Secondary ambulance triage service models and outcomes: a review of the evidence

Secondary ambulance triage is designed to reduce inefficient use of ambulance and emergency services when another health care response is more appropriate. This review provides an overview of existing secondary ambulance triage service models, their characteristics, key service elements related to performance and evidence of service utilisation and outcomes. A summary of recommendations developed from previous evaluations as well as enquiries conducted when serious incidents have occurred in telephone triage, is provided as a basis to inform the development of ‘best practice’ models in secondary ambulance triage.There was limited literature describing secondary ambulance triage practices. This is a likely reflection of its relatively limited application to date. Available evidence suggests secondary ambulance triage is in operation in only a limited number of jurisdictions internationally. Data derived primarily from the UK and Australia show that secondary ambulance triage services are referred only a small proportion (6-9%) of all emergency ambulance calls. Of these calls, between 17 and 67% are passed back to the ambulance service for ambulance dispatch. However, utilisation of secondary ambulance triage services appears to translate into substantial cost savings to ambulance and emergency services.Few serious adverse events have been reported as arising from secondary ambulance triage.However, a number of preventable patient deaths have been attributed to failings in telephone triage systems in general and the lessons learnt are also relevant to secondary ambulance triage.