Paramedic-Delivered Fibrinolysis in the Treatment of ST-Elevation Myocardial Infarction: Comparison of a Physician-Authorized versus Autonomous Paramedic Approach.

ABSTRACT

Background: For those patients who receive fibrinolysis in the treatment of ST-elevation myocardial infarction (STEMI), early treatment, i.e., within 2 hours of symptom onset, confers the greatest clinical benefit. This rationale underpins paramedic-delivered fibrinolysis in the prehospital setting. However, the current New Zealand approach requiring paramedics to first gain physician authorization, has proved inefficient and time consuming, particularly due to technological failings. Therefore, this study aimed to trial a new autonomous paramedic-delivered fibrinolysis model, examining the impact on time-to-treatment, paramedic diagnostic accuracy and patient outcomes. Methods: Utilizing a prospective observational approach, over a 24-month period, paramedics identified patients with a clinical presentation and electrocardiogram features consistent with STEMI, and initiated fibrinolysis. These patients were compared to a historic cohort who received fibrinolysis by paramedics within the same regions but following physician authorization. The main outcome measures were pain-to-needle (PTN) time and accuracy of paramedic diagnosis. A secondary end-point was 30-day and 6-month mortality and hospital length of stay (LOS). Results: A total of 174 patients received fibrinolysis (mean age, 64 years, SD ± 11.2). Median PTN time was 87 minutes (IQR = 58) for the historic cohort (n = 96), versus 65 minutes (IQR = 31) for the experimental cohort (n = 78), (p = 0.007). Autonomous paramedic diagnosis showed a sensitivity of 96% (95% CI 89-99) and specificity of 91% (95% CI 76-98). A significant reduction in both 30-day mortality and hospital LOS was observed among the experimental cohort (p = 0.04 and <0.001, respectively). No significant difference was observed between groups in terms of 6-month mortality. Conclusions: Prehospital fibrinolysis provided autonomously by paramedics without direct physician oversight is safe and feasible. Moreover, this independent approach can significantly improve time-to-treatment, resulting in short term mortality benefit and reduced hospital LOS.