A Surrogate Modelling Approach Based on Nonlinear Dimension Reduction for Uncertainty Quantification in Groundwater Flow Models.

In this paper, we develop a surrogate modelling approach for capturing the output field (e.g. the pressure head) from groundwater flow models involving a stochastic input field (e.g. the hydraulic conductivity). We use a Karhunen-Loève expansion for a log-normally distributed input field and apply manifold learning (local tangent space alignment) to perform Gaussian process Bayesian inference using Hamiltonian Monte Carlo in an abstract feature space, yielding outputs for arbitrary unseen inputs. We also develop a framework for forward uncertainty quantification in such problems, including analytical approximations of the mean of the marginalized distribution (with respect to the inputs). To sample from the distribution, we present Monte Carlo approach. Two examples are presented to demonstrate the accuracy of our approach: a Darcy flow model with contaminant transport in 2-d and a Richards equation model in 3-d.

A qualitative analysis evaluating the purposes and practices of clinical documentation.

OBJECTIVES: An important challenge for biomedical informatics researchers is determining the best approach for healthcare providers to use when generating clinical notes in settings where electronic health record (EHR) systems are used. The goal of this qualitative study was to explore healthcare providers' and administrators' perceptions about the purpose of clinical documentation and their own documentation practices. METHODS: We conducted seven focus groups with a total of 46 subjects composed of healthcare providers and administrators to collect knowledge, perceptions and beliefs about documentation from those who generate and review notes, respectively. Data were analyzed using inductive analysis to probe and classify impressions collected from focus group subjects. RESULTS: We observed that both healthcare providers and administrators believe that documentation serves five primary domains: clinical, administrative, legal, research, education. These purposes are tied closely to the nature of the clinical note as a document shared by multiple stakeholders, which can be a source of tension for all parties who must use the note. Most providers reported using a combination of methods to complete their notes in a timely fashion without compromising patient care. While all administrators reported relying on computer-based documentation tools to review notes, they expressed a desire for a more efficient method of extracting relevant data. CONCLUSIONS: Although clinical documentation has utility, and is valued highly by its users, the development and successful adoption of a clinical documentation tool largely depends on its ability to be smoothly integrated into the provider's busy workflow, while allowing the provider to generate a note that communicates effectively and efficiently with multiple stakeholders.

Impaired insulin-dependent glucose metabolism in granulosa-lutein cells from anovulatory women with polycystic ovaries.

BACKGROUND: Insulin resistance and hyperinsulinaemia are well-recognized characteristics of anovulatory women with polycystic ovary syndrome (PCOS) but, paradoxically, steroidogenesis by PCOS granulosa cells remains responsive to insulin. The hypothesis to be tested in this study is that insulin resistance in the ovary is confined to the metabolic effects of insulin (i.e. glucose uptake and metabolism), whereas the steroidogenic action of insulin remains intact. METHODS: Granulosa-lutein cells were obtained during IVF cycles from seven women with normal ovaries, six ovulatory women with PCO (ovPCO) and seven anovulatory women with PCO (anovPCO). Mean body mass index was in the normal range in all three groups. Granulosa-lutein cells were cultured with insulin (1, 10, 100 and 1000 ng/ml) and LH (1, 2.5 and 5 ng/ml). Media were sampled at 24 and 48 h and analysed for glucose uptake, lactate production and (48 h only) progesterone production. RESULTS: Insulin-stimulated glucose uptake by cells from anovPCO was attenuated at higher doses of insulin (100 and 1000 ng/ml) compared with that by cells from either ovPCO (P=0.02) or controls (P=0.02). Insulin and LH stimulated lactate production in a dose-dependent manner, but insulin-dependent lactate production was markedly impaired in granulosa-lutein cells from anovPCO compared with either normal (P=0.002) or ovPCO (P<0.0001). By contrast, there was no difference in insulin-stimulated progesterone production between granulosa-lutein cells from the three ovarian types. CONCLUSIONS: Granulosa-lutein cells from women with anovPCOS are relatively resistant to the effects of insulin-stimulated glucose uptake and utilization compared with those from normal and ovPCO, whilst maintaining normal steroidogenic output in response to physiological doses of insulin. These studies support the probability of a post-receptor, signalling pathway-specific impairment of insulin action in PCOS.

Assessing physician attitudes regarding use of an outpatient EMR: a longitudinal, multi-practice study.

A pre- and post-implementation assessment of physician attitudes was undertaken as part of the evaluation of the pilot implementations of an outpatient EMR in 6 practices of a large academic health system. Our results show that these physicians are ready adopters of computer technology when it demonstrates value-added for the effort required to use it. These physicians utilize email, the Internet, remote access to computer systems, and personal productivity software because they serve a valuable purpose in their academic and clinical work and in their personal lives. Much more critical to the acceptance of an EMR by physicians is its ability to facilitate efficient clinical workflows without negative effects on the valued relationships physicians have with their patients--those that are based on rapport, quality of care, and privacy.

Introducing handheld computing into a residency program: preliminary results from qualitative and quantitative inquiry.

Although published reports describe specific handheld computer applications in medical training, we know very little yet about how, and how well, handheld computing fits into the spectrum of information resources available for patient care and physician training. This paper reports preliminary quantitative and qualitative results from an evaluation study designed to track changes in computer usage patterns and computer-related attitudes before and after introduction of handheld computing. Pre-implementation differences between residents and faculty s usage patterns are interpreted in terms of a "work role" construct. We hypothesize that over time residents and faculty will adopt, adapt, or abandon handheld computing according to how, and how well, this technology supports their successful completion of work role-related tasks. This hypothesis will be tested in the second phase of this pre- and post-implementation study.

Evaluation of a filmless radiology pilot--a preliminary report.

The development of the Multimedia Electronic Medical Record System (MEMRS) promises new opportunities to significantly reduce the routine use of film as the medium for viewing radiological medical images. The effect of this change to digital media on physician workflow and the perceived value and utility of medical images is an area of ongoing investigation. In this study we examined oncology clinicians use of medical images in a MEMRS. We conducted observational studies of clinicians during a filmless radiology pilot study in which a filmless environment was simulated but the actual film was available on request. This observational study was the first step in a comprehensive evaluation designed to elucidate the issues surrounding the implementation of a filmless radiology environment. We identified and examined several of these issues, including physician concern regarding the utility of digital images for clinical use and comparison with film, the need to address the effects of image compression with clinicians, and the workflow changes necessary to incorporate digital image use into a clinical practice.

Attitudes of academic-based and community-based physicians regarding EMR use during outpatient encounters.

Physician satisfaction with EMR implementations has been reported in a number of recent studies. Most of these have reported on implementation of an EMR in a uniform practice setting rather than comparing satisfaction with implementation between settings. Our objectives in this study were to: 1) compare and contrast the attitudes of academic-based and community-based primary care physicians toward EMR use 6 months after implementation, and 2) investigate some of the factors influencing their attitudes toward the EMR implementation. Although physicians in both settings regularly use computers, the academic-based physicians use computers for a wider range of activities. Both groups endorse improvements in quality and communication as well as concern over rapport with the patient and privacy. There is considerable discrepancy between the two settings in ratings of the impact on workflow, with the community-based physicians being much more positive about the EMR. Factors that may account for this discrepancy may include overall expectations of computer systems as well as different rates of adaptation to use of the system.

Defining the role of anatomic pathology images in the multimedia electronic medical record--a preliminary report.

The development of the Multimedia Electronic Medical Record System (MEMRS) offers new opportunities for integrating medical imaging data with text-based clinical data. The effective integration of pathology images into the patient's medical record poses some significant technical and organizational challenges. Before these challenges can be met, it is imperative that we investigate the value and utility of providing these images to clinicians. In this study we examined attitudes towards use of pathology images in Image Engine, a MEMRS under development at the University of Pittsburgh Cancer Institute (UPCI). We conducted semi-structured standardized interviews with a cohort of practicing oncologists, all of whom had significant experience with Image Engine. This study is a first step towards elucidating the potential barriers, uses, and value of anatomic pathology images in the MEMRS.

Dichotomy between physicians' and patients' attitudes regarding EMR use during outpatient encounters.

Detrimental effects on physician-patient rapport are an often-voiced concern regarding the impacts of implementing an EMR in busy outpatient healthcare environments. Our objectives in this study were to: 1) identify significant concerns of physicians regarding implementation of an EMR in an outpatient clinic, both prior to implementation and after 6 months of use, and 2) assess patients' satisfaction with their outpatient encounters in this clinic, including general and EMR-specific factors. For physicians, physician-patient rapport was a concern prior to EMR implementation and increased with use of the system. In contrast, patients did not indicate a sense of loss of rapport with their physicians when an EMR was used during their outpatient visits. However, physicians and patients shared a concern about the privacy of medical information contained in an EMR.

Information resources assessment of a healthcare integrated delivery system.

While clinical healthcare systems may have lagged behind computer applications in other fields in the shift from mainframes to client-server architectures, the rapid deployment of newer applications is closing that gap. Organizations considering the transition to client-server must identify and position themselves to provide the resources necessary to implement and support the infrastructure requirements of client-server architectures and to manage the accelerated complexity at the desktop, including hardware and software deployment, training, and maintenance needs. This paper describes an information resources assessment of the recently aligned Pennsylvania regional Veterans Administration Stars and Stripes Health Network (VISN4), in anticipation of the shift from a predominantly mainframe to a client-server information systems architecture in its well-established VistA clinical information system. The multimethod assessment study is described here to demonstrate this approach and its value to regional healthcare networks undergoing organizational integration and/or significant information technology transformations.

Central CO2 chemoreception: a mechanism involving P2 purinoceptors localized in the ventrolateral medulla of the anaesthetized rat.

1. The involvement of P2 purinoceptors in chemosensory function in the ventrolateral regions of the medulla oblongata was investigated in the anaesthetized rat. We have investigated the effect of antagonizing, or desensitizing, P2 receptors in the retrofacial area of the ventrolateral medulla on factors modifying respiratory activity. 2. Bilateral microinjection of suramin (50 nl, 0.02 M), a P2 purinoceptor antagonist, into the retrofacial area in the artificially ventilated rat reduced resting phrenic nerve discharge. It also markedly affected the response of the phrenic nerve to increases in arterial CO2. Under conditions of hyperoxic, hypocapnic apnoea, the mean threshold for inducing phrenic nerve activity was raised significantly (from an end-tidal CO2 of 2.5 % to 4.5 %, n = 9). 3. In addition, the slope of the respiratory response curve to increases in CO2 was reduced after suramin. A similar effect was observed after desensitization of certain P2X receptors with alphabeta-methyleneATP. As arterial levels of O2 were greater than 100 mmHg, and an equivalent pattern of response was observed in sino-aortically denervated and vagotomized animals, we believe any contribution of the peripheral chemoreceptors to be minimal. 4. Our data suggest that respiratory neurones within the retrofacial area (Botzinger complex) represent part of the central site of action of CO2 on respiration. Moreover, our observations lead us to suggest that CO2-evoked changes in respiration are mediated at least in part by P2X purinoceptors.

Siegfried: System for Interactive Electronic Guidelines with Feedback and Resources for Instructional and Educational Development.

The proliferation of clinical practice guidelines (CPGs) has necessitated computerized solutions for guideline distribution and implementation. In this paper we describe a Web-based system that interactively presents CPGs at the point of care. Our system, known as Siegfried, provides a generalized solution for implementing CPGs by maintaining the guideline knowledge base separate from the application that presents the guidelines. As a result of this design, new CPGs can be easily added and existing CPGs can be expeditiously modified without additional programming. This system also solicits feedback from users regarding guideline recommendations and provides hypertext links to relevant Web-based instructional and educational resources.

Identification of design features to enhance utilization and acceptance of systems for Internet-based decision support at the point of care.

Extensive utilization of point-of-care decision support systems will be largely dependent on the development of user interaction capabilities that make them effective clinical tools in patient care settings. This research identified critical design features of point-of-care decision support systems that are preferred by physicians, through a multi-method formative evaluation of an evolving prototype of an Internet-based clinical decision support system. Clinicians used four versions of the system--each highlighting a different functionality. Surveys and qualitative evaluation methodologies assessed clinicians' perceptions regarding system usability and usefulness. Our analyses identified features that improve perceived usability, such as telegraphic representations of guideline-related information, facile navigation, and a forgiving, flexible interface. Users also preferred features that enhance usefulness and motivate use, such as an encounter documentation tool and the availability of physician instruction and patient education materials. In addition to identifying design features that are relevant to efforts to develop clinical systems for point-of-care decision support, this study demonstrates the value of combining quantitative and qualitative methods of formative evaluation with an iterative system development strategy to implement new information technology in complex clinical settings.

Structuring clinical practice guidelines in a relational database model for decision support on the Internet.

The rapid proliferation of clinical practice guidelines (CPGs) has made computerization increasingly useful to clinicians. Computerization, however, requires transformation of the content and logic of each guideline into a computer-accessible form. In this project, we sought to use a relational database to construct a generalized guideline knowledge base for use with Internet-based decision support applications. We hypothesized that knowledge representation schemes could be developed to capture guideline content and logic within the constraints of a relational database model. In this paper we describe a database schema based on a relational model for computerizing CPGs using a hybrid of structured and procedural knowledge representation schemes. We developed and refined this model in the context of five diverse CPGs and found it accommodated all necessary representational requirements.

Development and use of a Guideline Entry Wizard to convert text clinical practice guidelines to a relational format.

Computerization of clinical practice guidelines (CPGs) has been proposed as one solution to enhance the use of guidelines in influencing standard clinical care. However, the conversion of text guidelines to the format required by a computer program is a major barrier. Clinicians who best understand the content of CPGs are typically ill equipped to convert textual guidelines into a computer accessible format. The potential of knowledge acquisition tools to assist in this process has been documented in the literature. In this paper we describe an application prototype, the Guideline Entry Wizard, created to assist in the conversion of text CPGs to a structured format within a relational database. We have tested this application through the input of information from several CPG. The application is a prototype for a more advanced tool. We have used this prototype to enter several CPGs and have demonstrated its effectiveness in inputting guideline content into a knowledge base.