Epidemiology and aetiology of impaired level of consciousness in prehospital nontrauma patients in an urban setting

BackgroundThere is little information on the epidemiology and aetiology of nontraumatic loss of consciousness in patients in the Emergency Department, and this high-risk patient group has been poorly characterized in the prehospital setting as well. The aim of this study was to study the epidemiology and aetiology of nontraumatic impaired level of consciousness among the patients treated by an urban Emergency Medical Service (EMS) system in Finland.MethodsData of all emergency calls not related to trauma in an urban EMS system in southern Finland during 2012 were analysed. The inclusion criterion in this study was impaired level of consciousness as identified from the EMS run sheets. Diagnoses made in the receiving facility were cross-checked with the data.ResultsDuring the study period, the EMS was alerted to 22184 emergency calls. Of these, 306 calls met the inclusion criterion. The included patients could be categorized into four groups: seizures (32%), diabetes (24%), intoxication (17%) and impaired level of consciousness with no other obvious or specific cause (27%). The overall case fatality rate was 8%.ConclusionOf all EMS calls, patients who presented with an impaired level of consciousness represented 1.4% of all patients, but the fatality rate in those who remained with an impaired level of consciousness during the prehospital phase was considerable. Impaired level of consciousness was associated with a multitude of aetiologies, of which seizures were the most common.