Paramedic-initiated helivac to tertiary hospital for primary percutaneous coronary intervention: a strategy for improving treatment delivery times.

Background: In regions of New Zealand without coronary catheterisation laboratory (CCL) facilities, patients presenting with ST-elevation myocardial infarction (STEMI) are often subjected to prolonged delays before receiving primary percutaneous coronary intervention (PPCI) if it is the chosen reperfusion strategy. Therefore, we aimed to trial a new process of paramedic-initiated helivac of STEMI patients from the field directly to the CCL.

Methods: Utilising a prospective observational approach, over a 48-month period, paramedics identified patients with a clinical presentation and electrocardiogram features consistent with STEMI and transported them directly to the regional air ambulance base for helivac to the CCL (flight time 30-35 minutes). These patients were compared to two historic STEMI cohorts either transported by paramedics to the region's local hospital or self-presenting, prior to helivac. The primary outcome measures were: first medical contact-to-balloon (FMCTB) time and accuracy of paramedic diagnosis. Secondary outcome measures were mortality at 30 days and six months, and hospital length of stay (LOS).

Results: A total of 92 patients underwent helivac for PPCI (mean age of 64 years, SD ±10.3). Median FMCTB time was 155 minutes (IQR 27) for the historic cohorts (n=57), versus 102 minutes (IQR 16) for the experimental cohort (n=35, P<0.001). Paramedic diagnosis showed a sensitivity of 97% (95% CI: 85 to 99) and a specificity of 100% (95% CI: 84 to 100) with no inappropriate CCL activations. No significant difference was observed between groups in terms of 30 day and 6-month mortality. Hospital LOS was significantly shorter among the experimental cohort (P=0.01).

Conclusions: Paramedic-initiated helivac of STEMI patients from the field directly to the CCL for PPCI is safe and feasible and can significantly improve time-to-treatment to within benchmark timeframes, resulting in reduced hospital LOS.