Simple Triage Protocol Reduces Emergency Department Length of Stay

Emergency department (ED) overcrowding prolongs care, raises costs, and places added strain on clinical teams. Many hospitals cannot readily add beds, staff, or space, yet still need to move patients efficiently from triage to evaluation and disposition. Persistent queues also erode patient experience and can delay necessary treatment. A new study shows that a simple triage protocol can shorten ED stays without expanding capacity.

Researchers from Harvard University, Oxford University, and Mayo Clinic developed an evidence-based “vertical patient streaming” protocol that routes appropriate patients to a seated treatment area rather than a traditional bed. By standardizing decisions that are often made ad hoc, the approach aims to reduce variability and improve patient flow. The study, titled “Vertical Patient Streaming in Emergency Departments,” was published in Management Science.

The team first analyzed nearly 50,000 visits at Mayo Clinic Arizona to build a machine-learning model that predicts, using only triage information, whether a patient will ultimately require a bed. Inputs included the Emergency Severity Index (ESI) score, presenting complaint, and whether the department was over capacity. The researchers paired these predictions with mathematical models of patient flow to identify efficient routing strategies, resulting in a decision tree that clinicians can apply without new software or changes to hospital information systems.

A 13-week prospective field trial at Mayo Clinic Arizona’s new ED included 11,015 patients. Total ED length of stay fell by 11 minutes, a 4.2% reduction, while time from arrival to clinical disposition dropped by eight minutes, or 4.5%. There was no increase in 72-hour return visits, indicating that quality of care was maintained as throughput improved.

Because the protocol relies only on existing triage data and seated-care capacity already present in many EDs, the researchers note that it can be implemented quickly without new staffing or equipment. They estimate that a medium-sized ED seeing about 40,000 patients annually could recover nearly 6,800 bed-hours each year, creating capacity for roughly 2,000 additional patients and potentially generating about $3 million in additional reimbursement. The authors argue that analytics-guided operational changes can deliver meaningful gains without sacrificing safety.

“Our goal wasn’t to add technology to the emergency department. It was to give clinicians a practical, evidence-based way to decide which patients can safely receive care without occupying one of the department’s limited beds,” said Arshya Feizi, lead author of the study and a researcher at Harvard University.

“Our findings show that improving patient flow doesn’t always require expanding capacity. Sometimes the greatest opportunity comes from using existing resources more intelligently,” said Soroush Saghafian, co-author of the study and professor at Harvard University.