Automated computer system for differential diagnosis and defining the indications for pathogenetic therapy is described, which was used in 2816 patients and was effective in 97% of cases. The system includes computer-regulated Lancet surgical lasers (wavelength 10.6 microns, power 60 W, frequency 0.05-1.0 Hz) and Optodan physiotherapeutic laser (wavelength 0.85 micron, power 4 W, frequency 0.08-3 kHz).
The aims of this study were to assess the effectiveness of 2 automated electrocardiogram interpretation programs in patients with suspected acute coronary syndrome transported to hospital by ambulance in 1 rural region of Denmark with hospital discharge diagnosis used as the gold standard and to assess the effectiveness of cardiologists' triage decisions for these patients based on initial electrocardiogram. Twelve-lead electrocardiograms were recorded in ambulances using a LIFEPAK 12 monitor/defibrillator (Physio-Control, Inc., Redmond, Washington) and transmitted digitally to an attending cardiologist. If a diagnosis of ST elevation myocardial infarction was made, a patient was taken to a regional interventional center for primary percutaneous coronary intervention or to a local hospital. One thousand consecutive digital electrocardiograms and corresponding interpretations from LIFEPAK 12 were available, and these were subsequently interpreted by the University of Glasgow program. Electrocardiogram interpretations and cardiologists' decisions were compared to hospital discharge diagnoses. The sensitivity, specificity, and positive predictive values for a report of ST elevation myocardial infarction with respect to discharge diagnosis were 78%, 91%, and 81% for LIFEPAK 12 and 78%, 94%, and 87% for the Glasgow program. Corresponding data for attending cardiologists were 85%, 90%, and 81%. In conclusion, the Glasgow program had significantly higher specificity than the LIFEPAK 12 program (p = 0.02) and the cardiologists (p = 0.004). Triage decisions were effective, with good agreement between cardiologists' decisions and discharge diagnoses.
The assessment of extra-, intracellular and total body water (ECW, ICW, TBW) is important in many clinical situations. Bioimpedance spectroscopy (BIS) has advantages over dilution methods in terms of usability and reproducibility, but a careful analysis reveals systematic deviations in extremes of body composition and morbid states. Recent publications stress the need to set up and validate BIS equations in a wide variety of healthy subjects and patients with fluid imbalance. This paper presents two new equations for determination of ECW and ICW (referred to as body composition spectroscopy, BCS) based on Hanai mixture theory but corrected for body mass index (BMI). The equations were set up by means of cross validation using data of 152 subjects (120 healthy subjects, 32 dialysis patients) from three different centers. Validation was performed against bromide/deuterium dilution (NaBr, D2O) for ECW/TBW and total body potassium (TBK) for ICW. Agreement between BCS and the references (all subjects) was -0.4 +/- 1.4 L (mean +/- SD) for ECW, 0.2 +/- 2.0 L for ICW and -0.2 +/- 2.3 L for TBW. The ECW agreement between three independent reference methods (NaBr versus D2O-TBK) was -0.1 +/- 1.8 L for 74 subjects from two centers. Comparing the new BCS equations with the standard Hanai approach revealed an improvement in SEE for ICW and TBW by 0.6 L (24%) for all subjects, and by 1.2 L (48%) for 24 subjects with extreme BMIs (30). BCS may be an appropriate method for body fluid volume determination over a wide range of body compositions in different states of health and disease.
A decision support computer program (DSP) was used by the emergency room physician as a diagnostic tool on patients admitted with acute chest pain to guide the referral of these patients either to the Coronary Care Unit (CCU) or general ward. The DSP used Bayes' theorem on 38 anamnestic and clinical variables to classify patients into one of nine diagnoses. During a six months trial period 32 physicians used the DSP to diagnose 493 patients admitted with acute chest pain. The physicians referred the patients to CCU or general ward based on their clinical judgements, the ECG findings and the diagnostic estimates given by the DSP. The program correctly diagnosed 150 (84%) of 178 patients with acute myocardial infarction and 63 of 112 patients with unstable angina. However, acute ischemic heart disease (acute myocardial infarction or unstable angina) was correctly classified by the DSP for 259 (89%) of 290 patients. By using the DSP, the number of patients unnecessarily referred to CCU was reduced from 35% to 19% and the number of patients in need of CCU observation misallocated to general ward was reduced from 13% to 10%. Thus, use of the DSP in the emergency room on easily available anamnestic and clinical variables may improve referrals to the CCU, optimize therapy and resource use.
We investigate a user-driven collaborative knowledge engineering and interaction design process. The outcome is a knowledge-based support application tailored to physicians in the local dementia care community. The activity is organized as a part of a collaborative effort between different organizations to develop their local clinical practice. Six local practitioners used the generic decision-support prototype system DMSS-R developed for the dementia domain during a period and participated in evaluations and re-design. Additional two local domain experts and a domain expert external to the local community modeled the content and design of DMSS-R by using the modeling system ACKTUS. Obstacles and success factors occurring when enabling the end-users to design their own tools are detected and interpreted using a proposed framework for improving care through the use of clinical guidelines. The results are discussed.
From 1 July 1990 to 31 December 1991, all patients referred to the Allergy Section of the ENT Department, University Hospital, Lund, Sweden, (n = 678) answered a 134-item questionnaire presented on the screen of a personal computer by pressing Y (for yes) or N (for no) on the keyboard. The objective of this study was to compare the questionnaire responses from patients with allergic rhinitis (AR) with those of patients with perennial nonallergic rhinitis or vasomotor rhinitis (VMR). Nasal blockage was the predominant symptom in the VMR group, whereas the AR patients mainly suffered from eye irritation, sneezing, and, to some extent, rhinorrhea. Concomitant asthma was more prevalent in the AR group than in the VMR group, whose histories were characterized by symptoms associated with airway infections. About 60% of both groups reported problems with such nonspecific airway irritants as cigarette smoke and perfumes. With respect to the diagnostic reliability of the history, in the AR group the order of accuracy (according to the skin prick test results) of reported hypersensitivity to allergens was as follows: cat > timothy > birch > dust mite > mugwort. A history of hypersensitivity to molds as a cause of symptoms was of no diagnostic value. The findings suggest that there are several differences in the medical histories of AR and VMR patients that merit further investigation.
There are high rates of mental disorder in correctional environments, so effective mental health screening is needed. Implementation of the computerised mental health screen of the Correctional Service of Canada has led to improved identification of offenders with mental health needs but with high rates of false positives.
The goal of this study is to evaluate the use of an iterative classification tree (ICT) approach to mental health screening compared with a simple binary approach using cut-off scores on screening tools.
A total of 504 consecutive admissions to federal prison completed the screen and were also interviewed by a mental health professional. Relationships between screening results and more extended assessment and clinical team discussion were tested.
The ICT was more parsimonious in identifying probable 'cases' than standard binary screening. ICT was also highly accurate at detecting mental health needs (AUC=0.87, 95% CI 0.84-0.90). The model identified 118 (23.4%) offenders as likely to need further assessment or treatment, 87% of whom were confirmed cases at clinical interview. Of the 244 (48.4%) offenders who were screened out, only 9% were clinically assessed as requiring further assessment or treatment. Standard binary screening was characterised by more false positives and a comparable false negative rate.
The use of ICTs to interpret screening data on the mental health of prisoners needs further evaluation in independent samples in Canada and elsewhere. This first evaluation of the application of such an approach offers the prospect of more effective and efficient use of the scarce resource of mental health services in prisons. Although not required, the use of computers can increase the ease of implementing an ICT model.
A computer system for probabilistic diagnosis of jaundice was tested on a patient sample from a geographical area different from that for which it was first constructed. 144 consecutive patients with jaundice seen in two Stockholm hospitals were interviewed and examined to record a total of 82 indicants from history, demographic details, physical findings and laboratory tests. Data were compared with those of 319 jaundiced patients previously interviewed and examined at different London hospitals. It was found that disease incidences were different in the two patient samples. There were more patients with acute viral hepatitis, chronic active hepatitis and primary biliary cirrhosis in the London data base whereas the Stockholm data base included significantly more patients with Gilbert's syndrome and alcoholic cirrhosis. Indicant frequencies, standardised for disease incidence, differed with respect to age (Stockholm patients were on average six years older), time from onset of first symptom to hospital admission (Stockholm patients had on average a two-week shorter history of disease) and a number of symptoms such as nausea, vomiting, anorexia, weight loss, itching, pale stools and dark urine which were more frequent among the London patients. Differences in hospital admission policy was regarded as an important reason for the differences in indicant frequency. The results of probabilistic diagnosis were poor. Only 49% of the cases were correctly classified into twelve diagnostic groups. In particular the computer model was poor at separating different causes of malignant bile duct obstruction and at differentiating between malignant and benign bile duct obstruction. However, all cases of acute viral hepatitis were correctly classified and the computer model was 87% accurate in differentiating between medical and surgical jaundice. Reclassification of the 144 patients on their own data showed the computer system to be well calibrated and 97% of the cases were correctly classified according to this procedure. In conclusion, the computer system could not be directly transferred for use in a Swedish hospital but the results of reclassification were sufficiently encouraging to warrant prospective studies.