Abstract
Emergency department overcrowding represents a critical patient safety concern that has intensified globally over recent decades. This literature synthesis examines the relationship between corridor care, boarding practices, and adverse patient outcomes within emergency healthcare settings. Drawing upon systematic reviews, cohort studies, and qualitative research published between 2003 and 2025, this dissertation synthesises evidence demonstrating consistent associations between emergency department crowding and increased mortality, morbidity, treatment delays, medication errors, and patients leaving without being seen. The analysis reveals that boarding patients in corridors and non-clinical spaces creates conditions conducive to missed nursing care, compromised monitoring, and threats to patient dignity. Specific indicators, including boarding counts and occupancy scores, demonstrate utility in predicting safety events, whilst evidence suggests harm manifests non-linearly once threshold levels are exceeded. Notably, prolonged emergency department stays appear harmful primarily when combined with crowding conditions, suggesting corridor care represents systemic failure rather than mere spatial limitation. The findings underscore the urgent need for comprehensive system-level interventions addressing patient throughput, inpatient capacity, and boarding reduction, whilst implementing pragmatic risk-mitigation strategies including structured observation protocols and enhanced communication frameworks.
Introduction
Emergency departments serve as critical access points within healthcare systems, providing immediate care for acute illness and injury whilst functioning as safety nets for populations with limited healthcare access (Trzeciak and Rivers, 2003). Over recent decades, emergency departments globally have experienced unprecedented pressures, with demand consistently outstripping capacity and creating conditions wherein patients receive care in corridors, waiting areas, and other non-clinical spaces (Sartini et al., 2022). This phenomenon, variously termed corridor care, boarding, or holding, has emerged as one of the most pressing patient safety concerns in contemporary emergency medicine.
Corridor care occurs when emergency department demand exceeds physical and staffing capacity, forcing clinical teams to accommodate patients in hallways, overflow areas, and spaces never designed for clinical care delivery. This practice has become normalised in many healthcare systems despite representing a fundamental departure from accepted standards of safe care provision (Williams, 2023). The situation has been exacerbated by multiple intersecting factors, including ageing populations with complex comorbidities, workforce shortages, reduced inpatient bed capacity, and challenges in primary care access that redirect patients toward emergency services.
The academic and clinical significance of this topic cannot be overstated. Emergency department crowding affects every aspect of care delivery, from initial triage and assessment through treatment, disposition decisions, and eventual discharge or admission. When patients occupy corridors awaiting beds, they experience compromised privacy, reduced monitoring capability, and limited access to essential equipment and facilities. Simultaneously, clinical staff face impossible choices regarding care prioritisation, experiencing moral distress when unable to deliver care meeting professional standards (Eriksson et al., 2018).
From a public health perspective, emergency department overcrowding represents a system-wide failure with cascading consequences. Patients who leave without being seen may deteriorate in the community, returning in worse condition or suffering preventable harm. Treatment delays for time-sensitive conditions such as sepsis, stroke, and myocardial infarction can prove fatal. The accumulation of boarding patients reduces emergency department capacity to accept new arrivals, potentially affecting ambulance availability and response times across entire regions (Trzeciak and Rivers, 2003).
The social dimensions of corridor care warrant equal attention. Patients receiving care in corridors frequently report experiences of indignity, vulnerability, and dehumanisation. Elderly patients, those with mental health conditions, and individuals from disadvantaged backgrounds may be disproportionately affected, raising concerns regarding health equity and the fundamental ethical obligations of healthcare systems. Staff members, particularly nurses working in direct patient contact, report burnout, moral injury, and intentions to leave the profession when required to provide care under such conditions (Robertson, Ryan and Talpur, 2024).
This dissertation examines the evidence linking emergency department corridor care and overcrowding to adverse patient events. By synthesising findings from systematic reviews, observational studies, and qualitative research spanning over two decades, the analysis aims to establish the nature and magnitude of associations between crowding indicators and patient harm. Understanding these relationships is essential for informing policy responses, resource allocation decisions, and the development of mitigation strategies capable of protecting patients whilst system-level solutions are implemented.
Aim and objectives
The primary aim of this dissertation is to critically examine and synthesise the evidence regarding relationships between emergency department corridor care, overcrowding, and adverse patient outcomes.
The following objectives guide this investigation:
1. To identify and evaluate the key indicators used to measure emergency department overcrowding and their associations with patient safety events.
2. To examine the specific adverse outcomes linked to corridor care and boarding practices, including mortality, morbidity, treatment delays, and errors.
3. To explore the mechanisms through which overcrowding contributes to patient harm, including both direct clinical pathways and indirect systemic effects.
4. To analyse threshold effects and non-linear relationships between crowding levels and adverse event occurrence.
5. To evaluate the qualitative evidence regarding patient and staff experiences of corridor care, including impacts on dignity, wellbeing, and care quality perceptions.
6. To identify pragmatic risk-mitigation strategies and system-level interventions with potential to reduce harm associated with emergency department overcrowding.
Methodology
This dissertation employs a literature synthesis methodology, systematically examining and integrating evidence from multiple research traditions to develop comprehensive understanding of the relationships between emergency department overcrowding and adverse patient outcomes. Literature synthesis represents an appropriate methodological approach when seeking to consolidate findings across diverse study designs, populations, and healthcare contexts (Grant and Booth, 2009).
The evidence base for this synthesis derives from a structured search of academic databases conducted using systematic review protocols. Sources included peer-reviewed journal articles published between 2003 and 2025, encompassing systematic reviews, meta-analyses, cohort studies, cross-sectional analyses, and qualitative investigations. The temporal scope captures the evolution of evidence from early recognition of overcrowding as a safety concern through to contemporary research utilising sophisticated crowding metrics and large administrative datasets.
Inclusion criteria prioritised studies examining explicit relationships between emergency department crowding indicators and patient outcomes, including mortality, morbidity, adverse events, treatment delays, medication errors, and patient experience measures. Studies were required to be published in English in peer-reviewed journals or official government and organisational reports. Exclusion criteria eliminated opinion pieces, editorials without original data, and studies focused exclusively on operational efficiency without patient outcome measures.
The synthesis process involved several stages. Initial screening identified relevant titles and abstracts, followed by full-text review of potentially eligible studies. Data extraction captured study design, setting, population characteristics, crowding measures employed, outcome definitions, and key findings. Quality assessment considered methodological rigour, potential for bias, and generalisability of findings.
Synthesis proceeded through thematic analysis, grouping studies according to outcome categories, crowding indicators examined, and methodological approaches. Particular attention was paid to consistency of findings across studies, identification of contradictory evidence, and exploration of factors potentially explaining heterogeneity. The integration of quantitative and qualitative evidence enabled triangulation of findings, with experiential accounts from patients and staff providing context for statistical associations.
Limitations of this methodology warrant acknowledgement. Literature synthesis cannot generate new empirical findings and remains dependent upon the quality and completeness of primary studies. Publication bias may result in over-representation of positive findings, whilst heterogeneity in crowding definitions and outcome measures complicates direct comparison across studies. Despite these limitations, literature synthesis provides the most appropriate method for addressing the dissertation aim of establishing current evidence regarding overcrowding-outcome relationships.
Literature review
Historical development of evidence
Recognition of emergency department overcrowding as a patient safety threat has evolved substantially over the past two decades. Early work by Trzeciak and Rivers (2003) characterised emergency department overcrowding in the United States as an emerging threat to patient safety and public health, establishing conceptual foundations for subsequent research. Their analysis highlighted how crowding conditions could delay time-sensitive interventions and compromise care quality, whilst acknowledging limitations in available evidence regarding outcome effects.
The evidence base has expanded considerably since these initial observations. A timeline analysis reveals steady growth in publications, with accelerating research activity in recent years. Single publications appeared in 2003, 2014, 2015, and 2018, followed by three papers in 2019, one each in 2021 and 2022, five in 2023, two in 2024, and four in 2025. This pattern reflects increasing recognition of overcrowding severity and growing research capacity to investigate associated harms.
Systematic reviews have played a crucial role in consolidating findings across studies. Carter, Pouch and Larson (2014) conducted an early systematic review examining relationships between emergency department crowding and patient outcomes, reporting associations with mortality, morbidity, delayed treatment, medical errors, and patients leaving without being seen. Subsequent reviews by George and Evridiki (2015), Rasouli et al. (2019), and Sartini et al. (2022) have reinforced and extended these findings across diverse healthcare contexts.
The most comprehensive recent synthesis by Pearce et al. (2023) provides an overview of reviews describing measures, causes, and harms of emergency department crowding. This meta-review approach enables assessment of evidence quality and consistency across multiple primary reviews, strengthening confidence in associations between crowding and adverse outcomes.
Mortality and morbidity associations
Multiple systematic reviews consistently report associations between emergency department crowding and boarding with increased mortality. Rocha, Da Costa Farre and De Santana Filho (2021) conducted a systematic review specifically examining adverse events in emergency department boarding, finding clear associations with higher mortality rates alongside other negative outcomes. Their analysis demonstrated that boarding effects persist beyond the emergency department, affecting outcomes after hospital admission.
The relationship between crowding and mortality appears robust across different patient populations and healthcare settings, although effect magnitudes vary. Some studies report substantial mortality increases associated with crowding exposure, whilst others demonstrate weaker associations after controlling for patient characteristics and illness severity (Carter, Pouch and Larson, 2014). This variability likely reflects differences in crowding severity, duration of exposure, and capacity for compensatory care delivery.
Morbidity outcomes associated with crowding include increased intensive care unit admissions, longer hospital stays, higher rates of hospital-acquired complications, and greater likelihood of adverse events during treatment. Jun et al. (2025) demonstrated associations between emergency department overcrowding and in-hospital cardiac arrest occurrence, providing evidence for serious harm beyond delayed treatment effects.
Treatment delays and care quality
Treatment delays represent one of the most consistently documented consequences of emergency department overcrowding. When clinical spaces reach capacity and patients accumulate in corridors or holding areas, assessment, investigation, and treatment initiation inevitably slow. For time-sensitive conditions including sepsis, acute coronary syndromes, stroke, and trauma, such delays can prove determinative of outcomes.
Rasouli, Esfahani and Farajzadeh (2019) examined challenges and consequences of emergencies at hospitals, identifying delayed treatment as a primary mechanism through which crowding generates harm. Their systematic review highlighted how crowding disrupts established care pathways and prevents timely intervention delivery.
Beyond delays, crowding compromises care quality through multiple pathways. Medication errors increase as nurses and physicians work under pressure with inadequate space and equipment access (Alassaf et al., 2025). Care coordination becomes fragmented when patients are dispersed across clinical and non-clinical spaces, impeding communication between team members and increasing risk of important information being lost or overlooked.
Crowding indicators and measurement
Research has employed various indicators to quantify emergency department crowding, with different measures demonstrating variable associations with adverse outcomes. Understanding these measurement approaches is essential for interpreting findings and implementing monitoring systems in clinical practice.
Boarding counts, representing numbers of admitted patients awaiting inpatient beds whilst occupying emergency department space, show consistent associations with adverse events. Rocha, Da Costa Farre and De Santana Filho (2021) and Pearce et al. (2023) both report that boarding specifically predicts reduced care quality and increased adverse event rates.
Emergency department occupancy rate (EDOR) has demonstrated utility in multiple studies. Nan et al. (2024) developed methodology for scoring to assist emergency physicians in identifying overcrowding, finding that ED occupancy rate best matched physician perception and predicted adverse events. Eidstø et al. (2025) similarly employed occupancy measures when examining prolonged emergency department stays and patient safety.
Global crowding scores incorporating multiple parameters have shown associations with medication errors, care-coordination failures, treatment delays, patients leaving without being seen, and mortality in some cohorts. Alassaf et al. (2025) demonstrated correlation between emergency department crowding and adverse occurrences using composite crowding measures in a retrospective cohort study.
Importantly, different indicators may be appropriate for different purposes. Real-time operational monitoring may benefit from simple measures such as total census or boarding counts, whilst research examining outcome relationships may require more sophisticated composite scores capturing multiple dimensions of crowding severity.
Threshold effects and non-linear relationships
Emerging evidence suggests that crowding harms follow non-linear patterns, with risk rising substantially once threshold levels of total census or boarding patients are exceeded. This finding carries significant implications for capacity planning and operational management.
Nan et al. (2024) and Jun et al. (2025) both report evidence for threshold effects, indicating that harm does not increase proportionally with crowding but rather accelerates beyond certain levels. This pattern suggests that maintaining operations below critical thresholds may substantially reduce adverse event risk, whilst even modest threshold exceedance may generate disproportionate harm.
One large cohort study by Eidstø et al. (2025) found that prolonged emergency department length of stay alone was not an independent predictor of 10-day mortality when adjusted for confounders and crowding status. This nuanced finding suggests that context matters more than time alone, with crowding and blocked patient flow representing the primary harm mechanisms rather than duration of emergency department presence per se.
This distinction carries practical importance. Interventions focused solely on reducing individual patient length of stay may prove ineffective if underlying crowding conditions remain unaddressed. Conversely, maintaining flow and preventing boarding accumulation may protect patients even when some individuals experience prolonged emergency department stays.
Mechanisms of harm
Understanding the mechanisms through which crowding generates harm is essential for developing effective mitigation strategies. Evidence suggests multiple pathways operate simultaneously, creating cumulative risk for patients in overcrowded emergency departments.
Delayed assessment and treatment represent direct clinical mechanisms. When staff cannot assess patients promptly, deterioration may go unrecognised and time-sensitive interventions may be missed. George and Evridiki (2015) and Rasouli et al. (2019) both highlight assessment delays as primary harm pathways.
Missed nursing care occurs when nurses cannot complete essential tasks due to competing demands and inadequate time. Eriksson et al. (2018) documented registered nurses’ perceptions of safe care in overcrowded emergency departments, finding that nurses recognised how crowding prevented completion of fundamental care activities.
Medication errors increase under crowding conditions due to interruptions, inadequate verification processes, and communication failures. Rasouli, Esfahani and Farajzadeh (2019) identified medication errors as significant consequences of crowding, linked to environmental factors disrupting normal safety procedures.
Environmental factors specific to corridor care compound these risks. Patients in hallways experience reduced monitoring capability, limited equipment access, compromised privacy, and increased exposure to infection risk. Williams (2023) describes how corridor environments lack essential safety features designed into clinical spaces.
Qualitative evidence and lived experience
Qualitative and experiential research provides essential context for understanding crowding impacts beyond statistical associations. These studies capture the human dimensions of corridor care, documenting experiences of patients, families, and clinical staff.
Bentz, Brundisini and MacDougall (2023) conducted a rapid qualitative review examining perspectives and experiences regarding impacts of emergency department overcrowding. Their analysis describes overcrowded, boarded, and corridor patients as being in unsafe environments, with delayed, missed, or inappropriate care and threats to dignity characterising their experiences.
Williams (2023) specifically addresses corridor care in the emergency department, examining management of patient care in non-clinical areas. This practice-focused analysis highlights how corridor environments undermine fundamental requirements for safe care delivery whilst acknowledging the operational pressures making such practices seemingly unavoidable.
Robertson, Ryan and Talpur (2024) conducted a rapid review examining staff and patient experiences of crowding, corridor care, and boarding. Their findings reveal that corridor care undermines privacy, monitoring capability, basic nursing care, and nurse wellbeing. Staff report moral distress, burnout, and perceived compromised safety when working under overcrowded conditions.
Eriksson et al. (2018) documented registered nurses’ perceptions of safe care in overcrowded emergency departments, providing insight into professional experiences of delivering care under suboptimal conditions. Nurses recognised threats to patient safety whilst feeling unable to maintain standards they considered professionally acceptable.
System-level solutions and mitigation strategies
Addressing emergency department overcrowding requires both system-level solutions targeting root causes and pragmatic strategies mitigating harm whilst broader changes are implemented. The evidence supports multi-component approaches operating across different timeframes and organisational levels.
Pearce et al. (2023), in their overview of reviews describing global solutions and outcomes, identify throughput improvement, inpatient capacity expansion, and boarding reduction as fundamental system-level interventions. These approaches address underlying causes of crowding rather than merely managing symptoms.
Gross, Lane and Timm (2023) examined crowding in the emergency department with specific focus on challenges and best practices for paediatric care. Their analysis identifies population-specific considerations whilst endorsing general principles of capacity management and flow optimisation.
Sartini et al. (2022) provide a narrative review of overcrowding causes, consequences, and solutions, synthesising evidence regarding intervention effectiveness. Their analysis supports comprehensive approaches addressing input, throughput, and output factors contributing to crowding.
Pragmatic risk-mitigation strategies for implementation whilst system-level solutions are pursued include structured observation plans ensuring regular patient assessment in corridor areas, standardised checks preventing deterioration going unrecognised, clear communication protocols maintaining information flow across dispersed patient locations, and enhanced nurse autonomy enabling rapid response to changing patient needs (Williams, 2023; Pearce et al., 2023).
Discussion
Synthesis of evidence regarding overcrowding and adverse outcomes
The evidence synthesised in this dissertation demonstrates consistent associations between emergency department overcrowding, corridor care, and adverse patient outcomes. Across systematic reviews, cohort studies, and qualitative investigations spanning more than two decades, researchers have documented relationships between crowding conditions and increased mortality, morbidity, treatment delays, medication errors, care-coordination failures, and patients leaving without being seen.
This consistency across studies, methodologies, and healthcare contexts strengthens confidence in the existence of genuine causal relationships, despite limitations inherent in observational research. Whilst randomised controlled trials examining crowding effects would be ethically impermissible, the accumulation of observational evidence, supported by plausible biological and organisational mechanisms, supports conclusions that overcrowding causes harm rather than merely correlating with other harm-producing factors.
The finding that boarding specifically predicts adverse events beyond general crowding measures carries practical significance. Boarding represents a quantifiable, actionable indicator that can guide operational decision-making and trigger escalation protocols. Healthcare systems monitoring boarding counts can identify threshold exceedance and implement mitigation strategies before harm accumulates.
Understanding threshold effects and non-linear relationships
Evidence for non-linear relationships between crowding severity and adverse outcomes challenges assumptions underlying some capacity planning approaches. If harm increases proportionally with crowding, moderate overcrowding might be considered acceptable given resource constraints. However, threshold effects suggest that exceeding critical levels generates disproportionate harm, making capacity maintenance below thresholds substantially more valuable than previously recognised.
The finding by Eidstø et al. (2025) that prolonged emergency department stays are not independently associated with mortality when crowding status is controlled carries important implications. This suggests that context determines harm rather than duration alone. A patient remaining in the emergency department for extended periods whilst receiving appropriate care in adequate space may experience no increased risk, whilst a patient spending less time under crowded, resource-constrained conditions may face substantial danger.
This distinction should inform both research design and operational practice. Studies examining length of stay outcomes without controlling for crowding conditions may produce misleading conclusions. Operational approaches focused solely on individual patient throughput may prove ineffective if overall crowding conditions remain problematic.
Mechanisms and pathways to harm
Understanding harm mechanisms enables targeted intervention development. The evidence identifies multiple pathways through which crowding generates adverse outcomes, suggesting that effective mitigation requires addressing several mechanisms simultaneously.
Direct clinical mechanisms including delayed assessment, postponed treatment, and missed interventions represent primary harm pathways. These mechanisms operate independently of care setting, occurring whenever staff cannot attend to patients with appropriate promptness. However, corridor care exacerbates these mechanisms by removing patients from monitored environments, limiting equipment access, and impeding communication.
Process-related mechanisms including medication errors, care-coordination failures, and information loss reflect how crowding disrupts normal safety systems. Healthcare environments incorporate multiple redundancy features preventing errors from reaching patients. Crowding degrades these defences, allowing errors that would normally be intercepted to cause harm.
Environmental mechanisms specific to corridor care add additional risk layers. Corridors lack privacy features essential for thorough assessment and history-taking. Patients may conceal symptoms or withhold information when conversations can be overheard. Monitoring equipment may be unavailable or impractical to deploy. Infection control becomes compromised when patients are positioned in uncontrolled spaces with high traffic and inadequate hygiene facilities.
The human dimension: patients, families, and staff
Qualitative evidence documents human experiences that statistical analyses cannot capture. Patients receiving corridor care report feelings of vulnerability, indignity, and abandonment. These experiences may compound physical illness, generate psychological distress, and damage trust in healthcare systems. For elderly, confused, or mentally unwell patients, corridor environments may prove particularly distressing.
Staff experiences demand equal attention. Healthcare professionals enter their careers committed to providing excellent care and experience profound distress when circumstances prevent this. The moral injury arising from forced provision of substandard care contributes to burnout, turnover, and workforce attrition that further reduces capacity and worsens crowding. This vicious cycle threatens healthcare system sustainability.
Robertson, Ryan and Talpur (2024) document how corridor care undermines nurse wellbeing alongside patient safety. Recognising this dual impact should inform intervention prioritisation. Solutions protecting patients also protect staff, whilst failures allowing harm generation damage both populations simultaneously.
Implications for policy and practice
The evidence reviewed carries substantial implications for healthcare policy and operational practice. System-level solutions addressing root causes of emergency department crowding deserve priority attention and sustained investment. Expanding inpatient capacity, improving patient flow through hospitals, reducing unnecessary emergency department attendances, and addressing workforce shortages represent fundamental requirements.
However, system-level change occurs slowly whilst patients experience harm daily. Pragmatic mitigation strategies capable of rapid implementation deserve parallel attention. Structured observation protocols ensuring regular assessment of corridor patients, standardised communication systems maintaining information flow, and enhanced nurse autonomy enabling rapid response to deterioration can reduce harm whilst longer-term solutions are developed.
Crowding metrics should be incorporated into routine operational monitoring and quality reporting. Boarding counts and occupancy rates demonstrating associations with adverse events can trigger escalation protocols and inform resource deployment decisions. Transparency regarding crowding severity may also support advocacy for capacity investment.
Limitations and gaps in current evidence
Despite extensive research, important limitations and gaps persist. Definition heterogeneity complicates comparison across studies, with different investigations employing different crowding measures, threshold definitions, and outcome specifications. Standardisation efforts would strengthen future research.
Most evidence derives from high-income healthcare systems, limiting generalisability to resource-constrained settings where crowding may be more severe and mitigation options more limited. International research collaboration could address this gap whilst supporting knowledge transfer.
Intervention effectiveness evidence remains relatively limited. Whilst observational studies consistently document crowding-outcome associations, fewer investigations rigorously evaluate intervention impacts. Strengthening implementation research would support evidence-based practice improvement.
Long-term outcome studies are scarce. Most research examines immediate or short-term outcomes, with limited evidence regarding impacts on long-term recovery, chronic disease management, and healthcare utilisation patterns. Extended follow-up studies would provide more complete understanding of crowding consequences.
Conclusions
This dissertation has examined the evidence regarding relationships between emergency department corridor care, overcrowding, and adverse patient outcomes. The synthesis demonstrates that the stated objectives have been achieved through comprehensive analysis of available evidence.
Regarding the first objective concerning crowding indicators and their associations with safety events, the evidence clearly identifies boarding counts, occupancy rates, and composite crowding scores as useful measures demonstrating consistent associations with adverse outcomes. Different indicators may serve different purposes, with simple measures supporting operational monitoring whilst composite scores enable research examining outcome relationships.
The second objective examining specific adverse outcomes has been addressed through evidence demonstrating associations between corridor care and boarding with increased mortality, morbidity, treatment delays, medication errors, and patients leaving without being seen. These outcomes occur across diverse healthcare contexts, suggesting fundamental relationships rather than setting-specific phenomena.
The third objective exploring harm mechanisms has revealed multiple pathways through which overcrowding generates adverse outcomes, including delayed assessment and treatment, missed nursing care, medication errors, and environmental factors compromising monitoring, privacy, and infection control. These mechanisms operate simultaneously, creating cumulative risk for patients in overcrowded conditions.
The fourth objective analysing threshold effects has identified evidence for non-linear relationships between crowding severity and harm, with risk accelerating once critical thresholds are exceeded. The finding that prolonged emergency department stays cause harm primarily when combined with crowding conditions underscores the importance of context over duration alone.
The fifth objective evaluating qualitative evidence has documented patient and staff experiences revealing that corridor care threatens dignity, generates psychological distress, and produces moral injury among healthcare professionals. These human dimensions complement statistical findings and inform understanding of crowding impacts.
The sixth objective identifying mitigation strategies has revealed both system-level interventions addressing root causes and pragmatic approaches enabling harm reduction whilst longer-term solutions are implemented. Structured observation protocols, standardised communication systems, and enhanced nurse autonomy represent implementable strategies for immediate action.
The significance of these findings extends beyond academic understanding to inform urgent action within healthcare systems globally. Emergency department overcrowding represents a patient safety crisis demanding sustained attention and investment. The evidence synthesised here provides justification for prioritising capacity expansion, flow improvement, and boarding reduction as fundamental healthcare system requirements.
Future research should address current limitations through standardised definitions enabling cross-study comparison, investigations in resource-constrained settings expanding evidence generalisability, rigorous intervention effectiveness studies supporting practice improvement, and long-term follow-up examining extended outcome impacts. International collaboration could accelerate progress whilst supporting knowledge transfer across healthcare systems facing common challenges.
Ultimately, corridor care represents system failure rather than mere space limitation. Patients receiving care in hallways experience conditions incompatible with safe, dignified healthcare delivery. The evidence demands response commensurate with harm magnitude. Healthcare systems, policymakers, and clinical leaders bear responsibility for addressing this preventable source of patient harm with the urgency it deserves.
References
Alassaf, W., Albrahim, R., Abukhaled, J., Aldhaif, M., Mohammed, M., Baiz, A. and Aljahany, M., 2025. Correlation between emergency department crowding and adverse occurrences in an academic hospital: a retrospective cohort study. *Risk Management and Healthcare Policy*, 18, pp. 561-568. https://doi.org/10.2147/rmhp.s504578
Altun, M. and Kudu, E., 2025. Overcrowding in emergency departments: a scoping literature review. *Anatolian Journal of Emergency Medicine*. https://doi.org/10.54996/anatolianjem.1684632
Bentz, J., Brundisini, F. and MacDougall, D., 2023. Perspectives and experiences regarding the impacts of emergency department overcrowding: a rapid qualitative review. *Canadian Journal of Health Technologies*. https://doi.org/10.51731/cjht.2023.746
Carter, E., Pouch, S. and Larson, E., 2014. The relationship between emergency department crowding and patient outcomes: a systematic review. *Journal of Nursing Scholarship*, 46(2), pp. 106-115. https://doi.org/10.1111/jnu.12055
Eidstø, A., Tuominen, J., Ylä-Mattila, J., Huhtala, H., Palomäki, A. and Koivistoinen, T., 2025. Is a prolonged emergency department stay a risk for patient safety? *Journal of the American College of Emergency Physicians Open*, 6. https://doi.org/10.1016/j.acepjo.2025.100170
Eriksson, J., Gellerstedt, L., Hillerås, P. and Craftman, Å., 2018. Registered nurses’ perceptions of safe care in overcrowded emergency departments. *Journal of Clinical Nursing*, 27, pp. e1061-e1067. https://doi.org/10.1111/jocn.14143
Gaeta, S., Edwards, T., Bourenane, S., Gonzalez, C., McFarland, K. and Milling, D., 2019. Emergency department surge and overcrowding: an interdisciplinary solution for an institutional issue. *Journal of Clinical Oncology*, 37(27 suppl), p. 242. https://doi.org/10.1200/jco.2019.37.27_suppl.242
George, F. and Evridiki, K., 2015. The effect of emergency department crowding on patient outcomes. *Health Science Journal*, 9.
Grant, M.J. and Booth, A., 2009. A typology of reviews: an analysis of 14 review types and associated methodologies. *Health Information and Libraries Journal*, 26(2), pp. 91-108.
Gross, T., Lane, N. and Timm, N., 2023. Crowding in the emergency department: challenges and best practices for the care of children. *Pediatrics*. https://doi.org/10.1542/peds.2022-060972
Jun, J., Park, C., Park, I., Lee, J., Roh, Y. and Kim, M., 2025. Impact of emergency department overcrowding on the occurrence of in-hospital cardiac arrest. *PLOS ONE*, 20. https://doi.org/10.1371/journal.pone.0317457
Nan, S., Wittayachamnankul, B., Wongtanasarasin, W., Tangsuwanaruk, T., Sutham, K. and Thinnukool, O., 2024. An effective methodology for scoring to assist emergency physicians in identifying overcrowding in an academic emergency department in Thailand. *BMC Medical Informatics and Decision Making*, 24. https://doi.org/10.1186/s12911-024-02456-9
Pearce, S., Marchand, T., Shannon, T., Ganshorn, H. and Lang, E., 2023. Emergency department crowding: an overview of reviews describing measures causes, and harms. *Internal and Emergency Medicine*, pp. 1-22. https://doi.org/10.1007/s11739-023-03239-2
Pearce, S., Marr, E., Shannon, T., Marchand, T. and Lang, E., 2023. Overcrowding in emergency departments: an overview of reviews describing global solutions and their outcomes. *Internal and Emergency Medicine*, 19, pp. 483-491. https://doi.org/10.1007/s11739-023-03477-4
Rasouli, H., Esfahani, A. and Farajzadeh, M., 2019. Challenges, consequences, and lessons for way-outs to emergencies at hospitals: a systematic review study. *BMC Emergency Medicine*, 19. https://doi.org/10.1186/s12873-019-0275-9
Rasouli, H., Esfahani, A., Nobakht, M., Eskandari, M., Mahmoodi, S., Goodarzi, H. and Farajzadeh, M., 2019. Outcomes of crowding in emergency departments; a systematic review. *Archives of Academic Emergency Medicine*, 7. https://doi.org/10.22037/aaem.v7i1.332
Robertson, S., Ryan, T. and Talpur, A., 2024. Staff and patient experiences of crowding, corridor care and boarding: a rapid review. *Emergency Nurse*, 32(6). https://doi.org/10.7748/en.2024.e2215
Rocha, H., Da Costa Farre, A. and De Santana Filho, V., 2021. Adverse events in emergency department boarding: a systematic review. *Journal of Nursing Scholarship*, 53(4), pp. 487-494. https://doi.org/10.1111/jnu.12653
Sartini, M., Carbone, A., Demartini, A., Giribone, L., Oliva, M., Spagnolo, A., Cremonesi, P., Canale, F. and Cristina, M., 2022. Overcrowding in emergency department: causes, consequences, and solutions—a narrative review. *Healthcare*, 10(9), p. 1625. https://doi.org/10.3390/healthcare10091625
Trzeciak, S. and Rivers, E., 2003. Emergency department overcrowding in the United States: an emerging threat to patient safety and public health. *Emergency Medicine Journal*, 20(5), pp. 402-405. https://doi.org/10.1136/emj.20.5.402
Williams, C., 2023. ‘Corridor care’ in the emergency department: managing patient care in non-clinical areas safely and efficiently. *Emergency Nurse*, 31(5). https://doi.org/10.7748/en.2023.e2187
World Health Organization, 2019. *Patient safety: global action on patient safety*. Geneva: World Health Organization.
