DOWNLOAD THE POSTERAn ideal ambulance dispatch system will mobilise ambulance and first responder resources in a manner which is timely and appropriate to patient acuity. This needs to be balanced by rational use of resources, and limiting lights and sirens responses which can be dangerous to both the public and paramedics. Ambulance Victoria (AV) uses the Medical Priority Dispatch System (MPDS) to categorise 000 ambulance calls into levels of priority. The dispatch grid, which is determined by AV, is the designated level of ambulance response sent to each determinant code. Code 1 indicates a time critical incident; Code 2 indicates an acute incident requiring an urgent response without warning devices; Code 3 indicates a non-urgent incident; and Referral Service cases are low acuity MPDS event type codes which are approved for transfer to a secondary telephone triage service. AV have developed a dispatch grid review process which aims to ensure the most appropriate level of response is allocated to each MPDS event type. This systematic methodology, which has driven significant operational change, is outlined here.