This system also meets the UK target of a "call to needle time" (from the initial call for help to treatment) of less than 60 minutes.
The first study involved 201 patients with emergency chest pain living in the catchment area of a large teaching hospital in Scotland. Patients either received thrombolytics in hospital or were treated by paramedics in ambulances before they arrived in hospital.
The average call to needle time for patients treated before reaching hospital was 52 minutes, while patients from similar rural areas who were treated in hospital had an average time of 125 minutes. Patients from urban areas waited an average of 80 minutes for treatment.
Pre-hospital thrombolysis saved an average of 73 minutes over patients from rural areas and 28 minutes over patients from urban areas, say the authors. "Our data show a time saving of more than one hour in the prehospital group, we might expect two extra lives saved per 100 patients treated."
The second study shows that paramedics can safely administer thrombolysis in the community. All 64 paramedics serving South Devon Healthcare Trust were trained to diagnose heart attack and assess suitability for thrombolysis.
The goal of call to needle time in less than 60 minutes was met in 95% of cases, and 22% of patients would have received thrombolysis within 60 minutes of onset of symptoms. At present only 3% do so, say the authors.
"Autonomous paramedic prehospital thrombolysis seemed feasible and safe and was associated with improved call to needle times," they conclude.