Sunil Sookram

BIPHASIC Trial A Randomized Comparison of Fixed Lower Versus Escalating Higher Energy Levels for Defibrillation in Out-of-Hospital Cardiac Arrest

Background— There is little clear evidence as to the optimal energy levels for initial and subsequent shocks in biphasic waveform defibrillation. The present study compared fixed lower- and escalating higher-energy regimens for out-of-hospital cardiac arrest. Methods and Results— The Randomized Controlled Trial to Compare Fixed Versus Escalating Energy Regimens for Biphasic Waveform Defibrillation (BIPHASIC Trial) was a multicenter, randomized controlled trial of 221 out-of-hospital cardiac arrest patients who received ≥1 shock given by biphasic automated external defibrillator devices that were randomly programmed to provide, blindly, fixed lower-energy (150-150-150 J) or escalating higher-energy (200-300-360 J) regimens. Patient mean age was 66.0 years; 79.6% were male. The cardiac arrest was witnessed in 63.8%; a bystander performed cardiopulmonary resuscitation in 23.5%; and initial rhythm was ventricular fibrillation/ventricular tachycardia in 92.3%. The fixed lower- and escalating higher-energy regimen cases were similar for the 106 multishock patients and for all 221 patients. In the primary analysis in multishock patients, conversion rates differed significantly (fixed lower, 24.7%, versus escalating higher, 36.6%; P=0.035; absolute difference, 11.9%; 95% CI, 1.2 to 24.4). Ventricular fibrillation termination rates also were significantly different between groups (71.2% versus 82.5%; P=0.027; absolute difference, 11.3%; 95% CI, 1.6 to 20.9). For the secondary analysis of first shock success, conversion rates were similar between the fixed lower and escalating higher study groups (38.4% versus 36.7%; P=0.92), as were ventricular fibrillation termination rates (86.8% versus 88.8%; P=0.81). There were no distinguishable differences between regimens for survival outcomes or adverse effects. Conclusions— This is the first randomized trial to compare fixed lower and escalating higher biphasic energy regimens in out-of-hospital cardiac arrest, and it demonstrated higher rates of ventricular fibrillation conversion and termination with an escalating higher-energy regimen for patients requiring multiple shocks. These results suggest that patients in ventricular fibrillation benefit from higher biphasic energy levels if multiple defibrillation shocks are required.

Temporal trends in patient and treatment delay among men and women presenting with ST-elevation myocardial infarction

BACKGROUND over the last decade, there have been major changes in the treatment of ST-elevation myocardial infarction (STEMI). Whether these have resulted in changes in sex differences in time to treatment is unknown. We examined temporal trends in time to reperfusion therapy among men and women with STEMI. METHODS the study includes 2 cohorts of STEMI patients presenting to a large metropolitan region during the periods August 24, 2000, to August 20, 2002 (Cohort1, n = 753), and August 25, 2006, to December 31, 2008 (Cohort2, n = 885). RESULTS in both cohorts, compared with men, women were significantly older and had more comorbidities. Rate of emergency medical services use among women increased from 55% in Cohort1 to 66% in Cohort2 (P = .02). Median time from symptom onset to first medical contact was 84 minutes among men and 121 minutes among women (P < .01) in Cohort1 and 59 minutes among men and 81 minutes among women (P < .01) in Cohort2. Median door-to-balloon time was significantly longer among women compared with men in Cohort2. After multivariable adjustment, female sex was associated with a 34% (or 27-minute) increase in time from symptom onset to first medical contact and with a 23% (or 13-minute) increase in time from hospital arrival to reperfusion therapy. CONCLUSIONS in the last decade, there have been significant reductions in patient and system delay, especially among women. However, women continue to have longer presentation and treatment times, suggesting that there continue to be opportunities for improvement.

Bridging the Gap for Nonmetropolitan STEMI Patients Through Implementation of a Pharmacoinvasive Reperfusion Strategy

BACKGROUND Timely primary percutaneous coronary intervention (PCI) is the preferred reperfusion strategy in ST-elevation myocardial infarction (STEMI). However, universal access is limited outside metropolitan centres and portends worse outcomes for rural patients. This study evaluates the outcomes of STEMI patients treated in a metropolitan and nonmetroplitan setting within Vital Heart Response, an integrated reperfusion program developed to reduce reperfusion delay in Central and Northern Alberta. METHODS From October 2006 to March 2011, data on consecutive STEMI patients was prospectively recorded. Clinical characteristics, in-hospital management, and outcomes grouped by site of presentation are described. RESULTS There were 1990 metropolitan and 1602 nonmetropolitan STEMI patients. Metropolitan were older (62.7 vs 60.4 years; P < 0.001) and had more: angina (21.2% vs 16.5%; P < 0.001), dyslipidemia (45.3% vs 39.6%; P = 0.001), and hypertension (49.9% vs 46.6%; P = 0.047). The reperfusion strategy for metropolitan and nonmetropolitan: primary PCI (57.4% vs 22.9%; P < 0.001), fibrinolysis (26.3% vs 61.2%; P < 0.001), and no reperfusion (16.3% vs 15.9%; P = 0.855). First medical contact to reperfusion was delayed in nonmetropolitan with fibrinolysis and PCI, 8 and 125 minutes. A rescue PCI or coronary angiography within 24 hours was completed in 41.4% and 46.2%, respectively. Nonmetropolitan patients had fewer deaths (4.1% vs 6.8%; P = 0.001) with no difference in the composite outcome (death, reinfraction, congestive heart failure, cardiogenic shock) (16.8% vs 15.1%; P = 0.161) or major bleeding (7.9% vs 8.0%; P = 0.951). CONCLUSIONS Systematic application of a pharmacoinvasive strategy appears to be safe and effective for patients in whom a delay in mechanical reperfusion is anticipated.

The Pre-Hospital Fibrinolysis Experience in Europe and North America and Implications for Wider Dissemination

OBJECTIVES The primary objective of this report was to describe the infrastructures and processes of selected European and North American pre-hospital fibrinolysis (PHL) programs. A secondary objective is to report the outcome data of the PHL programs surveyed. BACKGROUND Despite its benefit in reducing mortality in patients with ST-segment elevation myocardial infarction, PHL remained underused in North America. Examination of existing programs may provide insights to help address barriers to the implementation of PHL. METHODS The leading investigators of PHL research projects/national registries were invited to respond to a survey on the organization and outcomes of their affiliated PHL programs. RESULTS PHL was successfully deployed in a wide range of geographic territories (Europe: France, Sweden, Vienna, England, and Wales; North America: Houston, Edmonton, and Nova Scotia) and was delivered by healthcare professionals of varying expertise. In-hospital major adverse outcomes were rare with mortality of 3% to 6%, reinfarction of 2% to 5%, and stroke of <2%. CONCLUSIONS Combining formal protocols for PHL for some patients with direct transportation of others to a percutaneous coronary intervention hospital for primary percutaneous coronary intervention would allow for tailored reperfusion therapy for patients with ST-segment elevation myocardial infarction. Insights from a variety of international settings may promote widespread use of PHL and increase timely coronary reperfusion worldwide.

Time from first medical contact to reperfusion in ST elevation myocardial infarction: A Which Early ST Elevation Myocardial Infarction Therapy (WEST) substudy

BACKGROUND Recent research and contemporary ST elevation myocardial infarction guidelines emphasize the importance of prompt reperfusion and have redefined the traditional time to treatment metric to include prehospital paramedical staff as the point of first medical contact. However, an important knowledge gap exists relating to data systematically addressing the impact of arrival at the hospital by ambulance and the delays inherent in transfer from a community hospital to tertiary centres for percutaneous coronary intervention (PCI). METHODS The Which Early ST Elevation Myocardial Infarction Therapy (WEST) study initiated treatment at the point of first medical contact, including prehospital contact. Patients were randomly assigned to receive fibrinolysis with usual care or coupled with mechanical cointervention, or primary PCI. To assess the impact of this strategy on time to treatment, the following randomly assigned patient groups were compared: prehospital versus in-hospital; those arriving at the hospital by ambulance versus ambulatory self transport; and those whose initial hospital care was a community versus PCI centre. RESULTS Of the 328 patients enrolled in the study, 221 received fibrinolysis and 107 received primary PCI. Compared with the in-hospital group, patients who underwent prehospital random assignment (44%, n=145) experienced a 48 min reduction in median (interquartile range) time from symptom onset to first study medication (87 min [65 min to 147 min] versus 135 min [95 min to 186 min]; P<0.001) and a 56 min reduction in time to first balloon inflation (148 min [117 min to 214 min] versus 204 min [166 min to 290 min]; P<0.001). Arrival by ambulance without prehospital random assignment (n=90) incurred a substantial delay from first medical contact to reperfusion (fibrinolysis 76 min [63 min to 105 min] and PCI 160 min [141 min to 212 min]) compared with prehospital random assignment (n=145; fibrinolysis 43 min [33 min to 54 min] and PCI 105 min [90 min to 127 min]) or ambulatory patients (n=93; fibrinolysis 47 min [32 min to 68 min] and PCI 108 min [85 min to 150 min]). Community (n=165) versus PCI hospital (n=163) random assignment was associated with a longer delay from first medical contact to reperfusion: fibrinolysis, 56 min versus 47 min (P=0.008) and primary PCI, 139 min versus 105 min (P=0.001). DISCUSSION Prehospital diagnosis, random assignment and treatment substantially reduced treatment delay with both pharmacological and mechanical reperfusion. Those activating the prehospital medical response system without receiving prehospital random assignment experienced the longest delay from first medical contact to reperfusion, indicating a lost opportunity to enhance ST elevation myocardial infarction patient outcomes.

Treatment choices in elderly patients with ST: elevation myocardial infarction—insights from the Vital Heart Response registry

Background Management of elderly patients with ST elevation myocardial infarction (STEMI) is challenging and they are under-represented in trials. Accordingly, we analysed reperfusion strategies and their effectiveness in patients with STEMI ≥75 years compared to <75 years within a comprehensive inclusive registry. Methods Consecutive patients with STEMI admitted to hospital and tracked within a regional registry (2006–2011) were analysed comparing reperfusion strategy (primary percutaneous coronary intervention (PPCI), fibrinolysis and no reperfusion) between patients ≥75 vs <75 years old as well as across the reperfusion strategies in those ≥75 years. Results There were 3588 patients with STEMI with 646 (18%) ≥75 years old. Elderly patients were more likely female (46.9% vs 18.4%) and had more prior: angina (28.2% vs 17.2%), myocardial infarction (MI; 22.8% vs 13.9%), hypertension (67.6% vs 44.2%), heart failure (2.3% vs 0.3%) and atrial fibrillation (2.2% vs 0.5%) (all p<0.001). The reperfusion strategy for patients ≥75 vs <75: PPCI 45.3% vs 41.2%, fibrinolysis 24.8% vs 45.7%, and no reperfusion 29.9% vs 13.1% (p<0.001). Time from symptoms to first medical contact (median, 93 vs 78 min p=0.008) and PPCI (median, 166 vs 136 min (p<0.001) were longer for ≥75 years. In those ≥75 years outcomes by reperfusion (PPCI, fibrinolysis and none) were: in-hospital death 13.3%, 9.4% and 19.7% (p=0.018), and composite of death, recurrent-MI, cardiogenic shock and congestive heart failure 28%, 20% and 33.2% (p=0.022). Conclusions Elderly patients have more comorbidities, worst in-hospital clinical outcomes and are less likely to receive reperfusion. Acknowledging physician selection of the reperfusion strategy; outcomes appear favourable in the elderly receiving fibrinolysis.

Pre-hospital management of anaphylaxis in one Canadian Urban Centre

STUDY AIM Anaphylaxis requires prompt recognition and management to improve patient outcomes. This study examined the diagnosis and treatment of anaphylactic reactions by the Emergency Medical Services (EMS) in a Canadian urban centre. METHODS Electronic patient care records (ePCRs), identifying allergy-related calls in the Edmonton-Zone for the year 2011, were retrospectively reviewed to confirm anaphylaxis diagnosis and record treatments. Data were abstracted and entered into the REDCap electronic platform. Descriptive and multivariable analyses were performed. Pre-hospital management included any care provided by paramedic personnel and/or first-aid treatment received prior to EMS arrival. RESULTS From 481 identified allergy-related case records, 136 (28%) met guideline criteria for anaphylaxis. Seventy-six (56%) of these confirmed cases were deemed high acuity by medical dispatchers. Self-medication and bystander first-aid was recorded in 60 (44%) anaphylactic events; 34 (25%) received epinephrine. Paramedics administered epinephrine in an additional 49 cases (36%); only 7% received all three primary pre-hospital anaphylaxis treatments: epinephrine, corticosteroids, and antihistamines. Factors associated with pre-hospital epinephrine administration included: previous episode of anaphylaxis (adjusted odds ratio [aOR]=4.9, 95% confidence interval [CI]: 1.30, 19.21); administration of corticosteroids by bystanders or EMS personnel (aOR=3.8, 95% CI: 1.36, 10.65); and transport severity (aOR=3.2, 95% CI: 1.21, 8.36). CONCLUSION Paramedics in this region demonstrated higher use of epinephrine than reported elsewhere; however, almost half of all patients meeting anaphylaxis criteria did not receive pre-hospital epinephrine. Instead, more patients received antihistamines. Efforts to improve adherence to anaphylaxis protocols and guidelines appear warranted.

Mode of hospital presentation in patients with non–ST-elevation myocardial infarction: Implications for strategic management

INTRODUCTION Contemporary non-ST-elevation myocardial infarction-acute coronary syndrome guidelines emphasize early-risk stratification and optimizing therapy including an invasive strategy in high-risk patients. To assess the feasibility of initiating this strategy in the prehospital environment, we examined how such patients are transported to hospital, their risk profile, and the proportion potentially eligible for such a strategy. METHODS Consecutive patients with ST-segment elevation myocardial infarction admitted in Edmonton were studied between September and November 2008 and divided according to their mode of transport to hospital: emergency medical services (EMS) versus self-presenting. Baseline characteristics, GRACE Risk Score, blinded core laboratory electrocardiogram analysis, cardiac biomarkers, in-hospital procedures, and outcomes were analyzed. RESULTS Thirty-five percent (93/263) of patients presented via EMS and often to percutaneous coronary intervention hospitals, that is, 64.5% versus 44.1% (P = .0016). They were older (75 vs 62 years, P < .001), more often female (43% vs 28.1%, P < .001), diabetic (34.4% vs 22.9%, P = .045), and hypertensive (72.0% vs 57.1%, P = .017) and had higher GRACE Risk Scores (median 166 vs 130, P < .001). Electrocardiogram analysis revealed more baseline Q waves (38.8% vs 25.5%, P = .031) and ST depression ≥2 mm (P = .027) in EMS-transported patients. Fewer EMS patients underwent cardiac catheterization (60.2% vs 88.2%, P < .001), and a paradoxical relationship existed between catheterization rates and GRACE Risk Score in the total cohort (low-risk: 93.4% vs high-risk: 59.3%, P < .001). The composite of death/re-myocardial infarction/congestive heart failure/shock was greater in EMS patients (unadjusted odds ratio 3.96, 95% CI 1.80-8.69, P = .001); these differences were attenuated after GRACE Risk Score adjustment. CONCLUSION Regional strategies using risk-based triage, early medical therapy, and timely triage to percutaneous coronary intervention centers represents an unrealized opportunity to enhance ST-segment elevation myocardial infarction care.

Providing Rapid Out of Hospital Acute Cardiovascular Treatment 4 (PROACT‐4)

Background Whether prehospital point‐of‐care (POC) troponin further accelerates the time to diagnosis in patients with chest pain (CP) is unknown. We conducted a randomized trial of POC‐Troponin testing in the ambulance. Methods and Results Patients with chest pain presenting by ambulance were randomized to usual care (UC) or POC‐Troponin; ST‐elevation myocardial infarction patients or those with noncardiovascular symptoms were excluded. Pre‐hospital high‐sensitivity troponin was analyzed on a POC device and available to the paramedic and emergency department (ED) staff. The final diagnosis was centrally adjudicated. The primary endpoint was time from first medical contact to discharge from ED or admission to hospital. We randomized 601 patients in 19 months; 296 to UC and 305 to POC‐Troponin. After ambulance arrival, the first troponin was available in 38 minutes in POC‐Troponin and 139 minutes in UC. In POC‐Troponin, the troponin was >0.01 ng/mL in 17.4% and >0.03 ng/mL in 9.8%. Patients spent a median of 9.0 hours from first medical contact to final disposition, and 165 (27.4%) were admitted to the hospital. The primary endpoint was shorter in patients randomized to POC‐Troponin (median 8.8 hours [6.2–10.8] compared to UC (median 9.1 hours [6.7–11.2]; P=0.05). There was no difference in the secondary endpoint of repeat ED visits, hospitalizations, or death in the next 30 days. Conclusions In this broad population of patients with CP, ambulance POC‐Troponin accelerated the time to final disposition. Enhanced and more cost‐effective early ED discharge of the majority of patients with CP calling 911 is an unrealized opportunity. Clinical Trial Registration URL: https://www.ClinicalTrials.gov/. Unique identifier: NCT01634425.

Can body temperature be maintained during aeromedical transport

BACKGROUND Aeromedical transport in northern areas may be associated with hypothermia. The objective of this study was to determine whether significant hypothermia (core temperature <35 masculineC) occurs in severely injured or ill intubated patients during transport by rotary wing aircraft. METHODS In this prospective cohort study, all intubated patients over 16 years of age who were transported by rotary wing aircraft from rural hospitals or trauma scenes in northern Alberta to regional hospitals in Edmonton were eligible for study. Esophageal thermometers were used to measure core temperature at 10-minute intervals during transport. RESULTS Of 133 potentially eligible patients, 116 were enrolled; 69 (59%) had esophageal thermometers inserted, and 47 (41%) had other temperature measurements. Severe hypothermia occurred in only 1% to 2% of cases, but 28% to 39% of patients met criteria for mild hypothermia prior to transport. Core temperatures did not fall during transport, despite the fact that warming techniques were documented in only 38% of cases. CONCLUSIONS During brief (<225 km) rotary wing aeromedical transport of severely injured or ill patients, significant hypothermia is uncommon and body temperature is generally well maintained with the use of simple passive measures. These findings do not justify recommendations for more aggressive core temperature monitoring during this type of aeromedical transport.