BMC Emergency Medicine - Latest Articles

Crotaline Fab antivenom appears to be effective in cases of severe North American pit viper envenomation: An integrative review

Eric Lavonas — 2009-06-22T00:00:00Z

Background: In 2000, the United States Food and Drug Administration approved Crotalidae Polyvalent Immune Fab (Ovine) (hereafter, FabAV), "for the management of patients with minimal to moderate North American Crotalid envenomation." Because whole-IgG pit viper antivenom is no longer available in the United States, FabAV is currently the only specific treatment option available to United States clinicians treating snakebite victims of any severity. No clinical trial data are available concerning the effectiveness of FabAV for treatment of severe snakebite, but several published articles describe its use in this setting. Methods: We performed a comprehensive review of the English-language medical literature to identify all publications (1996 to July, 2008) containing data about the administration of FabAV. Two trained reviewers separately extracted case-level data concerning the administration of FabAV to patients with severe envenomation by North American crotaline snakes to a standardized form. Descriptive statistics were used. In addition, we hand-searched the US National Poison Data System reports for the years 2000-2006 to identify and describe any reports of death that occurred after FabAV administration. Results: The literature review found 147 unique publications regarding FabAV. Twenty-four evaluable cases of severe human envenomation treated with FabAV were identified in 19 publications. Seven cases were described in five cohort studies, and 17 cases were described in 14 single patient case reports or non-cohort case series. Sixty-five specific severe venom effects were reported in these 24 patients, of which 50 effects (77%) improved or resolved after FabAV therapy. Initial control of all severe venom effects was achieved in 12 patients (50%). The rate at which initial control was achieved was significantly higher among patients reported in the cohort series than in the case series and non-cohort reports (100% vs. 29%, P = 0.005). The median dose of FabAV used to obtain initial control was 6 vials (range: 4 - 18 vials). Nine patients had severe venom effects that persisted despite FabAV therapy. Recurrent and/or delayed-onset severe defibrination syndrome occurred in 12 patients, most of whom did not receive recommended maintenance FabAV dosing. No patient developed systemic bleeding. Conclusions: In this structured literature review, FabAV appears to be effective in the management of severe crotaline snake envenomation. Incomplete response to therapy, recurrence of venom effects, and delayed-onset venom effects were reported in case reports, but not reported in cohort studies.

Negative predictive value and potential cost savings of acute nuclear myocardial perfusion imaging in low risk patients with suspected acute coronary syndrome: A prospective single blinded study

Jakob Forberg — 2009-06-19T00:00:00Z

Background: Previous studies from the USA have shown that acute nuclear myocardial perfusion imaging (MPI) in low risk emergency department (ED) patients with suspected acute coronary syndrome (ACS) can be of clinical value. The aim of this study was to evaluate the utility and hospital economics of acute MPI in Swedish ED patients with suspected ACS.MethodWe included 40 patients (mean age 55 +/- 2 years, 50% women) who were admitted from the ED at Lund University Hospital for chest pain suspicious of ACS, and who had a normal or non-ischemic ECG and no previous myocardial infarction. All patients underwent MPI from the ED, and the results were analyzed only after patient discharge. The current diagnostic practice of admitting the included patients for observation and further evaluation was compared to a theoretical "MPI strategy", where patients with a normal MPI test would have been discharged home from the ED. Results: Twenty-seven patients had normal MPI results, and none of them had ACS. MPI thus had a negative predictive value for ACS of 100%. With the MPI strategy, 2/3 of the patients would thus have been discharged from the ED, resulting in a reduction of total hospital cost by some 270 EUR and of bed occupancy by 0.8 days per investigated patient. Conclusion: Our findings in a Swedish ED support the results of larger American trials that acute MPI has the potential to safely reduce the number of admissions and decrease overall costs for low-risk ED patients with suspected ACS.

The impact of a fast track area on quality and effectiveness outcomes: A Middle Eastern emergency department perspective

Subashnie Devkaran — 2009-06-17T00:00:00Z

Background: Emergency department (ED) overcrowding is a ubiquitous problem with serious public health implications. The fast track area is a novel method which aims to reduce waiting time, patient dissatisfaction and morbidity. |The study objective was to determine the impact of a fast track area (FTA) on both effectiveness measures (i.e. waiting times [WT] and length of stay [LOS]) and quality measures (i.e. LWBS rates and mortality rates) in non-urgent patients. The secondary objective was to assess if a FTA negatively impacted on urgent patients entering the ED. Methods: The study took place in a 500 bed, urban, tertiary care hospital in Abu Dhabi, United Arab Emirates. This was a quasi-experimental, which examined the impact of a FTA on a pre-intervention control group (January 2005) (n = 4,779) versus a post-intervention study group (January 2006) (n = 5,706). Results: Mean WTs of Canadian Triage Acuity Scale (CTAS) 4 patients decreased by 22 min (95% CI 21 min to 24 min, P < 0.001). Similarly, mean WTs of CTAS 5 patients decreased by 28 min (95% CI 19 min to 37 min, P < 0.001) post FTA. The mean WTs of urgent patients (CTAS 2/3) were also significantly reduced after the FTA was opened (P < 0.001). The LWBS rate was reduced from 4.7% to 0.7% (95% CI 3.37 to 4.64; P < 0.001). Opening a FTA had no significant impact on mortality rates (P = 0.88). Conclusion: The FTA improved ED effectiveness (WTs and LOS) and quality measures (LWBS rates) whereas mortality rate remained unchanged.

Case reports describing treatments in the emergency medicine literature: Misleading and missing information

Tiffany Richason — 2009-06-15T00:00:00Z

Background: Although randomized trials and systematic reviews provide the "best evidence" for guiding medical practice, many emergency medicine journals still publish case reports (CRs). The quality of the reporting in these publications has not been assessed.ObjectivesIn this study we sought to determine the proportion of treatment-related case reports that adequately reported information about the patient, disease, interventions, co-interventions, outcomes and other critical information. Methods: We identified CRs published in 4 emergency medicine journals in 2000–2005 and categorized them according to their purpose (disease description, overdose or adverse drug reactioin, diagnostic test or treatment effect). Treatment-related CRs were reviewed for the presence or absence of 11 reporting elements. Results: All told, 1,316 CRs were identified; of these, 85 (6.5%; 95CI = 66, 84) were about medical or surgical treatments. Most contained adequate descriptions of the patient (99%; 95CI = 95, 100), the stage and severity of the patient's disease (88%; 95CI = 79, 93), the intervention (80%; 95CI = 70, 87) and the outcomes of treatment (90%; 95CI = 82, 95). Fewer CRs reported the patient's co-morbidities (45%; 95CI = 35, 56), concurrent medications (30%; 95CI = 21, 40) or co-interventions (57%; 95CI = 46, 67) or mentioned any possible treatment side-effects (33%; 95CI = 24, 44). Only 37% (95CI = 19, 38) discussed alternative explanations for favorable outcomes. Generalizability of treatment effects to other patients was mentioned in only 29% (95CI = 20, 39). Just 2 CRs (2.3%; 95CI = 1, 8) reported a 'denominator" (number of patients subjected to the same intervention, whether or not successful. Conclusion: Treatment-related CRs in emergency medicine journals often omit critical details about treatments, co-interventions, outcomes, generalizability, causality and denominators. As a result, the information may be misleading to providers, and the clinical applications may be detrimental to patient care.

Comparison of the Glidescope(R) and Pentax AWS(R) laryngoscopes to the Macintosh laryngoscope for use by Advanced Paramedics in easy and simulated difficult intubation.

Sajid Nasim — 2009-05-17T00:00:00Z

Background: Intubation of the trachea in the pre-hospital setting may be lifesaving in severely ill and injured patients. However, tracheal intubation is frequently difficult to perform in this challenging environment, is associated with a lower success rate, and failed tracheal intubation constitutes an important cause of morbidity. Novel indirect laryngoscopes, such as the Glidescope® and the AWS® laryngoscopes may reduce this risk. Methods: We compared the efficacy of these devices to the Macintosh laryngoscope when used by 25 Advanced Paramedics proficient in direct laryngoscopy, in a randomized, controlled, manikin study. Following brief didactic instruction with the Glidescope® and the AWS® laryngoscopes, each participant took turns performing laryngoscopy and intubation with each device, in an easy intubation scenario and following placement of a hard cervical collar, in a SimMan® manikin. Results: Both the Glidescope® and the AWS® performed better than the Macintosh, and demonstrate considerable promise in this context. The AWS® had the least number of dental compressions in all three scenarios, and in the cervical spine immobilization scenario it required fewer maneuvers to optimize the view of the glottis. Conclusion: The Glidescope® and AWS® devices possess advantages over the conventional Macintosh laryngoscope when used by Advanced Paramedics in normal and simulated difficult intubation scenarios in this manikin study. Further studies are required to extend these findings to the clinical setting.

Post-crash management of road traffic injury victims in Iran. Stakeholders' views on current barriers and potential facilitators

Davoud Khorasani-Zavareh — 2009-05-12T00:00:00Z

Background: Road traffic injuries are a major public health problem, especially in low- and middle-income countries. Post-crash management can play a significant role in minimizing crash consequences and saving lives. Iran has one of the highest mortality rates from road traffic injuries in the world. The present study attempts to fill the knowledge gap and explores stakeholders' perceptions of barriers to – and facilitators of – effective post-crash management in Iranian regions. Methods: Thirty-six semi-structured interviews were conducted with medical services personnel, police officers, members of Red Crescent, firefighters, public-health professionals, road administrators; some road users and traffic injury victims. A qualitative approach using grounded theory method was employed to analyze the material gathered. Results: The core variable was identified as "poor quality of post crash management". Barriers to effective post-crash management were identified as: involvement of laypeople; lack of coordination; inadequate pre-hospital services; shortcomings in infrastructure. Suggestions for laypeople included: 1) a public education campaign in first aid, the role of the emergency services, cooperation of the public at the crash site, and 2) target-group training for professional drivers, police officers and volunteers involved at the crash scene. An integrated trauma system and infrastructure improvement also is crucial to be considered for effective post-crash management. Conclusion: To sum up, it seems that the involvement of laypeople could be a key factor in making post-crash management more effective. But system improvements are also crucial, including the integration of the trauma system and its development in terms of human resources (staffing and training) and physical resources as well as the infrastructure development.

Undergraduate medical education in emergency medical care: A nationwide survey at German medical schools

Stefan Beckers — 2009-05-12T00:00:00Z

Background: Since June 2002, revised regulations in Germany have required "Emergency Medical Care" as an interdisciplinary subject, and state that emergency treatment should be of increasing importance within the curriculum. A survey of the current status of undergraduate medical education in emergency medical care establishes the basis for further committee work. Methods: Using a standardized questionnaire, all medical faculties in Germany were asked to answer questions concerning the structure of their curriculum, representation of disciplines, instructors' qualifications, teaching and assessment methods, as well as evaluation procedures. Results: Data from 35 of the 38 medical schools in Germany were analysed. In 32 of 35 medical faculties, the local Department of Anaesthesiology is responsible for the teaching of emergency medical care; in two faculties, emergency medicine is taught mainly by the Department of Surgery and in another by Internal Medicine. Lectures, seminars and practical training units are scheduled in varying composition at 97% of the locations. Simulation technology is integrated at 60% (n = 21); problem-based learning at 29% (n = 10), e-learning at 3% (n = 1), and internship in ambulance service is mandatory at 11% (n = 4). In terms of assessment methods, multiple-choice exams (15 to 70 questions) are favoured (89%, n = 31), partially supplemented by open questions (31%, n = 11). Some faculties also perform single practical tests (43%, n = 15), objective structured clinical examination (OSCE; 29%, n = 10) or oral examinations (17%, n = 6). Conclusion: Emergency Medical Care in undergraduate medical education in Germany has a practical orientation, but is very inconsistently structured. The innovative options of simulation technology or state-of-the-art assessment methods are not consistently utilized. Therefore, an exchange of experiences and concepts between faculties and disciplines should be promoted to guarantee a standard level of education in emergency medical care.

Modelling optimal location for pre-hospital helicopter emergency medical services

Nadine Schuurman — 2009-05-09T00:00:00Z

Background: Increasing the range and scope of early activation/auto launch helicopter emergency medical services (HEMS) may alleviate unnecessary injury mortality that disproportionately affects rural populations. To date, attempts to develop a quantitative framework for the optimal location of HEMS facilities have been absent. Methods: Our analysis used five years of critical care data from tertiary health care facilities, spatial data on origin of transport and accurate road travel time catchments for tertiary centres. A location optimization model was developed to identify where the expansion of HEMS would cover the greatest population among those currently underserved. The protocol was developed using geographic information systems (GIS) to measure populations, distances and accessibility to services. Results: Our model determined Royal Inland Hospital (RIH) was the optimal site for an expanded HEMS – based on denominator population, distance to services and historical usage patterns. Conclusion: GIS based protocols for location of emergency medical resources can provide supportive evidence for allocation decisions – especially when resources are limited. In this study, we were able to demonstrate conclusively that a logical choice exists for location of additional HEMS. This protocol could be extended to location analysis for other emergency and health services.

Using molecular similarity to highlight the challenges of routine immunoassay-based drug of abuse/toxicology screening in emergency medicine

Matthew Krasowski — 2009-04-28T00:00:00Z

Background: Laboratory tests for routine drug of abuse and toxicology (DOA/Tox) screening, often used in emergency medicine, generally utilize antibody-based tests (immunoassays) to detect classes of drugs such as amphetamines, barbiturates, benzodiazepines, opiates, and tricyclic antidepressants, or individual drugs such as cocaine, methadone, and phencyclidine. A key factor in assay sensitivity and specificity is the drugs or drug metabolites that were used as antigenic targets to generate the assay antibodies. All DOA/Tox screening immunoassays can be limited by false positives caused by cross-reactivity from structurally related compounds. For immunoassays targeted at a particular class of drugs, there can also be false negatives if there is failure to detect some drugs or their metabolites within that class. Methods: Molecular similarity analysis, a computational method commonly used in drug discovery, was used to calculate structural similarity of a wide range of clinically relevant compounds (prescription and over-the-counter medications, illicit drugs, and clinically significant metabolites) to the target ('antigenic') molecules of DOA/Tox screening tests. These results were compared with cross-reactivity data in the package inserts of immunoassays marketed for clinical testing. The causes for false positives for phencyclidine and tricyclic antidepressant screening immunoassays were investigated at the authors' medical center using gas chromatography/mass spectrometry as a confirmatory method. Results: The results illustrate three major challenges for routine DOA/Tox screening immunoassays used in emergency medicine. First, for some classes of drugs, the structural diversity of common drugs within each class has been increasing, thereby making it difficult for a single assay to detect all compounds without compromising specificity. Second, for some screening assays, common 'out-of-class' drugs may be structurally similar to the target compound so that they account for a high frequency of false positives. Illustrating this point, at the authors' medical center, the majority of positive screening results for phencyclidine and tricyclic antidepressants assays were explained by out-of-class drugs. Third, different manufacturers have adopted varying approaches to marketed immunoassays, leading to substantial inter-assay variability. Conclusion: The expanding structural diversity of drugs presents a difficult challenge for routine DOA/Tox screening that limit the clinical utility of these tests in the emergency medicine setting.

Smaller self-inflating bags produce greater guideline consistent ventilation in simulated cardiopulmonary resuscitation

Ziad Nehme — 2009-02-20T00:00:00Z

Background: Suboptimal bag ventilation in cardiopulmonary resuscitation (CPR) has demonstrated detrimental physiological outcomes for cardiac arrest patients. In light of recent guideline changes for resuscitation, there is a need to identify the efficacy of bag ventilation by prehospital care providers. The objective of this study was to evaluate bag ventilation in relation to operator ability to achieve guideline consistent ventilation rate, tidal volume and minute volume when using two different capacity self-inflating bags in an undergraduate paramedic cohort. Methods: An experimental study using a mechanical lung model and a simulated adult cardiac arrest to assess the ventilation ability of third year Monash University undergraduate paramedic students. Participants were instructed to ventilate using 1600 ml and 1000 ml bags for a length of two minutes at the correct rate and tidal volume for a patient undergoing CPR with an advanced airway. Ventilation rate and tidal volume were recorded using an analogue scale with mean values calculated. Ethics approval was granted. Results: Suboptimal ventilation with the use of conventional 1600 ml bag was common, with 77% and 97% of participants unable to achieve guideline consistent ventilation rates and tidal volumes respectively. Reduced levels of suboptimal ventilation arouse from the use of the smaller bag with a 27% reduction in suboptimal tidal volumes (p = 0.015) and 23% reduction in suboptimal minute volumes (p = 0.045). Conclusion: Smaller self-inflating bags reduce the incidence of suboptimal tidal volumes and minute volumes and produce greater guideline consistent results for cardiac arrest patients.