Medical Dispatch (EMD) - Protocol-Driven Call Processing
This section covers the medical dispatch portion of the exam: how a dispatcher moves a caller from Case Entry through the Medical Priority Dispatch System (MPDS) protocol to a determinant code, then delivers Dispatch Life Support. The exam tests whether you can follow the protocol in order, select the correct determinant, and give Pre-Arrival Instructions (PAIs) without skipping steps.
Case Entry comes first, every time
Case Entry captures the address of the emergency, the callback number, and the chief complaint ("Tell me exactly what happened"). No key questioning and no PAI begins until the address is confirmed. The chief complaint selects the protocol; every protocol has a numbered Chief Complaint and a scripted set of Key Questions.
Determinants and levels
Determinant levels run Echo, Delta, Charlie, Bravo, Alpha, Omega. Echo is the highest - immediate, life-threatening (for example, a patient not breathing). Delta is life-threatening, Charlie urgent, Bravo and Alpha less urgent, and Omega means the call is not an EMS emergency and should be routed to an alternative response.
Dispatch Life Support
Dispatch Life Support has four parts: Post-Dispatch Instructions (PDIs), Pre-Arrival Instructions (PAIs), prioritization, and the provision of information to the crew. PAIs are scripted, protocol-driven, and given after the appropriate response is dispatched.
Worked example
Caller: "My husband collapsed and isn't breathing right." Case Entry takes the address, then the callback number. The complaint selects the cardiac/respiratory arrest protocol. The key question asks whether the patient is breathing normally; the caller describes gasping. Gasping is agonal breathing and is treated as not breathing - determinant 9-E-1. The highest response is sent, and CPR instructions begin immediately. Reasoning: the abnormal breathing description does not downgrade the call; agonal respirations are ineffective breathing.
Traps
- Treating agonal gasps as "breathing" and downgrading the determinant.
- Starting key questions before confirming the address.
- Giving PAIs before the response is dispatched, or improvising outside the script.
- Using Omega for a genuine emergency because the caller sounds calm.