King County’s MCI Revolution: Why Triage Funnel Points Kill
Here’s the uncomfortable truth about how most EMS systems run mass casualty incidents: the structure we’ve been taught to build is itself creating the delays that cost lives.
The Seattle/King County Multiple Casualty Incident Plan looked at decades of MCI management, studied what actually happened during real incidents, and reached a conclusion that should change how every EMS provider thinks about scene architecture:
“A triage funnel point creates an unnecessary choke point, impeding patient care and will no longer be used.”
That’s not a suggestion. It’s a redesign of the entire system.
The Problem: Your Textbook MCI Is a Bottleneck Factory
Picture the traditional MCI setup you learned in class:
- Patients are extracted from the hazard zone
- They’re carried to a triage area — a single collection point
- A triage officer assesses each patient and assigns a category
- Tagged patients are moved to a treatment area
- Stabilized patients are moved again to a transport area
- Ambulances load patients and transport to hospitals
Count the hand-offs. Count the queues. Every one of those transitions is a place where patients wait, get lost, get re-sorted, or simply sit while the system catches up.
The triage funnel point is the worst offender. Every patient — regardless of acuity — gets funneled through a single triage officer or team before they can access treatment. If you have 20 patients and one triage team doing 60-second assessments, that’s 20 minutes before the last patient even gets categorized. In those 20 minutes, RED patients are waiting in line.
The King County Solution: Forward Momentum
King County’s plan is built on a single guiding philosophy: forward momentum. Everything is optimized to reduce on-scene time and accelerate the patient’s journey from point of injury to definitive surgical care. The “Golden Hour” drives every design decision.
Here’s what they changed:
1. Kill the Funnel Point
Patients extracted from the hazard zone go directly to the treatment area. There is no separate triage collection point. Triage happens during extraction, during movement, and at the treatment area — continuously, not at a standalone bottleneck.
The Treatment Unit Leader can divert patients directly to the transport corridor if they need immediate hospital care, skipping the treatment area entirely. The patient flows in one direction: out.
2. Transportation Corridor First
This is the single most impactful operational change in the plan. The very first arriving engine company establishes a protected transportation corridor before anything else.
What does this mean in practice? You identify a clear route from the incident to the street. Ambulances in, ambulances out. No apparatus blocking the path. No equipment dumped in the roadway. No bystanders milling in the access lane. Often secured by law enforcement.
Traditional approach: set up triage, then treatment, then eventually figure out how to get people out. King County flips it: secure the exit route first. If you can’t move patients off the scene, nothing else you build matters.
3. Sick / Not Sick
Instead of requiring providers to sort into four categories during the first chaotic minutes, King County uses a simplified binary decision:
| Classification | Triage Category | Action |
|---|---|---|
| SICK | RED (Immediate) | Needs intervention now. Priority treatment and transport. |
| NOT SICK | YELLOW or GREEN | Can wait. Granular sorting happens later in the Treatment Area. |
This doesn’t replace START or SALT — you still use the full algorithm. But the mental model shifts from “which of four categories?” to one question: “Is this patient going to die if I don’t act right now?”
It’s faster, it reduces decision paralysis, and it keeps people moving.
4. Treatment Adjacent to Transport
The treatment area is physically placed next to the transportation corridor. This isn’t a nice-to-have — it’s a core design principle. It minimizes the distance patients must be moved and streamlines coordination between the Treatment Unit Leader and Transportation Unit Leader.
When a RED patient is stabilized enough for transport, they move feet, not hundreds of yards, to the ambulance loading area.
5. 50% Rule for Rapid Resource Estimation
For rapid resource estimation in the first minutes, King County uses a simple planning assumption: assume 50% of patients will be SICK (Red) and 50% will be NOT SICK (Green/Yellow).
Is this perfectly accurate? No. But it gives you a working number before triage is complete. Dispatch reports a bus crash with 30 patients? You immediately request resources for ~15 critical patients. Adjust as better information comes in, but don’t wait for a complete triage count before calling for help.
Why This Works: Flow vs. Process
The traditional model is process-centered: triage is a process, treatment is a process, transport is a process. Each gets its own area, its own team, its own queue. The problem is that each process creates a line, and each line is a delay.
King County’s model is flow-centered: patients flow from hazard to treatment to transport. The system is designed to remove obstacles to that flow.
- No funnel points
- No collection areas
- No unnecessary hand-offs
- Treatment adjacent to transport
- Transportation corridor established first
- Standing orders so medics can act without waiting for radio permission
That last point matters. During a declared MCI in King County, EMS providers operate under MCI standing orders without contacting medical control for individual patient authorization. Because the medical control system itself becomes a bottleneck — if 20 medics all need to call the base hospital for orders on 20 patients, the radio system jams and patient care stops.
What You Can Use Tomorrow
You might not work in King County. Your jurisdiction might use a different MCI plan. But the principles are universal, and you can apply them anywhere:
- Establish egress first. Before you set up anything, make sure ambulances can get in and out. The transportation corridor is life.
- Think about flow. When you’re setting up a scene, ask: “Where are the bottlenecks? What’s going to slow down patient movement?” Then eliminate those bottlenecks before they form.
- Simplify your initial sort. Sick or not sick. Refine later. Don’t let the perfect sort prevent any sort.
- Keep patients moving in one direction. Hazard → Treatment → Transport → Hospital. Every time a patient moves sideways or backwards, you’re adding delay.
- Place treatment near transport. Even in your local system, you can influence where the treatment area goes. Put it adjacent to the ambulance loading area.
- Don’t let documentation delay care. Track the minimum essential — patient ID and hospital destination. Catch up on paperwork later.
The Bigger Picture
King County’s plan isn’t revolutionary because of a single innovation. It’s revolutionary because it asked a simple, uncomfortable question: “Are the systems we’ve been teaching actually helping patients, or are they helping us feel organized while patients wait?”
The answer forced a redesign from the ground up. Forward momentum. Eliminate chokepoints. Flow over process.
Your next MCI might be a 3-car pileup or a building collapse. Either way, the principles are the same: get patients moving toward definitive care as fast as possible, and don’t let your organizational structure become the thing that slows them down.