Background: Ambulance patients are usually transported to the hospital in the emergency medical service (EMS) system. The aim of this study was to describe the nonconveyance practice in the Helsinki EMS system and to report mortality following non-conveyance decisions. Methods:All prehospital patients ≥16 years attended by the EMS but not transported to a hospital during 2013-2017 were included in the study. EMS mission-and patientrelated factors were collected and examined in relation to patient death within 30 days of the EMS non-conveyance decision. Results:The EMS performed 324,207 missions with a patient during the study period.The patient was not transported in 95,909 (29.6%) missions; 72,233 missions met the study criteria. The patient mean age (standard deviation) was 59.5 (22.5) years; 55.5% of patients were female. The most common dispatch codes were malaise (15.0%), suspected decline in vital signs (14.0%), and falling over (12.9%). A total of 960 (1.3%) patients died within 30 days after the non-conveyance decision. Multivariate logistic regression analysis revealed that mortality was associated with the patient's inability to walk (odds ratio 3.19, 95% confidence interval 2.67-3.80), ambulance dispatch due to shortness of breath (2.73, 2.27-3.27), decreased level of consciousness (2.72, 1.75-4.10), decreased blood oxygen saturation (2.64, 2.27-3.06), and abnormal systolic blood pressure (2.48, 1.79-3.37). Conclusion:One-third of EMS missions did not result in patient transport to the hospital. Thirty-day mortality was 1.3%. Abnormalities in multiple respiratory-related vital signs were associated with an increased likelihood of death within 30 days.

Majority of the patients had prior medical records. Psychiatric disorders were strongly presented.