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Biomedical subjects

R A Jenders

Publications and source records attributed to R A Jenders.

At least 19 recordsLinked to original sources
PubMed2001

Challenges in using the Arden Syntax for computer-based nosocomial infection surveillance.

CONTEXT: Detection of outbreaks of infection in the hospital typically requires daily manual review of microbiology laboratory test results. This process is time-consuming, tedious, prone to error and may miss trends in infection. A standard formalism for procedural knowledge representation, the Arden Syntax, provides a vehicle for implementing algorithms for detecting such infections. OBJECTIVE: To design and implement a computer-based system for detection of concerning patterns of infection or antibiotic resistance. SETTING: Computer-based event monitor and central patient data repository at the Columbia-Presbyterian Medical Center (CPMC). RESULTS: We designed a two-phase system, including initial filtering of individual patient laboratory results by Arden Syntax Medical Logic Modules (MLMs) and subsequent aggregation and analysis across patients and locations using a statistical monitor. Preliminary data for the filtration phase demonstrate a 94.8% reduction in the volume of messages that must be considered in surveillance. CONCLUSIONS: Filtering raw laboratory results using a standard formalism eases the process of aggregating data across patients and sites as well as detecting trends in infection. There is a need for augmenting such formalisms in order to enable population-based decision support.

Algorithms↗
PubMed2000

Considering clustering: a methodological review of clinical decision support system studies.

Computer-based clinical decision support systems (CDSSs) are often implemented at a cluster level, but standard statistical methods for sample estimation and analysis may not be appropriate for such studies. This review aims to determine whether the design and analysis methods of cluster-based studies were adequately addressed in reports of CDSS studies. We retrieved 61 reports of the CDSS controlled trials and identified 24 studies meeting our inclusion criteria. Of these, none included sample size calculations that allowed for clustering, while 14 (58%) took account of clustering in the analysis. Although there is increasing recognition of the methodological issues associated with cluster design in health care, many medical informaticians are still not aware of these issues. Investigators should publish estimates of the intracluster correlation coefficients and variance components in their reports to guide the planning of the future studies.

Cluster Analysis↗
PubMed2000

Model-based immunization information routing.

We have developed a model for clinical information routing within an immunization registry. Components in this model include partners, contents and mechanisms. Partners are classified into senders, receivers and intermediates. Contents are classified into core contents and management information. Mechanisms are classified into topological control, temporal control, process control and communication channel control. Immunization reminders, forecasts and recalls in e-mail, fax and regular mail format are routed based on this model. Algorithms for deducing patient provider and patient clinical site relationships are developed to facilitate routing. A dummy provider within each site and a dummy site are created to manipulate routing for incomplete data. 46.63% of patients' primary providers and 92.58% of patients' clinical sites are successfully identified.

Computer Communication Networks↗
PubMed1999

Hospitalization and Alzheimer's disease: results from a community-based study.

BACKGROUND: Prior studies offer conflicting findings on whether Alzheimer's disease (AD) is associated with an increased risk of hospitalization. METHODS: We investigated AD and hospitalization in the Washington Heights-Inwood Columbia Aging Project (WHICAP), a community-based study of 2,334 elders in New York City. In 1996, an electronic medical records system was established that allows an e-mail alert to be sent to the research team whenever WHICAP subjects are admitted to Columbia-Presbyterian Medical Center (CPMC), the site of hospital care for the majority of subjects. RESULTS: Of the WHICAP cohort, 13.1% was admitted to CPMC in 21 months of follow-up; 17.5% of AD patients and 11.9% of unaffected subjects were admitted (p<.01). Multivariate logistic regression models showed that more advanced AD (Clinical Dementia Rating scale 3+) was a significant risk factor for hospitalization independently of age, gender, education, comorbid medical conditions, and death in the follow-up period (OR 2.3; 95% CI: 1.1, 4.6); subjects with mild or moderate AD did not show a significantly elevated risk. The prevalence of psychiatric symptoms did not differ between AD subjects who were hospitalized in the reporting period and AD subjects who were not hospitalized. Infectious disease was a more common discharge diagnosis for subjects with AD (p<.05). CONCLUSIONS: In this community-based cohort, subjects with severe AD were more likely to be hospitalized than unaffected subjects. The increased use of hospital care by these AD patients appears to be specific to AD but is not a result of psychiatric morbidity or end-of-life care. Rather, a greater risk of medical complications that require hospital care, especially infections, appears to be characteristic of severe AD.

Age Factors↗
PubMed1999

Trial of labor versus elective repeat cesarean section for the women with a previous cesarean section: a decision analysis.

In order to reduce the cesarean-delivery rate, more and more pregnant women are offered trials of labor (TOL) after their previous cesarean sections. TOL and elective repeat cesarean section (ERCS) have different risks and benefits. We constructed a decision analysis to explore this issue. Probabilities were derived from literature reviews. Health state utilities were derived from the authors' clinical judgement. The analysis considered the disutility of the procedures and the disutilities of the morbidity. Using the baseline assumption, ERCS was superior to TOL. One-way sensitivity analyses showed that the result was insensitive to all of the probability estimates and the disutilities of the morbidity. However, the result was sensitive to the patient's preference for ERCS, successful TOL, or failed TOL. The analysis indicates that the best delivery method for a woman who has had a previous cesarean section depends on patient's preference. More patients' preference studies are needed.

Cesarean Section, Repeat↗
PubMed1999

Use of a hospital practice management system to provide initial data for a pediatric immunization registry.

An ongoing challenge in the creation of clinical information systems is the capture of structured clinical information from health care providers while avoiding duplicate data recording. Because immunizations are reimbursable medical procedures, practice management systems that already capture such procedures may be used as a source of clinical data for information systems. We instituted a method for capturing such data on one campus of a multi-institution pediatric immunization registry. We measured the effectiveness of this capture by comparing it to manual audits of selected paper charts over 26 months. Of the immunizations documented by chart audit, 39.69% were captured by the practice management system. Of those not captured, we estimate that a substantial portion were immunizations administered elsewhere and as a result not submitted as a claim through the practice management system. In turn, this was affected by a rate of patient disengagement from primary care of 49%. We discuss the issues associated with using claims data to capture clinical information in the setting of an immunization registry and review possible explanations for this data capture rate.

Child↗
PubMed1999

Translating national childhood immunization guidelines to a computer-based reminder recall system within an immunization registry.

To translate national childhood immunization guidelines to a computer-based reminder recall system, hierarchical system architecture design and combined approach of tabular and procedural knowledge representation are taken. Nested branches with hierarchical combinations of single antecedent variables are used to avoid logical incompleteness, redundancy and inconsistency. Mapping to the local electronic medical vocabulary is implemented to facilitate the integration with the local information system architecture. 26 second-level modules with 195 original branches and 121 final branches after pruning are encoded. 99.67% of the reminders are confirmed to be correct by SQL query.

Child↗
PubMed1998

Design and implementation of a multi-institution immunization registry.

One of every four children in the USA is underimmunized. Surveys of children in New York City have documented rates of appropriate immunization as low as 37% in certain populations in northern Manhattan. In response to this, government and private agencies have undertaken efforts to improve immunization rates. As part of one such multiinstitution effort in northern Manhattan, we have begun implementation of a computer-based immunization registry. Key features of this registry system include adaptation of legacy software in order to perform initial capture of data in electronic format; design of a user interface using a World Wide Web server that provides data review and capture functions with appropriate security; implementation of a registry database with links to the server, communication links between hospital registration systems, a Master Patient Index, community providers and the central registry; and integration of decision support in the form of Medical Logic Modules encoded in the Arden Syntax. We discuss our design of this multi-institution immunization registry and implementation efforts to date.

Child↗
PubMed1998

Evolution of a knowledge base for a clinical decision support system encoded in the Arden Syntax.

Clinical decision support systems (CDSS) are being used increasingly in medical practice. Thus, long-term maintenance of the knowledge bases (KB) of such systems becomes important. To quantify changes that occur as a KB evolves, we studied the KB at the Columbia-Presbyterian Medical Center. This KB has a total of 229 Medical Logic Modules (MLMs) encoded in the Arden Syntax. Eliminating those never used in practice, we retrospectively analyzed 156 MLMs developed over 78 months. We noted 2020 distinct versions of these MLMs that included 5528 changed statements over time. These changes occurred primarily in the logic slot (38.7% of all changes), the action slot (17.8%), in queries (15.0%) and in the data slot exclusive of queries (12.4%). We conclude that long-term maintenance of a KB for a CDSS requires significant changes over time. We discuss the implications of these results for the design of KB editors for the Arden Syntax.

Artificial Intelligence↗
PubMed1997

Towards improved knowledge sharing: assessment of the HL7 Reference Information Model to support medical logic module queries.

Because clinical databases vary in structure, access methods and vocabulary used to represent data, the Arden Syntax does not define a standard model for querying databases. Consequently, database queries are encoded in ad hoc ways and enclosed in "curly braces" in Medical Logic Modules (MLMs). However, the nonstandard representation of queries impairs sharing of MLMs, an impediment that has come to be known as the "curly braces problem." As a first step in solving this problem, we evaluated the proposed HL7 Reference Information Model (RIM) as a foundation for a standard query model for the Arden Syntax. Specifically, we analyzed the MLM knowledge base at the Columbia-Presbyterian Medical Center and compared the queries in these MLMs to the RIM. We studied 488 queries in 104 MLMs, identifying 674 total query data elements. Laboratory tests accounted for 45.8% of these elements, while demographic and ADT data accounted for 37.6%. Pharmacy orders accounted for 10.5%, medical problems for 4.3% and MLM output messages for 1.6%. We found that the RIM encompasses all but those data elements signifying MLM output (1.6% of the total). We conclude that the majority of queries in the CPMC knowledge base access a relatively small set of data elements and that the RIM encompasses these elements. We propose extensions of this analysis to continue construction of an Arden query model capable of solving the "curly braces problem."

Artificial Intelligence↗
PubMed1996

Design of a clinical event monitor.

The issues and implementation of a clinical event monitor are described. An event monitor generates messages for providers, patients, and organizations based on clinical events and patient data. For example, an order for a medication might trigger the generation of a warning about a drug interaction. A model based on the active database literature has as its main components an event (which triggers a rule to fire), a condition (which tests whether an action ought to be performed), and an action (often the generation of a message). The details of implementing such a monitor are described, using as an example the Columbia-Presbyterian Medical Center clinical event monitor, which is based on the Arden Syntax for Medical Logic Modules.

Artificial Intelligence↗
PubMed1996

Assessment of a knowledge-acquisition tool for writing Medical Logic Modules in the Arden Syntax.

We have created a tool that allows users unfamiliar with the Arden Syntax and our underlying database to create Medical Logic Modules (MLMs). In a study of this tool (N 16), subjects found it easy to use (mean score - 4.69 on a scale of 1-5, 5 being best). Each subject created 3 MLMs of varying complexity following a protocol. On average, subjects required 312, 308 and 318 seconds, respectively, to complete each MLM. Comparison of clinicians to non-clinicians and those with to those without knowledge of Arden showed no significant difference. Of the 48 MLMs, 47 compiled and executed with appropriate output. Independent manual review of the MLM correlated well and found few errors. We conclude that our tool is easily used by inexperienced persons to write MLMs in the Arden Syntax.

Artificial Intelligence↗
PubMed1995

Medical decision support: experience with implementing the Arden Syntax at the Columbia-Presbyterian Medical Center.

We began implementation of a medical decision support system (MDSS) at the Columbia-Presbyterian Medical Center (CPMC) using the Arden Syntax in 1992. The Clinical Event Monitor which executes the Medical Logic Modules (MLMs) runs on a mainframe computer. Data are stored in a relational database and accessed via PL/I programs known as Data Access Modules (DAMs). Currently we have 18 clinical, 12 research and 10 administrative MLMs. On average, the clinical MLMs generate 50357 simple interpretations of laboratory data and 1080 alerts each month. The number of alerts actually read varies by subject of the MLM from 32.4% to 73.5%. Most simple interpretations are not read at all. A significant problem of MLMs is maintenance, and changes in laboratory testing and message output can impair MLM execution significantly. We are now using relational database technology and coded MLM output to study the process outcome of our MDSS.

Academic Medical Centers↗
PubMed1995

Using intermediate states to improve the ability of the Arden Syntax to implement care plans and reuse knowledge.

The Arden Syntax is one of a few knowledge representation languages currently in use for clinical decision support. While some of these languages are being used in active patient care settings, none have gained widespread acceptance as a clinical tool. Prior attempts to represent temporally complex care plans in the Arden Syntax have revealed difficulties in representing and tracking series of consecutive time-oriented events and recommendations, in sharing and reusing knowledge and in dealing with unobtainable data. In an attempt to improve Arden's ability to deal with these problems and demonstrate the importance of these factors, the clinical event monitor has been adapted to store coded data representing Intermediate States in the Columbia Presbyterian Medical Center (CPMC) central data repository. The Intermediate States define the current state of the patient as laid out in the care plan. Four care plans were constructed. The findings include an improved ability to track complex series of events and recommendations over long periods of time. The knowledge generated by the electronic care plans was able to be reused by the care plan that generated it, by other elements of the knowledge base and by non-decision support applications. Modular development, facilitated by the changes, simplified dealing with data not available to the central data repository by aiding the implementation of those parts of the care plan for which sufficient data is available.

Artificial Intelligence↗
PubMed1994

Use of open standards to implement health maintenance guidelines in a clinical workstation.

We are developing a clinical workstation which integrates access to health maintenance guidelines with access to a computer-based medical record. In order to enhance the portability of such a system, we emphasize the use of open standards which can be used in diverse clinical environments. We discuss the use of relational database and expert system technology to provide both patient-specific and patient-independent access to clinical guidelines. We use the Arden Syntax as the format for a textual library which facilitates the storage of structured medical knowledge.

Artificial Intelligence↗
PubMed1994

Indexing guidelines: applications in use of pulmonary artery catheters and pressure ulcer prevention.

In a busy clinical environment, access to knowledge must be rapid and specific to the clinical query at hand. This requires indices which support easy navigation within a knowledge source. We have developed a computer-based tool for trouble-shooting pulmonary artery waveforms using a graphical index. Preliminary results of domain knowledge tests for a group of clinicians exposed to the system (N = 33) show a mean improvement on a 30-point test of 5.33 (p < 0.001) compared to a control group (N = 19) improvement of 0.47 (p = 0.61). Survey of the experimental group (N = 25) showed 84% (p = 0.001) found the system easy to use. We discuss lessons learned in indexing this domain area to computer-based indexing of guidelines for pressure ulcer prevention.

Abstracting and Indexing↗