EMS Reverse Triage

Issues of Concern

Healthcare systems across the country experience periods when demand for services spikes above the baseline. These “surge” periods place significant stress on the system, particularly in areas with limited resources. Each system can manage surge demand to varying degrees, depending on the availability of resources and the ability to maximize their use.

"Surge capacity" refers to the maximum resources available during a given period. Hospitals typically operate at baseline capacity but can quickly expand this capacity by increasing resources or adjusting their management. Common methods for increasing capacity include calling in additional staff, opening “pop-up” inpatient units, and canceling elective surgeries or admissions.

During times of extreme demand, such as mass casualty incidents or disasters, even these standard capacity-enhancing techniques can become overwhelmed. Most healthcare systems employ triage protocols to identify the most critical patients who will require the most resources. In these situations, reverse triage helps redistribute resources by identifying the least critical patients who require fewer resources.

In periods of extreme surge, when demand exceeds supply, hospitals must determine which patients should receive access to finite resources, such as ventilators or blood products. In most hospital systems, inpatient beds are among the first resources to be consumed as demand increases.[2] Reverse triage addresses this critical deficiency by freeing inpatient beds for those who need them most.

In recent pilot trials of reverse triage, investigators have suggested that 10% to 20% of total bed capacity can be made available within the first 2 to 6 hours, with the full effect of a reverse triage system occurring within 24 to 48 hours. A study conducted in a health system with 3 hospitals found that reverse triage, compared to other methods (such as opening unstaffed licensed beds, canceling elective admissions, and filling open, staffed beds), had the greatest impact on generating surge bed capacity in all 3 locations despite significant differences in the patient populations served by these facilities.[3] The effect of reverse triage in the pediatric setting is more modest, generating a 10% to 13% increase in surge capacity by the end of the 96-hour study period. This effect is heavily dependent on pediatric psychiatry patients.[4]

A group of researchers at Johns Hopkins University, along with a panel of experts in emergency medicine and disaster preparedness, developed the reverse triage system to address inpatient capacity constraints during a disaster. For the system to operate as intended, the panel outlined several essential assumptions to ensure both safety and effectiveness. These assumptions can be grouped into 2 general categories: patient-centered and system-based.

In the patient-centered category, the quality of patient care is paramount and must not be compromised to increase capacity. Patients deemed safe for discharge will only have access to basic care in the community after dismissal. Additionally, patients with very poor prognoses and critical care needs, as well as pediatric patients, are considered separately from the general inpatient population.

In the system-based category, hospital systems must have a predetermined disaster plan in place, enabling the hospital to remain open and functional. The system should be capable of receiving necessary outside assistance within 48 to 72 hours. Alongside reverse triage, hospital systems should also continue to explore other means to improve capacity.

With these assumptions in mind, the challenge of reverse triage is determining which inpatients can be safely discharged. According to the expert panel, a patient qualifies for early discharge if no significant risk of a consequential medical event is expected within 72 hours of hospital discharge. Consequential events include irreversible impairment, unexpected death, and a reduction in function, but only if a critical intervention would be necessary to stabilize or improve the condition.

Critical interventions span a spectrum, from cardiopulmonary resuscitation to basic assistance with activities of daily living. Therefore, the more likely a patient will require critical interventions, the less likely they should be considered for early discharge through reverse triage.

When evaluating the likelihood of consequential medical events, clinicians must remember that even routinely discharged patients carry some risk for adverse events after leaving the hospital. A study estimates that adverse events occur in up to 19% of routinely discharged patients, and up to 12% experience preventable adverse events.[5] This baseline risk serves as a starting point when evaluating inpatients for early discharge under reverse triage and determining the individual risks associated with discharge.

A standardized system of inpatient classification was developed to help practitioners risk-stratify inpatients and determine the safest discharge plan. This system uses a 5-point scale, ranging from minimal risk (1) to very high risk (5), with maximum risk tolerance specified for each level.

The 1st group, the lowest risk category, includes patients with less than 4% risk of consequential medical events. These patients may have normal vital signs and can transition to oral antibiotics for a simple infection or oral anticoagulants for an uncomplicated deep venous thrombosis. These individuals are suitable for immediate discharge.

The 2nd group, with a less than 12% risk of requiring critical interventions, includes patients at low risk. These individuals may experience nonfatal medical events but can generally be discharged to family care or very low-acuity facilities.

The 3rd group, categorized as moderate risk, has a 33% chance of experiencing consequential events. Discharge to home care is not advised for this group. Suitable dispositions include transfer to moderate-acuity or skilled nursing facilities. This group may include patients who recently underwent major surgery and require intravenous pain management or antibiotics.

The 4th group, a high-risk category, has up to a 61% risk of needing critical care. Patients in this group should only be transferred to other major acuity facilities, as any delay in care could result in loss of life or limb. Examples include patients with strangulated hernias requiring emergency surgery, patients in active labor, or those with septic shock requiring intravenous vasopressors but not airway support.

The 5th group, the highest risk category, includes patients who are unstable for transport and have up to a 92% chance of experiencing consequential medical events. This group typically includes patients who require intensive care and thus cannot be moved.[6]

Once inpatients are appropriately classified into risk categories, suitable dispositions can be initiated. Although the goal is to create inpatient capacity, a potential limitation of the reverse triage system is that patients discharged early may return to the hospital due to a consequential medical event, worsening of their condition, or inappropriate discharge. Such occurrences can lead to a further surge in demand. However, the safety net of allowing patients to return for additional evaluation and management is necessary to prevent poor outcomes for those receiving care under the reverse triage system. Patients should be advised to return if they experience worsening symptoms or fail to improve as expected.

Patients who return to already strained healthcare systems present additional challenges. For example, a study suggests that patients who return to the emergency department after hospital discharge require longer treatment times and are twice as likely to be readmitted to the hospital.[7] These patients tend to have longer stays, incur higher charges, and, due to the increased likelihood of admission, create additional demand for limited resources, which undermines the efficiency of the reverse triage system.

Techniques to address surging healthcare demand remain an active area of research as hospital systems nationwide face increasing demand coupled with limited resources. While reverse triage has been proposed as a tool for managing surges during mass casualty or disaster events, several hospitals are assessing its feasibility for more routine situations, such as emergency department overcrowding. This application of reverse triage is undesirable, as it does not address the root cause of the problem—inpatient hospital bed availability. Reverse triage is designed to address a singular, overwhelming event that is unlikely to recur within a reasonable timeline, making it inherently self-limiting.

Although the reverse triage system could be applied to daily boarding and poor hospital flow planning, the acceptable level of risk for discharged patients is much lower in regular hospital operations compared to extreme events. As the tolerable level of risk decreases, the effectiveness of reverse triage also diminishes. Hospitals must determine the level of risk they are willing to accept in each situation and assess whether the capacity gained justifies the increased risk.

Ethical considerations play a critical role in determining the appropriateness of reverse triage models in healthcare. Healthcare professionals have a duty to provide care to those who seek medical attention, even during times of heightened demand. Simultaneously, healthcare institutions and public officials are responsible for stewarding resources effectively during crises. A 2009 report from the National Academy of Sciences on establishing standards of care in disaster situations highlights the potential tensions between these ethical obligations during a crisis.[8]

To mitigate such tensions, any surge capacity process, including reverse triage, must be transparent, consistent, and proportionate. These principles are essential to prevent the violation of ethical norms. Ensuring accountability for each member of the healthcare team is crucial for maintaining functional surge response systems. Despite full adherence to these guidelines, healthcare professionals may still face difficult ethical decisions that lead to moral injury. Therefore, any surge response model that limits care for patients, even those with a low risk of complications, must include resources to support healthcare professionals and prevent harm to those who serve as secondary victims of the crisis.

Clinical Significance

During a disaster, mass casualty incident, or epidemic, hospital systems often face a surge in demand for healthcare services that exceeds the available resources. Developing strategies to manage these periods of increased demand is crucial for maintaining healthcare system functionality under resource constraints. Reverse triage is one such strategy that can help allocate resources effectively, ensuring the greatest benefit to the highest number of patients. By discharging inpatients who can safely continue their care at an outside acute care facility or private residence, hospital beds become available for more critically ill patients.

While reverse triage offers a means of expanding hospital capacity, a standardized system is essential for determining which patients can be safely discharged. Such an approach ensures that morbidity and mortality associated with premature discharge are minimized. Hospital systems must evaluate discharge criteria at the individual level, considering factors such as risk tolerance, capacity needs, and available postdischarge resources. Tailoring these criteria to the specific needs of each system can enhance the effectiveness of reverse triage while maintaining high-quality care.