Abstract 1586: Accuracy of Prehospital Electrocardiograms Interpreted by Paramedics in Olmsted County: The Mayo Clinic Prehospital Electrocardiogram Program
Background: Accuracy prehospital electrocardiograms (PH ECG) interpretation by paramedics for patients with ST-elevation myocardial infarction (STEMI) remains unknown.
Methods: The Mayo Clinic PH ECG program was implemented during 9/2007 in Olmsted County (population 141,360) with Gold Cross Emergency Medical Services (GC EMS). The program included training 67 GC EMS paramedics, equipping 8 ambulances and 18 volunteer basic EMS services were excluded. During the pre-phase (6/1/2006 – 8/31/2007) and post-phase (10/1/2007–2/28/2009), 855 and 1122 patients, respectively, were transported by GC EMS. During pre-phase, there was no PH ECG protocol. During post-phase, PH ECG was diagnosed Definite STEMI when computer and paramedic had concordant interpretation of new ST-elevation; Possible STEMI when computer and paramedic had discordant interpretation; and Not STEMI. Time metrics from 911 call to hospital arrival and accuracy of PH ECG interpretation were analyzed
Results: PH ECG use increased from 45% to 78% patients comparing pre- versus post-phase (p<0.001). Time metrics are shown in Table⇓. During post-phase, 54 STEMI patients were transported by GC EMS. Of these, 26 patients were diagnosed as Definite STEMI, 19 patients had discordant computer and paramedic interpretation of ST-elevation, and 9 patients did not receive a PH ECG. The sensitivity, specificity, positive predictive value, and negative predictive value of PH ECG interpretation of Definite STEMI were 48.1%, 99.6%, 86.7%, 97.4%, respectively. Among false negatives, 57% were attributable to computer interpretation of no ST-elevation and 21% to cardiac arrests where PH ECG was not performed.
Conclusions: Paramedics increased use of and interpreted PH ECG with high specificity and positive predictive value. Sensitivity was moderate and could be improved by eliminating computer interpretation and relying solely on paramedic interpretation of new ST-elevation.