Search

The key to minimizing the effects of an intentionally caused disease outbreak is early detection of the attack and rapid identification of the affected individuals. The Bush administration's leadership in advocating for biosurveillance systems capable of monitoring for bioterrorism attacks suggests that we should move quickly to establish a nationwide early warning biosurveillance system as a defense against this threat. The spirit of collaboration and unity inspired by the events of 9-11 and the 2002 Olympic Winter Games in Salt Lake City provided the opportunity to demonstrate how a prototypic biosurveillance system could be rapidly deployed. In seven weeks we were able to implement an automated, real-time disease outbreak detection system in the State of Utah and monitored 80,684 acute care visits occurring during a 28-day period spanning the Olympics. No trends of immediate public health concern were identified.

Objective: To evaluate the performance of a computerized decision support system that combines two different decision support methodologies (a Bayesian network and a natural language understanding system) for the diagnosis of patients with pneumonia., Design: Evaluation study using data from a prospective, clinical study., Patients: All patients 18 years and older who presented to the emergency department of a tertiary care setting and whose chest x-ray report was available during the encounter., Methods: The computerized decision support system calculated a probability of pneumonia using information provided by the two systems. Outcome measures were the area under the receiver operating characteristic curve, sensitivity, specificity, predictive values, likelihood ratios, and test effectiveness., Results: During the 3-month study period there were 742 patients (45 with pneumonia). The area under the receiver operating characteristic curve was 0.881 (95% CI: 0.822, 0.925) for the Bayesian network alone and 0.916 (95% CI: 0.869, 0.949) for the Bayesian network combined with the natural language understanding system (p=0.01)., Conclusion: Combining decision support methodologies that process information stored in different data formats can increase the performance of a computerized decision support system.

Objective: To evaluate if a medical language processing (MLP) system is able to support real-time computerization of community-acquired pneumonia (CAP) guidelines., Methods: Prospective validation study in the emergency department of a tertiary care facility. All the chest x-ray reports available in real-time for an admission decision during a five-week period were included. The MLP system was compared to a physician for the automatic selection of eligible patients and on the extraction of radiographic findings required by five different CAP guidelines. The gold standard comprised of three independent physicians and reliability measures were calculated. The outcome measures were the area under the receiver operated characteristic curve (AUC) for selecting eligible patients, sensitivity, positive predictive value (PPV), and specificity for the extraction of radiographic findings., Results: During the five-week period, 243 reports were available in real-time. The AUCs on selecting eligible CAP patients were 89.7% (CI: 84.2%, 93.7%) for the MLP system, and 93.3% (CI: 83.9%, 97.8%) for the physician. The average sensitivity, PPV, and specificity for radiographic findings that assessed localization and extension of CAP were respectively: 94%, 87%, 96% (physician); and 34%, 90%, 95% (MLP system). Both, the MLP system and the physician had average sensitivity, PPV, and specificity of 97%, 97%, and 99%, respectively, when localization was not an issue. Reliability measures for the gold standard were above 70%., Conclusion: The MLP system was able to support real-time computerization of guidelines by selecting eligible patients and extracting radiographic findings that do not assess localization and extension of CAP.

Objective: To assess the ability of an integrated, real-time diagnostic system (Bayesian network) to identify patients with community-acquired pneumonia who are eligible for a computerized pneumonia guideline without requiring clinicians to enter additional data., Design: Prospective validation study., Patients: All patients 18 years and older who presented to the emergency department of a tertiary care hospital., Methods: The diagnostic system computed a probability of pneumonia for every patient. The final diagnosis was established using ICD-9 discharge diagnoses. Outcome measures were sensitivity, specificity, predictive values, likelihood ratios, area under the receiver operating characteristic curve, and test effectiveness., Results: During the 9-week study period there were 4,361 patients (112 pneumonia patients). The area under the receiver operating characteristic curve was 0.930 (CI: 0.907, 0.948). At a fixed sensitivity of 95%, the specificity was 68.5%, the positive predictive value 7.3%, the negative predictive value 99.8%, the positive likelihood ratio 3.0, the negative likelihood ratio 0.08, and the test effectiveness 2.05., Conclusion: The diagnostic system was able to detect patients who are eligible for a pneumonia guideline. The detection of eligible patients can be applied to automatically initiate and evaluate computerized guidelines.

Objective: Evaluate the effect of a radiology speech recognition system on a real-time computerized guideline in the emergency department., Methods: We collected all chest x-ray reports (n = 727) generated for patients in the emergency department during a six-week period. We divided the concurrently generated reports into those generated with speech recognition and those generated by traditional dictation. We compared the two sets of reports for availability during the patient's emergency department encounter and for readability., Results: Reports generated by speech recognition were available seven times more often during the patients' encounters than reports generated by traditional dictation. Using speech recognition reduced the turnover time of reports from 12 hours 33 minutes to 2 hours 13 minutes. Readability scores were identical for both kinds of reports., Conclusion: Using speech recognition to generate chest x-ray reports reduces turnover time so reports are available while patients are in the emergency department.

A medical language processing system called SymText, two other automated methods, and a lay person were compared against an internal medicine resident for their ability to identify pneumonia related concepts on chest x-ray reports. Sensitivity (recall), specificity, and positive predictive value (precision) are reported with respect to an independent panel of physicians. Overall the performance of SymText was similar to the physician and superior to the other methods. The automatic encoding of pneumonia concepts will support clinical research, decision making, computerized clinical protocols, and quality assurance in a radiology department.

Decision support systems that integrate guidelines have become popular applications to reduce variation and deliver cost-effective care. However, adverse characteristics of decision support systems, such as additional and time-consuming data entry or manually identifying eligible patients, result in a "behavioral bottleneck" that prevents decision support systems to become part of the clinical routine. This paper describes the design and the implementation of an integrated decision support system that explores a novel approach for bypassing the behavioral bottleneck. The real-time decision support system does not require health care providers to enter additional data and consists of a diagnostic and a management component.

We compare the performance of four computerized methods in identifying chest x-ray reports that support acute bacterial pneumonia. Two of the computerized techniques are constructed from expert knowledge, and two learn rules and structure from data. The two machine learning systems perform as well as the expert constructed systems. All of the computerized techniques perform better than a baseline keyword search and a lay person, and perform as well as a physician. We conclude that machine learning can be used to identify chest x-ray reports that support pneumonia.

Free-text documents are the main type of data produced by a radiology department in a hospital information system. While this type of data is readily accessible for clinical data review it can not be accessed by other applications to perform medical decision support, quality assurance, and outcome studies. In an attempt to solve this problem, natural language processing systems have been developed and tested against chest x-rays reports to extract relevant clinical information and make it accessible to other computer applications. We have used a natural language processing tool called SymText to extract relevant clinical information from a different type of radiology report, the Ventilation/Perfusion lung scan report. Results of this effort can be analyzed in terms of precision and recall. The overall precision was 0.88 and recall was 0.92. In addition, the natural language processing system functions differently in reports with and without an impression section. If this type of information can be successfully extracted from radiology reports, one can develop quality monitors for the diagnostic performance of the radiologist by correlating the impressions with gold standard data present in a hospital information system. Avoiding the manual effort previously necessary to create quality assurance data, can lead to a higher frequency of quality review in a radiology department.

We present the development and the evaluation of a Bayesian network for the diagnosis of community-acquired pneumonia. The Bayesian network is intended to be part of a larger decision support system which assists emergency room physicians in the management of pneumonia patients. Minimal data entry from the nurse or the physician, timely availability of clinical parameters, and high accuracy were requirements we tried to meet. Data from more than 32,000 emergency room patients over a period of 2 years (June 1995-June 1997) were extracted from the clinical information system to train and test the Bayesian network. The network performed well in discriminating patients with pneumonia from patients with other diseases. The Bayesian network achieved a sensitivity of 95%, a specificity of 96.5%, an area under the receiver operating characteristic of 0.98, and a predictive value positive of 26.8%. Our feasibility study demonstrates that the proposed Bayesian network is an appropriate method to detect pneumonia patients with high accuracy. The study suggests that the proposed Bayesian network may represent a successful component within a larger decision support system for the management of community-acquired pneumonia.

Our natural language understanding system outputs a list of diseases, findings, and appliances found in a chest x-ray report. The system described in this paper links those diseases and findings that are causally related. Using Bayesian networks to model the conceptual and diagnostic information found in a chest x-ray we are able to infer more specific information about the findings that are linked to diseases.