Medical Priority Dispatch System (MPDS)

The Medical Priority Dispatch System (MPDS) is a proven emergency response tool that helps 911 dispatchers prioritize medical calls based on urgency, ensuring the fastest care for those in life-threatening situations.

Why MPDS?

Effective November 6, 2025, Haldimand County will transition to the Medical Priority Dispatch System (MPDS)—a new, evidence-based approach to triaging 911 medical calls. The change is part of a province-wide initiative led by the Government of Ontario to improve emergency response and ensure the most critical patients receive care first.

The new system is being implemented at the Hamilton Central Ambulance Communications Center (CACC), which dispatches ambulances for Haldimand County and several neighbouring communities, ensuring consistent emergency call triaging across the region.

Under the previous system, paramedics were often dispatched in order of call time, which could delay care for more serious emergencies. MPDS changes that by:

Prioritizing life-threatening injuries
Improving response times for critical cases
Ensuring standardized and equitable response
Optimizing paramedic resources

MPDS is already used in more than 46 countries and thousands of emergency services worldwide. It will soon be the standard across Ontario.

How it works

The Medical Priority Dispatch System is a specialized tool used by Ambulance Communications Officers to assess 911 medical calls and determine which ones require the fastest response. It uses a structured, evidence-based approach to triage emergencies based on severity — ensuring that patients in the most critical condition receive care first.

Using MPDS, dispatchers can quickly identify:

Life-threatening emergencies – such as cardiac arrest, severe breathing issues, allergic reactions, or unconsciousness
Serious but stable conditions – urgent, but not immediately life-threatening
Minor injuries or illnesses – that can safely wait for care

Screenshot of the Priority Dispatch System with text saying "Watch MPDS in Action"

Built on decades of medical research and best practices, MPDS helps ensure that dispatch decisions are consistent, informed, and tailored to each patient’s needs.

What to Expect When You Call 911

When you dial 911 for a medical emergency, several trained professionals work together to get you the help you need.

A 911 communicator answers first and confirms the type of emergency.
An Ambulance Communications Officer then asks specific questions about your location, symptoms, and situation. These questions help determine how urgent your case is and which emergency services should respond — whether it’s police, fire, or an ambulance.

You may be asked similar questions again when emergency personnel arrive. This is normal and helps them assess and treat you effectively. Please answer clearly and completely; your responses help ensure the right care is provided.

Important: Answering questions does not delay help. In fact, the more details you provide, the faster and more accurately the right resources can be dispatched.

Understanding response times

The Medical Priority Dispatch System (MPDS) helps ensure that paramedics respond to the most urgent, life-threatening emergencies first. Our paramedics will still attend to non-critical situations — such as minor fractures, flu symptoms, or sprains — however, response times for these calls may be longer when crews are attending to more critical calls.

While waiting can be frustrating, it's essential to understand that delays occur because paramedics are actively responding to someone in critical need. Calls are prioritized based on urgency, and lower-priority calls are assigned to the most appropriate available resource rather than the first available resource.

What this means for you

If your call is non-critical, and all paramedic units are busy with more urgent emergencies, you may need to wait until a team becomes free. MPDS is designed to be flexible — paramedics en route to a lower-priority call can be reassigned if a more serious emergency arises. If this happens, another paramedic unit will be dispatched to assist you as soon as possible.

Throughout the process, dispatchers will stay in contact with you, so should your condition become more critical, your call may be re-prioritized to ensure timely care. You can also call 911 again if your situation becomes more serious.

Frequently asked questions

Why is this change happening?

This change ensures that patients with life-threatening conditions receive the quickest and best possible care before reaching the hospital. It gives paramedics the best opportunity to save lives.

Under the old system, paramedics could be tied up with non-urgent calls, leaving patients with more critical emergencies waiting longer for care.

Will non-urgent calls still get a response?

Yes, absolutely. Paramedics will still respond to lower-priority concerns such as sprains, flu symptoms, or minor fractures. However, response times for these calls may be longer when paramedics are focused on urgent, life-threatening cases.

What if my condition gets worse while I'm waiting?

An Ambulance Communications Officer will stay in contact with you through regular check-ins to monitor your symptoms while you wait.

If your condition worsens, they will re-prioritize your call and send help right away. If anything changes suddenly, please call 911 again immediately.

Can paramedics be redirected after being dispatched?

Yes. If a life-threatening emergency comes in while crews are en route to a non-critical call, they may be reassigned to ensure the most critical patients receive care first.

If this happens, another paramedic unit will be sent to assist you as soon as possible.

Will I see a doctor faster in the ER if I arrive by ambulance?

No. Hospitals use a triage system to determine the urgency of every patient’s condition, whether they arrived by ambulance or walked in. This ensures that the sickest and most critical patients are treated first.