Emergency departments (EDs) are the front line of healthcare, tasked with rapidly assessing and treating a diverse array of patients, from minor ailments to life-threatening emergencies. Effective triage, the process of sorting patients based on their acuity and need for immediate care, is paramount to ensuring that the most critical patients receive prompt attention while optimizing resource allocation. The Emergency Severity Index (ESI), a widely adopted triage system in the United States, aims to categorize patients into five levels, from Level 1 (most critical) to Level 5 (least critical). However, the accuracy and effectiveness of ESI, particularly version 4, in real-world settings has been a subject of ongoing investigation.
A recent cohort study encompassing over 5 million adult ED encounters across 21 hospitals delved into the critical issue of mistriage associated with ESI version 4. This research, conducted between 2016 and 2020, provides valuable insights into the rate of mistriage, the sensitivity of ESI in identifying critically ill patients, and the patient and visit characteristics that may contribute to triage inaccuracies. The findings underscore the importance of continuous quality improvement in triage processes to enhance patient safety, optimize resource utilization, and promote equitable care within the ED.
Understanding Emergency Department Mistriage: Scope and Significance
Mistriage in the ED context refers to the inaccurate assignment of a patient’s acuity level during triage. This can manifest as undertriage, where a patient’s condition is underestimated, potentially leading to delayed care for those with severe illnesses. Conversely, overtriage involves overestimating a patient’s acuity, which can result in unnecessary resource utilization and contribute to ED overcrowding. Both forms of mistriage can have significant implications for patient outcomes and ED operational efficiency.
The study highlighted that mistriage occurred in approximately one-third of the ED encounters analyzed. Alarmingly, the sensitivity of ESI version 4 in correctly identifying critically ill patients—those requiring life-stabilizing interventions—was found to be only 66%. This indicates a substantial rate of undertriage for patients with high-acuity conditions. While overtriage was more frequent, occurring in a larger proportion of cases, the clinical consequences of undertriage are often more severe, potentially leading to adverse patient outcomes.
The Impact of ED Crowding and the Role of Triage
ED crowding is a pervasive and growing concern, driven by increasing ED visits and the complexity of care required. This congestion can lead to prolonged wait times, which have been linked to poorer patient outcomes, including increased mortality, higher hospital admission rates, and patient dissatisfaction. Effective triage systems like ESI are intended to mitigate the negative effects of crowding by ensuring that patients are seen in a timely manner based on their medical urgency.
However, if the triage system itself is prone to inaccuracies, such as mistriage, it can inadvertently exacerbate the problems it is designed to solve. Undertriage can delay critical interventions for severely ill patients, while overtriage can further strain resources and contribute to bottlenecks in patient flow. Therefore, a reliable and accurate triage process is not just a matter of administrative efficiency; it is a critical component of patient safety and quality of care within the ED.
Methodology: Defining and Measuring Mistriage with EHR Data
A significant strength of this study lies in its innovative approach to defining and measuring mistriage. Recognizing the limitations of previous research that often relied on subjective expert opinions or small sample sizes, the researchers developed an electronic health record (EHR)-based algorithm to objectively assess triage accuracy.
This algorithm utilized operational definitions for each ESI level, leveraging readily available EHR data on ED interventions, resource utilization, and patient outcomes. A modified Delphi technique, involving a panel of emergency physicians and nurses, was employed to categorize ED interventions hierarchically, from least critical to most critical. These intervention levels, combined with resource use counts, formed the basis for defining undertriage and overtriage for each ESI level.
Validation and Application of the Mistriage Algorithm
Rigorous validation of the algorithm was conducted through multiple rounds of manual medical record review, ensuring accuracy in capturing mistriage events and agreement between human reviewers and the algorithm’s assessments. This validation process, involving over 400 medical records and achieving a high level of agreement, lends credibility to the study’s findings.
Once validated, the algorithm was applied to a massive dataset of over 5 million ED encounters, enabling a comprehensive assessment of mistriage rates across 21 EDs within a large integrated healthcare system. This large sample size and multi-center design enhance the generalizability of the study’s results to other similar ED settings.
Key Findings: Prevalence of Mistriage and Associated Factors
The application of the mistriage algorithm revealed a mistriage rate of 32.2% across the study cohort. While overtriage was more common (28.9%) than undertriage (3.3%), the study emphasized the clinical significance of undertriage, particularly in cases where critically ill patients were assigned lower acuity levels.
Figure. Assigned Emergency Severity Index (ESI), Version 4, Compared With Algorithm-Derived ESI.
Comparison of Assigned vs Algorithm-Derived Emergency Severity Index (ESI) Version 4 Triage Levels. Bar chart showing the distribution of patient encounters across ESI levels, highlighting undertriage and overtriage discrepancies. Illustrates mistriage rates in emergency department patient assessment.
The figure visually represents the discrepancies between the ESI levels assigned by triage nurses and those derived by the algorithm, highlighting the extent of both undertriage and overtriage across different ESI categories. Meaningful undertriage, defined as cases with significant clinical consequences, constituted a notable portion of all undertriaged encounters.
Disparities in Triage Accuracy: Sociodemographic and Clinical Factors
Multivariate analysis identified several sociodemographic and clinical characteristics associated with mistriage. Notably, younger patients, male patients, and Black patients were found to be at a higher risk of both undertriage and overtriage compared to their counterparts. Patients from socioeconomically disadvantaged neighborhoods and those who were not members of the integrated healthcare system also exhibited increased mistriage rates.
These findings raise concerns about potential biases in triage decision-making and highlight the need to address disparities in healthcare access and quality. The study also identified clinical factors associated with higher undertriage risk, including the use of high-risk medications like insulin or sulfonylureas, higher comorbidity burden, and recent intensive care unit (ICU) utilization. These clinical risk factors suggest opportunities for improving triage accuracy by incorporating more objective, data-driven elements into the triage process.
Implications for Quality Improvement and Future Directions
The study’s findings have significant implications for quality improvement efforts in ED triage. The high rate of mistriage, particularly undertriage of critically ill patients, underscores the need for strategies to enhance the accuracy and reliability of triage processes.
Moving Towards Data-Driven Triage
The researchers advocate for the development and implementation of more data-driven, standardized triage processes. Leveraging EHR data and prediction models can potentially reduce subjective biases and improve the consistency of triage assignments across different nurses and ED settings. The identification of specific clinical risk factors associated with mistriage provides actionable insights for developing targeted interventions and decision support tools for triage nurses.
The study acknowledges the release of ESI version 5, which incorporates updates aimed at improving the accuracy of identifying high-acuity patients and addresses potential biases in triage decisions. Future research is recommended to evaluate the impact of ESI version 5 on mistriage rates and to assess its effectiveness in mitigating the disparities identified in this study.
Addressing Disparities and Promoting Equity
The observed disparities in triage accuracy based on sociodemographic factors highlight the urgent need to address equity in ED care. Strategies to mitigate these disparities may include implicit bias training for triage nurses, the use of objective triage tools that minimize subjective judgments, and ongoing monitoring of triage accuracy across different patient populations.
Furthermore, the study emphasizes the importance of considering the trade-offs between undertriage and overtriage. While minimizing undertriage is paramount for patient safety, excessive overtriage can strain resources and contribute to ED crowding. A balanced approach, informed by data on patient outcomes and resource utilization, is needed to optimize triage processes and establish acceptable levels of both undertriage and overtriage.
Conclusion: Enhancing ED Triage for Safer and More Equitable Care
This comprehensive study provides compelling evidence of the prevalence of mistriage associated with ESI version 4 in a large, real-world ED setting. The development and validation of an EHR-based mistriage algorithm represent a significant methodological advancement, offering a robust tool for assessing triage accuracy and identifying areas for improvement.
The findings underscore the need for continuous quality improvement efforts focused on enhancing the accuracy, reliability, and equity of ED triage processes. Moving towards more data-driven and standardized triage protocols, incorporating objective risk factors, and addressing potential biases are crucial steps in ensuring that ED triage effectively serves its purpose: to prioritize the most critically ill patients and optimize resource allocation for the benefit of all patients seeking emergency care. As healthcare systems continue to grapple with increasing ED demands and the imperative to deliver high-quality, equitable care, research like this provides valuable insights and direction for improving the vital function of emergency department triage.
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