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Biomedical subjects

S Bryan

Publications and source records attributed to S Bryan.

At least 37 records · Page 2Linked to original sources
PubMed2000

Comparison of doses for bedside examinations of the chest with conventional screen-film and computed radiography: results of a randomized controlled trial.

PURPOSE: To compare the radiation doses received by patients during bedside chest radiography when a computed radiography system was used and when a 400-speed screen-film system was used. MATERIALS AND METHODS: A randomized controlled trial was performed whereby all patients who were admitted to an intensive care unit were randomly assigned at admission to have all radiographic chest images obtained with either computed or conventional screen-film radiography. Doses were measured for 1 year, during which 269 patients underwent imaging. For these patients, surface entry doses were measured by means of individual thermoluminescent dosimeters placed on the skin at the center of the radiation beam. In addition, data were collected relating to the patient and examination characteristics, as well as to repeat examinations. Effective doses were calculated. RESULTS: The patients in the two arms of the study were well matched. The surface entry doses were higher in the computed radiography group (median, 0.21 mGy for computed radiography and 0.16 mGy for conventional radiography), and the effective doses were also higher (median, 0.036 mSv for computed radiography and 0.027 mSv for conventional radiography). Fewer examinations were repeated when computed radiography was used. CONCLUSION: When computed radiography was used, patient doses increased. The speed of this computed radiography system, which uses phosphor plate imaging, equates approximately to a 300-speed screen-film system.

Adolescent↗
PubMed1999

Humoral immunity to commensal oral bacteria in human infants: salivary secretory immunoglobulin A antibodies reactive with Streptococcus mitis biovar 1, Streptococcus oralis, Streptococcus mutans, and Enterococcus faecalis during the first two years of life.

Secretory immunoglobulin A (SIgA) antibodies reactive with the pioneer oral streptococci Streptococcus mitis biovar 1 and Streptococcus oralis, the late oral colonizer Streptococcus mutans, and the pioneer enteric bacterium Enterococcus faecalis in saliva samples from 10 human infants from birth to age 2 years were analyzed. Low levels of salivary SIgA1 and SIgA2 antibodies reactive with whole cells of all four species were detected within the first month after birth, even though S. mutans and E. faecalis were not recovered from the mouths of the infants during the study period. Although there was a fivefold increase in the concentration of SIgA between birth and age 2 years, there were no differences between the concentrations of SIgA1 and SIgA2 antibodies reactive with the four species over this time period. When the concentrations of SIgA1 and SIgA2 antibodies reactive with all four species were normalized to the concentrations of SIgA1 and SIgA2 in saliva, SIgA1 and SIgA2 antibodies reactive with these bacteria showed a significant decrease from birth to 2 years of age. Adsorption of each infant's saliva with cells of one species produced a dramatic reduction of antibodies recognizing the other three species. Sequential adsorption of saliva samples removed all SIgA antibody to the bacteria, indicating that the SIgA antibodies were directed to antigens shared by all four species. The induction by the host of a limited immune response to common antigens that are likely not involved in adherence may be among the mechanisms that commensal streptococci employ to persist in the oral cavity.

Antibodies, Bacterial↗
PubMed1999

Evaluation of a hospital picture archiving and communication system.

OBJECTIVES: To establish the net costs to the hospital and the broad range of benefits associated with a hospital-wide picture archiving and communication system (PACS) that comprised digital acquisition, storage and transmission of radiological images via a hospital-wide network to 150 workstations. METHODS: 'Before and after' comparisons and time series analyses at Hammersmith Hospital (London, UK), and comparison with five other British hospitals where PACS was not being installed. The cost analysis considered implementation costs and changes in key elements of hospital running costs, including the impact of changes in the length of inpatient stays. A range of benefit measures were investigated, including image availability, avoidance of repeat imaging, avoidance of exposure to radiation, patient turn-round speed, time from examination to image availability in intensive care, avoidance of diagnostic 'errors' by casualty doctors, the additional diagnostic value of PACS-based images and clinician satisfaction. RESULTS: The annual equivalent capital cost of the PACS was 1.7 million Pounds (annual equivalent replacement cost: 0.8 million Pound). Overall, the PACS substantially increased running costs. No convincing evidence of a PACS-induced change in length of inpatient stay was found. PACS was associated with some improvements in the performance of the radiology department: improved image availability (97.7% versus 86.9%), lower repeat imaging rate (7.3% versus 9.9%) and 20% lower total radiation doses for examinations of the lateral lumbar spine. No improvements were identified in the quality of the radiology reporting service. Benefits outside radiology included shorter time from examination to image availability for routine uses in intensive care (19 versus 37 minutes), and a lower rate of diagnostic 'errors' in casualty (0.65% versus 1.51%). High levels of satisfaction with PACS were found amongst both providers and clinical users. CONCLUSIONS: PACS was almost universally preferred by users and brought many operational and clinical benefits. However, these advantages came at a significant capital and net running cost.

Cost-Benefit Analysis↗
PubMed1999

The benefits of hospital-wide picture archiving and communication systems: a survey of clinical users of radiology services.

This paper describes one element of a broad evaluation of a hospital-wide picture archiving and communication system (PACS): an assessment of the views of users of the radiology service, their major causes of dissatisfaction with the service, the incidence of image unavailability, and the consequences of images being unavailable. The principal research design was a "before and after" comparison at Hammersmith Hospital, as the hospital site introducing PACS. Several other hospitals were included in this survey, for comparison. Questionnaires were distributed several times before PACS was operational at Hammersmith, and on one occasion after. The overall response rate was 54%. The main pre-PACS radiology-related problem areas were: the non-availability of images, the non-availability of written reports when clinically required, and the time devoted by junior staff to image searching. PACS greatly reduced the perceived problem of image non-availability. But Hammersmith's problems with the availability of radiological reports still remained when PACS was operational. The time junior doctors spent in image-searching was dramatically reduced by the introduction of PACS.

Attitude of Health Personnel↗
PubMed1999

The effect of a picture archiving and communication system (PACS) on patient radiation doses for examination of the lateral lumbar spine.

This study was conducted to determine whether the doses for the radiographic examination of the lateral lumbar spine changed as a result of the introduction of a hospital-wide picture archiving and communication system (PACS). Doses were measured by thermoluminescent dosimeters (TLD) and dose-area product (DAP) meter readings for 100 patient examinations using a 300-speed conventional film/screen system and for 96 patient examinations when PACS was fully operational. Radiographic technique, exposure factors and patient characteristics were noted and effective doses were calculated, and a comparison was made of all variables. No significant differences between conventional and PACS working were found in surface entry and effective doses for single views of the lateral lumbar spine, but there was a 20% reduction in DAP readings with PACS. However, when summed doses for all images, including rejects, required to demonstrate the lateral lumbar spine for each patient were compared, PACS was found to be associated with significantly lower surface entry (TLD) dose, DAP reading and effective dose (28%, 36% and 16%, respectively) than conventional film. For single images of L1-5, when PACS was in use, there was a significant reduction in the DAP readings and increases in the area of the film/plate irradiated, the focus-to-skin distance and the focus-to-film distance. In addition, significantly fewer lumbosacral junction views were undertaken when PACS was in use. Since many confounding factors may have influenced the results over the period of dose measurement, regression models were used to determine the significance of PACS. These models showed that the use of PACS was not significant in causing any differences in the dose for single images as compared with when film was used, but was significant in the resulting total dose reductions for the examinations.

Adult↗
PubMed1999

A comparison of image reject rates when using film, hard copy computed radiography and soft copy images on picture archiving and communication systems (PACS) workstations.

A comparison has been made of the reject rates of plain images for three separate periods when film, computed radiography (CR) and PACS systems were in operation throughout the Hammersmith Hospital, London. There was a statistically significant reduction in the overall percentage reject rate across all examinations from 9.9% to 8.1% when the hospital changed from using a conventional film based system to a CR system. There was a further reduction in the reject rate to 7.3% when the hospital moved to a hospital-wide PACS system, but this change was not statistically significant. Using estimations of the total number of images used, the percentage reject rates were 6.6% for film, 5.5% for CR and 5.5% for PACS. Thus, if the radiation dose for each image is unchanged, and the same types of images are used for the examination of each body area, a move from conventional film imaging to phosphor plate imaging provides the potential to reduce the patient population dose.

Computer Systems↗
PubMed1999

Examining the influence of picture archiving communication systems and other factors upon the length of stay for patients with total hip and total knee replacements.

OBJECTIVES: To examine the influence of a picture archiving and communication system (PACS) on the length of stay (LOS) for patients receiving total hip replacement (THR) or total knee replacement (TKR) procedures. METHODS: A before-and-after design was used. Data were collected on all THR and TKR procedures at Hammersmith Hospital from 1993-96. A regression approach was used to examine the influence of PACS on LOS. Factors such as patient age, sex, and physician were controlled for. RESULTS: Type of admission and discharge, month of procedure, complications, and number of procedures all significantly influenced LOS for patients undergoing THR. For patients receiving TKR, age, sex, admission, prosthetic complications, number of procedures, and PACS significantly influenced LOS. CONCLUSIONS: While this study shows an apparent reduction of 25% in the average LOS for TKR patients at the time PACS was introduced, this is unlikely to be a true PACS effect and no similar reduction in LOS was shown for THR patients.

Aged↗
PubMed1998

Magnetic resonance imaging for the investigation of knee injuries: an investigation of preferences.

The conventional approach to the diagnosis and treatment of severe knee injuries is arthroscopy, a minimally invasive surgical procedure. Since arthroscopy is an invasive technique that carries risks, magnetic resonance imaging (MRI) is increasingly being used for diagnosis. MRI is potentially associated with diagnostic and therapeutic 'impacts', in that arthroscopy can be avoided. This paper reports a discrete choice conjoint analysis exercise that assessed the value placed on such 'impacts' by potential patients and investigated the degree to which respondents were willing to trade between process and outcome. The marginal rates of substitution between attributes were estimated. The results suggest that the diagnostic and therapeutic 'impacts' of MRI were valued by many respondents. The study has highlighted a number of important issues for the design and analysis of future health-related conjoint studies, including the use of treatment cost as an attribute, dealing with data from lexicographic respondents, and distinguishing between points of indifference and missing data.

Adult↗
PubMed1998

Health-related quality of life following liver transplantation.

The objectives of this study were to report on the health-related quality of life (QoL) experienced by patients following liver transplantation and to investigate the factors associated with its variation. A questionnaire comprising the SF-36 and EuroQol EQ-5D instruments was sent by post to 147 patients who had received a liver transplant, indicated by a chronic liver disease, in the previous 8 years. The scores of the respondents were compared to population norm scores. The variation in both the SF-36 and EQ-5D scores was explored. Many liver transplant patients experienced most satisfactory QoL levels post-transplantation although, in general terms, the levels were poorer than those seen in the general population. The variation in the post-transplant health-related QoL scores was found to be associated with a number of pre-transplant factors: disease severity (proxied by Child Pugh class), disease duration at the time of transplantation and liver transplant history (whether the patient had received a single or multiple transplants). In making clinical decisions about the use of transplantation for chronic liver diseases, consideration should be given to the key factors likely to affect subsequent health-related QoL.

Adolescent↗
PubMed1998

Humoral immunity to commensal oral bacteria in human infants: salivary antibodies reactive with Actinomyces naeslundii genospecies 1 and 2 during colonization.

The secretory immune response in saliva to colonization by Actinomyces naeslundii genospecies 1 and 2 was studied in 10 human infants from birth to 2 years of age. Actinomyces species were not recovered from the mouths of the infants until approximately 4 months after the eruption of teeth. However, low levels of secretory immunoglobulin A1 (SIgA1) and SIgA2 antibodies reactive with whole cells of A. naeslundii genospecies 1 and 2 were detected within the first month after birth. Although there was a fivefold increase in the concentration of SIgA between birth and age 2 years, there were no differences between the concentrations of SIgA1 and SIgA2 antibodies reactive with A. naeslundii genospecies 1 and 2 over this period. When the concentrations of SIgA1 and SIgA2 antibodies reactive with whole cells of A. naeslundii genospecies 1 and 2 were normalized to the concentrations of SIgA1 and SIgA2 in saliva, the A. naeslundii genospecies 1- and 2-reactive SIgA1 and SIgA2 antibodies showed a significant decrease from birth to 2 years of age. The fine specificities of A. naeslundii genospecies 1- and 2-reactive SIgA1 and SIgA2 antibodies were examined by Western blotting of envelope proteins. Similarities in the molecular masses of proteins recognized by SIgA1 and SIgA2 antibodies, both within and between subjects over time, were examined by cluster analysis and showed considerable variability. Taken overall, our data suggest that among the mechanisms Actinomyces species employ to persist in the oral cavity are the induction of a limited immune response and clonal replacement with strains differing in their antigen profiles.

Actinomyces↗
PubMed1998

Extrapolation of cost-effectiveness information to local settings.

Providers and purchasers of health care are increasingly looking to the results of economic evaluations for guidance when making their decisions. In this paper the authors argue that there are dangers involved in the naive and unthinking use of published cost-effectiveness information outside the setting in which the information was generated. In considering whether the results of a published study are likely to be relevant locally, decision-makers are encouraged to assess whether the values of the key parameters reported in the published study apply locally. The possible sources of variation are described: unit cost differences; differences in the prevalence, incidence or natural history of disease; and differences in the comparators. In situations where the only source of variation is that local unit costs are different, local values can be substituted in the published analysis and local cost-effectiveness results estimated. Where the other sources of variation exist, the decision-maker is required to make an assumption about the nature of the interaction between the sources of variation and the values of the cost-effectiveness parameters. Using an example, the authors argue that local threshold analysis can aid decision-making where the policy change being considered has a high probability either of increasing effectiveness or reducing costs. Without local re-analysis, there is a danger that local policy changes in line with the recommendations of published studies will promote inefficiency. Re-analysis in the local setting is, however, reliant on authors of economic evaluations being explicit about their methods and the comparators used in their analyses.

Cost-Benefit Analysis↗
PubMed1998

Radiology report times: impact of picture archiving and communication systems.

OBJECTIVE: We investigated the impact on radiologist reporting time of the change from conventional film to hard-copy computerized radiography and of the subsequent move to soft-copy images on picture archiving and communication system (PACS) workstations. MATERIALS AND METHODS: A controlled before and after research design was undertaken. Data were collected on four occasions: two relating to conventional film, one relating to hard-copy computerized radiography, and one relating to soft-copy PACS images. Data collection was by direct observation of radiology reporting sessions by independent health service researchers. Data were collected on report times, details of images viewed, characteristics of the radiologist, and details of interruptions. To control for potential biases in the before and after comparisons, ordinary least squares multiple regression analysis was used. The principal comparison was between reports with PACS and reports with computerized radiography hard-copy because no change was noted in the organization of the reporting process between these two data collection rounds other than the introduction of the PACS. RESULTS: Data were collected on a total of 5568 report observations. Report time in the PACS data collection period was not significantly different (p = .32) than that in the computerized radiography hard-copy period. Reporting with the PACS was associated with significantly more (p < .01) historical images (i.e., images of the same patient obtained in previous examinations) being viewed. CONCLUSION: Report time was not lengthened by the introduction of the PACS. The finding that more historical images were viewed when the PACS was in use indicates that the PACS brought about a positive change in reporting practice.

Bias↗
PubMed1998

The 1997 NASN research award winner. School nurses' perceptions of their interactions with nurse practitioners.

Relationships between traditional school nurses and nurse practitioners were studied using a descriptive research design. The study analyzed school nurses' perceptions of their professional interactions with nurse practitioners. A researcher-developed questionnaire was sent to 500 Missouri school nurses living in zip-code areas known to employ a high concentration of nurse practitioners. Of the 295 school nurses who responded, 148 had interacted professionally with a nurse practitioner in the previous 5 years. Analysis of the responses indicated an overall positive regard for the nurse practitioner role. Data from this study will be used to support and further improve working relationships between these two nursing specialty groups.

Attitude of Health Personnel↗
PubMed1997

Clinical economics review: cost-effectiveness in the therapy of liver disease.

There have been many advances made in the management of patients with liver disease both in diagnosis and in the treatment of underlying liver disease and its complications, although comparatively few of these have been rigorously subjected to full cost-effectiveness evaluation. In this review, we have analysed a small number of the therapeutic interventions; while these have been well evaluated clinically, very few have been analysed from the viewpoint of cost-effectiveness and, thus, it is difficult to make many definitive claims. It is hoped that future studies will consider these aspects as well.

Ascites↗
PubMed1996

Mammography screening: an incremental cost effectiveness analysis of double versus single reading of mammograms.

OBJECTIVE: To compare mammography reading by one radiologist with independent reading by two radiologists. DESIGN: An observational non-randomised trial at St Margaret's Hospital, Epping. SUBJECTS: 33 734 consecutive attenders for breast screening in the main trial and a sample of 132 attenders for assessment who provided data on private costs. INTERVENTIONS: Three reporting policies were compared: single reading, consensus double reading, and non-consensus double reading. MAIN OUTCOME MEASURES: Numbers of cancers detected, recall rates, screening and assessment costs, and cost effectiveness ratios. RESULTS: A policy of double reading followed by consensus detected an additional nine cancers per 10 000 women screened (95% confidence interval 5 to 13) compared with single reading. A non-consensus double reading policy detected an additional 10 cancers per 10 000 women screened (95% confidence interval 6 to 14). The difference in numbers of cancers detected between the consensus and non-consensus double reading policies was not significant (95% confidence interval -0.2 to 2.2). The proportion of women recalled for assessment after consensus double reading was significantly lower than after single reading (difference 2.7%; 95% confidence interval 2.4% to 3.0%). The recall rate with the non-consensus policy was significantly higher than with single reading (difference 3.0%; 2.5% to 3.5%). Consensus double reading cost less than single reading (saving 4853 pounds per 10 000 women screened). Non-consensus double reading cost more than single reading (difference 19 259 pounds per 10 000 women screened). CONCLUSIONS: In the screening unit studied a consensus double reading policy was more effective and less costly than a single reading policy.

Breast Neoplasms↗