Comparative analysis of emergency medical systems in the UK and Japan: recommendations for Japan based on on-site observations in the UK

Abstract

Background

Emergency Medical Systems (EMS) are central to modern healthcare, providing timely, specialized care. Although the United Kingdom (UK) and Japan have universal healthcare, their EMS models differ significantly. The UK emphasizes centralized trauma networks, advanced prehospital capabilities, standardized simulation training, robust research integration, and a high degree of specialization and division of labor. Japan’s EMS prioritizes accessibility through a tiered system and regional autonomy. Both systems face workforce sustainability issues and documentation inefficiencies. This study provides recommendations for enhancing Japan’s EMS by examining the UK system through on-site observations.

Methods

A qualitative observational study was conducted during a four-day site visit in May 2024 to key EMS institutions in London, including the Royal London Hospital Major Trauma Center, the London Air Ambulance, and allied educational and research facilities. Five Japanese emergency physicians with expertise in trauma care, ICU management, simulation-based training, and prehospital emergency services participated. Data collection included direct clinical observations, structured discussions with UK clinicians and administrators, and a review of institutional guidelines. Thematic analysis identified strengths, weaknesses, and potential applicability to Japan.

Results

In the UK, EMS leverages division of labor, specialization, centralization, and standardization to ensure efficient, high-quality care. Trauma networks, robust simulation-based education, integrated ICU management, and advanced HEMS systems are supported by unified research frameworks. However, workforce inefficiencies in staff allocation persist. Applying UK insights to Japan includes establishing dedicated trauma centers, standardizing care protocols, integrating systems, and enhancing research culture. Some strategies, such as integrated prehospital services, face feasibility challenges in Japan due to staffing issues.

Conclusion

On-site observations of the UK’s EMS highlight organizational efficiency and the benefits of integrated, specialized care. Incorporating UK-inspired frameworks could strengthen Japan’s EMS, especially by unifying systems and centralizing trauma care. Ongoing international collaboration and further comparative research are crucial for advancing global EMS practices.

Trial registration

Not applicable.

Introduction

Emergency Medical Services (EMS) is a cornerstone of modern healthcare, providing critical care during emergencies and playing a vital role in patient survival and outcomes [1]. The efficiency and quality of EMS systems, shaped by healthcare policies, cultural contexts, and resource allocation, vary significantly across countries [2]. Within this broader framework, Helicopter Emergency Medical Services (HEMS) provide rapid scene‑to‑hospital transfer and permit advanced interventions that bridge the gap between on-site emergencies and hospital-based treatments [3]. A registry-based cohort study in England demonstrated clinically meaningful differences in transport times and clinical outcomes between helicopter and ground transport for trauma patients, confirming the value of sophisticated pre‑hospital care [4]. Nonetheless, a geospatial analysis revealed disparities in service accessibility across socio-economic groups in the United Kingdom (UK), raising concerns about resource distribution fairness [5].

The UK and Japan—both high‑income nations with universal healthcare—illustrate contrasting EMS archetypes. The UK’s National Health Service (NHS) is lauded for centrally coordinated trauma networks, mandatory audits, and data‑driven quality improvement, which have translated into measurable survival gains [6, 7]. Japan, while also providing universal coverage, relies on a decentralized, prefecture-driven model that prioritizes accessibility across diverse geographic areas, but struggles with standardization and resource parity [8]. These structural contrasts have produced unique EMS strategies: the UK leverages Major Trauma Centres (MTCs) and regional networks for highly specialized, multidisciplinary care, whereas Japan’s three‑tier system combines local hospitals with a nationwide “doctor‑helicopter” network to maximize rapid access [9]. Japan’s system is further characterized as a hybrid of U.S. paramedic‑led and European physician‑led paradigms that remains “in transition,” constrained by a limited paramedic scope and uneven night‑time helicopter cover [10].

Rigorous comparative research is essential for revealing transferable best practices and context‑specific constraints [11]. Previous cross‑national work has tended to be topic‑specific—examining, for instance, prehospital airway management in Germany versus Japan [12] or patient‑satisfaction differentials between Japan and the United States [13]—while comprehensive, domain‑by‑domain observation of the UK and Japanese systems remains rare. Levine et al. (2007) identified this lack of granular, operationally focused comparisons as a critical research gap [11]. Recognizing that other high‑performing EMS models (e.g., Australia, Canada, Norway) could also yield insights, we selected the UK for in‑depth study because its long‑established, tax‑funded universal service shares island geography and mixed urban–rural demographics with Japan, maintains national trauma and cardiac‑arrest registries that enable outcome benchmarking, and offers extensive English‑language documentation that facilitates direct field observation [14].

Japan’s EMS still faces pronounced regional disparities in response times, quality assurance, and physician distribution—issues that parallel “geographical lottery” concerns reported even within the mature UK system [14, 15]. A population-based Japanese study also underscored the need for more consistent and equitable EMS delivery to align with global best practices [9]. These convergent challenges emphasize the value of systematic, bilateral comparison.

Accordingly, this study compares the EMS systems of the UK and Japan across five critical domains: trauma networks and systems, education and simulation, intensive care unit (ICU) management, HEMS, and research environments. Using qualitative, on‑site observational analysis, we seek actionable insights from the UK experience that can inform Japan’s ongoing EMS framework, while simultaneously highlighting lessons for equity and efficiency that may reciprocally benefit UK practice. By integrating complementary international perspectives, the findings aim to advance the global discourse on developing effective and equitable EMS systems.

Methods

Study design

This study employed a focused ethnographic design—a short, problem‑centred form of participant‑observation—through which five Japanese emergency physicians immersed themselves for four days (May 2024) in key London sites (Royal London Hospital Major Trauma Centre, London Air Ambulance base, Barts Simulation Centre, and the Blizard Institute). Guided by an interpretivist–constructivist paradigm and a pragmatic, practice‑improvement orientation, we regarded EMS workflows and professional interactions as socially constructed phenomena that can inform actionable, bedside‑to‑systems‑level improvements rather than wholesale policy redesign. This approach aims to understand the structural and functional attributes of the UK EMS and identify actionable insights for Japan. The research focused on pre-designed five critical domains of EMS: trauma networks and systems, education and simulation, ICU management, HEMS, and research environments. Data were collected during a site visit by Japanese emergency physicians to the Royal London Hospital and related institutions, facilitated by the Great Britain Sasakawa Foundation Butterfield Fund.

Framework for comparison

The five domains for analysis—trauma networks, education, ICU management, HEMS, and research—were established before the site visit. Their selection was guided by evidence from existing literature, which identifies these areas as critical components of high-performing emergency medical systems (Dijkink et al., 2017; WHO, 2005; TRAUMA SYSTEM Agenda for the Future, 2004). For instance, the importance of integrated trauma systems, simulation-based education, specialist-led ICU management, advanced prehospital interventions by HEMS, and a robust research culture are well-established as key determinants of quality and outcomes in emergency care. Grounding our analysis in these domains, therefore, provides a systematic and evidence-based framework for our comparative study. The relevance of this framework to the UK-Japan context was then confirmed by the research team, whose collective expertise spans these domains.

Participants

Five Japanese emergency physicians with professional expertise in prehospital and hospital-based emergency care participated in the observational study. Their backgrounds included extensive experience in trauma care, simulation-based education, ICU operations, and prehospital emergency services in Japan. This diverse expertise enabled comprehensive observations and interdisciplinary discussions. The team was deliberately composed of frontline clinicians, as the study’s primary aim was to identify translatable, operational practices at the clinical level, rather than to formulate high-level health policy.

Study setting

The site visit was conducted over four days in May 2024 at several key EMS facilities in London. At the Royal London Hospital Major Trauma Center (MTC)—one of Europe’s largest and busiest trauma centers, noted for its advanced trauma care, multidisciplinary teamwork, and integrated research initiatives (Fig. 1A)—the team also observed the ICU. Barts Health Simulation and Education Centers provided insights into the UK’s professional development and skill maintenance approach through scenario-based training. The London Air Ambulance Headquarters (HEMS Base) showcased advanced prehospital interventions, operational decision-making, and team coordination (Fig. 1B). Finally, the Blizard Institute, an internationally recognized trauma research facility focusing on clinical and translational injury research, illustrated how research is embedded into the UK’s EMS framework (Fig. 1C).

Fig. 1.

Key Components of the Emergency Medical System in London (A) Map of trauma care facilities in London, illustrating the integration of four Major Trauma Centres with 27 Trauma Units. These facilities collaborate for patient data sharing and education, forming a comprehensive trauma network (B)The London Air Ambulance, stationed at the Royal London Hospital helipad, provides rapid prehospital care and advanced interventions, exemplifying the UK’s sophisticated HEMS model (C) The Blizard Institute, a state-of-the-art research facility adjacent to the Royal London Hospital, fosters interdisciplinary collaboration and clinical innovation

Data collection

Data were obtained through direct observations, informal interviews and discussions, and the review of institutional documents. During site visits, participants examined clinical workflows, patient management protocols, and operational processes in EMS settings, including trauma multidisciplinary team meetings, ICU rounds, HEMS operations, and simulation-based training sessions. In addition, the Japanese delegation held discussions with UK clinicians and administrators to explore system design, key strengths, persisting challenges, trauma care pathways, educational approaches, resource allocation, and research integration. Relevant clinical guidelines, protocols, and institutional reports were also reviewed. Informal interviews and discussions were conducted with consenting healthcare staff, and no personal details were recorded.

We deliberately opted for informal discussions over structured interviews to foster an open and flexible exchange of ideas, which we considered vital for our study’s exploratory goals. This approach was chosen to encourage UK clinicians to share nuanced insights and unanticipated perspectives that a rigid question-and-answer format might constrain. While this method prioritizes richness of data and emergent themes, consistency for comparison was achieved during the subsequent data analysis phase, where all findings were systematically categorized according to the five pre-identified domains (as described in Sect. 2.5).

Data analysis

Field notes, discussion summaries, and observational data were analyzed using a thematic analysis approach. All five participating Japanese physicians collaboratively reviewed the collected data through structured group discussions. Data were initially open-coded and categorized into five predetermined domains (trauma networks, education, ICU management, HEMS, and research) to facilitate systematic comparison with the Japanese EMS system.

Within each domain, themes were identified through iterative group discussions until consensus was reached among all team members. Observed strengths, weaknesses, and potential applications for Japan were systematically identified and refined through this collaborative process. The lead researcher (KO) compiled the final thematic framework, which was then reviewed and validated by all team members to ensure accuracy and completeness of interpretation. Given the short, focused nature of the site visit, thematic saturation was considered to have been reached when group discussions no longer yielded new major themes within the five domains.

Ethical considerations

This study did not involve the collection of patient-identifiable information or clinical data. Consequently, formal approval from a research ethics committee was not required. Following the ethical guidelines of our hospital, which do not require formal ethics committee review for non-interventional observational studies using non-identifiable data, formal approval was not needed.

Results

Overall UK EMS characteristics

London’s EMS is organized around four key principles: division of labor, specialization, centralization, and standardization. The division of labor delineates roles among paramedics, trauma surgeons, and emergency physicians, allowing each group to focus on their area of expertise, which fosters a sustainable work environment. Specialization arises from dedicated teams consistently managing severe trauma, thereby deepening their clinical and procedural proficiency.

Centralization consolidates resources and expertise, facilitating streamlined triage, rapid patient transfers, and uniform treatment standards. As illustrated in Fig. 1A, this principle is spatially expressed in a network where four hub MTCs anchor 27 surrounding Trauma Units. Standardization supports these processes through unified protocols, consistent data-sharing, and transparent NHS performance metrics. Despite these efficiencies, we observed some workforce inefficiencies, where overlapping roles could impede junior doctors’ hands-on experience and raise concerns about cost-effectiveness.

Trauma networks and systems

The UK’s trauma care is distinguished by its advanced systematization and strategic distribution of medical resources (Table 1), forming a dedicated trauma system not yet formally established nationwide in Japan. This hub‑and‑spoke configuration, visually demonstrated in Fig. 1A, routes severely injured patients directly to the most appropriate MTC, while reserving Trauma Units for moderate cases. This system ensures that specialized teams can intervene rapidly and consistently.

Table 1.

Comprehensive summary of qualitative data for trauma networks and systems in UK and Japan

	Trauma system
Strengths of the UK	Advanced organization and systematization: An established network designed specifically for managing trauma patients has increased the efficiency of patient treatment. Appropriate distribution of medical resources: Trauma centers are strategically located throughout the region to prevent overcrowding at a single hospital. Specialized emergency medical care: Emergency medical personnel are highly trained to perform advanced medical procedures on-site.
Weaknesses of the UK/Areas for improvement	Human resources and cost issues: Because many specialists are needed, labor costs are high, and securing human resources is difficult. Human resources and training issues: Because there are so many people, young doctors have less experience. Communication complexity: Frequent handovers and information transfers between staff reduce communication efficiency. Capital investment and financial burden: The sustainability of free medical services may become an economic issue.
Possibilities for application in Japan	Establishment of a trauma center: Establishing a regional trauma center will enable the centralization and strengthening of care for trauma patients. Introduction of a quality assessment system: A system that makes medical data more transparent and provides feedback can improve the quality of medical services. Establishment of regional trauma treatment: Uniform standards for transportation and treatment at the regional level can ensure consistent care. Online sharing of educational resources: Using online resources such as the UK’s Centre for Trauma Sciences website can potentially improve the quality of trauma care in Japan.

Nonetheless, this highly structured network presents challenges. Sustaining a large, skilled workforce incurs significant human resource and cost demands. We also noted that the abundance of senior staff may inadvertently limit procedural opportunities for junior doctors, and that frequent handover between multiple teams risks creating communication complexity. Furthermore, the financial burden of continual capital investment looms as the system becomes more sophisticated.

Education and simulation

The UK’s approach to EMS education is defined by national investment in purpose-built simulation facilities that bridge theory and practice (Table 2), differing from Japan’s predominantly lecture-based training models. Clinicians regularly engage in practical, scenario-based training to hone both technical procedures and communication skills. This training is seamlessly integrated with clinical practice, as exemplified by the Blizard Institute’s location adjacent to the Royal London MTC (Fig. 1C). During our observation, we identified no significant shortcomings in this educational model.

Table 2.

Comprehensive summary of qualitative data for education and simulation in UK and Japan

	Education and simulation
Strengths of the UK	National infrastructure and investment: The British government invests heavily in educational and simulation facilities. Well-equipped simulation facilities: Hospitals have rooms that can recreate various scenarios, enabling training in realistic clinical environments. Practical training: Hospital staff can participate in simulation training free of charge, and as annual sessions are mandatory, they can receive ongoing education.
Weaknesses of the UK/Areas for improvement	None in particular
Possibilities for application in Japan	On-site simulation: Training based on scenarios in actual clinical settings is beneficial for identifying and correcting deficiencies. Shared simulation center: Cooperative management and funding could establish a shared facility that a wide range of medical professionals can use.

ICU management

ICU management in the UK focuses on improving patient data sharing and supporting staff welfare (Table 3). Observed practices, such as single-room ICU designs for patient privacy, stand in stark contrast to the open-floor layouts that are standard in Japan. Emerging supra-regional networks aim to provide immediate access to comprehensive clinical information, while structured shift schedules and mental health programs contribute to a stable clinical team. However, challenges persist. We observed that manual processes linked to older physical infrastructure could complicate infection control, dim lighting might exacerbate patient delirium, and the continued reliance on handwritten records reduces data integration efficiency.

Table 3.

Comprehensive summary of qualitative data for ICU management in UK and Japan

	ICU
Strengths of the UK	Sharing of patient information: Easy access to patient data throughout the NHS hospital facilitates medical reviews and ensures comprehensive care. Consideration for staff welfare: Significantly reduces the physical and mental burden on each staff member, promoting a more sustainable work environment.
Weaknesses of the UK/Areas for improvement	Manual Processes and Infection Control: Unautomated doors and required security clearance can pose infection control risks. Ambiance: Dim lighting in patient rooms can exacerbate delirium. Continuation of Handwritten Records: Handwritten records remain despite a highly systematized medical environment.
Possibilities for application in Japan	Strengthening psychological support: Introducing a more muscular support system within the emergency department can reduce stress among staff. Reducing barriers to intensive care: Making it easier to request intensive care can lead to more rapid and effective patient management.

HEMS operations

HEMS teams provide advanced, physician-led prehospital critical care, a capability that far exceeds standard paramedic interventions (Table 4). As exemplified by the London Air Ambulance (Fig. 1B), these specialized teams perform procedures such as prehospital emergency anesthesia, REBOA, and complex invasive interventions like thoracostomy [16, 17]. This ability to deliver advanced care at the scene improves patient stabilization before hospital arrival [18], and is supported by cohesive air-ground team collaboration and strong public engagement [19].

Table 4.

Comprehensive summary of qualitative data for HEMS operations in UK and Japan

	HEMS
Strengths of the UK	Blood transfusions before arrival at the hospital: Blood transfusions required during the treatment of severe trauma can be administered before arrival at the hospital. Integrated team activities: The air and ground teams work under a unified command structure and intervene appropriately in each case. Operational status visualization and training: The system’s operational status is transparent, and simulations can be carried out while waiting. Social penetration and dissemination: Pre-hospital emergency care has already deeply penetrated societyand become an indispensable medical service in citizens’ daily lives.
Weaknesses of the UK/Areas for improvement	Operational and financial constraints: Safety management relies heavily on pilots, so concerns about barriers to entry and training periods are possible. Financial issues and fundraising: There is no government subsidy, and it is funded by charity from the public, so there is no continuous secured funding.
Possibilities for application in Japan	Flight doctor training: Emergency response capabilities can be improved by emphasizing extensive theoretical and simulation training for flight doctors. Integrated team management: Emergency response can be improved by adopting a model in which medical declarations by pre-hospital doctors lead to efficient team formation. Safety equipment: Given the deterioration of public safety in Japan, adopting protective equipment such as stab-proof vests is beneficial.

Despite these clinical strengths, the system’s long-term viability faces challenges. We noted that operational and financial models, particularly the reliance on charity fundraising outside of London, create an uneven provision of care—a situation often described as a “geographical lottery” [14, 17]. This funding model differs significantly from Japan’s publicly funded “doctor helicopter” system. This disparity results in limited or no 24-hour physician coverage in many regions, raising concerns about equitable patient access [17].

Research environment

The UK research environment is characterized by a tight integration of clinical practice, education, and research, supported by a robust infrastructure (Table 5). This systemic approach differs from Japan’s research culture, which often relies more on individual physician efforts. This cohesive structure, physically represented by the Blizard Institute’s proximity to the MTC and HEMS base (Fig. 1C), fosters a culture that rapidly translates evidence into clinical practice. The accessibility of intervention studies, coupled with dedicated research staff, drives continuous innovation. While no explicit weaknesses were observed, we concluded that maintaining these advantages requires sustained investment and institutional commitment.

Table 5.

Comprehensive summary of qualitative data for research environment in UK and Japan

	Research
Strengths of the UK	Integration of research, education, and clinical practice: The close links between research, education, and clinical practice enable continuous improvement of medical care and an improved work-life balance. Ease of conducting intervention studies: Integrating clinical and research work makes conducting intervention studies easy. Well-developed research support system: Many researchers, including research nurses, work in the emergency field, which enhances the quality and efficiency of research activities.
Weaknesses of the UK/Areas for improvement	None in particular
Possibilities for application in Japan	Fostering a research mindset in doctors: Encouraging doctors to become deeply involved in research topics and incorporate research discussions into their regular clinical practice can help foster a more research-oriented culture in the Japanese medical field.

Discussion

This study highlights the complementary characteristics and shared challenges of EMS in the UK and Japan, providing actionable insights for improving Japan’s EMS framework. Key findings and recommendations for each domain are discussed below.

Trauma networks and systems

The UK’s trauma network, centered around MTCs, demonstrates the effectiveness of a centralized model in improving outcomes for severely injured patients [20]. In contrast, Japan’s tiered triage system efficiently utilizes regional medical resources but lacks a dedicated framework for managing severe trauma cases [21]. Furthermore, Omori et al. (2014) emphasized the importance of early medical intervention in addressing the rising number of trauma cases in Japan’s aging society [22]. Japan’s EMS is also essentially one‑tiered, with all transports provided by local fire‑department ambulances; this structure limits selective triage to high‑level centers and reinforces the need for formal regional trauma designations [23].

A recent systematic review of 32 countries reported that, even among high-income nations, fewer than half have a fully articulated, Level IV trauma system with a national registry. In contrast, most middle-income countries remain at WHO Maturity Levels I and II [24]. Against this international benchmark, Japan would benefit from designating regional trauma centers, mandating uniform transfer protocols, and developing a single, nationwide trauma registry. Such steps would deliver the advantages of the UK’s centralized model while retaining Japan’s strengths in community‑based care.

Education and simulation

The UK’s simulation-based training emphasizes practical skills and immediate feedback, supported by active participation from practicing clinicians [25]. This approach contrasts with Japan’s predominantly lecture-based education system, which offers limited opportunities for hands-on training [26]. Although ELST certification in Japan can involve up to ~ 1,100 h of initial education, no formal recertification cycle or mandated simulation exposure exists, raising concerns about skills maintenance [23]. Establishing centralized simulation centers in Japan, with collaborative participation from multiple medical institutions and active involvement of clinical practitioners as trainers, would provide a more practical and impactful training environment. Additionally, in situ simulation could enhance healthcare teams’ problem-solving skills in real-world settings.

ICU management

The UK’s ICUs feature single-room designs and specialist-led management, ensuring patient privacy and high-quality care [27]. Conversely, Japan’s open-floor ICUs support strong multidisciplinary collaboration but face challenges in maintaining patient privacy [28]. To address these issues, Japan could consider not only a hybrid ICU model—combining open spaces with private rooms to leverage the strengths of both systems—but also strategies to strengthen psychological support for staff and simplify intensive care referral protocols. These operational improvements, paralleling the UK’s balanced approach, could enhance both patient experiences and overall staff satisfaction.

HEMS

The UK’s HEMS excels with its flexible operations and adoption of advanced prehospital interventions, such as blood transfusions and REBOA, that measurably improve patient outcomes [29, 30].

International comparisons of high-performing retrieval services reveal four recurring features, independent of the funding model: clinician-supported central coordination, specialized crews, graduate-level training programs, and comprehensive QA/QI databases [31]. Incorporating these elements into Japan’s publicly funded doctor-helicopter system, together with national governance standards and a unified data registry, would likely strengthen the clinical impact while preserving the program’s existing equity of access.

UK experience also highlights the risk of uneven provision when physician-staffed teams rely on charity or volunteer funding: a national survey revealed that, outside London, only 29% of air-ambulance services had a doctor on board seven days a week, and virtually none provided 24-hour coverage. This “geographical lottery,” repeatedly described in international EMS reviews, also occurs among high-income countries, underscoring the importance of stable public financing and standardized governance [14]. Securing stable public funding for critical‑care crews from the outset could help Japan avoid similar geographic and diurnal gaps [17].

Although nationwide coverage has been achieved, the Japanese system still faces limitations in operational flexibility, protocol standardization, and the adoption of emerging technologies [32]. Notably, when the doctor‑helicopter concept was first scaled nationally, only nine bases were operational—illustrating how recently rotary‑wing critical care has evolved in Japan [23]. Priority actions, therefore, include: (i) revising landing and dispatch policies to widen access; (ii) introducing advanced pre‑hospital technologies; (iii) enhancing flight doctor training and integrated team management; (iv) adopting safety equipment to improve personnel security; and (v) raising public awareness of helicopter EMS. These steps, combined with the governance and data enhancements noted above, are crucial for creating a more agile and responsive service.

Research environment

In the UK, enhancing research capacity within the clinical environment has involved expanding the research delivery workforce beyond traditional nursing roles. Introducing Clinical Research Practitioners (CRPs) from various educational and professional backgrounds who receive on-the-job training in essential research competencies exemplifies this adaptive strategy [33]. These developments align with the UK’s broader policy initiatives, such as “The Future of Clinical Research Delivery: 2022 to 2025 implementation plan,” designed to foster a sustainable, well-supported workforce that integrates clinical research as a core element of healthcare provision [34]. By mitigating staffing shortages and ensuring resilient research infrastructures, the UK is a global leader in life sciences innovation and evidence-based practice.

By contrast, Japan’s research environment often depends on individual efforts, with younger physicians increasingly moving away from research due to limited institutional support [35]. Japan could benefit from adopting a rotation model that balances clinical duties with research activities while strengthening support systems by incorporating research-focused personnel. These measures would promote greater participation in research activities and improve the overall quality of clinical research in Japan. This shift in research culture also extends to data collection itself; prospective data capture embedded within retrieval teams is now regarded as core service infrastructure rather than an optional research add‑on [31].

Future system‑level exploration and research agenda

To maximize the translational value of this study, subsequent UK–Japan exchanges should pursue two complementary tracks—field inspection and joint research—while explicitly addressing the cultural and regulatory constraints that shape Japan’s EMS evolution.

System‑level inspections: Future site visits should extend beyond flagship Major Trauma Centers to include resource‑constrained district hospitals and rural bases. Observing how the NHS calibrates staffing, triage algorithms, and doctor-car/HEMS activation under varying budgets will clarify which elements of central coordination are transferable and which require adaptation to Japan’s prefecture-led governance. Particular attention should be paid to (i) pre‑hospital triage criteria and real‑time medical oversight; (ii) cross‑agency communication platforms; and (iii) post‑incident audit and verification processes that close the quality loop.

Joint research priorities: Demographically, both countries face a surge in low‑mechanism, blunt trauma among older adults. Multicenter, hospital-based intervention trials—co-designed and synchronized across London MTCs and high-volume Japanese centers—could evaluate frailty-adapted resuscitation bundles or geriatric trauma pathways, generating evidence with global relevance. Parallel pre‑hospital studies should test expanded paramedic competencies and night‑time HEMS deployment. Still, protocols must incorporate Japan-specific legal and cultural safeguards: the current physician-dependent model and restrictive drug/airway authorizations necessitate a phased implementation and robust medical control [10].

Integrating cultural‑legal context: Any UK‑derived practice must be filtered through Japan’s regulatory lens—where role demarcation between physicians and paramedics is culturally sensitive and legally codified—and through public expectations that EMS remain hospital‑directed rather than field‑autonomous [10]. Comparative projects should therefore include (i) stakeholder mapping to anticipate professional resistance, (ii) policy analysis to identify statutes requiring amendment, and (iii) sociological evaluations of public acceptance.

By coupling broadened on-site observation with hypothesis-driven, culturally attuned research, the next phase of collaboration can transition from descriptive insight to evidence-based system redesign that respects Japan’s unique legal and societal context while drawing fully on UK experience.

Limitations

Several caveats temper our findings in this study. First, the four‑day, qualitative site visit offers only a snapshot and inevitably misses seasonal or operational variation. Second, all observations were drawn from London—a region with the UK’s only NHS‑commissioned, 24 h physician‑staffed HEMS; a national survey shows most other areas rely on ad‑hoc, charity‑funded cover with minimal night capability [17], and international reviews characterize such uneven access as a “geographical lottery” [14]. Extrapolating London practice to the rest of the UK, or Japan, therefore risks over‑optimism.

Third, the investigators’ interpretation may be influenced by prior experience, and language or cultural nuances could have affected the interviews. Fourth, our observational team consisted exclusively of frontline clinicians. While this composition was deliberate to gain deep operational insights, as stated in our Methods, the absence of healthcare administrators or policy experts is a notable limitation. Consequently, our system-level recommendations should be interpreted as practitioner-generated perspectives that require further validation from administrative and policy viewpoints. Fifth, we reviewed high-resource centers; many UK units operate with leaner staffing and infrastructure, and retrieval models vary by geography and weather [31]. Sixth, global reviews reveal wide heterogeneity in trauma-system maturity, even among high-income countries, underscoring the challenge of wholesale transposition [24]. Finally, the study is descriptive; without outcome or cost data, we cannot quantify benefit. Future work should combine multi‑site observations, registry linkage, and economic analysis to test whether proposed adaptations improve patient‑centered outcomes.

Conclusion

This comparative analysis of UK and Japanese EMS highlights how centralized trauma networks, simulation-based training, integrated ICU management, advanced HEMS, and a research-driven culture support efficient emergency care delivery in the UK. In contrast, Japan’s tiered, community-focused EMS emphasizes accessibility and equitable coverage.

Drawing on UK strengths, Japan could consider establishing regional trauma centers, enhancing simulation training, adopting hybrid ICU models, refining HEMS operations, and fostering a robust research environment. These adaptations may improve patient outcomes, address resource disparities, and align Japan’s EMS with international best practices.

Authors’ contributions

K.O. conceived and designed the study, led the site visits, conducted data collection and analysis, and wrote the original draft of the manuscript. P.V. supervised the project design, facilitated access to UK institutions, provided critical review of the methodology, and contributed to manuscript revision. H.N., S.K., J.T., and N.Y. participated in the on-site observations, assisted with data collection and thematic analysis, and contributed to the interpretation of results. C.A. coordinated parts of the institutional visits, provided clinical insights, and reviewed and edited the manuscript. R.D. facilitated access to research facilities, contributed to data interpretation, and reviewed and edited the manuscript. All authors reviewed and approved the final manuscript.

Funding

This work was supported by the Great Britain Sasakawa Foundation 2023 Butterfield Fund (Grant Application No. B150). The funding source was not involved in the study design, data collection, analysis, or publication decision.

Data availability

The qualitative datasets generated and analyzed during the current study are not publicly available due to the nature of the observational data collected at healthcare institutions and the confidentiality of informal discussions with healthcare professionals. However, anonymized data supporting the conclusions of this article are available from the corresponding author on reasonable request and subject to appropriate data sharing agreements.

Declarations

Ethics approval and consent to participate

Due to the non-interventional nature of this research and the absence of patient-identifiable data, formal ethical committee approval was not deemed necessary.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.