Underuse of prehospital strategies to reduce time to reperfusion for ST-elevation myocardial infarction patients in 5 Canadian provinces

Abstract

Objective: Timely reperfusion therapy for ST-elevation myocardial infarction (STEMI) is an important determinant of outcome, yet targets for time to treatment are frequently unmet in North America. Prehospital strategies can reduce time to reperfusion. We sought to determine the extent to which emergency medical services (EMS) use these strategies in Canada. Methods: We carried out a cross-sectional survey in 2007 of ground EMS operators in British Columbia, Alberta, Ontario, Quebec and Nova Scotia. We focused on the use of 4 prehospital strategies: 1) 12-lead electrocardiogram (ECG), 2) routine expedited emergency department (ED) transfer of STEMI patients (from a referring ED to a percutaneous coronary intervention [PCI] centre), 3) prehospital bypass (ambulance bypass of local EDs to transport patients directly to PCI centres) and 4) prehospital fibrinolysis. Results: Ninety-seven ambulance operators were surveyed, representing 15 681 paramedics serving 97% of the combined provincial populations. Of the operators surveyed, 68% (95% confidence interval [CI] 59%-77%) had ambulances equipped with 12-lead ECGs, ranging from 40% in Quebec to 100% in Alberta and Nova Scotia. Overall, 47% (95% CI 46%-48%) of paramedics were trained in ECG acquisition and 40% (95% CI 39%-41%) were trained in ECG interpretation. Only 18% (95% CI 10%-25%) of operators had prehospital bypass protocols; 45% (95% CI 35%-55%) had protocols for expedited ED transfer. Prehospital fibrinolysis was available only in Alberta. All EMS operators in British Columbia, Alberta and Nova Scotia used at least 1 of the 4 prehospital strategies, and one-third of operators in Ontario and Quebec used 0 of 4. In major urban centres, at least 1 of the 3 prehospital strategies 12-lead ECG acquisition, bypass or expedited transfer was used, but there was considerable variation within and across provinces. Conclusion:The implementation of widely recommended prehospital STEMI strategies varies substantially across the 5 provinces studied, and relatively simple existing technologies, such as prehospital ECGs, are underused in many regions. Substantial improvements in prehospital services and better integration with hospital-based care will be necessary in many regions of Canada if optimal times to reperfusion, and associated outcomes, are to be achieved.

Effect of time to electrocardiogram on time from electrocardiogram to fibrinolysis in acute myocardial infarction patients

“…31 Research into improving the rate at which AMI patients call for an ambulance has been extensive but unsuccessful; thus, the utility of the prehospital ECG applies to only one half of AMI patients. Although one survey found that 90% of US emergency medical systems (EMSs) have ECG equipment, 32 the use of prehospital ECGs has been patchy across the United States and Canada 33 : less than 10% of STEMI patients receive a prehospital ECG. 31 Diagnostic quality prehospital ECGs increase on-scene time by an average of 5 to 6 minutes, 30 similar to the target door-to-ECG time derived in this study.…”

The effect of a charted history of depression on emergency department triage and outcomes in patients with acute myocardial infarction

“…Only half arrive by ambulance, 27 and less than 10% of American patients with ST-segment elevation myocardial infarction receive a prehospital electrocardiogram, 28 with lower numbers in Canada. 29 Because of a relatively small number of patients who received primary percutaneous coronary intervention, we did not have the statistical power to include all 19 of the possible covariables in the model for door-to-balloon time. 18 We chose covariables based on clinical importance rather than with stepwise selection (which results in biased parameter estimates).…”

The utility of the prehospital electrocardiogram

“…[3][4][5][6] Based on data from 2009, 47% of paramedics in Canada are trained to obtain a pECG. 7 Studies have shown that EMS providers can acquire diagnostic quality pECGs without delaying hospital transport appreciably. [8][9][10][11][12] Research has also demonstrated the benefits of pECGs for decreasing door-todrug time and door-to-balloon time in patients with STEMI.…”