A knowledge authoring tool for clinical decision support

Anesthesiologists in the operating room are unable to constantly monitor all data generated by physiological monitors. They are further distracted by clinical and educational tasks. An expert system would ideally provide assistance to the anesthesiologist in this data-rich environment. Clinical monitoring expert systems have not been widely adopted, as traditional methods of knowledge encoding require both expert medical and programming skills, making knowledge acquisition difficult. A software application was developed for use as a knowledge authoring tool for physiological monitoring. This application enables clinicians to create knowledge rules without the need of a knowledge engineer or programmer. These rules are designed to provide clinical diagnosis, explanations and treatment advice for optimal patient care to the clinician in real time. By intelligently combining data from physiological monitors and demographical data sources the expert system can use these rules to assist in monitoring the patient. The knowledge authoring process is simplified by limiting connective relationships between rules. The application is designed to allow open collaboration between communities of clinicians to build a library of rules for clinical use. This design provides clinicians with a system for parameter surveillance and expert advice with a transparent pathway of reasoning. A usability evaluation demonstrated that anesthesiologists can rapidly develop useful rules for use in a predefined clinical scenario.

Multivariate analysis in clinical monitoring: detection of intraoperative hemorrhage and light anesthesia

The number of vital sign variables measured during a typical surgery is beyond the simultaneous surveillance capabilities of most experienced clinicians. Most intraoperative events cause trend changes in multiple variables, and many clinical events can only be detected by investigating the inter-relationship between the direction and amplitude of these trend changes in the whole measurement array. We have compared the techniques of principal component analysis (PCA) and factor analysis (FA) in extracting latent variables to represent the underlying physiological mechanism. The detection performance of each method was tested on three simulated cases of intraoperative hemorrhage and a case of variation in depth of anesthesia. The results show that although the detection schemes based on PCA and FA both reduce dimensionality and detect changes in the variance, the FA-based method performs better in detecting subtle changes in the correlation structure.

The use of pharmacokinetic and pharmacodynamic end points to determine the dose of AQ4N, a novel hypoxic cell cytotoxin, given with fractionated radiotherapy in a phase I study

BACKGROUND

AQ4N (1,4-bis[[2-(dimethylamino)ethyl] amino]-5,8-dihydroxyanthracene-9, 10-dione bis-N-oxide dihydrochloride) is a prodrug which is selectively activated within hypoxic tissues to AQ4, a topoisomerase II inhibitor and DNA intercalator.

PATIENTS AND METHODS

In the phase I study, 22 patients with oesophageal carcinoma received an i.v. infusion of AQ4N (22.5-447 mg/m(2)) followed, 2 weeks later, by further infusion and radiotherapy. Pharmacokinetics and lymphocyte AQ4N and AQ4 levels were measured after the first dose. At 447 mg/m(2), biopsies of tumour and normal tissue were taken after AQ4N administration.

RESULTS

Drug-related adverse events were blue discolouration of skin and urine, grade 2-3 lymphopenia, grade 1-3 fatigue, grade 1-2 anaemia, leucopenia and nausea. There were no drug-related serious adverse events (SAEs). Three patients had reductions in tumour volume >50%, nine had stable disease. Pharmacokinetics indicated predictable clearance. Plasma area under the curve (AUC) at 447 mg/m(2) exceeded AQ4N concentrations in mice at therapeutic doses and tumour biopsies contained concentrations of AQ4 greater than those in normal tissue. Tumour concentrations of AQ4 exceeded in vitro IC(50) values for most cell lines investigated.

CONCLUSIONS

No dose-limiting toxic effects were observed and a maximum tolerated dose was not established. Tumour AQ4 concentrations and plasma AUC at 447 mg/m(2) exceeded active levels in preclinical models. This dose was chosen for future studies with radiotherapy.

A multicentre longitudinal observational study of changes in self reported health status in people with Parkinson's disease left untreated at diagnosis

BACKGROUND

The issue of when to start treatment in Parkinson's disease (PD) remains controversial. Some favour treatment at diagnosis while others opt for a "wait and watch" policy. The effect of the latter policy on the self reported health status of people with PD is unknown.

AIMS

To record self reported health status through longitudinal use of a validated PD specific questionnaire (PDQ-39) in untreated PD patients in multiple centres in the UK. To compare patients who were left untreated with those who were offered treatment during follow-up.

METHODS

A multicentre, prospective, "real life" observational audit based study addressing patient reported outcomes in relation to self reported health status and other sociodemographic details.

RESULTS

198 untreated PD were assessed over a mean period of 18 months. During two follow-up assessments, the self reported health status scores in all eight domains of the PDQ-39 and the overall PDQ-39 summary index worsened significantly (p<0.01) in patients left untreated. In a comparative group in whom treatment was initiated at or soon after diagnosis, there was a trend towards improvement in self reported health status scores after treatment was started.

CONCLUSIONS

This study addresses for the first time self reported health status, an indicator of health related quality of life, in untreated PD. The findings may strengthen the call for re-evaluation of the policy to delay treatment in newly diagnosed patients with PD.

An improved resolution structure of the human beta common receptor involved in IL-3, IL-5 and GM-CSF signalling which gives better definition of the high-affinity binding epitope

X-ray diffraction has been used to produce and refine a model of the extracellular domains of the beta common cytokine receptor. A minor improvement in resolution has resulted in improved electron-density maps, which have given a clearer indication of the position and stabilization of the key residues Tyr15, Phe79, Tyr347, His349, Ile350 and Tyr403 in the elbow region between domain 1 and domain 4 of the dimer-related molecule.

Whole body MR imaging: Applications in oncology

This article reviews technique and clinical applications of whole body MR imaging as a diagnostic tool in cancer staging. In particular the article reviews its role as an alternative to scintigraphy (bone scan and PET) in staging skeletal spread of disease, its role in assessing total tumour burden, its role in multiple myeloma and finally its evolving non oncologic role predominantly assessing total body composition.

Ethics of evidence based medicine in the primary care setting

Evidence based medicine has had an increasing impact on primary care over the last few years. In the UK it has influenced the development of guidelines and quality standards for clinical practice and the allocation of resources for drug treatments and other interventions. It has informed the thinking around patient involvement in decision making with the concept of evidence based patient choice. There are, however, concerns among primary care clinicians that evidence based medicine is not always relevant to primary care and that undue emphasis placed on it can lead to conflict with a clinician's duty of care and respect for patient autonomy. In this paper we consider the impact of evidence based medicine on primary care, and the ethical implications of its increasing prominence for clinicians and managers in primary care.

Systematic differences in electropherogram peak heights reported by different versions of the GeneScan software

DNA profiling using STRs on the 310 and 3100 Genetic Analyzers routinely generates electropherograms that are analyzed with the GeneScan software available from the instrument's manufacturer, Applied Biosystems. Users have been able to choose from three different smoothing options that have been known to result in significant differences in the peak heights that are reported. Improvements in the underlying algorithm of the most recent version of the software also result in significant and somewhat predictable differences in peak height values. Laboratories that have performed validation studies using older versions of GeneScan should either reanalyze the data generated in those validation studies with the newest version of the software or otherwise take into consideration the systematically higher peak height values obtained as they begin following the recommendation of the manufacturer and use the new algorithm.

Clinical Trials Update: CAPRICORN, COPERNICUS, MIRACLE, STAF, RITZ-2, RECOVER and RENAISSANCE and cachexia and cholesterol in heart failure. Highlights of the Scientific Sessions of the American College of Cardiology, 2001

This is a synopsis of presentations made at the American College of Cardiology (ACC) in 2001 summarising recent research developments relating to heart failure. Clinical studies of particular interest to physicians with an interest in heart failure and its prevention are reviewed. The COPERNICUS trial lends further support to the use of the beta-blocker, carvedilol, in severe heart failure and the CAPRICORN trial to its use in patients with post-infarction left ventricular systolic dysfunction. The MIRACLE study reinforces the evidence from three smaller trials that cardiac resynchronisation therapy is an effective treatment for the relief of symptoms in patients with severe heart failure and cardiac dyssynchrony. The STAF trial casts further doubt on the wisdom of cardioversion as a routine strategy for the management of chronic atrial fibrillation. The RITZ-2 trial suggests that an intravenous, non-selective endothelin antagonist is effective in improving haemodynamics and symptoms and possibly in reducing morbidity in severe heart failure. Observational studies in heart failure suggest that a moderate excess of body fat and elevated blood cholesterol may be desirable in patients with heart failure, challenging the current non-evidenced-based vogue for cholesterol lowering therapy in heart failure. The RENAISSANCE and RECOVER outcome studies of etanercept, a tumour necrosis factor (TNF) receptor analogue that blocks the effect of TNF, were stopped because of lack of evidence of benefit shortly after the ACC.