BACKGROUND AND OBJECTIVES: Recognition of stroke/TIA symptoms by emergency medical services (EMS) is instrumental in providing timely recanalization treatments. We assessed the recognition of stroke/TIA by EMS via the emergency medical call center (EMCC) dispatchers and out-of-hours health service (OOHS) dispatchers.
METHODS: In a registry study, based on 2015-2020 data from the Copenhagen EMS, we calculated sensitivity, positive predictive value (PPV), specificity, and negative predictive value (NPV) of dispatcher suspicion of stroke or transient ischemic attack (TIA) and compared against discharge diagnosis.
RESULTS: We included 462,029 contacts to EMCC and 2,573,865 contacts to OOHS. In total, 19,798 contacts had a stroke or TIA diagnosis at hospital discharge. Sensitivity was 0.64 for EMCC dispatchers and 0.25 for OOHS. PPV was 0.28 for EMCC and 0.22 for OOHS; specificity was 0.96 for EMCC and >0.99 for OOHS, and NPV was 0.99 for EMCC and >0.99 for OOHS. Sensitivity improved over the period of the study from 0.62 to 0.68 for EMCC and from 0.20 to 0.25 for OOHS. PPV did not change over the period for EMCC and decreased from 0.26 to 0.19 for OOHS. Both EMCC and OOHS more frequently overlooked stroke in women, in patients calling more than 3 hours after symptom onset, and for more severe strokes. For OHHS, advanced age correlated with lower recognition.
DISCUSSION: As the first study reporting on OOHS setting dispatcher stroke/TIA recognition, we find a need for the improvement of stroke/TIA recognition both in EMCC and in OOHS. Solutions may include specific training of dispatchers, public awareness campaigns, and new technological solutions.