Impact of the COVID-19 pandemic on Canadian emergency medical system management of out-of-hospital cardiac arrest: A retrospective cohort study.

AIM: We sought to describe the impact of the COVID-19 pandemic on the care provided by Canadian emergency medical system (EMS) clinicians to patients suffering out of hospital cardiac arrest (OHCA), and whether any observed changes persisted beyond the initial phase of the pandemic. METHODS: We analysed cases of adult, non-traumatic, OHCA from the Canadian Resuscitation Outcome Consortium (CanROC) registry who were treated between January 27th, 2018, and December 31st, 2021. We used adjusted regression models and interrupted time series analysis to examine the impact of the COVID-19 pandemic (January 27th, 2020 - December 31st, 2021)on the care provided to patients with OHCA by EMS clinicians. RESULTS: There were 12,947 cases of OHCA recorded in the CanROC registry in the pre-COVID-19 period and 17,488 during the COVID-19 period. We observed a reduction in the cumulative number of defibrillations provided by EMS (aRR 0.91, 95% CI 0.89 - 0.93, p < 0.01), a reduction in the odds of attempts at intubation (aOR 0.33, 95% CI 0.31 - 0.34, p < 0.01), higher rates of supraglottic airway use (aOR 1.23, 95% CI 1.16-1.30, p < 0.01), a reduction in vascular access (aOR for intravenous access 0.84, 95% CI 0.79 - 0.89, p < 0.01; aOR for intraosseous access 0.89, 95% CI 0.82 - 0.96, p < 0.01), a reduction in the odds of epinephrine administration (aOR 0.89, 95% CI 0.85 - 0.94, p < 0.01), and higher odds of resuscitation termination on scene (aOR 1.38, 95% CI 1.31 - 1.46, p < 0.01). Delays to initiation of chest compressions (2 min. vs. 3 min., p < 0.01), intubation (16 min. vs. 19 min., p = 0.01), and epinephrine administration (11 min. vs. 13 min., p < 0.01) were observed, whilst supraglottic airways were inserted earlier (11 min. vs. 10 min., p < 0.01). CONCLUSION: The COVID-19 pandemic was associated with substantial changes in EMS management of OHCA. EMS leaders should consider these findings to optimise current OHCA management and prepare for future pandemics.

Patient and Prehospital Predictors of Hospital Admission for Patients With and Without Histories of Diabetes Treated by Paramedics for Hypoglycemia: A Health Record Review Study.

OBJECTIVES: The objectives of this study were to describe the characteristics, management, and outcomes of patients treated by paramedics for hypoglycemia, and to determine the predictors of hospital admission for these patients within 72 hours of the initial hypoglycemia event. METHODS: We performed a health record review of paramedic call reports and emergency department records over a 12-month period. We queried prehospital databases to identify cases, which included all patients ⩾18 years with prehospital glucose readings of <72 mg/dl (<4.0 mmol/L) and excluded terminally ill and cardiac arrest patients. We developed and piloted a standardized data collection tool and obtained consensus on all data definitions before initiation of data extraction by trained investigators. Data analyses included descriptive statistics univariate and logistic regression presented as adjusted odds ratios (aOR) with 95% confidence intervals (95%CI). RESULTS: There were 791 patients with the following characteristics: mean age 56.2, male 52.3%, type 1 diabetes 11.6%, on insulin 43.3%, median initial glucose 54.0 mg/dl (3.0 mmol/L), from home 56.4%. They were treated by advanced care paramedics 80.1%, received intravenous D50 37.8%, intramuscular glucagon 17.8%, oral complex carbs/protein 25.7%, and accepted transport to hospital 70.2%. Among those transported, 134 (24.3%) were initially admitted and four more were admitted within 72 hours. One patient was admitted, discharged, and admitted again within 72 hours. Patients without documented histories of diabetes (aOR 2.35, CI 1.13-4.86), with cardiovascular disease (aOR 1.81, CI 1.10-3.00), on corticosteroids (aOR 4.63, CI 2.15-9.96), on oral hypoglycemic agent(s) (aOR 1.92, CI 1.02-3.62), or those given glucagon (aOR 1.77, CI 1.07-2.93) on scene were more likely to be admitted to hospital, whereas patients on insulin (aOR 0.49, CI 0.27-0.91), able to tolerate complex oral carbs/protein (aOR 0.22, CI 0.10-0.48), with final GCS scores of 15 (aOR 0.53, CI 0.34-0.83), or from public locations (aOR 0.40, CI 0.21-0.75) were less likely to be admitted. CONCLUSIONS: There are several patient and prehospital management characteristics which, in combination, could be incorporated into a safe clinical decision tool for patients who present with hypoglycemia.

Implementation of the Modified Canadian C-Spine Rule by Paramedics.

STUDY OBJECTIVE: The Canadian C-spine rule was modified and validated for use by the paramedics in a multicenter study where patients were assessed with the Canadian C-spine rule yet all transported with immobilization. This study evaluated the clinical impact of the modified Canadian C-spine rule when implemented by paramedics. METHODS: This single-center prospective cohort implementation study took place in Ottawa, Canada (from 2011 to 2015). Advanced and primary care paramedics were trained to use the modified Canadian C-spine rule, collect data on a standardized study form, and selectively transport eligible patients without immobilization. We evaluated all consecutive low-risk adult patients (Glasgow Coma Scale [GCS] 15, stable vital signs) at risk for a neck injury. We followed all patients without initial radiologic evaluation for 30 days. Analyses included descriptive statistics with 95% confidence intervals (CI), sensitivity, specificity, and kappa coefficients. RESULTS: The 4,034 enrolled patients had a mean age of 43 (range 16 to 99), and 53.4% were female. Motor vehicle collisions were the most common mechanism of injury (55.1%), followed by falls (23.9%). There were 11 clinically important injuries. The paramedics classified these injuries with a sensitivity of 90.9% (95% CI, 58.7 to 99.8) and specificity of 66.5% (95% CI, 65.1 to 68.0). There was no adverse event or resulting spinal cord injury. The kappa agreement between paramedics and investigators was 0.94. A total of 2,583 (64.0%) immobilizations were avoided using the modified Canadian C-spine rule. CONCLUSION: Paramedics could accurately apply the modified Canadian C-spine rule to low-risk trauma patients and significantly reduce the need for spinal immobilization during transport. This resulted in no adverse event or any spinal cord injury.

Characteristics, Prehospital Management, and Outcomes in Patients Assessed for Hypoglycemia: Repeat Access to Prehospital or Emergency Care.

BACKGROUND: In Ontario, Canada, there currently are no prehospital treat-and-release protocols and the safety of this practice remains unclear. We sought to describe the characteristics, management, and outcomes of patients with hypoglycemia treated by paramedics, and to determine the predictors of repeat access to prehospital or emergency department (ED) care within 72 hours of initial paramedic assessment. METHODS: We performed a health record review of paramedic call reports and ED records over a 12-month period. We queried prehospital databases to identify cases, which included all adult patients (≥ 18 years) with a prehospital glucose reading of <72mg/dl (4.0mmol/L) and excluded terminally ill and cardiac arrest patients. We developed and piloted a standardized data collection tool and obtained consensus on all data definitions before initiation of data extraction by trained investigators. Data analyses include descriptive statistics with standard deviations, Chi-square, t-tests, and logistic regression with adjusted odds ratios (AdjOR). RESULTS: There were 791 patients with the following characteristics: mean age 56.2, male 52.3%, known diabetic 61.6%, on insulin 46.1%, mean initial glucose 50.0 dl/mg (2.8 mmol/L), from home 56.3%. They were treated by an Advanced Care Paramedic 80.1%, received IV D50W 38.0%, IM glucagon 18.3%, PO complex carbs 26.6%, and accepted transport to hospital 69.4%. Of those transported, 134/556 (24.3%) were admitted and 9 (1.6%) died in the ED. Overall, 43 patients (5.4%) had repeat access to prehospital/ED care, among those, 8 (18.6%) were related to hypoglycemia. Patients on insulin were less likely to have repeat access to prehospital/ED care (AdjOR 0.4; 95%CI 0.2-0.9). This was not impacted by initial (or refusal of) transport (AdjOR 1.1; 95%CI 0.5-2.4). CONCLUSION: Although risk of repeat access to prehospital/ED care for patients with hypoglycemia exists, it was less common among patients taking insulin and was not predicted by an initial refusal of transport.

Safety and clinically important events in PCP-initiated STEMI bypass in Ottawa.

OBJECTIVE: The aim of this study was to determine what clinically important events occur in ST-elevation myocardial infarction (STEMI) patients transported for primary percutaneous coronary intervention (PCI) via a primary care paramedic (PCP) crew, and what proportion of such events could only be treated by advanced care paramedic (ACP) protocols. METHODS: We conducted a health record review of STEMI transports by PCP-only crews and those transferred from PCP to ACP crews (ACP-intercept) from 2011 to 2015. A piloted data collection form was used to extract clinically important events, interventions during transport, and mortality. RESULTS: We identified 214 STEMI bypass cases (118 PCP-only and 96 ACP-intercept). Characteristics were mean age 61.4 years; 44.4% inferior infarcts; mean response time 6 minutes, 19 seconds; total paramedic contact time 29 minutes, 40 seconds; and, in cases of ACP-intercept, 7 minutes, 46 seconds of PCP-only contact time. A clinically important event occurred in 127 (59.3%) of cases: SBP < 90 mm Hg (26.2%), HR < 60 (30.4%), HR > 100 (20.6%), arrhythmias 7.5%, altered mental status 6.5%, airway intervention 2.3%. Two patients (0.9%) arrested, both survived. Of the events identified, 42.5% could be addressed differently by ACP protocols. The majority related to fluid boluses for hypotension (34.6%). In the ACP-intercept group, ACPs acted on 51.6% of events. There were six (2.8%) in-hospital deaths. CONCLUSIONS: Although clinically important events are common in STEMI bypass patients, a smaller proportion of events would be addressed differently by ACP compared with PCP protocols. The majority of clinically important events were transient and of limited clinical significance. PCP-only crews can safely transport STEMI patients directly to primary PCI.

The Safety of Bypass to Percutaneous Coronary Intervention Facility by Basic Life Support Providers in Patients with ST-Elevation Myocardial Infarction in Prehospital Setting.

BACKGROUND: Most patients transferred from a non-percutaneous coronary intervention (PCI) facility for primary PCI do not meet target reperfusion times. Direct transportation of patients with ST-elevation myocardial infarction (STEMI) from the scene by advanced life support (ALS) paramedics has been shown to improve reperfusion times and outcomes. OBJECTIVE: The aim of this study was to determine whether it is safe to bypass the closest hospital and transport by basic life support (BLS) provider to a PCI facility. METHODS: This was a health records review of consecutive patients transported to a regional PCI center under an STEMI bypass protocol. Under the PCI bypass protocol, patients were eligible if they presented with symptoms of chest pain, a 12-lead electrocardiogram meeting STEMI criteria, and if transported to the regional PCI center within 60 min. The occurrence of predefined adverse events during transport was determined, which included bradycardia < 50 beats/min, tachycardia > 140 beats/min, hypotension, cardiac arrest, and death. RESULTS: There were 46 cases of STEMI bypass between February 2005 and February 2013. Mean transport time was 29.9 min (range 20-62 min). Mean contact-to-balloon time was 95.2 min (range 68-159 min). Twenty-five adverse events occurred in 20 patients during transport. In 16 of the 20 patients, the adverse events were transiently abnormal vital sign requiring no intervention. In 3 of the patients, the adverse event was clinically significant and it is believed that the patient would have benefitted from advanced cardiac life support care not within the scope of practice of the BLS providers. CONCLUSIONS: In our region, STEMI patients can be diagnosed accurately and transported safely on bypass to a PCI center for primary PCI while respecting target reperfusion times.

Barriers to Self-Reporting Patient Safety Incidents by Paramedics: A Mixed Methods Study.

BACKGROUND: A minimal amount of research exists examining the extent to which patient safety events occur within paramedicine and even fewer studies investigating patient safety systems for self-reporting by paramedics. The purpose of this study was to identify barriers to paramedic self-reporting of patient safety incidents (PSIs). METHODS: We randomly distributed paper-based surveys among 1,153 paramedics in an Ontario region in Canada. The survey described one of 5 different PSI clinical scenarios (near miss, adverse event, and minor, major or critical patient care variances) and listed 18 potential barriers to self-reporting PSIs as statements presented for rating on a 5-point Likert scale (very significant = 1 - very insignificant = 5). We invited comments on PSI self-reporting with 2 open-ended questions. We analyzed data with descriptive statistics, chi-square tests and Kruskal-Wallis H test. We used an inductive approach to qualitatively analyze emerging themes. RESULTS: We received responses from 1,133 paramedics (98.3%). Almost one third (28.4%) were Advanced Care Paramedics and 45.1% had >10 years' experience. The top 5 barriers to PSI self-reporting (very significant or significant, %) were the fear of being: punished (81.4%), suspended (79.6%), terminated (79.1%), investigated by Ministry of Health and Long-Term Care (78.4%), and decertified (78.0%). Overall, 64.1% responded they would self-report a given PSI. Intention to self-report a PSI varied according to scenario (22.8% near miss, 46.6% adverse event, 74.4% minor, 92.6% major, 95.6% critical). No association was found between level of training (p = 0.55) or years of experience (p = 0.10) and intention to self-report a PSI. Seven themes to improve PSI self-reporting by paramedics emerged from the qualitative data. CONCLUSIONS: A high proportion of fear-based barriers to self-reporting of PSIs exist among this study population. This suggests that a culture change is needed to facilitate the identification of future patient safety threats.

Impact of Expanding the Prehospital Stroke Bypass Time Window in a Large Geographic Region.

BACKGROUND AND PURPOSE: The Ontario Acute Stroke Medical Redirect Paramedic Protocol (ASMRPP) was revised to allow paramedics to bypass to designated stroke centers if total transport time would be <2 hours and total time from symptom onset <3.5 hours. We sought to evaluate the impact and safety of implementing the Revised ASMRPP. METHODS: We conducted a 12-month implementation study involving prehospital patients presenting with possible stroke symptoms. A total of 1317 basic and advanced life support paramedics, of 9 land services in 10 rural counties and 5 cities, used the Revised ASMRPP to take appropriate patients directly to 6 designated stroke centers. RESULTS: We enrolled 1277 patients with 98.8% paramedic compliance in form completion. Of these, 755 (61.2%) met the redirect criteria and had these characteristics: mean age 72.1 (range 16-101), male 51.1%, mean time scene to hospital 16.7 minutes (range 0-92). Paramedics demonstrated excellent interobserver agreement (κ, 0.94; 95% confidence interval, 0.91-0.96) and 97.9% accuracy in interpretation of the Revised ASMRPP. Prehospital adverse events occurred in 14.7% of patients, but few were life-threatening. Overall, 71.4% of 755 cases had a stroke code activated at the hospital and 23.2% received thrombolysis. For the 189 potential stroke patients picked up in 1 city, the ASMRPP classified thrombolysis administration with sensitivity 100% and specificity 37.3% and a final diagnosis of stroke, with sensitivity 86.1% and specificity 41.9%. CONCLUSIONS: In a large urban-rural area with 9 paramedic services, we demonstrated accurate, safe, and effective implementation of the Revised ASMRPP. These revisions will allow more patients with stroke to benefit from early treatment.

Effectiveness and safety of a prehospital program of continuous positive airway pressure (CPAP) in an urban setting.

BACKGROUND: Continuous positive airway pressure (CPAP) is commonly used in the treatment of acute cardiogenic pulmonary edema (ACPE) and acute exacerbations of chronic obstructive pulmonary disease (AECOPD). In-hospital evidence is robust: CPAP has been shown to improve respiratory status and to reduce intubation rates. There is less evidence on prehospital CPAP, although the emergency medical services (EMS) adoption of this modality is increasing. The objectives of this study were to 1) measure the effectiveness of prehospital CPAP on morbidity, mortality, and transport times; and 2) audit the selection of patients by medics for appropriateness and safety. METHODS: We conducted a before-and-after study from August 1 to October 31 in 2010 and 2011, before and after the implementation of prehospital CPAP in a city of one million people with large rural areas. Medics were trained to apply CPAP to patients with respiratory distress and a presumed diagnosis of ACPE or AECOPD. Charts were selected using the search criteria of the chief complaint of shortness of breath, emergent transport to hospital, and any patients receiving CPAP in the field. Data extracted from ambulance call reports and hospital records were analysed with appropriate univariate statistics. RESULTS: A total of 373 patients enrolled (186 pre-non-invasive ventilation [NIV] and 187 post-NIV), mean age 71.5 years, female 51.4%, and final diagnoses of ACPE 18.9%, AECOPD 21.9%. In the post group of 84 patients meeting NIV criteria, 41.6% received NIV; and of 102 patients not meeting the criteria, 5.2% received NIV. There were 12 minor adverse events in 36 applications (33.3%) as per protocol. Comparing post versus pre, there were higher rates of emergency department (ED) NIV (20.0% v. 13.4%, p<0.0001) and higher overall mortality (18.8% v. 14.9%, p<0.0001). There were no differences in ED intubation (2.1% v. 2.3%, p<0.001) and length of stay (6.8 v. 8.7 days, p=0.24). CONCLUSION: Despite the robust in-hospital data supporting its use, we could not find benefit from CPAP in our prehospital setting with respect to morbidity, mortality, and length of stay. EMS must exercise caution in making the decision to invest in the equipment and training required to implement prehospital CPAP.

Prehospital use of furosemide for the treatment of heart failure.

INTRODUCTION: The diagnosis and management of acute decompensated heart failure (HF) in the prehospital setting can be challenging. The objectives of this study are to evaluate the appropriateness of furosemide use by Emergency Medical Services (EMS) and its association with adverse outcomes. METHODS: This study was a multi-centre health records review of EMS patients who received prehospital furosemide or had an emergency department (ED) diagnosis of HF. We included acutely ill patients ≥50 years of age with shortness of breath transported by land EMS. Univariate and logistic regression analyses were performed to determine associations between furosemide use and serious adverse outcomes (acute renal failure, intubation, vasopressors or death). RESULTS: The study population consisted of 330 patients (N=58, furosemide given by EMS but no HF diagnosed in ED; N=110, furosemide given, HF diagnosed; N=162, no furosemide given, HF diagnosed). The median dose of intravenous furosemide was 80 mg (range 20-80 mg). Serious adverse outcomes occurred in 61 patients (19.0%, 23.6% and 14.8% of the three groups, respectively; p=0.18). The adjusted ORs for adverse events with furosemide use was 0.62 (95% CI 0.33 to 1.43) in patients with a diagnosis of HF and 1.14 (95% CI 0.58 to 2.23) in those without. CONCLUSIONS: More than a third of patients who received prehospital furosemide did not have an HF diagnosis, suggesting that the prehospital diagnosis of HF can be challenging. Serious adverse outcomes were identified in all patient groups and we found no statistically significant associations between furosemide use and adverse events.

Reduction in mortality as a result of direct transport from the field to a receiving center for primary percutaneous coronary intervention.

OBJECTIVES: This study sought to determine whether mortality complicating ST-segment elevation myocardial infarction (STEMI) was impacted by the design of transport systems. BACKGROUND: It is recommended that regions develop systems to facilitate rapid transfer of STEMI patients to centers equipped to perform primary percutaneous coronary intervention (PCI), yet the impact on mortality from the design of such systems remains unknown. METHODS: Within the framework of a citywide system where all STEMI patients are referred for primary PCI, we compared patients referred directly from the field to a PCI center to patients transported beforehand from the field to a non-PCI-capable hospital. The primary outcome was all-cause mortality at 180 days. RESULTS: A total of 1,389 consecutive patients with STEMI were assessed by the emergency medical services (EMS) and referred for primary PCI: 822 (59.2%) were referred directly from the field to a PCI center, and 567 (40.8%) were transported to a non-PCI-capable hospital first. Death at 180 days occurred in 5.0% of patients transferred directly from the field, and in 11.5% of patients transported from the field to a non-PCI-capable hospital (p < 0.0001. After adjusting for baseline characteristics in a multivariable logistic regression model, mortality remained lower among patients referred directly from the field to the PCI center (odds ratio: 0.52, 95% confidence interval: 0.31 to 0.88, p = 0.01). Similar results were obtained by using propensity score methods for adjustment. CONCLUSIONS: A STEMI system allowing EMS to transport patients directly to a primary PCI center was associated with a significant reduction in mortality. Our results support the concept of STEMI systems that include pre-hospital referral by EMS.

The role of paramedics in a primary PCI program for ST-elevation myocardial infarction.

Time to reperfusion is linked to survival in patients presenting with ST-elevation myocardial infarction (STEMI). Primary percutaneous coronary intervention (PCI) is now considered the dominant strategy when it can be performed quickly. Because the number of cardiac catherization facilities is limited, health care workers have attempted to develop systems to ensure access to primary PCI for all patients with STEMI. The pre-hospital ECG has been shown to be a valuable tool to identify STEMI early and its use in the field has allowed paramedics to alert the medical team of an incoming patient with STEMI. Paramedics have come to play an important role in the early identification of patients with STEMI who make use of the emergency medical services. We review evidence that supports the role of the paramedics in patients presenting with STEMI.

A citywide protocol for primary PCI in ST-segment elevation myocardial infarction.

BACKGROUND: If primary percutaneous coronary intervention (PCI) is performed promptly, the procedure is superior to fibrinolysis in restoring flow to the infarct-related artery in patients with ST-segment elevation myocardial infarction. The benchmark for a timely PCI intervention has become a door-to-balloon time of less than 90 minutes. Whether regional strategies can be developed to achieve this goal is uncertain. METHODS: We developed an integrated-metropolitan-area approach in which all patients with ST-segment elevation myocardial infarction were referred to a specialized center for primary PCI. We sought to determine whether there was a difference in door-to-balloon times between patients who were referred directly from the field by paramedics trained in the interpretation of electrocardiograms and patients who were referred by emergency department physicians. RESULTS: Between May 1, 2005, and April 30, 2006, a total of 344 consecutive patients with ST-segment elevation myocardial infarction were referred for primary PCI: 135 directly from the field and 209 from emergency departments. Primary PCI was performed in 93.6% of patients. The median door-to-balloon time was shorter in patients referred from the field (69 minutes; interquartile range, 43 to 87) than in patients needing interhospital transfer (123 minutes; interquartile range, 101 to 153; P<0.001). Door-to-balloon times of less than 90 minutes were achieved in 79.7% of patients who were transferred from the field and in 11.9% of those transferred from emergency departments (P<0.001). CONCLUSIONS: Guideline door-to-balloon-times were more often achieved when trained paramedics independently triaged and transported patients directly to a designated primary PCI center than when patients were referred from emergency departments.

Comparison of early mortality of paramedic-diagnosed ST-segment elevation myocardial infarction with immediate transport to a designated primary percutaneous coronary intervention center to that of similar patients transported to the nearest hospital.

Speed of reperfusion is critical in ST-segment elevation myocardial infarction (STEMI). We assessed the safety and feasibility of an integrated metropolitan approach in which advanced-care paramedics interpret the prehospital electrocardiogram and independently refer patients with STEMI to a designated center for primary percutaneous coronary intervention (PCI). We developed and implemented a protocol in which paramedics trained in electrocardiographic interpretation bypassed the nearest emergency room and referred patients with suspected STEMI directly to a designated primary PCI center (paramedic-referred primary PCI). Outcomes of these patients were compared with those of a retrospective cohort of 225 consecutive patients with STEMI transported by ambulance to the nearest hospital emergency department. We treated 108 consecutive patients with STEMI using ambulance services according to the paramedic-referred primary PCI protocol. Primary PCI was performed in 93.5% versus 8.9% in the control group, and the median door-to-balloon time was 63 versus 125 minutes in the control group (p <0.0001 for 2 comparisons). Thrombolytic therapy was prescribed to 80.4% of the control group, with a median door-to-needle time of 41 minutes. In-hospital mortality was 1.9% in the paramedic-referred primary PCI group versus 8.9% in the control group (p = 0.017) and remained significantly lower after statistical adjustment for baseline risk. In conclusion, paramedic-referred primary PCI is a safe and feasible strategy for treating STEMI that is associated with rapid and effective reperfusion and very low in-hospital mortality.

Diagnostic performance and potential clinical impact of advanced care paramedic interpretation of ST-segment elevation myocardial infarction in the field.

OBJECTIVES: Most studies of pre-hospital management of ST-elevation myocardial infarction (STEMI) have involved physicians accompanying the ambulance crew, or electrocardiogram (ECG) transmission to a physician at the base hospital. We sought to determine if Advanced Care Paramedics (ACPs) could accurately identify STEMI on the pre-hospital ECG and contribute to strategies that shorten time to reperfusion. METHODS: A STEMI tool was developed to: 1) measure the accuracy of the ACPs at diagnosing STEMI; and 2) determine the potential time saved if ACPs were to independently administer thrombolytic therapy. Using registry data, we subsequently estimated the time saved by initiating thrombolytic therapy in the field compared with in-hospital administration by a physician. RESULTS: Between August 2003 and July 2004, a correct diagnosis of STEMI on the pre-hospital ECG was confirmed in 63 patients. The performance of the ACPs in identifying STEMI on the ECG resulted in a sensitivity of 95% (95% confidence interval [CI] 86%-99%), a specificity of 96% (95% CI 94%-98%), a positive predictive value (PPV) of 82% (95% CI 71%-90%), and a negative predictive value (NPV) of 99% (95% CI 97%-100%). ACP performance for appropriately using thrombolytic therapy resulted in a sensitivity of 92% (95% CI 78%-98%), a specificity of 97% (95% CI 94%-98%), a PPV of 73% (95% CI 59%-85%) and an NPV of 99% (95% CI 97%-100%). We estimated that the median time saved by ACP administration of thrombolytic therapy would have been 44 minutes. CONCLUSIONS: ACPs can be trained to accurately interpret the pre-hospital ECG for the diagnosis of STEMI. These results are important for the design of regional integrated programs aimed at reducing delays to reperfusion.