Biomedical subjects

Silvia Miksch

Publications and source records attributed to Silvia Miksch.

16 recordsLinked to original sources

PubMed2006

How can information extraction ease formalizing treatment processes in clinical practice guidelines? A method and its evaluation.

OBJECTIVE: Formalizing clinical practice guidelines (CPGs) for a subsequent computer-supported processing is a challenging, but burdensome and time-consuming task. Existing methods and tools to support this task demand detailed medical knowledge, knowledge about the formal representations, and a manual modeling. Furthermore, formalized guideline documents mostly fall far short in terms of readability and understandability for the human domain modeler. METHODS AND MATERIAL: We propose a new multi-step approach using information extraction methods to support the human modeler by both automating parts of the modeling process and making the modeling process traceable and comprehensible. This paper addresses the first steps to obtain a representation containing processes which is independent of the final guideline representation language. RESULTS: We have developed and evaluated several heuristics without the need to apply natural language understanding and implemented them in a framework to apply them to several guidelines from the medical subject of otolaryngology. Findings in the evaluation indicate that using semi-automatic, step-wise information extraction methods are a valuable instrument to formalize CPGs. CONCLUSION: Our evaluation shows that a heuristic-based approach can achieve good results, especially for guidelines with a major portion of semi-structured text. It can be applied to guidelines irrespective to the final guideline representation format.

Artificial Intelligence↗

PubMed2006

Improving medical protocols by formal methods.

OBJECTIVES: During the last decade, evidence-based medicine has given rise to an increasing number of medical practice guidelines and protocols. However, the work done on developing and distributing protocols outweighs the efforts on guaranteeing their quality. Indeed, anomalies like ambiguity and incompleteness are frequent in medical protocols. Recent efforts have tried to address the problem of protocol improvement, but they are not sufficient since they rely on informal processes and notations. Our objective is to improve the quality of medical protocols. APPROACH: The solution we suggest to the problem of quality improvement of protocols consists in the utilisation of formal methods. It requires the definition of an adequate protocol representation language, the development of techniques for the formal analysis of protocols described in that language and, more importantly, the evaluation of the feasibility of the approach based on the formalisation and verification of real-life medical protocols. For the first two aspects we rely on earlier work from the fields of knowledge representation and formal methods. The third aspect, i.e. the evaluation of the use of formal methods in the quality improvement of protocols, constitutes our main objective. The steps with which we have carried out this evaluation are the following: (1) take two real-life reference protocols which cover a wide variety of protocol characteristics; (2) formalise these reference protocols; (3) check the formalisation for the verification of interesting protocol properties; and (4) determine how many errors can be uncovered in this way. RESULTS: Our main results are: a consolidated formal language to model medical practice protocols; two protocols, each both modelled and formalised; a list of properties that medical protocols should satisfy; verification proofs for these protocols and properties; and perspectives of the potentials of this approach. Our results have been evaluated by a panel of medical experts, who judged that the problems we detected in the protocols with the help of formal methods were serious and should be avoided. CONCLUSIONS: We have succeeded in demonstrating the feasibility of formal methods for improving medical protocols.

Artificial Intelligence↗

PubMed2006

CareVis: integrated visualization of computerized protocols and temporal patient data.

OBJECTIVE: Currently, visualization support for patient data analysis is mostly limited to the representation of directly measured data. Contextual information on performed treatment steps is an important source to find reasons and explanations for certain phenomena in the measured patient data, but is mostly spared out in the analysis process. This work aims to fill this gap via integrating classical data visualization and visualization of treatment information. METHODS AND MATERIAL: We considered temporal as well as logical data aspects and applied a user-centered development approach that was guided by user input gathered via a user study, design reviews, and prototype evaluations. Furthermore, we investigated the novel PlanningLine glyph, that is used to represent plans in the temporal domain, via a comparative empirical user study. RESULTS: Our interactive visualization approach CareVis provides multiple simultaneous views to cover different aspects of the complex underlying data structure of treatment plans and patient data. The tightly coupled views use visualization methods well-known to domain experts and are designed to facilitate users' tasks. The views are based on the concepts of clinical algorithm maps and LifeLines which have been extended in order to cope with the powerful and expressive plan representation language Asbru. Initial feedback of physicians was encouraging and is accompanied by empirical evidence which verifies that PlanningLines are well suited to manage temporal uncertainty. CONCLUSION: The interactive integration of different visualization methods forms a novel way of combining, relating, and analyzing different kinds of medical data and information that otherwise would be separated.

Algorithms↗

PubMed2005

Genotypic and phenotypic characteristics of Pseudomonas aeruginosa isolates associated with ulcerative keratitis.

A collection of 63 isolates of Pseudomonas aeruginosa associated with ulcerative keratitis, collected from six centres in England, were typed using serotyping and random amplified polymorphic DNA-PCR, and screened for several variable virulence-related genotypes and phenotypes. Sixty-one percent of the isolates were of either serotype O1 or serotype O11, but there was no evidence for a common clone. The majority of isolates (59%) were PCR-positive for exoU rather than for exoS (38%), and carried a-type fliC genes (76%) rather than b-type (24%). Isolates were PCR-positive for pyoverdine-receptor types at a prevalence of 38% for type I, 46 % for type II and 8 % for type III. All but one of the isolates exhibited twitching activity. There was a correlation between the presence of exoS and twitching activity (P = 0.04), suggesting that a combination of exoS genotype and good twitching activity may have a role to play in ExoU-independent corneal virulence.

ADP Ribose Transferases↗

PubMed2004

Automatic control of the inspired oxygen fraction in preterm infants: a randomized crossover trial.

In preterm infants receiving supplemental oxygen, manual control of the inspired oxygen fraction is often time-consuming and inappropriate. We developed a system for automatic oxygen control and hypothesized that this system is more effective than routine manual oxygen control in maintaining target arterial oxygen saturation levels. We performed a randomized controlled crossover clinical trial in 12 preterm infants receiving nasal continuous positive airway pressure and supplemental oxygen. Periods with automatic and routine manual oxygen control were compared with periods of optimal control by a fully dedicated person. The median (range) percentage of time with arterial oxygen saturation levels within target range (87-96%) was 81.7% (39.0-99.8) for routine manual oxygen control, 91.0% (41.4-99.3) for optimal control, and 90.5% (59.0-99.4) for automatic control (ANOVA: p = 0.01). Pairwise post hoc comparisons revealed a statistically significant difference between automatic and routine manual oxygen control (Dunnett's test: p = 0.02). The frequency of manual oxygen adjustments was lowest in automatic control (Friedman's test: p < 0.001). Automatic oxygen control may optimize oxygen administration to preterm infants receiving nasal continuous positive airway pressure and reduce nursing time spent with oxygen control.

Automation↗

PubMed2004

Facilitating knowledge maintenance of clinical guidelines and protocols.

Clinical protocols and guidelines are widely used in the medi-cal domain to improve disease management techniques. Different software systems are in development to support the de-sign and the execution of such guidelines. The bottleneck in the guideline software developing process is the transformation of the text-based clinical guidelines into a formal representation, which can be used by the execution software. This paper introduces a method and a tool that was designed to provide a solution for that bottleneck. The so-called Guideline Markup Tool (GMT) facilitates the translation of guidelines into a formal representation written in XML. This tool enables the protocol designer to create links between the original guideline and its formal representation and ease the editing of guidelines applying design patterns in the form of macros. The usefulness of our approach is illustrated using GMT to edit Asbru protocols. We performed a usability study with eight participants to examine the usefulness of the GMT and of the Asbru macros, which showed that the proposed approach is very appropriate to author and maintain clinical guidelines.

Clinical Protocols↗

PubMed2004

Communicating the logic of a treatment plan formulated in Asbru to domain experts.

This paper presents an interactive visualization for medical treatment plans that are formulated in the plan representation language Asbru. So far, most attention of the protocol-based care community was focused towards formal guideline representation and authoring partly supported by graphical tools. The intention of this work is to go the opposite way and communicate the logic of a computerized treatment plan to physicians, nursing-, and other medical personnel visually. The visualization is based on the idea of flow-chart algorithms widely used in medical education and practice. This concept has been extended in order to cope with the powerful and expressive guideline representation language Asbru. Furthermore, a number of interactive navigational and overview extensions are used to intuitively support the understanding of the logic of plans. The user-centered development approach applied for these interactive visualization methods has been guided by user input gathered via a user study, design reviews, and prototype evaluations as described in this document.

Algorithms↗

PubMed2004

TimeWrap--a method for automatic transformation of structured guideline components into formal process-representations.

Guideline and protocol representation languages have reached a level of complexity where auxiliary methods are needed to support the authoring of protocols in the particular language. Several approaches and methods exist that claim high knowledge about both, the medical context and the formal requirements. Therefore, we need knowledge-based methods to facilitate the human plan designer and create the protocols of the particular language as automated as possible. We present a three-step wrapper method, called TimeWrap, to extract information, in particular temporal issues, out of semistructured data and integrate it in a formal representation. We illustrate our approach using the guideline-representation language Asbru and examples from guidelines to treat conjunctivitis.

Conjunctivitis↗

PubMed2004

Advanced temporal data abstraction for guideline execution.

Temporal data abstraction bridges the gap between snap shot values delivered by monitoring devices and laboratory tests on one side and high-level medical concepts used in guidelines and by medical professionals on the other side. Within this field, the detection and abstraction of repeated patterns is a complex and important challenge. A repeated pattern is a combination of events or intervals which occur multiple times in a formally describable temporal relation. While there are many approaches to detect patterns in time series without prior definition of target concepts, we describe the application of temporal data abstraction in the context of guideline execution. Here predefined concepts of temporal patterns must be compared with measurement series describing the patient state. We discuss the requirements coming from both high-frequency domains such as intensive care units and low-frequency domains such as diabetes monitoring and show our solution based on a new version of the Asgaard data abstraction unit. It interfaces the dynamically changing patient state to the guideline execution unit and features abstraction modules ranging from simple calculations to statistical measures calculated for sliding time windows.

Artificial Intelligence↗

PubMed2004

Protocure: supporting the development of medical protocols through formal methods.

Medical guidelines and protocols describe the optimal care for a specific group of patients and therefore, when properly applied, improve the quality of patient care. During the last decade, a large number of medical guidelines and protocols have been published. However, the work done on developing and disseminating them far outweighs the efforts on guaranteeing their quality. Indeed, anomalies like ambiguity and incompleteness are frequent in medical guidelines and protocols. An approach grounded on a formal representation, can answer these needs, as we have demonstrated in the Protocure project'. The Protocure II project will aim at integrating formal methods in the life cycle of guidelines.

Clinical Protocols↗

PubMed2004

Tracing the formalization steps of textual guidelines.

This paper presents a new guideline authoring tool, called Guideline Markup Tool (GMT). It proposes two useful features, which are missing in existing tools. First, it facilitates the translation of a free-text guideline into a formal representation, providing special XML macros. Second, it can be used to create links between the original guideline and its formal representation. Therefore, the GMT eases the implementation of clinical guidelines in a formal representation, which can be used in monitoring and therapy planning systems.

Artificial Intelligence↗

PubMed2002

Combining diagnosis and treatment using ASBRU.

Traditionally, diagnosis and treatment have been seen as two distinct tasks. Consequently, most approaches to computer supported health care focus on one of the two-mostly on diagnosis or rather on the interpretation of measurements which is much better understood and formalised. However, in practice diagnosis and treatment overlap and influence each other in many ways. Combinations range from repeatedly going through the diagnosis-treatment loop over a period of time to permanent monitoring of the patients' health condition as it is done in intensive care units. In this article we describe how to model these combinations using the clinical protocol-representation language ASBRU. It implements treatment steps in a hierarchy of skeletal, time-oriented plans. Diagnosis can either be described in a declarative way in the conditions, under which treatment steps are taken or it can be modelled explicitly as plans of their own right. We demonstrate our approach using examples taken from the American Association of Paediatricians' guideline for the treatment of hyperbilirubinemia in the new-born.

Clinical Protocols↗

PubMed2002

Visualization methods for data analysis and planning in medical applications.

Time plays an important role in medicine, both the past and the future. The medical history of a patient represents the past, which needs to be understood by the physician to make the right decisions. The past contains two different kinds of information: measured data (such as blood pressure) and incidents (such as seizures). Planning therapies, on the other hand, requires looking into the future to a certain extent. Visual representations exist for both the past and the future, and they are very useful for getting a better understanding of data or a plan. This paper surveys visualization techniques for both data analysis and planning, and compares them based on a number of criteria.

Computer Graphics↗

PubMed2002

Development and evaluation of VIE-PNN, a knowledge-based system for calculating the parenteral nutrition of newborn infants.

Calculating the daily changing composition of parenteral nutrition for small newborn infants is troublesome and time consuming routine work in neonatal intensive care. The task needs expertise and experience and is prone to inherent calculation errors. We designed VIE-PNN (Vienna Expert System for Parenteral Nutrition of Neonates), a knowledge-based system (KBS) in order to reduce daily routine work and calculation errors. VIE-PNN was redesigned several times because the clinicians accepted the system only when it saved time. The most recent version of VIE-PNN uses an Hypertext Markup Language (HTML)-based client-server architecture and is integrated into the intranet of the local patient data management system. Since more than 3 years all parenteral nutrition plans are calculated using VIE-PNN. Evaluating the system's performance and the users contentedness, we compared 50 nutrition plans calculated in parallel using VIE-PNN or a hand-held calculator, retrospectively analyzed more than 5000 nutrition plans stored in VIE-PNNs database and evaluated a user questionnaire. Nutrition plans were calculated in a mean time of 2.4 versus 7.1min using VIE-PNN or the hand-held calculator. Errors and omissions in the nutrition plans were detected in 22% versus 56% and errors in the VIE-PNN's plans occurring only with interactively changed values. Reviews of stored plans show that a mean of 4 out of 16 parameters were interactively changed. VIE-PNN was well accepted. Most important reasons for the successful operation of VIE-PNN in the daily routine work were time savings and robustness of the system.

Artificial Intelligence↗

PubMed2002

Verification of temporal scheduling constraints in clinical practice guidelines.

The computerization of clinical practice guidelines is a significant scientific challenge for the medical informatics community. One frequently reported factor hindering this objective is the existence of deficiencies within guideline knowledge. In this paper, we focus on the detection of flaws within temporal scheduling constraints. Temporal scheduling constraints are important elements of therapy management, and are frequently incorporated in clinical practice guidelines. We present a suitable verification method that is based on calculating the minimal network of temporal constraints on the execution of guideline activities. Our method serves three purposes: (1) it checks whether temporal scheduling constraints are consistent with scheduling constraints implied by control flow operators and the hierarchical structuring of a guideline; (2) it yields suggestions for an equivalent, yet more explicit representation of non-minimal constraints; (3) it can be used by the guideline interpreter to assemble feasible time intervals for the execution of each guideline activity. We evaluate our approach by applying it to a guideline specified in the Asbru language. For this purpose, we implemented a prototype verifier. Although we concentrate on the guideline representation language Asbru as the demonstration medium of our method within this paper, our approach can be reused to verify several alternative guideline representation formats.

Humans↗

PubMedDate not supplied

Comparing computer-interpretable guideline models: a case-study approach.

OBJECTIVES: Many groups are developing computer-interpretable clinical guidelines (CIGs) for use during clinical encounters. CIGs use "Task-Network Models" for representation but differ in their approaches to addressing particular modeling challenges. We have studied similarities and differences between CIGs in order to identify issues that must be resolved before a consensus on a set of common components can be developed. DESIGN: We compared six models: Asbru, EON, GLIF, GUIDE, PRODIGY, and PROforma. Collaborators from groups that created these models represented, in their own formalisms, portions of two guidelines: American College of Chest Physicians cough guidelines [correction] and the Sixth Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure. MEASUREMENTS: We compared the models according to eight components that capture the structure of CIGs. The components enable modelers to encode guidelines as plans that organize decision and action tasks in networks. They also enable the encoded guidelines to be linked with patient data-a key requirement for enabling patient-specific decision support. RESULTS: We found consensus on many components, including plan organization, expression language, conceptual medical record model, medical concept model, and data abstractions. Differences were most apparent in underlying decision models, goal representation, use of scenarios, and structured medical actions. CONCLUSION: We identified guideline components that the CIG community could adopt as standards. Some of the participants are pursuing standardization of these components under the auspices of HL7.

Decision Support Systems, Clinical↗