Clinical decision support: Knowledge representation and uncertainty management

Programa Doutoral em Engenharia BiomédicaDecision-making in clinical practice is faced with many challenges due to the inherent risks of being a health care professional. From medical error to undesired variations in clinical practice, the mitigation of these issues seems to be tightly connected to the adherence to Clinical Practice Guidelines as evidence-based recommendations The deployment of Clinical Practice Guidelines in computational systems for clinical decision support has the potential to positively impact health care. However, current approaches to Computer-Interpretable Guidelines evidence a set of issues that leave them wanting. These issues are related with the lack of expressiveness of their underlying models, the complexity of knowledge acquisition with their tools, the absence of support to the clinical decision making process, and the style of communication of Clinical Decision Support Systems implementing Computer-Interpretable Guidelines. Such issues pose as obstacles that prevent these systems from showing properties like modularity, flexibility, adaptability, and interactivity. All these properties reflect the concept of living guidelines. The purpose of this doctoral thesis is, thus, to provide a framework that enables the expression of these properties. The modularity property is conferred by the ontological definition of Computer-Interpretable Guidelines and the assistance in guideline acquisition provided by an editing tool, allowing for the management of multiple knowledge patterns that can be reused. Flexibility is provided by the representation primitives defined in the ontology, meaning that the model is adjustable to guidelines from different categories and specialities. On to adaptability, this property is conferred by mechanisms of Speculative Computation, which allow the Decision Support System to not only reason with incomplete information but to adapt to changes of state, such as suddenly knowing the missing information. The solution proposed for interactivity consists in embedding Computer-Interpretable Guideline advice directly into the daily life of health care professionals and provide a set of reminders and notifications that help them to keep track of their tasks and responsibilities. All these solutions make the CompGuide framework for the expression of Clinical Decision Support Systems based on Computer-Interpretable Guidelines.A tomada de decisão na prática clínica enfrenta inúmeros desafios devido aos riscos inerentes a ser um profissional de saúde. Desde o erro medico até às variações indesejadas da prática clínica, a atenuação destes problemas parece estar intimamente ligada à adesão a Protocolos Clínicos, uma vez que estes são recomendações baseadas na evidencia. A operacionalização de Protocolos Clínicos em sistemas computacionais para apoio à decisão clínica apresenta o potencial de ter um impacto positivo nos cuidados de saúde. Contudo, as abordagens atuais a Protocolos Clínicos Interpretáveis por Maquinas evidenciam um conjunto de problemas que as deixa a desejar. Estes problemas estão relacionados com a falta de expressividade dos modelos que lhes estão subjacentes, a complexidade da aquisição de conhecimento utilizando as suas ferramentas, a ausência de suporte ao processo de decisão clínica e o estilo de comunicação dos Sistemas de Apoio à Decisão Clínica que implementam Protocolos Clínicos Interpretáveis por Maquinas. Tais problemas constituem obstáculos que impedem estes sistemas de apresentarem propriedades como modularidade, flexibilidade, adaptabilidade e interatividade. Todas estas propriedades refletem o conceito de living guidelines. O propósito desta tese de doutoramento é, portanto, o de fornecer uma estrutura que possibilite a expressão destas propriedades. A modularidade é conferida pela definição ontológica dos Protocolos Clínicos Interpretáveis por Maquinas e pela assistência na aquisição de protocolos fornecida por uma ferramenta de edição, permitindo assim a gestão de múltiplos padrões de conhecimento que podem ser reutilizados. A flexibilidade é atribuída pelas primitivas de representação definidas na ontologia, o que significa que o modelo é ajustável a protocolos de diferentes categorias e especialidades. Quanto à adaptabilidade, esta é conferida por mecanismos de Computação Especulativa que permitem ao Sistema de Apoio à Decisão não só raciocinar com informação incompleta, mas também adaptar-se a mudanças de estado, como subitamente tomar conhecimento da informação em falta. A solução proposta para a interatividade consiste em incorporar as recomendações dos Protocolos Clínicos Interpretáveis por Maquinas diretamente no dia a dia dos profissionais de saúde e fornecer um conjunto de lembretes e notificações que os auxiliam a rastrear as suas tarefas e responsabilidades. Todas estas soluções constituem a estrutura CompGuide para a expressão de Sistemas de Apoio à Decisão Clínica baseados em Protocolos Clínicos Interpretáveis por Máquinas.The work of the PhD candidate Tiago José Martins Oliveira is supported by a grant from FCT - Fundação para a Ciência e a Tecnologia (Portuguese Foundation for Science and Technology) with the reference SFRH/BD/85291/ 2012

Infections Related to the Use of Medical Devices and Changes in the Oropharyngeal Flora

Background: Humans exist in mutualistic balance with a large range of microbiota. Illness and hospitalization can disturb this balance and contribute to hospital-acquired infections (HAIs), which occur most often in critically ill patients. The use of medical devices such as central venous catheters (CVCs) and endotracheal tubes (ETTs) is essential in the care of critically ill patients. At the same time, they increase the risk of HAI by forcing or disrupting the normal barriers in the human body. All such devices eventually become colonized with microbes (usually normal flora), that form biofilms on the surface of the foreign material and subsequently lead to infection. The three types of devices related to the majority of HAIs in the intensive care unit are ETTs, urinary catheters, and CVCs.Aim: The present research was conducted to study: (i) changes in oropharyngeal microbial flora during hospitalization; (ii) compare biofilm formation on widely used ETTs with different surface properties and to explore factors potentially predictive of biofilm formation; (iii) the incidence of catheter-related infections and the impact of implementing a simple hygiene insertion bundle; (iiii) compare the blood compatibility of widely used CVCs.Paper I: In a clinical observational study, oropharyngeal cultures were collected from 487 individuals: 77 controls, 193 ward patients, and 217 critically ill patients. The results indicated that occurrence of an abnormal oropharyngeal flora is an early and frequent event in hospitalized patients, particularly the critically ill. Also, colonization with gut flora in the oropharynx was common in critically ill patients. Treatment with proton pump inhibitors was associated with colonization of gut flora in the oropharynx. The result of paper I reinforces the hypothesis that proton pump inhibitor use increases the risk of pneumonia by changing the oral flora, harboring gut bacteria which then may be micro aspirated into the lungs.Paper II: In a clinical observational study, biofilm formation on three widely used ETTs was compared in critically ill patients. Biofilm formation on the tubes was found to be an early and frequent event, and high-grade biofilm formation on the ETTs was associated with development of VAP. Compared to uncoated polyvinyl chloride (PVC) ETTs, silicone-coated and noble-metal-coated PVC ETTs were independently associated with reduced high-grade biofilm formation. Methods aimed at the continuous monitoring of biofilm formation are warranted. Routines for biofilm removal need further study.Paper III: This retrospective study compared the incidence of catheter-related infections and catheter-related bloodstream infections during a 2-year period starting 1 year before and ending 1 year after the implementation of a simple hygiene insertion bundle. A total of 1,722 catheter insertions were included. The incidence of catheter-related infections and catheter-related bloodstream infections in this Scandinavian cohort was low. Thus, it seems that the implementation of a simple hygiene insertion bundle was effective in reducing catheter-related infections. The use of multiple-lumen catheters was associated with increased risk of catheter-related infections.Paper IV: In an experimental study, the blood compatibility of three coated and three uncoated CVC materials was evaluated in a modified Chandler loop model imitating the flow of blood in a vein. When in contact with blood, all the tested catheters had some impact on blood cells, contact coagulation, the complement system, or inflammatory markers, although the effects varied significantly. A polyurethane catheter coated with chlorohexidine and silver sulfadiazine showed the most unfavorable blood compatibility profile. A silicone dialysis catheter exhibited the greatest variation in the blood compatibility tests. Poor blood compatibility could cause inflammation and facilitate the development of catheter-related thrombosis in patients receiving these central venous catheters, but clinical significance has to be studied further

Identifying and reducing inappropriate use of medications using Electronic Health Records

Inappropriate use of medications (IUM) is a global problem that can lead to unnecessary harm to the patients and unnecessary costs across the health care system. Identifying and reducing IUM has been a long-lasting challenge and currently, no systematic and automated solution exists to address it. IUM can be manually identified by experts using medication appropriateness criteria (MAC). In this research I first conducted a review of approaches used to identify IUM and reduce IUM. Next, I developed a conceptual model for representing the MAC, and then developed a tool and a workflow for translating the MAC into structured form. Because indications are an important component of the MAC, I conducted a critical appraisal of existing knowledge sources that can be used to that end, namely the medication-indication knowledge-bases. Finally, I demonstrated how these structured MAC can be used to identify patients who are potentially subject to IUM and evaluated the accuracy of this approach. This research identifies the knowledge gaps and technological challenges in identifying and reducing IUM and addresses some of these gaps through the creation of a representation for MAC, a repository of structured MAC, and a set of tools that can assist in evaluating the impact of interventions aimed to reduce IUM or assess its downstream effects. This research also discusses the limitations of existing methods for executing computable decision support rules and proposes solutions needed to enhance these methods so they can support implementation of the MAC

Efficient Decision Support Systems

This series is directed to diverse managerial professionals who are leading the transformation of individual domains by using expert information and domain knowledge to drive decision support systems (DSSs). The series offers a broad range of subjects addressed in specific areas such as health care, business management, banking, agriculture, environmental improvement, natural resource and spatial management, aviation administration, and hybrid applications of information technology aimed to interdisciplinary issues. This book series is composed of three volumes: Volume 1 consists of general concepts and methodology of DSSs; Volume 2 consists of applications of DSSs in the biomedical domain; Volume 3 consists of hybrid applications of DSSs in multidisciplinary domains. The book is shaped decision support strategies in the new infrastructure that assists the readers in full use of the creative technology to manipulate input data and to transform information into useful decisions for decision makers

The social organisation of practice nurses' knowledge utilisation-an ethnographic study

In the study reported in this thesis a conceptual framework drawing on a range of social, organisational and educational theories was used to underpin an investigation into the social organisation of practice nurses’ knowledge utilisation. Particular attention was paid to the concept of ‘clinical mindlines’. Changes in healthcare delivery, particularly in primary care, have resulted in changes to practice nurses’ roles. Macro level policy has focused increasingly on standardisation of care within the primary care environment, specifically in relation to management of chronic/long term conditions. Practice nurses have additionally taken on roles that include diagnostic and treatment elements for which they were not prepared for in their initial training. Set against this background ethnographic data were generated relating to meso level organisation of knowledge utilisation in two study sites. Interviews, observation and documentary analysis of available knowledge sources including guidelines and protocols were used to generate data relating to how knowledge is accessed and subsequently used at the micro level of the clinical patient encounter. Findings illustrated that a mixture of organisational and individual factors impacted on knowledge utilisation. Practice nurses used a combination of knowledge which they applied within the context of the individual patient encounter. This was accessed partly through their ‘mindlines’ developed from education, clinical experience and social learning and partly through accessing a ‘bricolage’ of knowledge which included seeking advice from a variety of sources. Specific elements of note were enthusiasm towards evidence based practice, both amongst the nurses and at practice level and a supportive organisational culture towards continuing education and sharing of knowledge. Standardisation embedded into computer templates that guided the chronic disease management consultations had both a positive and negative influence, positive in its focus on improving evidence based care, whilst negative in promoting template driven care that takes little account of individual patient need. Organisational elements constraining effective knowledge dissemination and use included information being disseminated to the practice nurses through vertical rather than horizontal networking; professional training that had not prepared nurses to deal with uncertainty; the part time nature of the practice nurse role; limitations in accessing evidence in ‘real time’ and lack of applicability of evidence to all patient scenarios