CJEM Articles: George A. Wells
Displaying 1-10 of 12 results
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July
2012
14
4
Ekaterina Turko, Erik P. Hess, George A. Wells, Ian G. Stiell, My-Linh Tran, Venkatesh Thiruganasambandamoorthy
Background:
Previous studies have indicated that the suboptimal performance of the San Francisco Syncope Rule (SFSR) is likely due to the misclassification of the “abnormal electrocardiogram (ECG)” variable. We sought to identify specific emergency department (ED) ECG and cardiac monitor abnormalities that better predict cardiac outcomes within 30 days in adult ED syncope patients.
Methods:
This health records review included patients 16 years or older with syncope and excluded patients with ongoing altered mental status, alcohol or illicit drug use, seizure, head injury leading to loss of consciousness, or severe trauma requiring admission. We collected patient characteristics, 22 ECG variables, cardiac monitoring abnormalities, SFSR “abnormal ECG” criteria, and outcome (death, myocardial infarction, arrhythmias, or cardiac procedures) data. Recursive partitioning was used to develop the “Ottawa Electrocardiographic Criteria.”
Results:
Among 505 included patient visits, 27 (5.3%) had serious cardiac outcomes. We found that patients were at risk for cardiac outcomes within 30 days if any of the following were present: second-degree Mobitz type 2 or third-degree atrioventricular (AV) block, bundle branch block with first-degree AV block, right bundle branch with left anterior or posterior fascicular block, new ischemic changes, nonsinus rhythm, left axis deviation, or ED cardiac monitor abnormalities. The sensitivity and specificity of the Ottawa Electrocardiographic Criteria were 96% (95% CI 80–100) and 76% (95% CI 75–76), respectively.
Conclusion:
We successfully identified specific ED ECG and cardiac monitor abnormalities, which we termed the Ottawa Electrocardiographic Criteria, that predict serious cardiac outcomes in adult ED syncope patients. Further studies are required to identify which adult ED syncope patients require cardiac monitoring in the ED and the optimal duration of monitoring and to confirm the accuracy of these criteria. -
May
2012
14
3
Bjug Borgundvaag, Brian H. Rowe, Catherine M. Clement, David Birnie, Eddy Lang, Gabriel E. Blecher, George A. Wells, Ian G. Stiell, Jeffrey J. Perry, Kirk Magee, Rob Stenstrom, Robert J. Brison, Trevor Langhan
Objective:
It is believed that when patients present to the emergency department (ED) with recent-onset atrial fibrillation or flutter (RAFF), controlling the ventricular rate before cardioversion improves the success rate. We evaluated the influence of rate control medication and other variables on the success of cardioversion.
Methods:
This secondary analysis of a medical records review comprised 1,068 patients with RAFF who presented to eight Canadian EDs over 12 months. Univariate analysis was performed to find associations between predictors of conversion to sinus rhythm including use of rate control, rhythm control, and other variables. Predictive variables were incorporated into the multivariate model to calculate adjusted odds ratios (ORs) associated with successful cardioversion.
Results:
A total of 634 patients underwent attempted cardioversion: 428 electrical, 354 chemical, and 148 both. Adjusted ORs for factors associated with successful electrical cardioversion were use of rate control medication, 0.39 (95% confidence interval [CI] 0.21–0.74); rhythm control medication, 0.28 (95% CI 0.15–0.53); and CHADS2 score > 0, 0.43 (95% CI 0.15–0.83). ORs for factors associated with successful chemical cardioversion were use of rate control medication, 1.29 (95% CI 0.82–2.03); female sex, 2.37 (95% CI 1.50–3.72); and use of procainamide, 2.32 (95% CI 1.43–3.74).
Conclusion:
We demonstrated reduced successful electrical cardioversion of RAFF when patients were pretreated with either rate or rhythm control medication. Although rate control medication was not associated with increased success of chemical cardioversion, use of procainamide was. Slowing the ventricular rate prior to cardioversion should be avoided. -
September
2010
12
5
Erik P. Hess, George A. Wells, Ian G. Stiell, Jeffrey J. Perry, Lisa A. Calder, Venkatesh Thiruganasambandamoorthy, Veronique L. Roger
Objective: We sought to assess sex differences in clinical presentation, management and outcome in emergency department (ED) patients with chest pain, and to measure the association between female sex and coronary angiography within 30 days.
Methods: We conducted a prospective cohort study in an urban academic ED between Jul. 1, 2007, and Apr. 1, 2008. We enrolled patients over 24 years of age with chest pain and possible acute coronary syndrome (ACS).
Results: Among the 970 included patients, 386 (39.8%) were female. Compared with men, women had a lower prevalence of known coronary artery disease (21.0% v. 34.2%, p < 0.001) and a lower frequency of typical pain (37.1% v. 45.7%, p = 0.01). Clinicians classified a greater proportion of women as having a low (< 10%) pretest probability for ACS (85.0% v. 76.4%, p = 0.001). Despite similar rates of electrocardiography, troponin T and stress testing between sexes, there was a lower rate of acute myocardial infarction (AMI) (4.7% v. 8.4%, p = 0.03) and positive stress test results (4.4% v. 7.9%, p = 0.03) in women. Women were less frequently referred for coronary angiography (9.3% v. 18.9%, p < 0.001). The adjusted association between female sex and coronary angiography was not significant (odds ratio 0.63, 95% confidence interval 0.37–1.10).
Conclusion: Women had a lower rate of AMI and a lower rate of positive stress test results despite similar rates of testing between sexes. Although women were less frequently referred for coronary angiography, these data suggest that sex differences in management were likely appropriate for the probability of disease.
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March
2010
12
2
Christian Vaillancourt, George A. Wells, Ian G. Stiell, Karin R. Phillips, Manya Charette
Objective: The general objective of this study was to explore the challenges of establishing an out of hospital cardiac arrest (OOHCA) surveillance program in Canada. More specifically, we attempted to determine the organizational structure of the delivery of emergency medical services (EMS) in Canada, describe the cardiac arrest data collection infrastructure in each province and determine which OOHCA variables are being collected.
Methods: We conducted a national survey of 82 independent EMS health authorities in Canada. Methodology experts devel oped the survey and distribution using a modified Dillman tech nique. We distributed 67 surveys electronically (84%) and the rest by regular mail. We weighted each survey response by the popu lation of the catchment area represented by the responding health authority (2004 census). Descriptive statistics are reported.
Results: We received 60 completed surveys, representing a 73% response rate. The responding health authorities' catchment areas represented 80% of the Canadian population (territories excluded). Our survey results highlight a lack of common OOHCA data definitions used among health authorities, sporadic use of data quality assurance procedures, rare linkages to in hospital survival outcomes and potential confidentiality issues. Other chal lenges raised by respondents included determining warehousing location and finding financial resources for a national OOHCA registry.
Conclusion: Results from this survey demonstrate that, although it is challenging, it is possible to collect OOHCA data and access in hospital survival outcomes. Collaborative efforts with the Resuscitation Outcomes Consortium and other potential provin cial partners should be explored.
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March
2010
12
2
Erik P. Hess, George A. Wells, Ian G. Stiell, Jeffrey J. Perry, Pam Ladouceur
Objective: We derived a clinical decision rule to determine which emergency department (ED) patients with chest pain and possible acute coronary syndrome (ACS) require chest radiography.
Methods: We prospectively enrolled patients over 24 years of age with a primary complaint of chest pain and possible ACS over a 6 month period. Emergency physicians completed standardized clinical assessments and ordered chest radiographs as appropriate. Two blinded investigators independently classified chest radiographs as "normal," "abnormal not requiring intervention" and "abnormal requiring intervention," based on review of the radiology report and the medical record. The primary outcome was abnormality of chest radiographs requiring acute intervention. Analyses included interrater reliability assessment (with κ statistics), univariate analyses and recursive partitioning.
Results: We enrolled 529 patients during the study period between Jul. 1, 2007, and Dec. 31, 2007. Patients had a mean age of 59.9 years, 60.3% were male, 4.0% had a history of con gestive heart failure and 21.9% had a history of acute myocardial infarction. Only 2.1% (95% confidence interval [CI] 1.1%-3.8%) of patients had radiographic abnormality of the chest requiring acute intervention. The κ statistic for chest radiograph classification was 0.81 (95% CI 0.66-0.95). We derived the following rule: patients can forgo chest radiography if they have no history of congestive heart failure, no history of smoking and no abnormalities on lung auscultation. The rule was 100% sensitive (95% CI 32.0%-40.4%) and 36.1% specific (95% CI 32.0%-40.4%).
Conclusion: This rule has potential to reduce health care costs and enhance ED patient flow. It requires validation in an independent patient population before introduction into clinical practice.
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March
2010
12
2
Erik P. Hess, George A. Wells, Ian G. Stiell, Jeffrey J. Perry, Pam Ladouceur
Objective: We derived a clinical decision rule to determine which emergency department (ED) patients with chest pain and possible acute coronary syndrome (ACS) require chest radiography.
Methods: We prospectively enrolled patients over 24 years of age with a primary complaint of chest pain and possible ACS over a 6 month period. Emergency physicians completed standardized clinical assessments and ordered chest radiographs as appropri ate. Two blinded investigators independently classified chest radi ographs as "normal," "abnormal not requiring intervention" and "abnormal requiring intervention," based on review of the radiol ogy report and the medical record. The primary outcome was abnormality of chest radiographs requiring acute intervention. Analyses included interrater reliability assessment (with κ statistics), univariate analyses and recursive partitioning.
Results: We enrolled 529 patients during the study period between Jul. 1, 2007, and Dec. 31, 2007. Patients had a mean age of 59.9 years, 60.3% were male, 4.0% had a history of con gestive heart failure and 21.9% had a history of acute myocardial infarction. Only 2.1% (95% confidence interval [CI] 1.1%-3.8%) of patients had radiographic abnormality of the chest requiring acute intervention. The κ statistic for chest radiograph classification was 0.81 (95% CI 0.66-0.95). We derived the following rule: patients can forgo chest radiography if they have no history of congestive heart failure, no history of smoking and no abnormalities on lung auscultation. The rule was 100% sensitive (95% CI 32.0%-40.4%) and 36.1% specific (95% CI 32.0%-40.4%). Conclusion: This rule has potential to reduce health care costs and enhance ED patient flow. It requires validation in an independent patient population before introduction into clinical practice.
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July
2008
10
4
Allan S. Jaffe, Erik P. Hess, George A. Wells, Ian G. Stiell, Judd E. Hollander, Patricia Erwin, Venkatesh Thiruganasambandamoorthy, Victor M. Montori
Objective: We sought to determine the diagnostic accuracy of clinical prediction rules to exclude acute coronary syndrome (ACS) in the emergency department (ED) setting.
Methods: We searched MEDLINE, EMBASE, Web of Science and the Cochrane Database of Systematic Reviews. We contacted content experts to identify additional articles for review. Reference lists of included studies were hand searched. We selected articles for review based on the following criteria: 1) enrolled consecutive ED patients; 2) incorporated variables from the history or physical examination, electrocardiogram and cardiac biomarkers; 3) did not incorporate cardiac stress testing or coronary angiography into prediction rule; 4) based on original research; 5) prospectively derived or validated; 6) did not require use of a computer; and 7) reported sufficient data to construct a 2 × 2 contingency table. We assessed study quality and extracted data independently and in duplicate using a standardized data extraction form.
Results: Eight studies met inclusion criteria, encompassing 7937 patients. None of the studies verified the prediction rule with a reference standard on all or a random sample of patients. Six studies did not report blinding prediction rule assessors to reference standard results, and vice versa. Three prediction rules were prospectively validated. Sensitivities and specificities ranged from 94% to 100% and 13% to 57%, and positive and negative likelihood ratios from 1.1 to 2.2 and 0.01 to 0.17, respectively.
Conclusion: Current prediction rules for ACS have substantial methodological limitations and have not been successfully implemented in the clinical setting. Future methodologically sound studies are needed to guide clinical practice.
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January
2008
10
1
Christian Vaillancourt, George A. Wells, Ian G. Stiell
Objectives: Cardiopulmonary resuscitation (CPR) is a crucial yet weak link in the chain of survival for out-of-hospital cardiac arrest. We sought to understand the determinants of bystander CPR and the factors associated with successful training.
Methods: For this systematic review, we searched 11 electronic databases, 1 trial registry and 9 scientific websites. We performed hand searches and contacted 6 content experts. We reviewed without restriction all communications pertaining to who should learn CPR, what should be taught, when to repeat training, where to give CPR instructions and why people lack the motivation to learn and perform CPR. We used standardized forms to review papers for inclusion, quality and data extraction. We grouped publications by category and classified recommendations using a standardized classification system that was based on level of evidence.
Results: We reviewed 2409 articles and selected 411 for complete evaluation. We included 252 of the 411 papers in this systematic review. Differences in their study design precluded a meta-analysis. We classified 22 recommendations; those with the highest scores were 1) 9-1-1 dispatch- assisted CPR instructions, 2) teaching CPR to family members of cardiac patients, 3) Braslow's self-training video, 4) maximizing time spent using manikins and 5) teaching the concepts of ambiguity and diffusion of responsibility. Recommendations not supported by evidence include mass training events, pulse taking prior to CPR by laymen and CPR using chest compressions alone.
Conclusion: We evaluated and classified the potential impact of interventions that have been proposed to improve bystander CPR rates. Our results may help communities design interventions to improve their bystander CPR rates.
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March
2005
7
2
Erica Battram, George A. Wells, Ian Ball, Ian G. Stiell, John E. Mahoney, Linda Papa
Objectives: There is no set of prospectively validated criteria to identify the emergency department (ED) patients with renal colic who are most likely to eventually have to undergo an intervention. This study prospectively assessed predictors of intervention in this patient population.
Methods: This prospective cohort study included adult patients with renal colic who presented to 2 tertiary care hospital EDs. Patients had an 18-variable data form completed by an emergency physician and a radiological study to confirm urolithiasis. After discharge, patients were followed at 1 and 4 weeks to assess for intervention. The outcome criteria included the patient having had at least 1 of the following procedures performed: extracorporeal shockwave lithotripsy (ESWL), ureteroscopy, percutaneous nephrostomy or open surgery. Data were analyzed using appropriate univariate techniques, and those variables associated with intervention were combined using logistic regression analysis.
Results: Over an 8-month period, 245 patients with confirmed urolithiasis were followed; 20% (95% confidence interval [CI] 15%-25%) eventually had a procedure to remove their calculi. Three variables were significantly correlated with having a procedure: i) size of calculus ≥ 6 mm (odds ratio [OR] 10.7, 95% CI 4.6-24.8), ii) location of calculus above mid-ureter (OR 6.9, 95% CI 3.0-15.9), and iii) Visual Analogue Scale score for pain at discharge from the ED ≥ 2 cm (OR 2.6, 95% CI 1.0-6.8). The area under receiver operating characteristic curve was 0.77 (95% C I 0.70-0.84) (p < 0.001). If all variables were present there was a 90% probability of the patient having an intervention performed within 4 weeks of discharge from the ED. Conversely, if none of the variables were present there was only a 4% probability of an intervention. Overall, the model had a sensitivity of 92% (95% CI 89%-96%) and a specificity of 63% (95% CI 57%-69%).
Conclusions: This study has identified variables that could potentially be used to identify those renal colic patients who require an intervention after ED evaluation. Future studies will prospectively validate this model.
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May
2002
4
3
Andreas Laupacis, Brian Holroyd, Brian Rowe, Catherine M. Clement, Daniel Cass, Gary H. Greenberg, George A. Wells, Glen Bandiera, Howard Lesiuk, Iain MacPhail, Ian G. Stiell, James Worthington, Jonathan Dreyer, Laurie Morrison, Mark Reardon, Mary A. Eisenhauer, Michael Schull, R. Douglas McKnight, Richard Verbeek, Robert Brison
Clinical prediction rules are decision-making tools that incorporate three or more variables from the history, physical examination or simple tests. They help clinicians make diagnostic or therapeutic decisions by standardizing the collection and interpretation of clinical data. There is growing interest in the methodological standards for their development and validation. This article describes the methods used to derive the Canadian C-Spine Rule and provides a valuable reference for investigators planning to develop future clinical prediction rules.
