Emergency Department Syndromic Surveillance Research Articles

ED syndromic surveillance for novel H1N1 spring 2009

Purpose The aim of this study is to demonstrate the use of emergency department (ED) syndromic surveillance in the setting of a novel and unexpected H1N1 influenza outbreak. Basic Procedures Data collection from ED electronic medical records was used to track initial chief complaint and discharge International Classification of Diseases, Ninth Revision, codes related to influenza-like illness (ILI). An alert threshold was generated using cumulative sum sequential analysis technique. The data were retrospectively analyzed to identify alerts that correlated with novel influenza H1N1 illness. Main Findings Our system alerted for ILI earlier than both the official national Centers for Disease Control and Prevention (CDC) press release for novel H1N1 and the first laboratory confirmed case in our county. Principal Conclusions Emergency department syndromic surveillance can be used to detect unexpected ILI before laboratory confirmation and serve as an adjunct to traditional laboratory-guided public health alerts. Early identification may allow for more efficient laboratory testing and early implementation of respiratory isolation precautions.

Analysis of the Korean Emergency Department Syndromic Surveillance System: Mass Type Acute Diarrheal Syndrome

ObjectivesThis study was designed to compare the data from the emergency department syndromic surveillance system of Korea in detection and reporting of acute diarrheal syndrome (mass type) with the data from the Korea Food and Drug Administration. And to offer fundamental materials for making improvements in current surveillance system was our purpose.MethodsA study was conducted by reviewing the number of cases reported as acute diarrheal syndrome (mass type) from the Korean Center for Disease Control and Prevention between June, 2002 and July, 2008. And the data were compared with the number of mass food poisoning cases during the same period, reported from the Korea Food and Drug Administration. The difference between two groups was measured and their transitions were compared.ResultsThe emergency department syndromic surveillance system's reports of the numbers of acute diarrheal syndrome (mass type) cases were different from the transition of mass food poisonings, reported by the Korea Food and Drug Administration. Their reports were not accurate and they could not follow the trends of increase in mass food poisonings since 2002.ConclusionsCurrent problems in the emergency department syndromic surveillance system in Korea are mostly related to inaccuracies of daily data reporting system. Manual data input by the reporters could play a big role in such inaccuracies. There need to be improvements in the ways of reporting data, such as automated information transport system linking electronic medical record.

Progression and impact of the first winter wave of the 2009 pandemic H1N1 influenza in New South Wales, Australia

A range of surveillance systems were used to assess the progression and impact of the first wave of pandemic H1N1 influenza in New South Wales, Australia during the southern hemisphere winter. Surveillance methods included laboratory notifications, near real-time emergency department syndromic surveillance, ambulance despatch surveillance, death certificate surveillance and purpose-built web-based data systems to capture influenza clinic and intensive care unit activity. The epidemic lasted 10 weeks. By 31 August 2009, 1,214 people with pandemic H1N1 influenza infection were hospitalised (17.2 per 100,000 population), 225 were admitted to intensive care (3.2 per 100,000), and 48 died (0.7 per 100,000). Children aged 0-4 years had the highest hospitalisation rates, while adults aged 50-54 had the highest rates of intensive care admission. During the epidemic period, overall presentations to emergency departments were 6% higher than in 2008, while presentations for influenza-like illness were 736% higher. At the peak, confirmed cases of pandemic H1N1 influenza consumed 15% of intensive care capacity. Excess mortality from influenza and pneumonia was lower than in recent influenza seasons. Health services, particularly emergency departments and intensive care units, were substantially affected by the epidemic. Mortality from influenza was comparable with previous seasons.

Emergency department syndromic surveillance system for early detection of 5 syndromes: a pilot project in a reference teaching hospital in Genoa, Italy.

Early detection is fundamental for achieving effective control of infectious disease outbreaks. We described the development of a local chief complaint emergency department (ED)-based syndromic surveillance system to improve public health response in Genoa, Italy. The five syndromes under investigation by the syndromic surveillance system were influenza-like illness (ILI), low-respiratory tract illness (LRTI), not-haemorrhagic gastroenteritis, acute hepatitis, fever-with-rash (maculo-papular or vescicular) syndrome. Syndrome coding, data capture, transmission and processing, statistical analysis to assess indicators of disease activity and alert thresholds, and signal response were operatively described. Preliminary results on ILI syndromic surveillance showed that new system allowed the activation of the alert state with a specificity of 90.3% and a sensitivity of 72.9% in predicting epidemiological relevant events, such as > or = 10 accesses to ED for ILI in 3 days. The new syndromic surveillance system allowed to alert the public health institutions 2.5 days before than the local surveillance system based on sentinel physicians and paediatricians, permitting the early activation of the necessary measures for the containment and for burden reduction of the epidemic event. It is noteworthy that the syndromic surveillance epidemic cut-off was overcome once before and 4 times after influenza outbreak detected by sentinel-based surveillance system: all episodes were contemporary with Respiratory Syncytial Virus and Parainfluenza Virus circulation, as detected by regional reference laboratory.

Identifying pneumonia outbreaks of public health importance: can emergency department data assist in earlier identification?

To retrospectively review the performance of a near real-time Emergency Department (ED) Syndromic Surveillance System operating in New South Wales for identifying pneumonia outbreaks of public health importance. Retrospective data was obtained from the NSW Emergency Department data collection for a rural hospital that has experienced a cluster of pneumonia diagnoses among teenage males in August 2006. ED standard reports were examined for signals in the overall count for each respiratory syndrome, and for elevated counts in individual subgroups including; age, sex and admission to hospital status. Using the current thresholds, the ED syndromic surveillance system would have trigged a signal for pneumonia syndrome in children aged 5-16 years four days earlier than the notification by a paediatrician and this signal was maintained for 14 days. If the ED syndromic surveillance system had been operating it could have identified the outbreak earlier than the paediatrician's notification. This may have permitted an earlier public health response. By understanding the behaviour of syndromes during outbreaks of public health importance, response protocols could be developed to facilitate earlier implementation of control measures.

Privacy protection versus cluster detection in spatial epidemiology.

Patient data that includes precise locations can reveal patients' identities, whereas data aggregated into administrative regions may preserve privacy and confidentiality. We investigated the effect of varying degrees of address precision (exact latitude and longitude vs the center points of zip code or census tracts) on detection of spatial clusters of cases. We simulated disease outbreaks by adding supplementary spatially clustered emergency department visits to authentic hospital emergency department syndromic surveillance data. We identified clusters with a spatial scan statistic and evaluated detection rate and accuracy. More clusters were identified, and clusters were more accurately detected, when exact locations were used. That is, these clusters contained at least half of the simulated points and involved few additional emergency department visits. These results were especially apparent when the synthetic clustered points crossed administrative boundaries and fell into multiple zip code or census tracts. The spatial cluster detection algorithm performed better when addresses were analyzed as exact locations than when they were analyzed as center points of zip code or census tracts, particularly when the clustered points crossed administrative boundaries. Use of precise addresses offers improved performance, but this practice must be weighed against privacy concerns in the establishment of public health data exchange policies.

Syndromic surveillance using regional emergency medicine internet

Study objectiveWe demonstrate the feasibility and utility of emergency department (ED) syndromic surveillance using a regional emergency medicine Internet application to minimize impact on ED and public health staffing. MethodsRegional (multi-ED) surveillance was established for 2 periods, one characterized by a high-profile national sports event and the other during an international disease outbreak. Counts of patient visits meeting syndrome criteria and total patient visits were reported daily on the secure regional emergency medicine Internet site and downloaded by public health staff. Trends were analyzed and displayed on the secure Web site. ED participants were surveyed about the acceptability and time cost of the project. ResultsIn the first (“All Star Game”) project, 8 departments reported daily counts for 4 weeks, covering more than 26,000 patient visits. In the second (“severe acute respiratory syndrome” [SARS]) project, an average of 11 departments in the same region reported daily data on febrile respiratory illnesses, travel, and contacts for 10 weeks. Experience with the first project allowed for rapid implementation of the second project during a 3-day period. In both instances, the surveillance efforts were undertaken without the need for extraordinary ED or public health staffing requirements. ConclusionA regional emergency medicine Internet approach permitted rapid implementation of multisite syndromic surveillance without additional staff. Some problems were identified with the first project, related to clinician checklist completion and manual data tabulation and entry. The SARS project addressed these by simplifying data collection and restricting it to triage.

Use of emergency department chief complaint and diagnostic codes for identifying respiratory illness in a pediatric population.

(1) To determine the value of emergency department chief complaint (CC) and International Classification of Disease diagnostic codes for identifying respiratory illness in a pediatric population and (2) to modify standard respiratory CC and diagnostic code sets to better identify respiratory illness in children. We determined the sensitivity and specificity of CC and diagnostic codes by comparing code groups with a criterion standard. CC and diagnostic codes for 500 pediatric emergency department patients were retrospectively classified as respiratory or nonrespiratory. Respiratory diagnostic codes were further classified as upper or lower respiratory. The criterion standard was a blinded, reviewer-assigned illness category based on history, physical examination, test results, and treatment. We also modified our respiratory code sets to better identify respiratory illness in this population. Four hundred ninety-six charts met inclusion criteria. By the criterion standard, 87 (18%) patients had upper and 47 (10%) had lower respiratory illness. The specificity of CC and diagnostic codes groups was >0.97 [95% confidence interval (CI) 0.95-0.98]. The code group sensitivities were as follows: CC was 0.47 (95% CI 0.38-0.55), upper respiratory diagnostic was 0.56 (95% CI 0.45-0.67), lower respiratory diagnostic was 0.87 (95% CI 0.74-0.95), and combined CC and/or diagnostic was 0.72 (95% CI 0.63-0.79). Modifying the respiratory code sets to better identify respiratory illness increased sensitivity but decreased specificity. Diagnostic and CC codes have substantial value for emergency department syndromic surveillance. Adapting our respiratory code sets to a pediatric population forced a tradeoff between sensitivity and specificity.

Investigation of an electronic emergency department information system as a data source for respiratory syndrome surveillance.

Emergency department syndromic surveillance may provide early warning of disease outbreaks due to bioterrorism or natural phenomena. The purpose of this investigation was to explore how an electronic emergency department information system could be used as a data source for respiratory syndrome surveillance. The process of data collection, entry, and transmission is described, and then a subset of data elements with potential epidemiological value is selected. The quality of the data contained in the system was evaluated by conducting a retrospective analysis of emergency department visits recorded in the system during 2001 and by reviewing clinical charts of cases with respiratory diagnoses. Diagnosis codes, discharge disposition, and demographic data were relatively complete; additional clinical data were not. Diagnosis codes were rapidly and reliably recorded. Data available in the system allows a description of emergency department visits for respiratory syndrome in terms of age, gender, location, severity of illness, and distribution in time. Encrypted data were transmitted every four hours to the health department without added work for emergency department personnel. Although significant obstacles remain, electronic emergency department information systems such as this may provide rapid, reliable data for syndromic surveillance.

Enhanced drop-in syndromic surveillance in New York City following September 11, 2001.

After the 2001 World Trade Center disaster, the New York City Department of Health was under heightened alert for bioterrorist attacks in the city. An emergency department (ED) syndromic surveillance system was implemented with the assistance of the Centers for Disease Control and Prevention to ensure early recognition of an increase or clustering of disease syndromes that might represent a disease outbreak, whether natural or intentional. The surveillance system was based on data collected 7 days a week at area EDs. Data collected were translated into syndromes, entered into an electronic database, and analyzed for aberrations in space and time within 24 hours. From September 14-27, personnel were stationed at 15 EDs on a 24-hour basis (first staffing period); from September 29-October 12, due to resource limitations, personnel were stationed at 12 EDs on an 18-hour basis (second staffing period). A standardized form was used to obtain demographic information and classify each patient visit into 12 syndrome categories. Seven of these represented early manifestations of bioterrorist agents. Data transfer and analysis for time and space clustering (alarms) by syndrome and age occurred daily. Retrospective analyses examined syndrome trends, differences in reporting between staffing periods, and the staff's experience during the project. A total of 67,536 reports were received. The system captured 83.9% of patient visits during the first staffing period, and 60.8% during the second staffing period (P < 0.01). Five syndromes each accounted for more than 1% of visits: trauma, asthma, gastrointestinal illness, upper/lower respiratory infection with fever, and anxiety. Citywide temporal alarms occurred eight times for three of the major bioterrorism-related syndromes. Spatial clustering alarms occurred 16 times by hospital location and 9 times by ZIP code for the same three syndromes. No outbreaks were detected. On-site staffing to facilitate data collection and entry, supported by daily analysis of ED visits, is a feasible short-term approach to syndromic surveillance during high-profile events. The resources required to operate such a system, however, cannot be sustained for the long term. This system was changed to an electronic-based ED syndromic system using triage log data that remains in operation.

The National Capitol Region's Emergency Department syndromic surveillance system: do chief complaint and discharge diagnosis yield different results?

We compared syndromic categorization of chief complaint and discharge diagnosis for 3,919 emergency department visits to two hospitals in the U.S. National Capitol Region. Agreement between chief complaint and discharge diagnosis was good overall (kappa=0.639), but neurologic and sepsis syndromes had markedly lower agreement than other syndromes (kappa statistics 0.085 and 0.105, respectively).

New Hampshire emergency department syndromic surveillance system

New Hampshire emergency department syndromic surveillance system