Is a randomised controlled trial of take home naloxone distributed in emergency settings likely to be feasible and acceptable? Findings from a UK qualitative study exploring perspectives of people who use opioids and emergency services staff.

OBJECTIVE: Distribution of take-home naloxone (THN) by emergency services may increase access to THN and reduce deaths and morbidity from opioid overdose. As part of a feasibility study for a randomised controlled trial (RCT) of distribution of THN kits and education within ambulance services and Emergency Departments (EDs), we used qualitative methods to explore key stakeholders' perceptions of feasibility and acceptability of delivering the trial. METHODS: We undertook semi-structured interviews and focus groups with 26 people who use opioids and with 20 paramedics and ED staff from two intervention sites between 2019 and 2021. Interviews and focus groups were recorded, transcribed verbatim and analysed using Framework Analysis. RESULTS: People using opioids reported high awareness of overdose management, including personal experience of THN use. Staff perceived emergency service provision of THN as a low-cost, low-risk intervention with potential to reduce mortality, morbidity and health service use. Staff understood the trial aims and considered it compatible with their work. All participants supported widening access to THN but reported limited trial recruitment opportunities partly due to difficulties in consenting patients during overdose. Procedural problems, restrictive recruitment protocols, limited staff buy-in and patients already owning THN limited trial recruitment. Determining trial effectiveness was challenging due to high levels of alternative community provision of THN. CONCLUSIONS: Distribution of THN in emergency settings was considered feasible and acceptable for stakeholders but an RCT to establish the effectiveness of THN delivery is unlikely to generate further useful evidence due to difficulties in recruiting patients and assessing benefits.

The DiPEP study: an observational study of the diagnostic accuracy of clinical assessment, D-dimer and chest x-ray for suspected pulmonary embolism in pregnancy and postpartum.

OBJECTIVE: To identify clinical features associated with pulmonary embolism (PE) diagnosis and determine the accuracy of decision rules and D-dimer for diagnosing suspected PE in pregnant/postpartum women DESIGN: Observational cohort study augmented with additional cases. SETTING: Emergency departments and maternity units at eleven prospectively recruiting sites and maternity units in the United Kingdom Obstetric Surveillance System (UKOSS) POPULATION: 324 pregnant/postpartum women with suspected PE and 198 pregnant/postpartum women with diagnosed PE METHODS: We recorded clinical features, elements of clinical decision rules, D-dimer measurements, imaging results, treatments and adverse outcomes up to 30 days MAIN OUTCOME MEASURES: Women were classified as having PE on the basis of imaging, treatment and adverse outcomes by assessors blind to clinical features and D-dimer. Primary analysis was limited to women with conclusive imaging to avoid work-up bias. Secondary analyses included women with clinically diagnosed or ruled out PE. RESULTS: The only clinical features associated with PE on multivariate analysis were age (odds ratio 1.06; 95% confidence interval 1.01-1.11), previous thrombosis (3.07; 1.05-8.99), family history of thrombosis (0.35; 0.14-0.90), temperature (2.22; 1.26-3.91), systolic blood pressure (0.96; 0.93-0.99), oxygen saturation (0.87; 0.78-0.97) and PE-related chest x-ray abnormality (13.4; 1.39-130.2). Clinical decision rules had areas under the receiver-operator characteristic curve ranging from 0.577 to 0.732 and no clinically useful threshold for decision-making. Sensitivities and specificities of D-dimer were 88.4% and 8.8% using a standard threshold and 69.8% and 32.8% using a pregnancy-specific threshold. CONCLUSIONS: Clinical decision rules and D-dimer should not be used to select pregnant or postpartum women with suspected PE for further investigation. Clinical features and chest x-ray appearances may have counter-intuitive associations with PE in this context. TWEETABLE ABSTRACT: Clinical decision rules and D-dimer are not helpful for diagnosing pregnant/postpartum women with suspected PE.

Interventions to improve the management of pain in emergency departments: systematic review and narrative synthesis.

INTRODUCTION: Pain management in emergency departments (ED) is often inadequate despite the availability of effective analgesia, with many patients receiving insufficient and untimely analgesia. We conducted a systematic literature review to identify interventions that could improve pain management in the ED. METHODS: We systematically searched seven databases for studies reporting pain management outcomes after intervention to change professional practice to improve pain management in the ED, compared with pain management before or without intervention. Data was synthesised using principles of narrative synthesis. RESULTS: We identified 43 relevant studies, including 40 uncontrolled before-and-after studies. Interventions included implementation of guidelines and protocols, educational interventions, pain scoring tools and changes in nursing roles, with many multifaceted interventions incorporating two or more of these elements. Interventions aimed to improve assessment and documentation of pain, knowledge and awareness of pain management and reduce time to analgesia. Due to the high probability of bias in study design and significant variation between studies, it was not possible to estimate the overall effectiveness of interventions, or identify which had the greatest impact. Intervention to improve pain management was reported to have some positive impact in most studies, but these findings may be explained by limitations in study design. CONCLUSIONS: Many interventions reported improvements in pain management, but current evidence is insufficient to recommend any for widespread adoption. In order to improve pain management we need to understand more about the theory underlying interventions, the context in which interventions work, and develop interventions based on this stronger theoretical understanding.

Pre-hospital prediction of adverse outcomes in patients with suspected COVID-19: Development, application and comparison of machine learning and deep learning methods.

BACKGROUND: COVID-19 infected millions of people and increased mortality worldwide. Patients with suspected COVID-19 utilised emergency medical services (EMS) and attended emergency departments, resulting in increased pressures and waiting times. Rapid and accurate decision-making is required to identify patients at high-risk of clinical deterioration following COVID-19 infection, whilst also avoiding unnecessary hospital admissions. Our study aimed to develop artificial intelligence models to predict adverse outcomes in suspected COVID-19 patients attended by EMS clinicians. METHOD: Linked ambulance service data were obtained for 7,549 adult patients with suspected COVID-19 infection attended by EMS clinicians in the Yorkshire and Humber region (England) from 18-03-2020 to 29-06-2020. We used support vector machines (SVM), extreme gradient boosting, artificial neural network (ANN) models, ensemble learning methods and logistic regression to predict the primary outcome (death or need for organ support within 30 days). Models were compared with two baselines: the decision made by EMS clinicians to convey patients to hospital, and the PRIEST clinical severity score. RESULTS: Of the 7,549 patients attended by EMS clinicians, 1,330 (17.6%) experienced the primary outcome. Machine Learning methods showed slight improvements in sensitivity over baseline results. Further improvements were obtained using stacking ensemble methods, the best geometric mean (GM) results were obtained using SVM and ANN as base learners when maximising sensitivity and specificity. CONCLUSIONS: These methods could potentially reduce the numbers of patients conveyed to hospital without a concomitant increase in adverse outcomes. Further work is required to test the models externally and develop an automated system for use in clinical settings.

Magnesium sulphate in the treatment of acute asthma: evaluation of current practice in adult emergency departments.

BACKGROUND: A recent meta-analysis showed that intravenous and nebulised magnesium sulphate have similar levels of evidence to support their use in the treatment of acute asthma in adults. This consisted of weak evidence of effect on respiratory function and hospital admissions, with wide confidence intervals ranging from no effect to significant positive effects. Current BTS/SIGN guidelines suggest an equivocal role for intravenous magnesium sulphate and no role for nebulised magnesium sulphate. A study was performed to assess what emergency physicians currently do in their management of acute asthma. METHOD: A postal survey was undertaken of all adult emergency departments within the UK. A structured questionnaire was sent to all clinical leads in emergency medicine about their current usage of both intravenous and nebulised magnesium sulphate in the treatment of acute asthma. RESULTS: 180 of the 251 emergency departments in the UK responded (72%). Magnesium sulphate was used in 93%, mostly because it was expected to relieve breathlessness (70%) or reduce HDU/ITU admissions (51%). It was predominantly given to those patients with acute severe asthma (84%) and life-threatening exacerbations (87%), with most stating they would give the drug if there was no response to repeated nebulisers (68%). In comparison, nebulised magnesium sulphate was only used in two emergency departments (1%). The main reason for not administering the drug via a nebuliser was insufficient evidence (51%). CONCLUSIONS: Intravenous magnesium sulphate is widely used for acute asthma, usually for patients with severe or life-threatening asthma who have not responded to initial treatment. Nebulised magnesium sulphate, by contrast, is hardly used at all. The use of intravenous magnesium sulphate is more extensive than current guidelines or available evidence would appear to support.

Accessibility versus confidentiality of information in the emergency department.

INTRODUCTION: In the emergency department (ED), clinicians can benefit greatly from having access to information at the point of care. It has been suggested that using computerised information systems could improve the accessibility of information. However, making information accessible, while maintaining confidentiality, is one of the main challenges of implementing information systems. This article presents the ED staff perspectives about the accessibility and confidentiality of information in the ED. METHOD: The authors undertook a qualitative study in March-April 2007. Data were collected using in-depth semi-structured interviews with the ED staff of an ED located in Northern England. In total, 34 interviews were conducted and transcribed verbatim. Data were analysed using framework analysis. RESULTS: The results showed that the ED staff had role-based access to the current information systems, and these systems met only a small part of their information needs. As a result, different sources were used to get access to the needed information. Although the ED staff believed that improving the accessibility of information could be helpful in emergency care services, there were concerns about the confidentiality of information. The confidentiality of information could be threatened--for example, by sharing passwords, misusing patient information or by unauthorised staff having access to patient information. CONCLUSION: To design a system, the accessibility and confidentiality of information should be addressed in parallel. A balance between these two is needed, as the failure of each of these may negatively influence the use of the system.

Clinical diagnosis of acute coronary syndrome in patients with chest pain and a normal or non-diagnostic electrocardiogram.

BACKGROUND: Clinical features may be used to determine which patients with suspected acute coronary syndrome (ACS), but a normal or non-diagnostic ECG, should be selected for further investigation or inpatient care. We aimed to measure the diagnostic value of clinical features for ACS. METHODS: Standardised data relating to presenting characteristics, associated features and risk factors were collected at seven chest pain units established for the ESCAPE trial. All patients received troponin measurement at least 6 h after last significant symptoms, creatine kinase MB(mass) gradient over 2 h and, if appropriate, treadmill exercise testing. The reference standard of ACS was defined as troponin >0.03 ng/ml, creatine kinase MB(mass) gradient >3.0 ng/ml or early positive treadmill exercise test. RESULTS: 1576 patients were analysed, including 132 (8.4%) with ACS. Patients with ACS were older, had longer symptom duration, were more likely to be a man, hypertensive and an ex-smoker or have pain radiating to their right arm. On multivariate analysis, only age, duration, sex and radiation of pain to the right arm were independently associated with ACS. Likelihood ratios (95% CI) were radiation of pain to the right arm, 2.9 (95% CI 1.4 to 6.3), male sex 1.2 (95% CI 1.0 to 1.3) and female sex 0.79 (95% CI 0.62 to 1.0). The area under the receiver operator characteristic curve for age was 0.629 (95% CI 0.573 to 0.686) and for duration was 0.546 (95% CI 0.481 to 0.610). CONCLUSION: Clinical features have very limited value for diagnosing ACS in patients with a normal or non-diagnostic ECG. Radiation of pain to the right arm increases the likelihood of ACS.

Hospital admissions with head injury following publication of NICE guidance.

BACKGROUND: A recent update suggested that the National Institute for Health and Clinical Excellence (NICE) guidance on head injury had led to safe early discharge, evidence of a reduction in the numbers of admitted patients and cost savings in some centres. The aim of this study was to use national Hospital Episodes Statistics (HES) data to determine whether admissions with head injury have changed since the NICE guidance was introduced. METHODS: HES data coded as S00-S09 "Injuries to the head" from 1998-9 to 2006-7 were examined for admissions, age and length of stay. RESULTS: Admissions rates did not change markedly until 2003 when the NICE head injury guidelines were issued. From 2003, admissions increased for all adult age groups but not for children. Mean length of stay remained constant between 1998 and 2007, so bed days increased in proportion to admission rates. CONCLUSION: Adult head injury admissions in England have increased markedly since the introduction of the NICE guidelines. Given that there is little evidence that hospital admission is beneficial for patients with minor head injury, NICE head injury guidance appears to have failed to promote cost effective care.

The value of clinical features in the diagnosis of acute pulmonary embolism: systematic review and meta-analysis.

BACKGROUND: Clinical assessment of patients with suspected pulmonary embolus (PE) is used to estimate the probability of PE and determine what (if any) diagnostic testing is required. AIM: We aimed to estimate the diagnostic value of individual clinical features used to determine the pre-test probability of acute PE. DESIGN: Systematic review and meta-analysis. METHODS: We searched electronic databases (1966 to May 2007) and the bibliographies of retrieved articles for any article that reported the diagnostic performance of clinical features compared to a reference standard diagnostic test in patients with suspected acute pulmonary embolism. Likelihood ratios were calculated for each feature and pooled using a random effects model, as implemented by MetaDiSc statistical software. RESULTS: We identified 18 studies for inclusion with a total of 5997 patients. The most useful features (pooled likelihood ratio) for ruling in PE were syncope (2.38), shock (4.07), thrombophlebitis (2.20), current DVT (2.05), leg swelling (2.11), sudden dyspnoea (1.83), active cancer (1.74), recent surgery (1.63), haemoptysis (1.62) and leg pain (1.60); while the most useful features for ruling out PE were the absence of sudden dyspnoea (0.430), any dyspnoea (0.521) and tachypnea (0.561). All other clinical features had likelihood ratios near to one. Many of the analyses involved pooling results that had significant heterogeneity, so these estimates should be used with caution. CONCLUSION: Individual clinical features only slightly raise or lower the probability of PE. In isolation, they have limited diagnostic value and none can be used to rule in or rule out PE without further testing.

Intravenous and nebulised magnesium sulphate for acute asthma: systematic review and meta-analysis.

OBJECTIVES: To estimate the effect of intravenous and nebulised magnesium sulphate upon hospital admissions and pulmonary function in adults and children with acute asthma. METHODS: We undertook a systematic review and meta-analysis of randomised and quasi-randomised trials of intravenous or nebulised magnesium sulphate in acute asthma. Trials were identified by searches of the electronic literature, relevant journal websites and conference proceedings, and contact with authors and experts. Data were pooled using random effects meta-analysis of the relative risk (RR) of hospital admission and the standardised mean difference (SMD) in pulmonary function. RESULTS: 24 studies (15 intravenous, 9 nebulised) incorporating 1669 patients were included. Intravenous treatment was associated in adults with weak evidence of an effect upon respiratory function (SMD 0.25, 95% confidence interval (CI) -0.01 to 0.51; p = 0.05), but no significant effect upon hospital admission (RR 0.87, 95% CI 0.70 to 1.08; p = 0.22), and in children with a significant effect upon respiratory function (SMD 1.94, 95% CI 0.80 to 3.08; p<0.001) and hospital admission (RR 0.70, 95% CI 0.54 to 0.90; p = 0.005). Nebulised treatment was associated in adults with weak evidence of an effect upon respiratory function (SMD 0.17, 95% CI -0.02 to 0.36; p = 0.09), and hospital admission (RR 0.68, 95% CI 0.46 to 1.02; p = 0.06), and in children with no significant effect upon respiratory function (SMD -0.26, 95% CI -1.49 to 0.98; p = 0.69) or hospital admission (RR 2.0, 95% CI 0.19 to 20.93; p = 0.56). CONCLUSION: Intravenous magnesium sulphate appears to be an effective treatment in children. Further trials are needed of intravenous and nebulised magnesium sulphate in adults and nebulised magnesium sulphate in children.

How should we diagnose suspected deep-vein thrombosis?

BACKGROUND: Many different approaches are used to diagnose suspected deep-vein thrombosis (DVT), but there has been little formal comparison of strategies. AIM: To identify the most cost-effective strategy for the UK National Health Service (NHS). DESIGN: Systematic review, meta-analysis and cost-effectiveness analysis. METHODS: We identified 18 strategies and estimated the diagnostic performance of constituent tests by systematic review and meta-analysis. Outcomes of testing and treatment were estimated from published data or by an expert panel. Costs were estimated from NHS reference costs and published data. We built a decision-analysis model to estimate, for each strategy, the overall accuracy, costs, and outcomes (valued as quality-adjusted life-years, QALYs), compared to a 'no testing, no treatment' alternative. Probabilistic analysis estimated the net benefit of each strategy at varying thresholds for willingness to pay for health gain. RESULTS: At the thresholds for willingness to pay recommended by the National Institute for Clinical Excellence (20,000 pounds sterling-30,000 pounds sterling per QALY), the optimal strategy was to discharge patients with a low or intermediate Wells score and negative D-dimer, limiting ultrasound to those with a high score or positive D-dimer. Strategies using radiological testing for all patients were only cost-effective at 40,000 pound sterling per QALY or more. DISCUSSION: The optimal strategy for DVT diagnosis is to use ultrasound selectively in patients with a high clinical risk or positive D-dimer. Radiological testing for all patients does not appear to be a cost-effective use of health service resources.

Measurement of the clinical and cost-effectiveness of non-invasive diagnostic testing strategies for deep vein thrombosis.

OBJECTIVES: To estimate the diagnostic accuracy of non-invasive tests for proximal deep vein thrombosis (DVT) and isolated calf DVT, in patients with clinically suspected DVT or high-risk asymptomatic patients, and identify factors associated with variation in diagnostic performance. Also to identify practical diagnostic algorithms for DVT, and estimate the diagnostic accuracy, clinical effectiveness and cost-effectiveness of each. DATA SOURCES: Electronic databases (to April 2004). A postal survey of hospitals in the UK. REVIEW METHODS: Selected studies were assessed against validated criteria. A postal survey of hospitals in the UK was undertaken to describe current practice and availability of tests, and identify additional diagnostic algorithms. Pooled estimates of sensitivity, specificity and likelihood ratios were obtained for each test using random effects meta-analysis. The effect of study-level covariates was explored using random effects metaregression. A decision-analytic model was used to combine estimates from the meta-analysis and estimate the diagnostic performance of each algorithm in a theoretical population of outpatients with suspected DVT. The net benefit of using each algorithm was estimated from a health service perspective, using cost--utility analysis, assuming thresholds of willingness to pay of pound 20,000 and pound 30,000 per quality-adjusted life-year (QALY). The model was analysed probabilistically and cost-effectiveness acceptability curves were generated to reflect uncertainty in estimated cost-effectiveness. RESULTS: Individual clinical features are of limited diagnostic value, with most likelihood ratios being close to 1. Wells clinical probability score stratifies proximal, but not distal, DVT into high-, intermediate- and low-risk categories. Unstructured clinical assessment by experienced clinicians may have similar performance to Wells score. In patients with clinically suspected DVT, D-dimer has 91% sensitivity and 55% specificity for DVT, although performance varies substantially between assays and populations. D-dimer specificity is dependent on pretest clinical probability, being higher in patients with a low clinical probability of DVT. Plethysmography and rheography techniques have modest sensitivity for proximal DVT, poor sensitivity for distal DVT, and modest specificity. Ultrasound has 94% sensitivity for proximal DVT, 64% sensitivity for distal DVT and 94% specificity. Computed tomography scanning has 95% sensitivity for all DVT (proximal and distal combined) and 97% specificity. Magnetic resonance imaging has 92% sensitivity for all DVT and 95% specificity. The diagnostic performance of all tests is worse in asymptomatic patients. The most cost-effective algorithm discharged patients with a low Wells score and negative D-dimer without further testing, and then used plethysmography alongside ultrasound, with venography in selected cases, to diagnose the remaining patients. However, the cost-effectiveness of this algorithm was dependent on assumptions of test independence being met and the ability to provide plethysmography at relatively low cost. Availability of plethysmography and venography is currently limited at most UK hospitals, so implementation would involve considerable reorganisation of services. Two algorithms were identified that offered high net benefit and would be feasible in most hospitals without substantial reorganisation of services. Both involved using a combination of Wells score, D-dimer and above-knee ultrasound. For thresholds of willingness to pay of pound 10,000 or pound 20,000 per QALY the optimal strategy involved discharging patients with a low or intermediate Wells score and negative D-dimer, ultrasound for those with a high score or positive D-dimer, and repeat scanning for those with positive D-dimer and a high Wells score, but negative initial scan. For thresholds of pound 30,000 or more a similar strategy, but involving repeat ultrasound for all those with a negative initial scan, was optimal. CONCLUSIONS: Diagnostic algorithms based on a combination of Wells score, D-dimer and ultrasound (with repeat if negative) are feasible at most UK hospitals and are among the most cost-effective. Use of repeat scanning depends on the threshold for willingness to pay for health gain. Further diagnostic testing for patients with a low Wells score and negative D-dimer is unlikely to represent a cost-effective use of resources. Recommendations for research include the evaluation of the costs and outcomes of using the optimal diagnostic algorithms in routine practice, the development and evaluation of algorithms appropriate for specific groups of patients with suspected DVT, such as intravenous drug abusers, pregnant patients and those with previous DVT, the evaluation of the role of plethysmography: interaction with other diagnostic tests, outcome of low-risk patients with negative plethysmography and measurement of the costs of providing plethysmography, and methodological research into the incorporation of meta-analytic data into decision-analytic modelling.

Safe discharge: an irrational, unhelpful and unachievable concept.

Emergency doctors often decide whether to advise hospital admission or discharge by assessing whether a decision to discharge home is considered safe. This implies that hospital admission may be recommended on the basis of exceeding an arbitrarily defined risk of adverse outcome, rather than weighing the potential benefits, risks and costs of hospital admission. This approach is likely to lead to irrational decision making, unnecessary hospitalisation and unrealistic expectations regarding risk. Instead of using the concept of a safe discharge, we should take a more rational approach to decision making, weighing the benefits, risks and costs of hospitalisation against a default option of discharge home. Hospital admission should be recommended only if the expected benefits outweigh the risks and can be accrued at an acceptable cost. Guidelines should be developed using this approach and used to promote and support rational decision making.

Prediction of mortality among emergency medical admissions.

BACKGROUND: The Rapid Acute Physiology Score (RAPS) and Rapid Emergency Medicine Score (REMS) are risk adjustment methods for emergency medical admissions developed for use in audit, research, and clinical practice. Each predicts in hospital mortality using four (RAPS) or six (REMS) variables that can be easily recorded at presentation. We aimed to evaluate the predictive value of REMS, RAPS, and their constituent variables. METHODS: Age, heart rate, respiratory rate, blood pressure, Glasgow Coma Score (GCS) and oxygen saturation were recorded for 5583 patients who were transported by emergency ambulance, admitted to hospital and then followed up to determine in hospital mortality. The discriminant power of each variable, RAPS, and REMS were compared using the area under the receiver operator characteristic curve (AROCC). Multivariate analysis was used to identify which variables were independent predictors of mortality. RESULTS: REMS (AROCC 0.74; 95% CI 0.70 to 0.78) was superior to RAPS (AROCC 0.64; 95% CI 0.59 to 0.69) as a predictor of in hospital mortality. Although all the variables, except blood pressure, were associated with mortality, multivariate analysis showed that only age (odds ratio 1.74, p < 0.001), GCS (2.10, p < 0.001), and oxygen saturation (OR 1.36, p = 0.01) were independent predictors. A combination of age, oxygen saturation, and GCS (AROCC 0.80, 95% CI 0.77 to 0.83) was superior to REMS in our population. CONCLUSION: REMS is a better predictor of mortality in emergency medical admissions than RAPS. Age, GCS, and oxygen saturation appear to be the most useful predictor variables. Inclusion of other variables in risk adjustment scores, particularly blood pressure, may reduce their value.

How do clinical features help identify paediatric patients with fractures following blunt wrist trauma?

OBJECTIVE: Wrist injuries are a common presentation to the emergency department (ED). There are no validated decision rules to help clinicians evaluate paediatric wrist trauma. This study aimed to identify which clinical features are diagnostically useful in deciding the need for a wrist radiograph, and then to develop a clinical decision rule. METHODS: This prospective cohort study was carried out in the ED of Sheffield Children's Hospital. Eligible patients were recruited if presenting within 72 hours following blunt wrist trauma. A standardised data collection form was completed for all patients. The outcome measure was the presence or absence of a fracture. Univariate analysis was performed with the chi2 test. Associated variables (p<0.2) were entered into a multivariate model. Classification and regression tree (CART) analysis was used to derive the clinical decision rule. RESULTS: In total, 227 patients were recruited and 106 children were diagnosed with fractures (47%). Of 10 clinical features analysed, six were found by univariate analysis to be associated with a fracture. CART analysis identified the presence of radial tenderness, focal swelling, or an abnormal supination/pronation as the best discriminatory features. Cross fold validation of this decision rule had a sensitivity of 99.1% (95% confidence interval 94.8% to 100%) and a specificity of 24.0% (17.2% to 32.3%). The radiography rate would be 87%. CONCLUSIONS: Radial tenderness, focal swelling, and abnormal supination/pronation are associated with wrist fractures in children. The clinical decision rule derived from these features had a high sensitivity, but low specificity, and would not substantially alter our current radiography rate. The potential for a clinical decision rule for paediatric wrist trauma appears limited.

Meta-analysis of plethysmography and rheography in the diagnosis of deep vein thrombosis.

BACKGROUND: Plethysmography and rheography techniques have been widely studied as diagnostic tests for deep vein thrombosis (DVT). This study aimed to systematically review the accuracy of these tests for diagnosing clinically suspected DVT. METHODS: The following databases were searched: Medline, EMBASE, CINAHL, Web of Science, Cochrane Database of Systematic Reviews, Cochrane Controlled Trials Register, Database of Reviews of Effectiveness, the ACP Journal Club (1966 to 2004), and citation lists of retrieved articles. Studies that compared plethysmography or rheography to a reference standard of ultrasound or contrast venography were selected. Standardised data were extracted and study quality determined against validated criteria. Data were analysed by random effects meta-analysis and meta-regression. RESULTS: The meta-analysis included 78 studies, reporting 82 patient cohorts. Sensitivity and specificity (95% CI) were: 75% (73% to 77%) and 90% (89% to 91%) for impedance plethysmography, 83% (81% to 85%) and 81% (79% to 82%) for strain-gauge plethysmography, 85% (79% to 90%) and 91% (81% to 95%) for air plethysmography, 91% (87% to 94%) and 71% (66% to 75%) for light-reflex rheography, and 86% (83% to 89%) and 93% (91% to 95%) for phleborheography. Meta-regression was limited by poor reporting of studies. There was some evidence that diagnostic performance depended on the proportion of males in the cohort and reporting of study setting. CONCLUSIONS: Although plethysmography and rheography techniques add diagnostic value, they have inadequate diagnostic performance to act as a stand-alone test in DVT diagnosis. Evaluation of their role in combination with other tests, or standardised clinical assessment, is required.

Utility of admission cardiac troponin and "Ischemia Modified Albumin" measurements for rapid evaluation and rule out of suspected acute myocardial infarction in the emergency department.

OBJECTIVE: To assess if the combination of cardiac troponin (cTn) and Ischemia Modified Albumin (IMA) can be used for early exclusion of acute myocardial infarction (AMI). METHODS: Prospective consecutive admissions to the emergency department (ED) with undifferentiated chest pain were assessed clinically and by electrocardiography. A total of 539 patients (335 men, 204 women; median age 51.9 years) considered at low risk of AMI had blood drawn on admission. If the first sample was less than 12 hours from onset of chest pain, a second sample was drawn two hours later, at least six hours from onset of chest pain. Creatine kinase MB isoenzyme (CKMB) mass was measured on the first sample and CKMB mass and cTnT on the second sample. An aliquot from the first available sample was frozen and subsequently analysed for IMA. If cTnT had not been measured on the original sample cTnI was measured (n = 189). RESULTS: Complete data were available for 538/539 patients. IMA or cTn was elevated in the admission sample of all patients with a final diagnosis of AMI (n = 37) with IMA alone elevated in 2/37, cTn alone in 19/37, and both in 16/37. In 173/501 patients in whom AMI was excluded both tests were negative. In the non-AMI group 22 patients had elevation of both IMA and cTn in the initial sample, suggesting ischaemic disease. CONCLUSION: Admission measurement of cardiac troponin plus IMA can be used for early classification of patients presenting to the ED to assist in patient triage.

Variation in the diagnostic performance of D-dimer for suspected deep vein thrombosis.

BACKGROUND: Numerous studies have evaluated the accuracy of D-dimer in diagnosing suspected deep vein thrombosis (DVT), but results are conflicting. AIM: To overview estimates of the diagnostic accuracy of D-dimer and identify causes of variation. DESIGN: Systematic review, meta-analysis and meta-regression. METHODS: We searched Medline, EMBASE, CINAHL, Web of Science, Cochrane Database of Systematic Reviews, Cochrane Controlled Trials Register, Database of Reviews of Effectiveness, the ACP Journal Club, citation lists, and contacted manufacturers. We selected studies that compared D-dimer to a reference standard in patients with suspected DVT. Data were analysed by random effects meta-analysis and meta-regression. RESULTS: We included 97 studies reporting 198 assays in 99 different patient groups. Overall estimated sensitivity and specificity of D-dimer were 90.5% and 54.7%, but both estimates were subject to significant heterogeneity (p < 0.001). Meta-regression identified that some heterogeneity was explained by study setting, exclusion criteria, whether recruitment was consecutive or the study prospective, whether D-dimer and the reference standard were measured blind, and whether the D-dimer threshold was determined a priori. Sensitivity and specificity also varied between ELISA (94% and 45% respectively), latex (89% and 55%) and whole blood agglutination assays (87% and 68%). Sensitivity was higher for proximal than distal DVT. Specificity was dependent upon whether clinical probability of DVT was high (specificity 51%), intermediate (67%) or low (78%). DISCUSSION: D-dimer has good sensitivity, but poor specificity, for DVT. Estimates are subject to substantial heterogeneity from various sources. D-dimer specificity appears to be strongly dependent upon the pre-test clinical probability of DVT.

Is a chest pain observation unit likely to be cost effective at my hospital? Extrapolation of data from a randomised controlled trial.

OBJECTIVES: The ESCAPE trial showed that chest pain observation unit (CPOU) care appeared to be cost effective compared with routine care. This finding may not be generalizable to hospitals that currently admit fewer patients than the trial hospital or that require higher direct costs to provide CPOU care. This study aimed to explore these issues in sensitivity analyses and develop a nomogram to allow prediction of whether a CPOU will be cost effective in a specific hospital. METHODS: Data from the ESCAPE trial was used to populate a decision analysis model comparing CPOU with routine care. Sensitivity analyses examined the effect of varying the admission rate with routine care and the direct running costs of CPOU care following which the nomogram was created. RESULTS: CPOU care provided improved outcome (0.3936 v 0.3799 QALYs) at lower cost (pound sterling 478 v pound sterling 556 per patient), with fewer patients admitted (37% v 54%). Mean cost of CPOU and routine care was pound sterling 116 and pound sterling 73, respectively, and of inpatient hospital stay was pound sterling 312. The mean post-discharge cost for CPOU and routine care was pound sterling 253 and pound sterling 309, respectively. Sensitivity analyses showed that CPOU care will not reduce costs at a hospital that currently admits fewer than 35% of patients, or a hospital that expects to incur direct CPOU running costs of pound sterling 60 per patient more than the trial hospital. CONCLUSIONS: Findings of the ESCAPE trial are likely to be generalizable to most settings. The nomogram presented here can be used to predict cost effectiveness in a specific hospital.

Who waits longest in the emergency department and who leaves without being seen?

OBJECTIVES: To determine which patient characteristics are associated with prolonged waiting times in the emergency department and which characteristics are associated with an increased risk of leaving without being seen. METHODS: Multivariate analysis of routine data collected at the Northern General Hospital, Sheffield between 1 January and 31 December 2001. Patient age, sex, triage priority, postcode, initiator of attendance, mode of arrival, time, day, and month of presentation were examined as potential predictors of waiting time and risk of leaving without being seen. RESULTS: Waiting time data for 71,331 patients were analysed, along with a further 5512 patients who left without being seen. Older patients and those with lower triage priority had longer waiting times, while ambulance borne patients had slightly shorter waiting times. Sex, source of referral, and postcode did not predict waiting times. The most powerful predictors of waiting time related to time of presentation, with longer waits being associated with presentation at night, on Mondays or Sundays, and during autumn months. Patients who left without being seen were more likely to be younger, male, lower triage priority, non-ambulance borne, self referred, and presenting at the times when waiting times were longest. CONCLUSION: Time of presentation, rather than individual patient characteristics, seem to be the most powerful predictors of waiting time. This suggests that concerns about inequity of waiting times should be addressed by reorganisation of staff duty rosters.