Mixed-Methods Investigation of Rural Emergency Medical Services ST-Elevation Myocardial Infarction Time to Percutaneous Coronary Intervention: High- vs Low-Performing Agencies.

Background: Patients with ST-elevation myocardial infarction (STEMI) cared for by rural emergency medical services (EMS) agencies commonly do not have first medical contact-to-percutaneous coronary intervention (PCI) time within the recommended goal of 90 minutes. In this study we identify factors associated with performance variation among rural EMS agencies in first medical contact-to-PCI time.

Methods: In this explanatory, sequential, mixed-methods study, we ranked eight rural county EMS agencies by continuous first medical contact-to-PCI time, accounting for loaded mileage, using data from a regional STEMI registry (2016-2019). A qualitative researcher conducted 28, one-hour, semi-structured interviews from January- March 2021 with the EMS director, training officer, medical director, and four paramedics at the top two high- and bottom two low-performing rural EMS agencies. Key informants were blinded to agency STEMI performance. Interviews were structured to identify positive deviance by exploring agencies' clinical approach to patients with chest pain, their organizational culture, structure, and quality improvement (QI) activities regarding STEMI care, and recommendations for improving STEMI performance. Interviews were digitally recorded and transcribed verbatim by a professional transcription service. We established a codebook and performed a thematic analysis using an inductive approach. We summarized and compared data across agencies to identify commonalities and differences between high- and low-performing agencies. Findings were reviewed and validated by an expert panel.

Results: The top two highest-performing EMS agencies had a median first medical contact-to-PCI time of 79 minutes (interquartile range [IQR] 65-91) minutes vs 98 minutes (IQR 82-120) among the bottom two lowest-performing agencies, P<.001. Both high- and low-performing agencies identified issues with electrocardiogram (ECG) transmitting technology and cumbersome hospital activation communications. However, top-performing agencies shared a culture that encourages early EMS activation of the cardiac catheterization lab after STEMI recognition. Top-performing agencies also placed a higher value on QI and training. These agencies prioritized mission and chain of command over staff relationships/interpersonal bonds; have stable, strong leadership; provide opportunities for career advancement; and collaborate with community leaders.

Conclusion: Top-performing rural EMS agencies for STEMI care promote early activation, have a strong chain of command, are mission focused, and have a greater focus on quality improvement and training.