Objective Secondary telephone triage to divert low-acuity patients to alternative non-ambulance services before ambulance arrival has been trialled in the UK and USA as a management strategy to cope with the increase in ambulance demand. The objective of this systematic review was to examine the literature on the structure, safety and success of secondary triage systems.

Methods For inclusion in the study, the telephone triage system had to be a secondary process, receiving referred patients who had already been categorised as low priority by a primary triage process. Two independent reviewers conducted the search to identify relevant studies. Six articles and one report were identified.

Results The major theme of the papers was the safety and accuracy of secondary telephone triage in identifying low-acuity patients. Two studies also discussed patient satisfaction. There was a low incidence of adverse events, as expected as these patients had already been subjected to primary telephone triage. In the studies identifying ambulance dispatch as a potential final disposition, at least half of the patients were diverted away from ambulance dispatch. In the studies that identified self/home care as a final disposition, a maximum of 31% of patients were categorised to this outcome. Otherwise all patients were recommended for assessment by a healthcare professional other than ambulance clinicians. Patients appeared to be satisfied with secondary telephone triage on follow-up.

Conclusions These results suggest that, while secondary triage of these patients is safe, further research is required to determine its most appropriate structure and its effect on ambulance demand.