith et al., 2022). This method compensates for the limitations of linear simulations and enhances clinical adaptability. Immediate feedback during decision-making processes allows exploration of different clinical scenarios in a risk-free environment, deepening understanding of trauma cases and thoracic trauma management, which may improve clinical reasoning and decision-making skills (Masha’al and Rababa, 2020, Smith et al., 2022).

Online simulation with decision-based branching video learning (Online SimuBranch) may enhance nurses' clinical reasoning abilities in thoracic trauma care. This approach uses narrative storytelling to digitally present thoracic trauma scenarios along a timeline, integrating interactive questions, demonstrations, instructional content and decision-making tasks to immerse participants. The participants select clinical interventions for various trauma stages (primary survey, secondary survey and definitive care) (ATLS, 2025) and enter corresponding simulated scenarios that allow for personalized and flexible learning. This method contributes to competency in trauma response and reinforces trauma care knowledge and clinical reasoning skills. Implementing online trauma education courses can alleviate the burden of fixed in-person training, expand course offerings to a wider audience, improve learning effectiveness and ensure acquisition of essential trauma care knowledge and clinical reasoning skills. Therefore, this study aimed to evaluate the effectiveness of an online simulation with decision-based branching videos (Online SimuBranch) thoracic trauma course in improving nurses' knowledge of thoracic trauma care and clinical reasoning abilities.