Publications by authors named "Jonathan Dreyer"

24 Publications

  • Page 1 of 1

Improving Quality of Care Through a Mandatory Provincial Audit Program: Ontario's Emergency Department Return Visit Quality Program.

Ann Emerg Med 2021 02 13;77(2):193-202. Epub 2020 Nov 13.

Department of Pediatrics, University of Toronto, Toronto, Ontario, Canada; Division of Paediatric Emergency Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada.

The Emergency Department Return Visit Quality Program was launched in Ontario, Canada, to promote a culture of quality. It mandates the province's largest-volume emergency departments (EDs) to audit charts of patients who had a return visit leading to hospital admission, including some of their 72-hour all-cause return visits with admission and all of their 7-day ones with sentinel diagnoses (ie, acute myocardial infarction, subarachnoid hemorrhage, and pediatric sepsis), and submit their findings to a governmental agency. This provides an opportunity to identify possible adverse events and quality issues, which hospitals can then address through quality improvement initiatives. A group of emergency physicians with quality improvement expertise analyzed the submitted audits and accompanying narrative templates, using a general inductive approach to develop a novel classification of recurrent quality themes. Since the Return Visit Quality Program launched in 2016, 125,698 return visits with admission have been identified, representing 0.93% of the 86 participating EDs' 13,559,664 visits. Overall, participating hospitals have conducted 12,852 detailed chart audits, uncovering 3,010 (23.4%) adverse events/quality issues and undertaking hundreds of quality improvement provincewide projects as a result. The inductive analysis revealed 11 recurrent themes, classified into 3 groupings: patient characteristics (ie, patient risk profile and elder care), ED team actions or processes (ie, physician cognitive lapses, documentation, handover/communication between providers, radiology, vital signs, and high-risk medications or medication interactions), and health care system issues (ie, discharge planning/community follow-up, left against medical advice/left without being seen, and imaging/testing availability). The Return Visit Quality Program is the largest mandatory audit program for EDs and provides a novel approach to identify local adverse events/quality issues to target for improved patient safety and quality of care. It provides a blueprint for health system leaders to enable clinicians to develop an approach to organizational quality, as well as for teams to construct an audit system that yields defined issues amenable to improvement.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.annemergmed.2020.09.449DOI Listing
February 2021

Door-To-Triage Time in a Canadian Tertiary-Care Center.

J Emerg Med 2021 Jan 8;60(1):121-124. Epub 2020 Sep 8.

Department of Emergency Medicine, London Health Science Centre, London, Ontario, Canada; Division of Emergency Medicine, Department of Medicine, Western University, London, Ontario, Canada.

Background: The interval from patient arrival to triage is arguably the most dangerous time a patient spends in the emergency department (ED), as they are an unknown entity until assessed by a health care professional.

Objective: We sought to quantify door-to-triage time (DTT), an important factor in patient safety that has not yet been quantified in Canada.

Methods: Data were collected from all ambulatory patients presenting to a tertiary-care ED during a consecutive 7-day period. Demographic information, arrival time (door time), triage time, and Canadian Triage and Acuity Score (CTAS) were collected. DTT was compared across variables using Kruskal-Wallis one-way analysis of variance.

Results: Seven hundred and seventy-five patients were included in the study, representing 82.9% of ambulatory patients. DTT was variable (1-86 min) with a median of 12 min (interquartile range [IQR] 6-21 min). Patients in the 5 percentile with the longest DTT waited a median of 54 min (IQR 48-63 min). DTT varied across days of the week (p < 0.01); the longest wait was on Monday (median 22 [IQR 11-43] min) and the shortest on Sunday (median 8 [IQR 5-12] min). There was no relationship between DTT and CTAS (p = 0.12).

Conclusions: DTT is an important variable affecting patient safety. Given site-specific factors, replication across additional centers is necessary. Additional research evaluating factors affecting DTT, different triage paradigms, and quality improvement interventions should be undertaken.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jemermed.2020.07.015DOI Listing
January 2021

Interrater Reliability, Accuracy, and Triage Time Pre- and Post-implementation of a Real-Time Electronic Triage Decision-Support Tool.

Ann Emerg Med 2020 04 26;75(4):524-531. Epub 2019 Sep 26.

Schwartz/Reisman Emergency Medicine Institute, Sinai Health System, Toronto, Ontario, Canada; Department of Family and Community Medicine, Division of Emergency Medicine, University of Toronto, Toronto, Ontario, Canada.

Study Objective: The electronic Canadian Triage and Acuity Scale (eCTAS) is a real-time electronic triage decision-support tool designed to improve patient safety and quality of care by standardizing the application of the Canadian Triage and Acuity Scale (CTAS). The objective of this study is to determine interrater agreement of triage scores pre- and post-implementation of eCTAS.

Methods: This was a prospective, observational study conducted in 7 emergency departments (EDs), selected to represent a mix of triage documentation practices, hospital types, and patient volumes. A provincial CTAS auditor observed triage nurses in the ED pre- and post-implementation of eCTAS and assigned an independent CTAS score in real time. Research assistants independently recorded triage time. Interrater agreement was estimated with κ statistics with 95% confidence intervals (CIs).

Results: A total of 1,491 individual triage assessments (752 pre-eCTAS, 739 post-implementation) were audited during 42 7-hour triage shifts (21 pre-eCTAS, 21 post-implementation). Exact modal agreement was achieved for 567 patients (75.4%) pre-eCTAS compared with 685 patients (92.7%) triaged with eCTAS. With the auditor's CTAS score as the reference, eCTAS significantly reduced the number of patients over-triaged (12.0% versus 5.1%; Δ 6.9; 95% CI 4.0 to 9.7) and under-triaged (12.6% versus 2.2%; Δ 10.4; 95% CI 7.9 to 13.2). Interrater agreement was higher with eCTAS (unweighted κ 0.89 versus 0.63; quadratic-weighted κ 0.93 versus 0.79). Median triage time was 312 seconds (n=3,808 patients) pre-eCTAS and 347 seconds (n=3,489 patients) with eCTAS (Δ 35 seconds; 95% CI 29 to 40 seconds).

Conclusion: A standardized, electronic approach to performing triage assessments improves both interrater agreement and data accuracy without substantially increasing triage time.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.annemergmed.2019.07.048DOI Listing
April 2020

Prospective Validation of the Emergency Heart Failure Mortality Risk Grade for Acute Heart Failure.

Circulation 2019 02;139(9):1146-1156

ICES, Toronto, Ontario, Canada (D.S.L., M.J.S., T.O., A.C., T.A.S., P.C.A., J.V.T.).

Background: Improved risk stratification of acute heart failure in the emergency department may inform physicians' decisions regarding patient admission or early discharge disposition. We aimed to validate the previously-derived Emergency Heart failure Mortality Risk Grade for 7-day (EHMRG7) and 30-day (EHMRG30-ST) mortality.

Methods: We conducted a multicenter, prospective validation study of patients with acute heart failure at 9 hospitals. We surveyed physicians for their estimates of 7-day mortality risk, obtained for each patient before knowledge of the model predictions, and compared these with EHMRG7 for discrimination and net reclassification improvement. We also prospectively examined discrimination of the EHMRG30-ST model, which incorporates all components of EHMRG7 as well as the presence of ST-depression on the 12-lead ECG.

Results: We recruited 1983 patients seeking emergency department care for acute heart failure. Mortality rates at 7 days in the 5 risk groups (very low, low, intermediate, high, and very high risk) were 0%, 0%, 0.6%, 1.9%, and 3.9%, respectively. At 30 days, the corresponding mortality rates were 0%, 1.9%, 3.9%, 5.9%, and 14.3%. Compared with physician-estimated risk of 7-day mortality (PER7; c-statistic, 0.71; 95% CI, 0.64-0.78) there was improved discrimination with EHMRG7 (c-statistic, 0.81; 95% CI, 0.75-0.87; P=0.022 versus PER7) and with EHMRG7 combined with physicians' estimates (c-statistic, 0.82; 95% CI, 0.76-0.88; P=0.003 versus PER7). Model discrimination increased nonsignificantly by 0.014 (95% CI, -0.009-0.037) when physicians' estimates combined with EHMRG7 were compared with EHMRG7 alone ( P=0.242). The c-statistic for EHMRG30-ST alone was 0.77 (95% CI, 0.73-0.81) and 30-day model discrimination increased nonsignificantly by addition of physician-estimated risk to 0.78 (95% CI, 0.73-0.82; P=0.187). Net reclassification improvement with EHMRG7 was 0.763 (95% CI, 0.465-1.062) when assessed continuously and 0.820 (0.560-1.080) using risk categories compared with PER7.

Conclusions: A clinical model allowing simultaneous prediction of mortality at both 7 and 30 days identified acute heart failure patients with a low risk of events. Compared with physicians' estimates, our multivariable model was better able to predict 7-day mortality and may guide clinical decisions.

Clinical Trial Registration: URL: https://www.clinicaltrials.gov . Unique identifier: NCT02634762.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1161/CIRCULATIONAHA.118.035509DOI Listing
February 2019

Are reductions in emergency department length of stay associated with improvements in quality of care? A difference-in-differences analysis.

BMJ Qual Saf 2016 07 13;25(7):489-98. Epub 2015 Aug 13.

Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada.

Background: We sought to determine whether patients seen in hospitals who had reduced overall emergency department (ED) length of stay (LOS) in the 2 years following the introduction of the Ontario Emergency Room Wait Time Strategy were more likely to experience improvements in other measures of ED quality of care for three important conditions.

Methods: Retrospective medical record review using difference-in-differences analysis to compare changes in performance on quality indicators over the 3-year period between 11 Ontario hospitals where the median ED LOS had improved from fiscal year 2008 to 2010 and 13 matched sites where ED LOS was unchanged or worsened. Patients with acute myocardial infarction (AMI), asthma and paediatric and adult upper limb fractures in these hospitals in 2008 and 2010 were evaluated with respect to 18 quality indicators reflecting timeliness and safety/effectiveness of care in the ED. In a secondary analysis, we examined shift-level ED crowding at the time of the patient visit and performance on the quality indicators.

Results: Median ED LOS improved by up to 26% (63 min) from 2008 to 2010 in the improved hospitals, and worsened by up to 47% (91 min) in the unimproved sites. We abstracted 4319 and 4498 charts from improved and unimproved hospitals, respectively. Improvement in a hospital's overall median ED LOS from 2008 to 2010 was not associated with a change in any of the other ED quality indicators over the same time period. In our secondary analysis, shift-level crowding was associated only with indicators that reflected timeliness of care. During less crowded shifts, patients with AMI were more likely to be reperfused within target intervals (rate ratio 1.59, 95% CI 1.03 to 2.45), patients with asthma more often received timely administration of steroids (rate ratio 1.88, 95% CI 1.59 to 2.24) and beta-agonists (rate ratio 1.47, 95% CI 1.25 to 1.74), and adult (but not paediatric) patients with fracture were more likely to receive analgesia or splinting within an hour (rate ratio 1.66, 95% CI 1.22 to 2.26).

Conclusions: These results suggest that a policy approach that targets only reductions in ED LOS is not associated with broader improvements in selected quality measures. At the same time, there is no evidence that efforts to address crowding have a detrimental effect on quality of care.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1136/bmjqs-2015-004189DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4941160PMC
July 2016

Differential survival for men and women from out-of-hospital cardiac arrest varies by age: results from the OPALS study.

Acad Emerg Med 2014 Dec;21(12):1503-11

Department of Emergency Medicine, Yale University School of Medicine, New Haven, CT.

Background: The effect of sex on survival in out-of-hospital cardiac arrest (OHCA) is controversial. Some studies report more favorable outcomes in women, while others suggest the opposite, citing disparities in care. Whether sex predicts differential age-specific survival is still uncertain.

Objectives: The objective was to study the sex-associated variation in survival to hospital discharge in OHCA patients as well as the relationship between age and sex for predicting survival.

Methods: The Ontario Prehospital Advanced Life Support (OPALS) registry, collected in a large study of rapid defibrillation and advanced life support programs, is Utstein-compliant and has data on OHCA patients (1994 to 2002) from 20 communities in Ontario, Canada. All adult OHCAs not witnessed by emergency medical services (EMS) and treated during one of the three main OPALS phases were included. Clinically significant variables were chosen a priori (age, sex, witnessed arrest, initial cardiopulmonary resuscitation [CPR], shockable rhythm, EMS response interval, and OPALS study phase) and entered into a multivariable logistic regression model with survival to hospital discharge as the outcome, with sex and age as the primary risk factors. Fractional polynomials were used to explore the relationship between age and survival by sex.

Results: A total of 11,479 (out of 20,695) OPALS cases met inclusion criteria and 10,862 (94.6%) had complete data for regression analysis. As a group, women were older than men (median age = 74 years vs. 69 years, p < 0.01), had fewer witnessed arrests (43% vs. 49%; p < 0.01), had fewer initial ventricular fibrillation/ventricular tachycardia rhythms (24% vs. 42%; p < 0.01), had a lower rate of bystander CPR (12% vs. 17%; p < 0.01), and had lower survival (1.7% vs. 3.2%; p < 0.01). Survival to hospital admission and return of spontaneous circulation did not differ between women and men (p > 0.05). The relationship between age, sex, and survival to hospital discharge could not be analyzed in a single regression model, as age did not have a linear relationship with survival for men, but did for women. Thus, age was kept as a continuous variable for women but was transformed for men using fractional polynomials [ln(age) + age(3) ]. In sex-stratified regression models, the adjusted probability of survival for women decreased as age increased (adjusted odds ratio = 0.88, 95% confidence interval = 0.81 to 0.96, per 5-year increase in age) while for men, the probability of survival initially increased with age until age 65 years and then decreased with increasing age. Women had a higher probability of survival until age 47 years, after which men maintained a higher probability of survival.

Conclusions: Overall OHCA survival for women was lower than for men in the OPALS study. Factors related to the sex differences in survival (rates of bystander CPR and shockable rhythms) may be modifiable. The probability of survival differed across age for men and women in a nonlinear fashion. This differential influence of age on survival for men and women should be considered in future studies evaluating survival by sex in OHCA population.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/acem.12540DOI Listing
December 2014

Familiarity with radiation exposure dose from diagnostic imaging for acute pulmonary embolism and current patterns of practice.

CJEM 2014 Sep;16(5):393-404

Objective: To assess the current level of knowledge and practice patterns of emergency physicians regarding radiation exposure from diagnostic imaging modalities for investigating acute pulmonary embolism (PE).

Methods: An online survey was sent to adult emergency physicians working at two academic tertiary care adult emergency departments (EDs) to determine imaging choices for investigating PE in various patient populations and to assess their current knowledge of radiation doses and risks. A retrospective chart review was performed for all adult patients who underwent computed tomographic pulmonary angiography (CTPA) and/or ventilation-perfusion (V/Q) scanning in the same EDs.

Results: The survey response rate was 72.1% (31 of 43 physicians). For patients < 30 years old, 83.9% of physicians chose V/Q scanning as their test of choice, regardless of gender. Although only a third of respondents knew the estimated radiation dose of a V/Q scan (37.5%) and a CTPA (32%), the majority were aware that V/Q scans involved less ionizing radiation than CTPAs. In the retrospective review, 663 charts were reviewed, including 201 CTPAs and 462 V/Q scans. V/Q scanning was the preferred modality in female patients (75.9% v. CTPA 24.1% [OR 2.1; 95% CI 1.5-2.9]) and in patients < 30 years old (87.9% v. CTPA 12.1% [OR 4.8; 95% CI 2.4-9.4]).

Conclusions: Although surveyed physicians possessed limited knowledge of radiation doses of CTPA and V/Q scans, they preferentially used the lower radiation V/Q scans in younger patients, particularly females, in both the survey vignettes and in clinical practice. This may reflect efforts to reduce radiation exposures at our institution.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.2310/8000.2013.131118DOI Listing
September 2014

The relationship between out-of-hospital airway management and outcome among trauma patients with Glasgow Coma Scale Scores of 8 or less.

Prehosp Emerg Care 2011 Apr-Jun;15(2):184-92. Epub 2011 Feb 10.

Department of Emergency Medicine, UCSD Center for Resuscitation Science, San Diego, California 92103-8676, USA.

Background: Airway management remains a fundamental component of optimal care of the severely injured patient, with endotracheal intubation representing the definitive strategy for airway control. However, multiple studies document an association between out-of-hospital intubation and increased mortality for severe traumatic brain injury.

Objectives: To explore the relationship between out-of-hospital intubation attempts and outcome among trauma patients with Glasgow Coma Scale (GCS) scores ≤ 8 across sites participating in the Resuscitation Outcomes Consortium (ROC).

Methods: The ROC Epistry-Trauma, an epidemiologic database of prehospital encounters with critically injured trauma victims, was used to identify emergency medical services (EMS)-treated patients with GCS scores ≤ 8. Multiple logistic regression was used to explore the association between intubation attempts and vital status at discharge, adjusting for the following covariates: age, gender, GCS score, hypotension, mechanism of injury, and ROC site. Sites were then stratified by frequency of intubation attempts and chi-square test for trend was used to associate the frequency of intubation attempts with outcome.

Results: A total of 1,555 patients were included in this analysis; intubation was attempted in 758 of these. Patients in whom intubation was attempted had higher mortality (adjusted odds ratio [OR] 2.91, 95% confidence interval [CI] 2.13-3.98, p < 0.01). However, sites with higher rates of attempted intubation had lower mortality across all trauma victims with GCS scores ≤ 8 (OR 1.40, 95% CI 1.15-1.72, p < 0.01).

Conclusions: Patients in whom intubation is attempted have higher adjusted mortality. However, sites with a higher rate of attempted intubation have lower adjusted mortality across the entire cohort of trauma patients with GCS scores ≤ 8. Coma Scale score.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3109/10903127.2010.545473DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4091894PMC
July 2011

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

CMAJ 2010 Oct 23;182(14):1527-32. Epub 2010 Aug 23.

Department of Emergency Medicine, Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Ont.

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).
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1503/cmaj.091974DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2950184PMC
October 2010

The impact of delays to admission from the emergency department on inpatient outcomes.

BMC Emerg Med 2010 Jul 9;10:16. Epub 2010 Jul 9.

Department of Epidemiology and Biostatistics, Schulich School of Medicine and Dentistry, University of Western Ontario, Canada.

Background: We sought to determine the impact of delays to admission from the Emergency Department (ED) on inpatient length of stay (LOS), and IP cost.

Methods: We conducted a retrospective analysis of 13,460 adult (>or= 18 yrs) ED visits between April 1 2006 and March 30 2007 at a tertiary care teaching hospital with two ED sites in which the mode of disposition was admission to ICU, surgery or inpatient wards. We defined ED Admission Delay as ED time to decision to admit > 12 hours. The primary outcomes were IP LOS, and total IP cost.

Results: Approximately 11.6% (n = 1558) of admitted patients experienced admission delay. In multivariate analysis we found that admission delay was associated with 12.4% longer IP LOS (95% CI 6.6% - 18.5%) and 11.0% greater total IP cost (6.0% - 16.4%). We estimated the cumulative impact of delay on all delayed patients as an additional 2,183 inpatient days and an increase in IP cost of $2,109,173 at the study institution.

Conclusions: Delays to admission from the ED are associated with increased IP LOS and IP cost. Improving patient flow through the ED may reduce hospital costs and improve quality of care. There may be a business case for investments to reduce emergency department admission delays.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/1471-227X-10-16DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2912828PMC
July 2010

Survival after application of automatic external defibrillators before arrival of the emergency medical system: evaluation in the resuscitation outcomes consortium population of 21 million.

J Am Coll Cardiol 2010 Apr;55(16):1713-20

Johns Hopkins University, Baltimore, Maryland 21287, USA.

Objectives: The purpose of this study was to assess the effectiveness of contemporary automatic external defibrillator (AED) use.

Background: In the PAD (Public Access Defibrillation) trial, survival was doubled by focused training of lay volunteers to use an AED in high-risk public settings.

Methods: We performed a population-based cohort study of persons with nontraumatic out-of-hospital cardiac arrest before emergency medical system (EMS) arrival at Resuscitation Outcomes Consortium (ROC) sites between December 2005 and May 2007. Multiple logistic regression was used to assess the independent association between AED application and survival to hospital discharge.

Results: Of 13,769 out-of-hospital cardiac arrests, 4,403 (32.0%) received bystander cardiopulmonary resuscitation but had no AED applied before EMS arrival, and 289 (2.1%) had an AED applied before EMS arrival. The AED was applied by health care workers (32%), lay volunteers (35%), police (26%), or unknown (7%). Overall survival to hospital discharge was 7%. Survival was 9% (382 of 4,403) with bystander cardiopulmonary resuscitation but no AED, 24% (69 of 289) with AED application, and 38% (64 of 170) with AED shock delivered. In multivariable analyses adjusting for: 1) age and sex; 2) bystander cardiopulmonary resuscitation performed; 3) location of arrest (public or private); 4) EMS response interval; 5) arrest witnessed; 6) initial shockable or not shockable rhythm; and 7) study site, AED application was associated with greater likelihood of survival (odds ratio: 1.75; 95% confidence interval: 1.23 to 2.50; p < 0.002). Extrapolating this greater survival from the ROC EMS population base (21 million) to the population of the U.S. and Canada (330 million), AED application by bystanders seems to save 474 lives/year.

Conclusions: Application of an AED in communities is associated with nearly a doubling of survival after out-of-hospital cardiac arrest. These results reinforce the importance of strategically expanding community-based AED programs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jacc.2009.11.077DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3008654PMC
April 2010

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

BMJ 2009 Oct 29;339:b4146. Epub 2009 Oct 29.

Department of Emergency Medicine, University of Ottawa, Canada.

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.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2770593PMC
http://dx.doi.org/10.1136/bmj.b4146DOI Listing
October 2009

Physician workload and the Canadian Emergency Department Triage and Acuity Scale: the Predictors of Workload in the Emergency Room (POWER) Study.

CJEM 2009 Jul;11(4):321-9

School of Hotel Administration, Cornell University, New York, New York, Unites States.

Introduction: The Canadian Emergency Department Triage and Acuity Scale (CTAS) is a 5-level triage tool used to determine the priority by which patients should be treated in Canadian emergency departments (EDs). To determine emergency physician (EP) workload and staffing needs, many hospitals in Ontario use a case-mix formula based solely on patient volume at each triage level. The purpose of our study was to describe the distribution of EP time by activity during a shift in order to estimate the amount of time required by an EP to assess and treat patients in each triage category and to determine the variability in the distribution of CTAS scoring between hospital sites.

Methods: Research assistants directly observed EPs for 592 shifts and electronically recorded their activities on a moment-by-moment basis. The duration of all activities associated with a given patient were summed to derive a directly observed estimate of the amount of EP time required to treat the patient.

Results: We observed treatment times for 11 716 patients in 11 hospital-based EDs. The mean time for physicians to treat patients was 73.6 minutes (95% confidence interval [CI] 63.6-83.7) for CTAS level 1, 38.9 minutes (95% CI 36.0-41.8) for CTAS-2, 26.3 minutes (95% CI 25.4-27.2) for CTAS-3, 15.0 minutes (95% CI 14.6-15.4) for CTAS-4 and 10.9 minutes (95% CI 10.1-11.6) for CTAS-5. Physician time related to patient care activities accounted for 84.2% of physicians' ED shifts.

Conclusion: In our study, EPs had very limited downtime. There was significant variability in the distribution of CTAS scores between sites and also marked variation in EP time related to each triage category. This brings into question the appropriateness of using CTAS alone to determine physician staffing levels in EDs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1017/s1481803500011350DOI Listing
July 2009

Effect of transport interval on out-of-hospital cardiac arrest survival in the OPALS study: implications for triaging patients to specialized cardiac arrest centers.

Ann Emerg Med 2009 Aug 23;54(2):248-55. Epub 2009 Jan 23.

Arizona Emergency Medicine Research Center, Department of Emergency Medicine, College of Medicine, The University of Arizona, Tucson, AZ.

Study Objective: To identify any association between out-of-hospital transport interval and survival to hospital discharge in victims of out-of-hospital cardiac arrest.

Methods: Data from the Ontario Prehospital Advanced Life Support Study (January 1, 1991, to December 31, 2002), an Utstein-compliant registry of out-of-hospital cardiac arrest patients from 21 communities, were analyzed. Logistic regression identified factors that were independently associated with survival in consecutive adult, nontraumatic, out-of-hospital cardiac arrest patients and in the subgroup with return of spontaneous circulation.

Results: A total of 18,987 patients met criteria and 15,559 (81.9%) had complete data for analysis (study group). Return of spontaneous circulation was achieved in 2,299 patients (14.8%), and 689 (4.4%) survived to hospital discharge. Median transport interval was 4.0 minutes (25th quartile 3.0 minutes; 75th quartile 6.2 minutes) for survivors and 4.2 minutes (25th quartile 3.0, 75th quartile 6.2) for nonsurvivors. Logistic regression revealed multiple factors that were independently associated with survival: witnessed arrest (odds ratio 2.61; 95% confidence interval [CI] 2.05 to 3.34), bystander cardiopulmonary resuscitation (odds ratio 2.22; 95% CI 1.82 to 2.70), initial rhythm of ventricular fibrillation/tachycardia (odds ratio 2.22; 95% CI 1.97 to 2.50), and shorter emergency medical services (EMS) response interval (odds ratio 1.26; 95% CI 1.20 to 1.33). There was no association between transport interval and survival in either the study group (odds ratio 1.01; 95% CI 0.99 to 1.05) or the return of spontaneous circulation subgroup (odds ratio 1.04; 95% CI 0.99, 1.08).

Conclusion: In a large out-of-hospital cardiac arrest study from demographically diverse EMS systems, longer transport interval was not associated with decreased survival. Given the growing evidence showing major influence from specialized postarrest care, these findings support conducting clinical trials that assess the effectiveness and safety of bypassing local hospitals to take patients to regional cardiac arrest centers.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.annemergmed.2008.11.020DOI Listing
August 2009

Comparison of the Cerebral Performance Category score and the Health Utilities Index for survivors of cardiac arrest.

Ann Emerg Med 2009 Feb 1;53(2):241-248. Epub 2008 May 1.

Department of Emergency Medicine, Ottawa Health Research Institute, University of Ottawa, Ottawa, Ontario, Canada.

Study Objective: The Cerebral Performance Category score is an easy to use but unvalidated measure of functional outcome after cardiac arrest. We evaluate the comparability of results from the Cerebral Performance Category scale versus those of the validated but more complex Health Utilities Index scale for health-related quality of life.

Methods: This prospective substudy of the Ontario Prehospital Advanced Life Support (OPALS) Study included adult out-of-hospital cardiac arrest patients treated in 20 cities. This prospective cohort study included all survivors of out-of-hospital adult cardiac arrest enrolled in phase II (rapid basic life support with defibrillation) and phase III (advanced life support) of the OPALS Study, as well as the intervening run-in phase. Survivors were interviewed at 12 months for Cerebral Performance Category Score and the Health Utilities Index Mark 3 (Health Utilities Index).

Results: Of 8,196 eligible out-of-hospital cardiac arrest patients between 1995 and 2002, 418 (5.1%) survived to discharge, and 305 (3.7%) completed the Health Utilities Index interview and had Cerebral Performance Category scored at 12 months. The 305 patients had the following data: mean age 63.9 years; male 78.0%; paramedic-witnessed arrest 25.6%; bystander cardiopulmonary resuscitation 32.1%; initial rhythm ventricular fibrillation/ventricular tachycardia 86.9%, Cerebral Performance Category 1 267, Cerebral Performance Category 2 26, Cerebral Performance Category 3 12. Overall, the median scores (interquartile range) were Cerebral Performance Category 1 (1 to 1) and Health Utilities Index 0.84 (0.61 to 0.97). The Cerebral Performance Category score ruled out good quality of life (Health Utilities Index >0.80), with a sensitivity of 100% (95% confidence interval [CI] 98% to 100%) and specificity 27.1% (95% CI 20% to 35%); thus, when the Cerebral Performance Category score was 2 or 3, it was unlikely that the Health Utilities Index score would be good. The Cerebral Performance Category score had sensitivity 55.6% (95% CI 42% to 67%) and specificity 96.8% (95% CI 94% to 98%) for predicting poor quality of life (Health Utilities Index >0.40); ie, when Cerebral Performance Category was 1, it was highly unlikely that the Health Utilities Index score would be poor. The weighted kappa was 0.39 and the interclass correlation was 0.51.

Conclusion: This represents the largest study yet conducted of the performance of the Cerebral Performance Category score in 1-year survivors of out-of-hospital cardiac arrest. Overall, the Cerebral Performance Category score classified patients well for their quality of life, ruling out a good Health Utilities Index score with high sensitivity and ruling in poor Health Utilities Index score with high specificity. The Cerebral Performance Category is an important tool in that it indicates broad functional outcome categories that are useful for a number of key clinical and research applications but should not be considered a substitute for the Health Utilities Index.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.annemergmed.2008.03.018DOI Listing
February 2009

Comparison of the Canadian CT Head Rule and the New Orleans Criteria in patients with minor head injury.

JAMA 2005 Sep;294(12):1511-8

Department of Emergency Medicine, University of Ottawa, Ottawa, Ontario, Canada.

Context: Current use of cranial computed tomography (CT) for minor head injury is increasing rapidly, highly variable, and inefficient. The Canadian CT Head Rule (CCHR) and New Orleans Criteria (NOC) are previously developed clinical decision rules to guide CT use for patients with minor head injury and with Glasgow Coma Scale (GCS) scores of 13 to 15 for the CCHR and a score of 15 for the NOC. However, uncertainty about the clinical performance of these rules exists.

Objective: To compare the clinical performance of these 2 decision rules for detecting the need for neurosurgical intervention and clinically important brain injury.

Design, Setting, And Patients: In a prospective cohort study (June 2000-December 2002) that included 9 emergency departments in large Canadian community and university hospitals, the CCHR was evaluated in a convenience sample of 2707 adults who presented to the emergency department with blunt head trauma resulting in witnessed loss of consciousness, disorientation, or definite amnesia and a GCS score of 13 to 15. The CCHR and NOC were compared in a subgroup of 1822 adults with minor head injury and GCS score of 15.

Main Outcome Measures: Neurosurgical intervention and clinically important brain injury evaluated by CT and a structured follow-up telephone interview.

Results: Among 1822 patients with GCS score of 15, 8 (0.4%) required neurosurgical intervention and 97 (5.3%) had clinically important brain injury. The NOC and the CCHR both had 100% sensitivity but the CCHR was more specific (76.3% vs 12.1%, P<.001) for predicting need for neurosurgical intervention. For clinically important brain injury, the CCHR and the NOC had similar sensitivity (100% vs 100%; 95% confidence interval [CI], 96%-100%) but the CCHR was more specific (50.6% vs 12.7%, P<.001), and would result in lower CT rates (52.1% vs 88.0%, P<.001). The kappa values for physician interpretation of the rules, CCHR vs NOC, were 0.85 vs 0.47. Physicians misinterpreted the rules as not requiring imaging for 4.0% of patients according to CCHR and 5.5% according to NOC (P = .04). Among all 2707 patients with a GCS score of 13 to 15, the CCHR had sensitivities of 100% (95% CI, 91%-100%) for 41 patients requiring neurosurgical intervention and 100% (95% CI, 98%-100%) for 231 patients with clinically important brain injury.

Conclusion: For patients with minor head injury and GCS score of 15, the CCHR and the NOC have equivalent high sensitivities for need for neurosurgical intervention and clinically important brain injury, but the CCHR has higher specificity for important clinical outcomes than does the NOC, and its use may result in reduced imaging rates.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1001/jama.294.12.1511DOI Listing
September 2005

The University of Michigan Student Health Physics Society's Radiation and Health Physics World Wide Web Site.

Health Phys 2005 May;88(5 Suppl):S115-20

Department of Nuclear Engineering and Radiological Sciences at the University of Michigan, Ann Arbor, MI 48109-2104, USA.

The University of Michigan Student Health Physics Society's (UMSHPS) Radiation and Health Physics World Wide Web Site is an informative database of radiation and health physics related topics. With over 1,000 visitors each day, the UMSHPS web site provides professionals and the general public with a valuable resource for information and research. Users of this site can either search for information by topic or submit questions directly to the qualified members the national Health Physics Society. During the past year, progress has been made in replacing the site's older, less versatile framework with new search engines and refined submittal forms, as well as a "Frequently Asked Questions" section. Within the database, references will include brief summaries of the site's available information and target audience. Although these changes have been beneficial for the site, the UMSHPS continuously seeks professional opinions and ideas to further the services that this online resource can provide to the profession and to the general public.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1097/01.hp.0000156071.04822.53DOI Listing
May 2005

Retrospective application of the NEXUS low-risk criteria for cervical spine radiography in Canadian emergency departments.

Ann Emerg Med 2004 Apr;43(4):507-14

Department of Emergency Medicine, University of Ottawa, Ottawa, Ontario, Canada.

Study Objective: We evaluate the accuracy, reliability, and potential impact of the National Emergency X-Radiography Utilization Study (NEXUS) low-risk criteria for cervical spine radiography, when applied in Canadian emergency departments (EDs).

Methods: The Canadian C-Spine Rule derivation study was a prospective cohort study conducted in 10 Canadian EDs that recruited alert and stable adult trauma patients. Physicians completed a 20-item data form for each patient and performed interobserver assessments when feasible. The prospective assessments included the 5 individual NEXUS criteria but not an explicit interpretation of the overall need for radiography according to the criteria. Patients underwent plain radiography, flexion-extension views, and computed tomography at the discretion of the treating physician. Patients who did not have radiography were followed up with a structured outcome assessment by telephone to determine clinically important cervical spine injury, a previously validated outcome measurement. Analyses included sensitivity and specificity with 95% confidence interval (CI), kappa coefficient, and potential radiography rates.

Results: Among 8,924 patients, 151 (1.7%) patients had an important cervical spine injury. The combined NEXUS criteria identified important cervical spine injury with a sensitivity of 92.7% (95% CI 87% to 96%) and a specificity of 37.8% (95% CI 37% to 39%). Application of the NEXUS criteria would have potentially reduced cervical spine radiography rates by 6.1% from the actual rate of 68.9% to 62.8%. Of 11 patients with important injuries not identified, 2 were treated with internal fixation and 3 with a halo.

Conclusion: This retrospective validation found the NEXUS low-risk criteria to be less sensitive than previously reported. The NEXUS low-risk criteria should be further explicitly and prospectively evaluated for accuracy and reliability before widespread clinical use outside of the United States.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.annemergmed.2003.10.036DOI Listing
April 2004

The Canadian C-spine rule versus the NEXUS low-risk criteria in patients with trauma.

N Engl J Med 2003 Dec;349(26):2510-8

Department of Emergency Medicine, University of Ottawa, Ottawa, Ont, Canada.

Background: The Canadian C-Spine (cervical-spine) Rule (CCR) and the National Emergency X-Radiography Utilization Study (NEXUS) Low-Risk Criteria (NLC) are decision rules to guide the use of cervical-spine radiography in patients with trauma. It is unclear how the two decision rules compare in terms of clinical performance.

Methods: We conducted a prospective cohort study in nine Canadian emergency departments comparing the CCR and NLC as applied to alert patients with trauma who were in stable condition. The CCR and NLC were interpreted by 394 physicians for patients before radiography.

Results: Among the 8283 patients, 169 (2.0 percent) had clinically important cervical-spine injuries. In 845 (10.2 percent) of the patients, physicians did not evaluate range of motion as required by the CCR algorithm. In analyses that excluded these indeterminate cases, the CCR was more sensitive than the NLC (99.4 percent vs. 90.7 percent, P<0.001) and more specific (45.1 percent vs. 36.8 percent, P<0.001) for injury, and its use would have resulted in lower radiography rates (55.9 percent vs. 66.6 percent, P<0.001). In secondary analyses that included all patients, the sensitivity and specificity of CCR, assuming that the indeterminate cases were all positive, were 99.4 percent and 40.4 percent, respectively (P<0.001 for both comparisons with the NLC). Assuming that the CCR was negative for all indeterminate cases, these rates were 95.3 percent (P=0.09 for the comparison with the NLC) and 50.7 percent (P=0.001). The CCR would have missed 1 patient and the NLC would have missed 16 patients with important injuries.

Conclusions: For alert patients with trauma who are in stable condition, the CCR is superior to the NLC with respect to sensitivity and specificity for cervical-spine injury, and its use would result in reduced rates of radiography.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1056/NEJMoa031375DOI Listing
December 2003

Evaluation of D-dimer in the diagnosis of suspected deep-vein thrombosis.

N Engl J Med 2003 Sep;349(13):1227-35

Department of Medicine, Ottawa Hospital, University of Ottawa, Ottawa, Ont, Canada.

Background: Several diagnostic strategies using ultrasound imaging, measurement of D-dimer, and assessment of clinical probability of disease have proved safe in patients with suspected deep-vein thrombosis, but they have not been compared in randomized trials.

Methods: Outpatients presenting with suspected lower-extremity deep-vein thrombosis were potentially eligible. Using a clinical model, physicians evaluated the patients and categorized them as likely or unlikely to have deep-vein thrombosis. The patients were then randomly assigned to undergo ultrasound imaging alone (control group) or to undergo D-dimer testing (D-dimer group) followed by ultrasound imaging unless the D-dimer test was negative and the patient was considered clinically unlikely to have deep-vein thrombosis, in which case ultrasound imaging was not performed.

Results: Five hundred thirty patients were randomly assigned to the control group, and 566 to the D-dimer group. The overall prevalence of deep-vein thrombosis or pulmonary embolism was 15.7 percent. Among patients for whom deep-vein thrombosis had been ruled out by the initial diagnostic strategy, there were two confirmed venous thromboembolic events in the D-dimer group (0.4 percent; 95 percent confidence interval, 0.05 to 1.5 percent) and six events in the control group (1.4 percent; 95 percent confidence interval, 0.5 to 2.9 percent; P=0.16) during three months of follow-up. The use of D-dimer testing resulted in a significant reduction in the use of ultrasonography, from a mean of 1.34 tests per patient in the control group to 0.78 in the D-dimer group (P=0.008). Two hundred eighteen patients (39 percent) in the D-dimer group did not require ultrasound imaging.

Conclusions: Deep-vein thrombosis can be ruled out in a patient who is judged clinically unlikely to have deep-vein thrombosis and who has a negative D-dimer test. Ultrasound testing can be safely omitted in such patients.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1056/NEJMoa023153DOI Listing
September 2003

The Canadian C-spine rule performs better than unstructured physician judgment.

Ann Emerg Med 2003 Sep;42(3):395-402

Division of Emergency Medicine, University of Toronto, Toronto, Ontario, Canada.

Study Objectives: We compare the predictive accuracy of emergency physicians' unstructured clinical judgment to the Canadian C-Spine rule.

Methods: This prospective multicenter cohort study was conducted at 10 Canadian urban academic emergency departments. Included in the study were alert, stable, adult patients with a Glasgow Coma Scale score of 15 and trauma to the head or neck. This was a substudy of the Canadian C-Spine and CT Head Study. Eligible patients were prospectively evaluated before radiography. Physicians estimated the probability of unstable cervical spine injury from 0% to 100% according to clinical judgment alone and filled out a data form. Interobserver assessments were done when feasible. Patients underwent cervical spine radiography or follow-up to determine clinically important cervical spine injuries. Analyses included comparison of areas under the receiver operating characteristic (ROC) curve with 95% confidence intervals (CIs) and the kappa coefficient.

Results: During 18 months, 6265 patients were enrolled. The mean age was 36.6 years (range 16 to 97 years), and 50.1% were men. Sixty-four (1%) patients had a clinically important injury. The physicians' kappa for a 0% predicted probability of injury was 0.46 (95% CI 0.28 to 0.65). The respective areas under the ROC curve for predicting cervical spine injury were 0.85 (95% CI 0.80 to 0.89) for physician judgment and 0.91 (95% CI 0.89 to 0.92) for the Canadian C-Spine rule (P <.05). With a threshold of 0% predicted probability of injury, the respective indices of accuracy for physicians and the Canadian C-Spine rule were sensitivity 92.2% versus 100% (P <.001) and specificity 53.9% versus 44.0% (P <.001).

Conclusion: Interobserver agreement of unstructured clinical judgment for predicting clinically important cervical spine injury is only fair, and the sensitivity is unacceptably low. The Canadian C-Spine rule was better at detecting clinically important injuries with a sensitivity of 100%. Prospective validation has recently been completed and should permit widespread use of the Canadian C-Spine rule.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/s0196-0644(03)00422-0DOI Listing
September 2003

Outpatient oral prednisone after emergency treatment of chronic obstructive pulmonary disease.

N Engl J Med 2003 Jun;348(26):2618-25

Department of Medicine, University of Ottawa, Ottawa, Ont, Canada.

Background: In this randomized, double-blind, placebo-controlled trial, we studied the effectiveness of prednisone in reducing the risk of relapse after outpatient exacerbations of chronic obstructive pulmonary disease (COPD).

Methods: We enrolled 147 patients who were being discharged from the emergency department after an exacerbation of COPD and randomly assigned them to 10 days of treatment with 40 mg of oral prednisone once daily or identical-appearing placebo. All patients received oral antibiotics for 10 days, plus inhaled bronchodilators. The primary end point was relapse, defined as an unscheduled visit to a physician's office or a return to the emergency department because of worsening dyspnea, within 30 days after randomization.

Results: The overall rate of relapse at 30 days was lower in the prednisone group than in the placebo group (27 percent vs. 43 percent, P=0.05), and the time to relapse was prolonged in those taking prednisone (P=0.04). After 10 days of therapy, patients in the prednisone group had greater improvements in forced expiratory volume in one second than did patients in the placebo group (mean [+/-SD] increase from base line, 34+/-42 percent vs. 15+/-31 percent; P=0.007). Patients in the prednisone group also had significant improvements in dyspnea, as measured by the transitional dyspnea index (P=0.04) and by the dyspnea domain of the Chronic Respiratory Disease Index Questionnaire (P=0.02), but not in health-related quality of life (P=0.14).

Conclusions: Outpatient treatment with oral prednisone offers a small advantage over placebo in treating patients who are discharged from the emergency department with an exacerbation of COPD.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1056/NEJMoa023161DOI Listing
June 2003

Transport refusal by hypoglycemic patients after on-scene intravenous dextrose.

Acad Emerg Med 2002 Aug;9(8):855-7

University of Western Ontario Faculty of Medicine, London, ON, Canada.

Objectives: Administration of intravenous (IV) dextrose to hypoglycemic patients is delegated to advanced care paramedics in Ontario. Following a quality assurance review, which revealed that 47% of patients refused transport after receiving IV dextrose, the authors studied whether such patients seek additional medical care in the three days following the initial refusal.

Methods: Sequential ambulance call reports for on-scene treatments of hypoglycemia were examined, and a standardized telephone survey of the patients was conducted. Patient satisfaction was assessed using a five-point Likert scale. Data were collected from April 1999 to March 2000.

Results: One hundred patients were studied, with ages ranging from 20 to 92 years (mean 53.2 years). The average Glasgow Coma Scale (GCS) score on presentation was 8.7 +/- 3.5. The average blood glucose level before administration of IV dextrose was 1.91 +/- 0.63 mmol/L. Sixty-eight percent of the patients refused transport. Significant differences between the transported group and the refusal group were age (transported 64.7 years, refused 47.8 years, p = 0.002) and initial blood glucose (transported 1.8, refused 2.1, p = 0.001). No difference was found in terms of repeat access to health care for related complaints. Patient satisfaction was high in both groups, with no difference in the overall satisfaction with paramedics' care (4.76 +/- 0.58 vs 4.75 +/- 0.45).

Conclusions: The practice of treating patients for symptomatic hypoglycemia and leaving them at the scene appears to be safe. Further study is required to confirm this.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/j.1553-2712.2002.tb02179.xDOI Listing
August 2002