Laurie J Morrison

University of Toronto, Toronto, Ontario, Canada

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Publications (202)1369.94 Total impact

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    ABSTRACT: Background: increasing number of people living in high-rise buildings presents unique challenges to care and may cause delays for 911-initiated first responders (including paramedics and fire department personnel) responding to calls for out-of-hospital cardiac arrest. We examined the relation between floor of patient contact and survival after cardiac arrest in residential buildings. Methods: We conducted a retrospective observational study using data from the Toronto Regional RescuNet Epistry database for the period January 2007 to December 2012. We included all adult patients (≥ 18 yr) with out-of-hospital cardiac arrest of no obvious cause who were treated in private residences. We excluded cardiac arrests witnessed by 911-initiated first responders and those with an obvious cause. We used multivariable logistic regression to determine the effect on survival of the floor of patient contact, with adjustment for standard Utstein variables. Results: During the study period, 7842 cases of out-of-hospital cardiac arrest met the inclusion criteria, of which 5998 (76.5%) occurred below the third floor and 1844 (23.5%) occurred on the third floor or higher. Survival was greater on the lower floors (4.2% v. 2.6%, p = 0.002). Lower adjusted survival to hospital discharge was independently associated with higher floor of patient contact, older age, male sex and longer 911 response time. In an analysis by floor, survival was 0.9% above floor 16 (i.e., below the 1% threshold for futility), and there were no survivors above the 25th floor. Interpretation: In high-rise buildings, the survival rate after out-of-hospital cardiac arrest was lower for patients residing on higher floors. Interventions aimed at shortening response times to treatment of cardiac arrest in high-rise buildings may increase survival.
    Full-text · Article · Jan 2016 · Canadian Medical Association Journal
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    ABSTRACT: Introduction: This study examined the relationship between gender and outcomes of non-traumatic out-of-hospital cardiac arrest (OHCA). Methods: All eligible, consecutive, non-traumatic Emergency Medical Services (EMS) treated OHCA patients in the Resuscitation Outcomes Consortium between December 2005 and May 2007. Patient age was analyzed as a continuous variable and stratified in two age cohorts: 15-45 and >55 years of age (yo). Unadjusted and adjusted (based on Utstein characteristics) chi square tests and logistic regression models were employed to examine the relationship between gender, age and survival outcomes. Results: This study enrolled 14,690 patients: of which 36.4% were women with a mean age of 68.3 and 63.6% of them men with a mean age of 64.2. Women survived to hospital discharge less often than men (6.4% vs. 9.1%, p<0.001); the unadjusted OR was 0.69, 95%CI: 0.60, 0.77 whereas when adjusted for all Utstein predictors the difference was not significant (OR: 1.16, 95%CI: 0.98, 1.36, p= 0.07). The adjusted survival rate for younger women (15-45 yo) was 11.1% vs. 9.8% for younger men (OR: 1.66, 95%CI: 1.04, 2.64, p=0.03) but no difference in discharge rates was observed in the >55 cohort (OR: 0.94, 95%CI: 0.78, 1.15, p=0.57). Conclusions: Women who suffer OHCAs have lower rates of survival and have unfavourable Utstein predictors. When survival is adjusted for these predictors survival is similar between men and women except in younger women suggesting that age modifies the association of gender and survival from OHCA; a result that supports a protective hormonal effect among premenopausal women.
    No preview · Article · Dec 2015 · Resuscitation
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    ABSTRACT: Background: Bystander cardiopulmonary resuscitation (CPR) improves the likelihood of survival from out-of-hospital cardiac arrest (OHCA), yet it is performed in only 30% of cases. The 2010 guidelines promote chest-compression-only bystander CPR-a change intended to increase willingness to provide CPR. Objectives: 1) To determine whether the Canadian general public is more willing to perform chest-compression-only CPR compared to traditional CPR; 2) to characterize public knowledge of OHCA; and 3) to identify barriers and facilitators to bystander CPR. Methods: A 32-item survey assessing resuscitation knowledge, and willingness to provide CPR were disseminated in five Canadian regions. Descriptive statistics were used to characterize response distribution. Logistic regression analysis was applied to assess shifts in intention to provide CPR. Results: A total of 428 completed surveys were analysed. When presented with a scenario of being a bystander in an OHCA, a greater proportion of respondents were willing to provide chest-compression-only CPR compared to traditional CPR for all victims (61.5% v. 39.7%, p<0.001), when the victim was a stranger (55.1% v. 38.8%, p<0.001), or when the victim was an unkempt individual (47.9% v. 28.5%, p<0.001). When asked to describe an OHCA, 41.4% said the heart stopped beating, and 20.8% said it was a heart attack. Identified barriers and facilitators included fear of litigation and lack of skill confidence. Conclusions: This study identified gaps in knowledge, which may impair the ability of bystanders to act in OHCA. Most respondents expressed greater willingness to provide chest-compression-only CPR, but this was mediated by victim characteristics, skill confidence, and recognition of a cardiac arrest.
    No preview · Article · Dec 2015 · Canadian Journal of Emergency Medicine
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    ABSTRACT: Background During cardiopulmonary resuscitation (CPR) in patients with out-of-hospital cardiac arrest, the interruption of manual chest compressions for rescue breathing reduces blood flow and possibly survival. We assessed whether outcomes after continuous compressions with positive-pressure ventilation differed from those after compressions that were interrupted for ventilations at a ratio of 30 compressions to two ventilations. Methods This cluster-randomized trial with crossover included 114 emergency medical service (EMS) agencies. Adults with non-trauma-related cardiac arrest who were treated by EMS providers received continuous chest compressions (intervention group) or interrupted chest compressions (control group). The primary outcome was the rate of survival to hospital discharge. Secondary outcomes included the modified Rankin scale score (on a scale from 0 to 6, with a score of ≤3 indicating favorable neurologic function). CPR process was measured to assess compliance. Results Of 23,711 patients included in the primary analysis, 12,653 were assigned to the intervention group and 11,058 to the control group. A total of 1129 of 12,613 patients with available data (9.0%) in the intervention group and 1072 of 11,035 with available data (9.7%) in the control group survived until discharge (difference, -0.7 percentage points; 95% confidence interval [CI], -1.5 to 0.1; P=0.07); 7.0% of the patients in the intervention group and 7.7% of those in the control group survived with favorable neurologic function at discharge (difference, -0.6 percentage points; 95% CI, -1.4 to 0.1, P=0.09). Hospital-free survival was significantly shorter in the intervention group than in the control group (mean difference, -0.2 days; 95% CI, -0.3 to -0.1; P=0.004). Conclusions In patients with out-of-hospital cardiac arrest, continuous chest compressions during CPR performed by EMS providers did not result in significantly higher rates of survival or favorable neurologic function than did interrupted chest compressions. (Funded by the National Heart, Lung, and Blood Institute and others; ROC CCC number, NCT01372748 .).
    Full-text · Article · Nov 2015 · New England Journal of Medicine
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    Full-text · Article · Nov 2015 · Circulation
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    ABSTRACT: Background: The frequency of lethal overdose due to prescription and non-prescription drugs is increasing in North America. The aim of this study was to estimate overall and regional variation in incidence and outcomes of out-of-hospital cardiac arrest due to overdose across North America. Methods: We conducted a retrospective cohort study using case data for the period 2006-2010 from the Resuscitation Outcomes Consortium, a clinical research network with 10 regional clinical centers in United States and Canada. Cases of out-of-hospital cardiac arrest due to drug overdose were identified through review of data derived from prehospital clinical records. We calculated incidence of out-of-hospital cardiac arrest due to overdose per 100,000 person-years and proportion of the same among all out-of-hospital cardiac arrests. We analyzed the association between overdose cardiac arrest etiology and resuscitation outcomes. Results: Included were 56,272 cases, of which 1351 were due to overdose. Regional incidence of out-of-hospital cardiac arrest due to overdose varied between 0.5 and 2.7 per 100,000 person years (p<0.001), and proportion of the same among all treated out-of-hospital cardiac arrests ranged from 0.8% to 4.0%. Overdose cases were younger, less likely to be witnessed, and less likely to present with a shockable rhythm. Compared to non-overdose, overdose was directly associated with return of spontaneous circulation (OR: 1.55; 95% CI: 1.35-1.78) and survival (OR: 2.14; 95% CI: 1.72-2.65). Conclusions: Overdose made up 2.4% of all out-of-hospital cardiac arrest, although incidence varied up to 5-fold across regions. Overdose cases were more likely to survive than non-overdose cases.
    No preview · Article · Nov 2015 · Resuscitation
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    Full-text · Article · Oct 2015 · Circulation
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    Full-text · Article · Oct 2015 · Circulation
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    ABSTRACT: The process for evaluating the resuscitation science has evolved considerably over the past 2 decades. The current process, which incorporates the use of the GRADE methodology, culminated in the 2015 CoSTR publication, which in turn will inform the international resuscitation councils' guideline development processes. Over the next few years, the process will continue to evolve as ILCOR moves toward a more continuous evaluation of the resuscitation science. © 2015 American Heart Association, Inc., European Resuscitation Council, and International Liaison Committee on Resuscitation.
    No preview · Article · Oct 2015 · Resuscitation
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    Full-text · Article · Oct 2015 · Resuscitation
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    ABSTRACT: Background: PulsePoint Respond is a novel mobile device application that notifies citizens within 400m (∼1/4 mile) of a suspected cardiac arrest to facilitate resuscitation. Our objectives were to 1) characterize users, and 2) understand their behavior after being sent a notification. We sought to identify challenges for optimal implementation of PulsePoint-mediated bystander resuscitation. Methods: PulsePoint Respond users sent a notification between 04/07/2012 and 06/16/2014 were invited to participate in an online survey. At the beginning of our study, PulsePoint Respond was active in more than 600 US communities. Results: There were 1274 completed surveys (response rate 1448/6777, 21.4%). Respondents were firefighters (28%), paramedics (18%), emergency medical technicians (9%), nurses (7%), MDs (1%), other health care professionals (12%), and non-health care professionals (42%). Of those who received a PulsePoint notification, only 23% (189/813) responded to the PulsePoint notification. Of those who responded, 28% (52/187) did not arrive on scene. Of those who did arrive on scene, only 32% (44/135) found a person unconscious and not breathing normally. Of those who arrived on scene prior to emergency medical services and found a cardiac arrest victim, 79% (11/14) performed bystander cardiopulmonary resuscitation. Conclusions: Challenges for optimal implementation of PulsePoint Respond include technical aspects of the notifications (audio volume, precision of location information), excessive activation radii, insufficient user density in the community, and suboptimal cardiac arrest notification specificity. PulsePoint Respond has the potential to improve the community response to cardiac arrest, with 80% of responders attempting basic life support when they found a cardiac arrest victim prior to EMS.
    No preview · Article · Oct 2015 · Resuscitation
  • E.C. Ho · S. Cheskes · P. Angaran · L. Morrison · T. Aves · C. Zhan · P. Dorian

    No preview · Article · Oct 2015 · The Canadian journal of cardiology
  • C. Landry · K.S. Allan · K. Connelly · L.J. Morrison · P. Dorian

    No preview · Article · Oct 2015 · The Canadian journal of cardiology

  • No preview · Article · Sep 2015 · International Journal of Stroke
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    ABSTRACT: β-Blocker therapy is one of the most commonly prescribed treatments for patients with cardiac conditions. In patients with out-of-hospital cardiac arrest (OHCA), however, recent data suggest that prior treatment with β-blockers could be harmful by lowering the incidence of a shockable presenting rhythm. The main objective of our study was to determine the association between prior β-blocker use and mortality in OHCA patients. Methods: An observational study was conducted using the Toronto Rescu Epistry database that captured consecutive OHCA patients from 2005 to 2010. Patients older than 65 years with nontraumatic cardiac arrest and attempted resuscitation were included. Patients prescribed β-blockers within 90 days of the arrest were compared with those without such therapy. The primary outcome was all-cause mortality at 30 days. Potential confounders were accounted for by inverse probability of treatment weighting using the propensity score. Results: The median age of 8,266 OHCA patients was 79 years, 41% were women, and 2,911 (35.2%) were prescribed a β-blocker prior to cardiac arrest. Patients prescribed β-blockers were more likely to have existing cardiac risk factors and cardiovascular conditions. In the propensity-weighted cohort, there were no differences in the presenting rhythm, with 18.4% of patients in the β-blocker group having a shockable rhythm vs 17.5% in the no β-blocker group (standardized difference .023). In addition, 30-day mortality was not significantly different between patients prescribed β-blockers and no β-blockers (95.6% vs 95.1%, P = .36). Conclusion: β-Blocker use was not associated with lower rates of shockable rhythms or mortality among older patients with OHCA.
    No preview · Article · Jul 2015
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    ABSTRACT: The American Heart Association (AHA) commends the recently released Institutes of Medicine (IOM) report titled, "Strategies to Improve Cardiac Arrest Survival: A Time to Act (2015)." The AHA recognizes the unique opportunity created by the report to meaningfully advance the objectives of improving outcomes for sudden cardiac arrest. For decades, the AHA has focused on the goal of reducing morbidity and mortality from cardiovascular disease though robust support of basic, translational, clinical, and population research. The AHA also has developed a rigorous process using the best available evidence to develop scientific, advisory, and guideline documents. These core activities of development and dissemination of scientific evidence have served as the foundation for a broad range of advocacy initiatives and programs that serve as a foundation for advancing the AHA and IOM goal of improving cardiac arrest outcomes. In response to the IOM report's call to action, the AHA is announcing 4 new commitments to increase cardiac arrest survival: 1) the AHA will provide up to $5 million in funding over 5 years to incentivize resuscitation data interoperability; 2) the AHA will actively pursue philanthropic support for local and regional implementation opportunities to increase cardiac arrest survival by improving out-of-hospital and in-hospital systems of care; 3) the AHA will actively pursue philanthropic support to launch an AHA resuscitation research network; and 4) the AHA will cosponsor an "National Cardiac Arrest Summit" to facilitate the creation of a national cardiac arrest collaborative that will unify the field and identify common goals to improve survival. In addition to AHA's historic and ongoing commitment to improving cardiac arrest care and outcomes, these new initiatives are responsive to each of the IOM recommendations and demonstrate the AHA's leadership in the field. However, successful implementation of the IOM recommendations will require a timely response by all stakeholders identified in the report, and a coordinated approach to achieve our common goal if improved cardiac arrest outcomes. © 2015 American Heart Association, Inc.
    No preview · Article · Jun 2015 · Circulation
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    ABSTRACT: Survival is less than 10% for pediatric patients following out-of-hospital cardiac arrest. It is not known if more time on the scene of the cardiac arrest and advanced life support interventions by emergency services personnel are associated with improved survival. This study was performed to determine which times on the scene and which prehospital interventions were associated with improved survival. We studied patients aged 3 days to 19 years old with out-of-hospital cardiac arrest, using the Resuscitation Outcomes Consortium cardiac arrest database from 11 North American regions, from 2005 to 2012. We evaluated survival to hospital discharge according to on-scene times (< 10, 10 to 35 and>35minutes). Data were available for 2244 patients (1017 infants, 594 children and 633 adolescents). Infants had the lowest rate of survival (3.7%) compared to children (9.8%) and adolescents (16.3%). Survival improved over the 7 year study period especially among adolescents. Survival was highest in the 10 to 35minute on-scene time group (10.2%) compared to the>35minute group (6.9%) and the<10minute group (5.3%, p=0.01). Intravenous or intra-osseous access attempts and fluid administration were associated with improved survival, whereas advanced airway attempts were not associated with survival and resuscitation drugs were associated with worse survival. In this observational study, a scene time of 10 to 35minutes was associated with the highest survival, especially among adolescents. Access for fluid resuscitation was associated with increased survival but advanced airway and resuscitation drugs were not. Copyright © 2015. Published by Elsevier Ireland Ltd.
    No preview · Article · Jun 2015 · Resuscitation
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    ABSTRACT: A recent mixed-methods study on the state of emergency medical services (EMS) research in Canada led to the generation of nineteen actionable recommendations. As part of the dissemination plan, a survey was distributed to EMS stakeholders to determine the anticipated impact and feasibility of implementing these recommendations in Canadian systems. An online survey explored both the implementation impact and feasibility for each recommendation using a five-point scale. The sample consisted of participants from the Canadian National EMS Research Agenda study (published in 2013) and additional EMS research stakeholders identified through snowball sampling. Responses were analysed descriptively using median and plotted on a matrix. Participants reported any planned or ongoing initiatives related to the recommendations, and required or anticipated resources. Free text responses were analysed with simple content analysis, collated by recommendation. The survey was sent to 131 people, 94 (71.8%) of whom responded: 30 EMS managers/regulators (31.9%), 22 researchers (23.4%), 15 physicians (16.0%), 13 educators (13.8%), and 5 EMS providers (5.3%). Two recommendations (11%) had a median impact score of 4 (of 5) and feasibility score of 4 (of 5). Eight recommendations (42%) had an impact score of 5, with a feasibility score of 3. Nine recommendations (47%) had an impact score of 4 and a feasibility score of 3. For most recommendations, participants scored the anticipated impact higher than the feasibility to implement. Ongoing or planned initiatives exist pertaining to all recommendations except one. All of the recommendations will require additional resources to implement.
    No preview · Article · Jun 2015 · Canadian Journal of Emergency Medicine
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    ABSTRACT: We sought to 1) identify best practices for training and mentoring clinician researchers, 2) characterize facilitators and barriers for Canadian emergency medicine researchers, and 3) develop pragmatic recommendations to improve and standardize emergency medicine postgraduate research training programs to build research capacity. We performed a systematic review of MEDLINE and Embase using search terms relevant to emergency medicine research fellowship/graduate training. We conducted an email survey of all Canadian emergency physician researchers. The Society for Academic Emergency Medicine (SAEM) research fellowship program was analysed, and other similar international programs were sought. An expert panel reviewed these data and presented recommendations at the Canadian Association of Emergency Physicians (CAEP) 2014 Academic Symposium. We refined our recommendations based on feedback received. Of 1,246 potentially relevant citations, we included 10 articles. We identified five key themes: 1) creating training opportunities; 2) ensuring adequate protected time; 3) salary support; 4) infrastructure; and 5) mentorship. Our survey achieved a 72% (67/93) response rate. From these responses, 42 (63%) consider themselves clinical researchers (i.e., spend a significant proportion of their career conducting research). The single largest constraint to conducting research was funding. Factors felt to be positive contributors to a clinical research career included salary support, research training (including an advanced graduate degree), mentorship, and infrastructure. The SAEM research fellowship was the only emergency medicine research fellowship program identified. This 2-year program requires approval of both the teaching centre and each applying fellow. This program requires training in 15 core competencies, manuscript preparation, and submission of a large grant to a national peer-review funding organization. We recommend that the CAEP Academic Section create a process to endorse research fellowship/graduate training programs. These programs should include two phases: Phase I: Research fellowship/graduate training would include an advanced research university degree and 15 core learning areas. Phase II: research consolidation involves a further 1-3 years with an emphasis on mentorship and scholarship production. It is anticipated that clinician scientists completing Phase I and Phase II training at a CAEP Academic Section-endorsed site(s) will be independent researchers with a higher likelihood of securing external peer-reviewed funding and be able to have a meaningful external impact in emergency medicine research.
    Full-text · Article · May 2015 · Canadian Journal of Emergency Medicine
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    ABSTRACT: Traditional variables used to explain survival following out-of-hospital cardiac arrest (OHCA) account for only 72% of survival, suggesting that other unknown factors may influence outcomes. Research on other diseases suggests that neighbourhood factors may partly determine health outcomes. Yet, this approach has rarely been used for OHCA. This work outlines a methodology to investigate multiple neighbourhood factors as determinants of OHCA outcomes. A retrospective, observational cohort study design will be used. All adult non-emergency medical service witnessed OHCAs of cardiac etiology within the city of Toronto between 2006 and 2010 will be included. Event details will be extracted from the Toronto site of the Resuscitation Outcomes Consortium Epistry-Cardiac Arrest, an existing population-based dataset of consecutive OHCA patients. Geographic information systems technology will be used to assign patients to census tracts. Neighbourhood variables to be explored include the Ontario Marginalization Index (deprivation, dependency, ethnicity, and instability), crime rate, and density of family physicians. Hierarchical logistic regression analysis will be used to explore the association between neighbourhood characteristics and 1) survival-to-hospital discharge, 2) return-of-spontaneous circulation at hospital arrival, and 3) provision of bystander cardiopulmonary resuscitation (CPR). Receiver operating characteristics curves will evaluate each model's ability to discriminate between those with and without each outcome. Discussion This study will determine the role of neighbourhood characteristics in OHCA and their association with clinical outcomes. The results can be used as the basis to focus on specific neighbourhoods for facilitating educational interventions, CPR awareness programs, and higher utilization of automatic defibrillation devices.
    Preview · Article · May 2015 · Canadian Journal of Emergency Medicine

Publication Stats

9k Citations
1,369.94 Total Impact Points


  • 1998-2015
    • University of Toronto
      • • Department of Medicine
      • • Institute of Health Policy, Management and Evaluation
      • • Division of Cardiology
      • • Sunnybrook Health Sciences Centre
      Toronto, Ontario, Canada
  • 2012
    • University of North Carolina at Chapel Hill
      • Department of Emergency Medicine
      Chapel Hill, NC, United States
  • 2011
    • McMaster University
      • Department of Clinical Epidemiology and Biostatistics
      Hamilton, Ontario, Canada
  • 2010
    • Royal Melbourne Hospital
      Melbourne, Victoria, Australia
    • Oslo University Hospital
      Kristiania (historical), Oslo County, Norway
    • Singapore General Hospital
      Tumasik, Singapore
  • 2009-2010
    • St. Michael's Hospital
      • Department of Surgery
      Toronto, Ontario, Canada
  • 2008-2010
    • Royal United Hospital Bath NHS Trust
      Bath, England, United Kingdom
    • Rosalind Franklin University of Medicine and Science
      North Chicago, Illinois, United States
  • 2005-2009
    • Christus St. Michaels' Hospital
      텍사캐나, Arkansas, United States
  • 2002-2008
    • Sunnybrook Health Sciences Centre
      • Department of Emergency Services
      Toronto, Ontario, Canada
  • 2001
    • The University of Western Ontario
      • Division of Emergency Medicine
      London, Ontario, Canada