Reliability of a Swedish pre-hospital dispatch system in prioritizing patients

The need of emergency help often begins with a call to a dispatch center. The operator uses a medical index to prioritize dispatches. Since the resources of ambulances are limited, it is important that the priority grading decided by the operator at the dispatch center is as adequate as possible. In the county of Jamtland in Sweden, a system for triage named METTS-A (Medical Emergency Triage and Treatment System-A) has been in use since 2009, when the patient is coded according to priority level. The aim of this study was to analyse the sensitivity and specificity of the priority grading made by the dispatch center in comparison with the METTS-A priority assessed by the ambulance nurse. Statistics from a data-base in northern Sweden were analyzed. The material covered every ambulance that was dispatched, 6986 times during the period of data collecting. The results show a high sensitivity but low specificity in the dispatch system. The results also indicate that over prioritization exists since most of the patients with a high acute need of an ambulance are correctly identified, while many patients without that need are also given a high priority ambulance service. Therefore the conclusions were that both over- and under prioritizations were made.