A citywide program that relies on patient referral by paramedics dramatically shortened door-to-balloon times and halved in-hospital mortality among patients with ST-segment elevation myocardial infarction.
Launched in May 2005 in Ottawa (population 800,000), the program allows specially trained paramedics to triage and transport STEMI patients directly to a percutaneous coronary intervention (PCI) center, bypassing the emergency department. The program was developed after researchers had shown that paramedics there could accurately interpret prehospital ECGs and identify STEMI, Dr. Michel R. Le May and his associates reported.
Paramedics with advanced training in cardiac life support perform and interpret 12-lead ECGs at the scene, then triage and transport patients with STEMI to the city's designated PCI center at the University of Ottawa Heart Institute, bypassing the city's four EDs. The paramedics also use a dedicated phone line to notify the cardiology team to anticipate the patient's arrival and assemble near the catheterization laboratory.
During the first year of the program, 135 STEMI patients were thus referred directly from the field by paramedics, said Dr. Le May of the heart institute and his associates (N. Engl. J. Med. 2008;358:231–40).
Another 209 STEMI patients went through the usual process of presenting to one of the four EDs either on their own or by ambulance not staffed by specially trained paramedics. These patients were triaged by an ED nurse, evaluated by an ED physician, and immediately transferred to the designated PCI center by ambulance. All the EDs were within a 10-minute ambulance ride of the PCI center. The median door-to-balloon time was significantly shorter for patients referred from the field (69 minutes) than for those transferred from EDs (123 minutes).
Door-to-balloon times of less than 90 minutes, as recommended in current guidelines, were achieved in 80% of patients referred from the field, compared with only 12% of those transferred from EDs, the investigators said.
“Before implementation of this approach, these patients (almost 40% of the entire cohort) would have been brought to the nearest hospital ED and considered for fibrinolysis. In this respect, the change in referral practice clearly benefited a substantial proportion of patients,” Dr. Le May and his associates noted.
In-hospital mortality was 3% for patients referred directly by paramedics, compared with 6% for those transferred from EDs. “Before we re-engineered our strategies, in-hospital mortality [for STEMI] was 10% for patients presenting to our city's EDs between 2002 and 2004,” they said.