Catherine M. Clement

The Canadian CT Head Rule for patients with minor head injury

BACKGROUND There is much controversy about the use of computed tomography (CT) for patients with minor head injury. We aimed to develop a highly sensitive clinical decision rule for use of CT in patients with minor head injuries. METHODS We carried out this prospective cohort study in the emergency departments of ten large Canadian hospitals and included consecutive adults who presented with a Glasgow Coma Scale (GCS) score of 13-15 after head injury. We did standardised clinical assessments before the CT scan. The main outcome measures were need for neurological intervention and clinically important brain injury on CT. FINDINGS The 3121 patients had the following characteristics: mean age 38.7 years); GCS scores of 13 (3.5%), 14 (16.7%), 15 (79.8%); 8% had clinically important brain injury; and 1% required neurological intervention. We derived a CT head rule which consists of five high-risk factors (failure to reach GCS of 15 within 2 h, suspected open skull fracture, any sign of basal skull fracture, vomiting >2 episodes, or age >65 years) and two additional medium-risk factors (amnesia before impact >30 min and dangerous mechanism of injury). The high-risk factors were 100% sensitive (95% CI 92-100%) for predicting need for neurological intervention, and would require only 32% of patients to undergo CT. The medium-risk factors were 98.4% sensitive (95% CI 96-99%) and 49.6% specific for predicting clinically important brain injury, and would require only 54% of patients to undergo CT. INTERPRETATION We have developed the Canadian CT Head Rule, a highly sensitive decision rule for use of CT. This rule has the potential to significantly standardise and improve the emergency management of patients with minor head injury.

Vasopressin versus epinephrine for inhospital cardiac arrest: a randomised controlled trial.

BACKGROUND Survival rates for cardiac arrest patients, both in and out of hospital, are poor. Results of a previous study suggest better outcomes for patients treated with vasopressin than for those given epinephrine, in the out-of-hospital setting. Our aim was to compare the effectiveness and safety of these drugs for the treatment of in-patient cardiac arrest. METHODS We did a triple-blind randomised trial in the emergency departments, critical care units, and wards of three Canadian teaching hospitals. We assigned adults who had cardiac arrest and required drug therapy to receive one dose of vasopressin 40 U or epinephrine 1 mg intravenously, as the initial vasopressor. Patients who failed to respond to the study intervention were given epinephrine as a rescue medication. The primary outcomes were survival to hospital discharge, survival to 1 h, and neurological function. Preplanned subgroup assessments included patients with myocardial ischaemia or infarction, initial cardiac rhythm, and age. FINDINGS We assigned 104 patients to vasopressin and 96 to epinephrine. For patients receiving vasopressin or epinephrine survival did not differ for hospital discharge (12 [12%] vs 13 [14%], respectively; p50.67; 95% CI for absolute increase in survival 211.8% to 7.8%) or for 1 h survival (40 [39%] vs 34 [35%]; p50.66; 210.9% to 17.0%); survivors had closely similar median mini-mental state examination scores (36 [range 19-38] vs 35 [20-40]; p50.75) and median cerebral performance category scores (1 vs 1). INTERPRETATION We failed to detect any survival advantage for vasopressin over epinephrine. We cannot recommend the routine use of vasopressin for inhospital cardiac arrest patients, and disagree with American Heart Association guidelines, which recommend vasopressin as alternative therapy for cardiac arrest.

A Trial of an Impedance Threshold Device in Out-of-Hospital Cardiac Arrest

BACKGROUND The impedance threshold device (ITD) is designed to enhance venous return and cardiac output during cardiopulmonary resuscitation (CPR) by increasing the degree of negative intrathoracic pressure. Previous studies have suggested that the use of an ITD during CPR may improve survival rates after cardiac arrest. METHODS We compared the use of an active ITD with that of a sham ITD in patients with out-of-hospital cardiac arrest who underwent standard CPR at 10 sites in the United States and Canada. Patients, investigators, study coordinators, and all care providers were unaware of the treatment assignments. The primary outcome was survival to hospital discharge with satisfactory function (i.e., a score of ≤3 on the modified Rankin scale, which ranges from 0 to 6, with higher scores indicating greater disability). RESULTS Of 8718 patients included in the analysis, 4345 were randomly assigned to treatment with a sham ITD and 4373 to treatment with an active device. A total of 260 patients (6.0%) in the sham-ITD group and 254 patients (5.8%) in the active-ITD group met the primary outcome (risk difference adjusted for sequential monitoring, -0.1 percentage points; 95% confidence interval, -1.1 to 0.8; P=0.71). There were also no significant differences in the secondary outcomes, including rates of return of spontaneous circulation on arrival at the emergency department, survival to hospital admission, and survival to hospital discharge. CONCLUSIONS Use of the ITD did not significantly improve survival with satisfactory function among patients with out-of-hospital cardiac arrest receiving standard CPR. (Funded by the National Heart, Lung, and Blood Institute and others; ROC PRIMED ClinicalTrials.gov number, NCT00394706.).

Implementation of the Canadian C-Spine Rule: prospective 12 centre cluster randomised trial

Objective To evaluate the effectiveness of an active strategy to implement the validated Canadian C-Spine Rule into multiple emergency departments. Design Matched pair cluster randomised trial. Setting University and community emergency departments in Canada. Participants 11 824 alert and stable adults presenting with blunt trauma to the head or neck at one of 12 hospitals. Interventions Six hospitals were randomly allocated to the intervention and six to the control. At the intervention sites, active strategies were used to implement the Canadian C-Spine Rule, including education, policy, and real time reminders on radiology requisitions. No specific intervention was introduced to alter the behaviour of doctors requesting cervical spine imaging at the control sites. Main outcome measure Diagnostic imaging rate of the cervical spine during two 12 month before and after periods. Results Patients were balanced between control and intervention sites. From the before to the after periods, the intervention group showed a relative reduction in cervical spine imaging of 12.8% (95% confidence interval 9% to 16%; 61.7% v 53.3%; P=0.01) and the control group a relative increase of 12.5% (7% to 18%; 52.8% v 58.9%; P=0.03). These changes were significant when both groups were compared (P<0.001). No fractures were missed and no adverse outcomes occurred. Conclusions Implementation of the Canadian C-Spine Rule led to a significant decrease in imaging without injuries being missed or patient morbidity. Final imaging rates were much lower at intervention sites than at most US hospitals. Widespread implementation of this rule could lead to reduced healthcare costs and more efficient patient flow in busy emergency departments worldwide. Trial registration Clinical trials NCT00290875.

A prospective cluster-randomized trial to implement the Canadian CT Head Rule in emergency departments

Background: The Canadian CT Head Rule was developed to allow physicians to be more selective when ordering computed tomography (CT) imaging for patients with minor head injury. We sought to evaluate the effectiveness of implementing this validated decision rule at multiple emergency departments. Methods: We conducted a matched-pair cluster-randomized trial that compared the outcomes of 4531 patients with minor head injury during two 12-month periods (before and after) at hospital emergency departments in Canada, six of which were randomly allocated as intervention sites and six as control sites. At the intervention sites, active strategies, including education, changes to policy and real-time reminders on radiologic requisitions were used to implement the Canadian CT Head Rule. The main outcome measure was referral for CT scan of the head. Results: Baseline characteristics of patients were similar when comparing control to intervention sites. At the intervention sites, the proportion of patients referred for CT imaging increased from the “before” period (62.8%) to the “after” period (76.2%) (difference +13.3%, 95% CI 9.7%–17.0%). At the control sites, the proportion of CT imaging usage also increased, from 67.5% to 74.1% (difference +6.7%, 95% CI 2.6%–10.8%). The change in mean imaging rates from the “before” period to the “after” period for intervention versus control hospitals was not significant (p = 0.16). There were no missed brain injuries or adverse outcomes. Interpretation: Our knowledge–translation-based trial of the Canadian CT Head Rule did not reduce rates of CT imaging in Canadian emergency departments. Future studies should identify strategies to deal with barriers to implementation of this decision rule and explore more effective approaches to knowledge translation. (ClinicalTrials.gov trial register no. NCT00993252)

Variation in management of recent-onset atrial fibrillation and flutter among academic hospital emergency departments.

STUDY OBJECTIVE Although recent-onset atrial fibrillation and flutter are common arrhythmias managed in the emergency department (ED), there is insufficient evidence to help physicians choose between 2 competing treatment strategies, rate control and rhythm control. We seek to evaluate variation in ED management practices for recent-onset atrial fibrillation and flutter patients at multiple Canadian sites and to determine whether hospital site was an independent predictor of attempted cardioversion. METHODS We conducted a cross-sectional survey by health records review on an observational cohort of all eligible adult recent-onset atrial fibrillation and flutter cases, with onset of symptoms less than 48 hours, treated at 8 academic hospital EDs during a 12-month period, and evaluated the variation in practice among sites for important management strategies. RESULTS Among the 1,068 study patients, 88.3% had atrial fibrillation and 11.7% had atrial flutter. The proportion of cases managed with rhythm control was 59.4% (interhospital range 42% to 85%) and, among these, electrocardioversion was attempted first for 44.2% (range 7% to 69%). There was variation in most management strategies, including use of rate control drugs 54.9% (range 37% to 65%), choice of procainamide as rhythm control drug 62.1% (range 15% to 89%), referral to cardiology in the ED 30.7% (range 16% to 64%), use of heparin 13.7% (range 1% to 29%), and outpatient cardiology referral 43.0% (range 30% to 65%). Adverse events were relatively uncommon and transient for patients undergoing attempts at pharmacologic (13.0%) or electrocardioversion (12.1%). Overall, 83.3% of patients were discharged home from the ED (range 73% to 90%). After controlling for 12 covariates, multivariate logistic regression found that factors independently associated with attempted cardioversion were age (odds ratio [OR] 0.97; 95% confidence interval [CI] 0.95 to 0.98), history of electrocardioversion (OR 2.73; 95% CI 1.56 to 4.80), associated heart failure (OR 0.29; 95% CI 0.09 to 0.95), and hospital site (ORs ranged from 0.38 to 3.05). CONCLUSION We demonstrated a high degree of variation in management approaches for recent-onset atrial fibrillation and flutter patients treated in academic hospital EDs. Individual hospital site, age, previous cardioversion, and associated heart failure were independent predictors for the use of rhythm control.

Association of the Ottawa Aggressive Protocol with rapid discharge of emergency department patients with recent-onset atrial fibrillation or flutter

OBJECTIVE There is no consensus on the optimal management of recent-onset episodes of atrial fibrillation or flutter. The approach to these conditions is particularly relevant in the current era of emergency department (ED) overcrowding. We sought to examine the effectiveness and safety of the Ottawa Aggressive Protocol to perform rapid cardioversion and discharge patients with these arrhythmias. METHODS This cohort study enrolled consecutive patient visits to an adult university hospital ED for recent-onset atrial fibrillation or flutter managed with the Ottawa Aggressive Protocol. The protocol includes intravenous chemical cardioversion, electrical cardioversion if necessary and discharge home from the ED. RESULTS A total of 660 patient visits were included, 95.2% involving atrial fibrillation and 4.9% involving atrial flutter. The mean age of patients enrolled was 64.5 years. In total, 96.8% were discharged home and, of those, 93.3% were in sinus rhythm. All patients were initially administered intravenous procainamide, with a 58.3% conversion rate. A total of 243 patients underwent subsequent electrical cardioversion with a 91.7% success rate. Adverse events occurred in 7.6% of cases: hypotension 6.7%, bradycardia 0.3% and 7-day relapse 8.6%. There were no cases of torsades de pointes, stroke or death. The median lengths of stay in the ED were as follows: 4.9 hours overall, 3.9 hours for those undergoing conversion with procainamide and 6.5 hours for those requiring electrical conversion. CONCLUSION This is the largest study to date to evaluate the Ottawa Aggressive Protocol, a unique approach to cardioversion for ED patients with recent-onset episodes of atrial fibrillation and flutter. Our data demonstrate that the Ottawa Aggressive Protocol is effective, safe and rapid, and has the potential to significantly reduce hospital admissions and expedite ED care.

A Risk Scoring System to Identify Emergency Department Patients With Heart Failure at High Risk for Serious Adverse Events

OBJECTIVES There are no validated guidelines to guide physicians with difficult disposition decisions for emergency department (ED) patients with heart failure (HF). The authors sought to develop a risk scoring system to identify HF patients at high risk for serious adverse events (SAEs). METHODS This was a prospective cohort study at six large Canadian EDS that enrolled adult patients who presented with acute decompensated HF. Each patient was assessed for standardized clinical and laboratory variables as well as for SAEs defined as death, intubation, admission to a monitored unit, or relapse requiring admission. Adjusted odds ratios for predictors of SAEs were calculated by stepwise logistic regression. RESULTS In 559 visits, 38.1% resulted in patient admission. Of 65 (11.6%) SAE cases, 31 (47.7%) occurred in patients not initially admitted. The multivariate model and resultant Ottawa Heart Failure Risk Scale consists of 10 elements, and the risk of SAEs varied from 2.8% to 89.0%, with good calibration between observed and expected probabilities. Internal validation showed the risk scores to be very accurate across 1,000 replications using the bootstrap method. A threshold of 1, 2, or 3 total scores for admission would be associated with sensitivities of 95.2, 80.6, or 64.5%, respectively, all better than current practice. CONCLUSIONS Many HF patients are discharged home from the ED and then suffer SAEs or death. The authors have developed an accurate risk scoring system that could ultimately be used to stratify the risk of poor outcomes and to enable rational and safe disposition decisions.

International Survey of Emergency Physicians’ Awareness and Use of the Canadian Cervical-Spine Rule and the Canadian Computed Tomography Head Rule

OBJECTIVES The derivation and validation studies for the Canadian Cervical-Spine (C-Spine) Rule (CCR) and the Canadian Computed Tomography (CT) Head Rule (CCHR) have been published in major medical journals. The objectives were to determine: 1) physician awareness and use of these rules in Australasia, Canada, the United Kingdom, and the United States and 2) physician characteristics associated with awareness and use. METHODS A self-administered e-mail and postal survey was sent to members of four national emergency physician (EP) associations using a modified Dillman technique. Results were analyzed using repeated-measures logistic regression models. RESULTS The response rate was 54.8% (1,150/2,100). Reported awareness of the CCR ranged from 97% (Canada) to 65% (United States); for the CCHR it ranged from 86% (Canada) to 31% (United States). Reported use of the CCR ranged from 73% (Canada) to 30% (United States); for the CCHR, it was 57% (Canada) to 12% (United States). Predictors of awareness were country, type of rule, full-time employment, younger age, and teaching hospital (p < 0.05). Significant differences in use of the CCR by country were observed, but not for the CCHR. Teaching hospitals were more likely to use the CCR than nonteaching hospitals, but less likely to use the CCHR. CONCLUSIONS This large international study found notable differences among countries with regard to knowledge and use of the CCR and CCHR. Awareness and use of both rules were highest in Canada and lowest in the United States. While younger physicians, those employed full-time, and those working in teaching hospitals were more likely to be aware of a decision rule, age and employment status were not significant predictors of use. A better understanding of factors related to awareness and use of emergency medicine (EM) decision rules will enhance our understanding of knowledge translation and facilitate strategies to enhance dissemination and implementation of future rules.

Association of injury mechanism with the risk of cervical spine fractures

OBJECTIVE A full understanding of an injury event and the mechanical forces involved should be important for predicting specific anatomical patterns of injury. Yet, information on the mechanism of injury is often overlooked as a predictor for specific anatomical injury in clinical decision-making. We measured the relationship between mechanism of injury and risk for cervical spine fracture. METHODS Our case-control study is a secondary analysis of data collected from the Canadian C-Spine Rule (CCR) study. Data were collected from 1996 to 2002 and included patients presenting to the emergency departments of 9 tertiary care centres after sustaining acute blunt trauma to the head or neck. Cases are defined as patients who were categorized in the CCR study with a clinically important cervical spine fracture. Controls had no radiologic evidence of cervical spine injury. Bivariate and multivariate unconditional logistic regression models were used. Results are presented as odds ratios (ORs) with 95% confidence intervals (CIs). RESULTS Among the 17,208 patients in the CCR study, 320 (2%)received a diagnosis of a cervical spine fracture. Axial loads, falls, diving incidents and nontraffic motorized vehicle collisions (e.g., collisions involving snowmobiles or all-terrain vehicles) were injury mechanisms that were significantly related to a higher risk of fracture. For motor vehicle collisions, the risk of cervical spine injury increased with the posted speed, being involved in a head-on collision or a rollover, or not wearing a seat belt (p < 0.05). The occurrence of cervical spine fracture was negligible in simple rear-end collisions (1 in 3694 cases; OR 0.015, 95% CI 0.002-0.104]). CONCLUSION Our study quantitatively demonstrates the relationship between specific mechanisms of injury and the risk of a cervical spine fracture. A full understanding of the injury mechanism would assist providers of emergency health care in assessing risk for injury in trauma patients.