Emergency department syndromic surveillance providing early warning of seasonal respiratory activity in England.

Seasonal respiratory infections place an increased burden on health services annually. We used a sentinel emergency department syndromic surveillance system to understand the factors driving respiratory attendances at emergency departments (EDs) in England. Trends in different respiratory indicators were observed to peak at different points during winter, with further variation observed in the distribution of attendances by age. Multiple linear regression analysis revealed acute respiratory infection and bronchitis/bronchiolitis ED attendances in patients aged 1-4 years were particularly sensitive indicators for increasing respiratory syncytial virus activity. Using near real-time surveillance of respiratory ED attendances may provide early warning of increased winter pressures in EDs, particularly driven by seasonal pathogens. This surveillance may provide additional intelligence about different categories of attendance, highlighting pressures in particular age groups, thereby aiding planning and preparation to respond to acute changes in EDs, and thus the health service in general.

Using an Emergency Department Syndromic Surveillance System to investigate the impact of extreme cold weather events.

This report describes the development of novel syndromic cold weather public health surveillance indicators for use in monitoring the impact of extreme cold weather on attendances at EDs, using data from the 2010-11 and 2011-12 winters. A number of new surveillance indicators were created specifically for the identification and monitoring of cold weather related ED attendances, using the diagnosis codes provided for each attendance in the Emergency Department Syndromic Surveillance System (EDSSS), the first national syndromic surveillance system of its kind in the UK. Using daily weather data for the local area, a time series analysis to test the sensitivity of each indicator to cold weather was undertaken. Diagnosis codes relating to a health outcome with a potential direct link to cold weather were identified and assigned to a number of 'cold weather surveillance indicators'. The time series analyses indicated strong correlations between low temperatures and cold indicators in nearly every case. The strongest fit with temperature was cold related fractures in females, and that of snowfall was cold related fractures in both sexes. Though currently limited to a small number of sentinel EDs, the EDSSS has the ability to give near real-time detail on the magnitude of the impact of weather events. EDSSS cold weather surveillance fits well with the aims of the Cold Weather Plan for England, providing information on those particularly vulnerable to cold related health outcomes severe enough to require emergency care. This timely information aids those responding to and managing the effects on human health, both within the EDs themselves and in the community as a whole.

The impact of thunderstorm asthma on emergency department attendances across London during July 2013.

BACKGROUND: This study illustrates the potential of using emergency department attendance data, routinely accessed as part of a national syndromic surveillance system, to monitor the impact of thunderstorm asthma. METHODS: The Emergency Department Syndromic Surveillance System (EDSSS) routinely monitors anonymised attendance data on a daily basis across a sentinel network of 35 emergency departments. Attendance data for asthma, wheeze and difficulty breathing are analysed on a daily basis. RESULTS: A statistically significant spike in asthma attendances in two EDSSS emergency departments in London was detected on 23 July 2013, coinciding with a series of large violent thunderstorms across southern England. There was also an increase in the reported severity of these attendances. CONCLUSIONS: This preliminary report illustrates the potential of the EDSSS to monitor the impact of thunderstorms on emergency department asthma attendances. Further work will focus on how this system can be used to quantify the impact on emergency departments, thus potentially improving resource planning and also adding to the thunderstorm asthma evidence-base.

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.

Are these emergency department performance data real?

We have recently demonstrated that the distribution of total time spent by patients in emergency departments (EDs) in England shows a peak immediately prior to the current Department of Health target of 4 hours. We aimed to investigate whether this suggested that performance data were being manipulated. We collected data from 117 EDs, and 616,067 patient episodes were included in the analysis. Evidence of manipulation of performance data appears to be present in a small proportion of episodes, but because of the numbers involved, it could equate to over 50,000 episodes per year in EDs in England.

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.

Has the assessment of isolated ankle injuries altered since 1993?

BACKGROUND: Performance of emergency departments in England and Wales has declined in recent years. Data from the authors' department has shown that junior doctors now see fewer patients and spend longer over their assessment than was the case previously. This study aimed to determine how the assessment of patients with isolated ankle injuries changed over an 11 year period. METHODS: A retrospective case note review was conducted. Data regarding the duration of assessment, clinical information recorded, investigations, and treatments were retrieved. RESULTS: During the period studied 13 555 patients presented with isolated ankle injuries; case notes of 550 of these patients were reviewed in the present study. Linear regression demonstrated that the median length of time from arrival in the department until seen by a clinician increased (b = 3.0 min/year, 95% CI 0.7 to 5.2, p = 0.015), but the median length of time from seeing a clinician until leaving the department was unchanged (b = 0.6 min/year, 95% CI -1.3 to 2.5, p = 0.475). More clinical information was being recorded, but the proportion of patients having radiographs of the ankle (b = 0.24% per year, 95% CI -1.40% to 1.87%, p = 0.751) or in whom a fracture was diagnosed (b = -0.20% per year, 95% CI -1.59% to 1.19% per year, p = 0.752) remained unchanged. CONCLUSION: It appears from this study that the duration of assessment of patients with minor injuries is not changing although this result should be interpreted cautiously.

Targets and moving goal posts: changes in waiting times in a UK emergency department.

OBJECTIVES: To describe changes in the case mix, demographics, waiting times (WTs; time from arrival in the emergency department (ED) until seen by a clinician) and treatment times (TTs; time from seeing a clinician until leaving the ED) of adult patients presenting to the EDs in Sheffield, UK, between 1993 and 2003. DESIGN: A retrospective analysis of routinely collected data. RESULTS: Of a total of 252,156 patients included in the study, the proportion of attendees aged 16-29 years decreased from 38.7% in 1993 to 28.8% in 2003 (rate of change (b) = -1.10% per year, 95% CI -1.20% to -0.82%, p < 0.001) whereas the proportion aged 80-99 years increased from 6.2% to 10.4% (b = 0.37% per year, 95% CI 0.29% to 0.45%, p < 0.001). The proportion of "minors" (patients not arriving by ambulance and subsequently discharged) fell from 71.1% in 1993 to 60.8% in 2003 (b = -1.04% per year, 95% CI -1.36% to -0.73%, p < 0.001). WTs increased from a median of 21 minutes in 1993 to 48 minutes in 2003 (b = 3.5 min per year, 95% CI 2.23 min to 4.77 min, p < 0.001). The median TT for minors was unchanged but that for majors (patients arriving by ambulance and admitted to hospital from the ED) increased from 55 to 205 minutes (b = 11.55 min per year, 95% CI 6.54 min to 16.55 mins, p = 0.01). CONCLUSION: The demographics, case mix, and waiting times of patients presenting to EDs in Sheffield changed considerably over an 11 year period. There is evidence that the service for minor case patients improved slightly at the end of the period studied, but this is possibly at the expense of a deteriorating experience for major case patients.

Headache management--are we doing enough? An observational study of patients presenting with headache to the emergency department.

OBJECTIVES: To identify the causes of acute headache presenting to the emergency department (ED), assess the adequacy of history, examination, and investigation, and determine which clinical features are predictive of secondary headache. METHOD: A retrospective study of alert (GCS>or=14) patients presenting with headache, to an ED over a one year period. Patients were followed up for three months. The adequacy of history, examination, and investigation were compared with published standards. Analysis using Bayes's theorem determined which clinical features were predictive of secondary headache. RESULTS: Headache in alert patients accounted for 0.5% (n = 353) of new patient episodes, 81.2% (n = 280) of patients had a primary headache disorder. One patient (0.3%) had an adequate history recorded. No patient had a complete examination recorded. Seventy seven (21.8%) patients underwent computed tomography of the head; 80.5% (n = 62) were normal. Lumbar puncture was performed in 23 (6.5%) cases; 18 (78.3%) were normal. A number of clinical features were found to be predictive of secondary headache. CONCLUSION: Headache is an uncommon symptom in alert patients presenting to the ED. The recorded history, examination, and subsequent investigation do not comply with published standards. A number of predictive features have been identified that may permit the development of a clinical prediction rule to improve the management of this patient group.