Browsing by Subject "method"

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    A Comparison of Simple Analytical Methods for Determination of Fluoride in Microlitre-Volume Plasma Samples
    (Karger, 2019-04) Zohoori, F. Vida; Maguire, Anne; Martinez-Mier, E. Angeles; Buzalaf, Marília Afonso Rabelo; Sanderson, Roy; Eckert, George J.; Cariology, Operative Dentistry and Dental Public Health, School of Dentistry
    The aim was to compare potential methods for fluoride analysis in microlitre-volume plasma samples containing nano-gram amounts of fluoride. Methods: A group of 4 laboratories analysed a set of standardised biological samples as well as plasma to determine fluoride concentration using 3 methods. In Phase-1, fluoride analysis was carried out using the established hexamethyldisiloxane (HMDS)-diffusion method (1 mL-aliquot/analysis) to obtain preliminary measurement of agreement between the laboratories. In Phase-2, the laboratories analysed the same samples using a micro-diffusion method and known-addition technique with 200 µL-aliquot/analysis. Coefficients of Variation (CVs) and intra-class correlation coefficients (ICCs) were estimated using analysis of variance to evaluate the amount of variation within- and between-laboratories. Based on the results of the Phase-2 analysis, 20 human plasma samples were analysed and compared using the HMDS-diffusion method and known-addition technique in Phase-3. Results: Comparison of Phase-1 results showed no statistically significant difference among the laboratories for the overall data set. The mean between- and within-laboratory CVs and ICCs were < 0.13 and ≥0.99, respectively, indicating very low variability and excellent reliability. In Phase-2, the overall results for between-laboratory variability showed a poor CV (1.16) and ICC (0.44) for the micro-diffusion method, whereas with the known-addition technique the corresponding values were 0.49 and 0.83. Phase-3 results showed no statistically significant difference in fluoride concentrations of the plasma samples measured with HMDS-diffusion method and known- addition technique, with a mean (SE) difference of 0.002 (0.003) µg/mL. In conclusion, the known-addition technique could be a suitable alternative for the measurement of fluoride in plasma with microlitre-volume samples.
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    Decision Support from Local Data: Creating Adaptive Order Menus from Past Clinician Behavior
    (Elsevier, 2014-04) Klann, Jeffrey G.; Szolovits, Peter; Downs, Stephen; Schadow, Gunther; Department of Pediatrics, IU School of Medicine
    Objective Reducing care variability through guidelines has significantly benefited patients. Nonetheless, guideline-based clinical decision support (CDS) systems are not widely implemented or used, are frequently out-of-date, and cannot address complex care for which guidelines do not exist. Here, we develop and evaluate a complementary approach - using Bayesian network (BN) learning to generate adaptive, context-specific treatment menus based on local order-entry data. These menus can be used as a draft for expert review, in order to minimize development time for local decision support content. This is in keeping with the vision outlined in the US Health Information Technology Strategic Plan, which describes a healthcare system that learns from itself. Materials and Methods We used the Greedy Equivalence Search algorithm to learn four 50-node domain-specific BNs from 11,344 encounters: abdominal pain in the emergency department, inpatient pregnancy, hypertension in the urgent visit clinic, and altered mental state in the intensive care unit. We developed a system to produce situation-specific, rank-ordered treatment menus from these networks. We evaluated this system with a hospital-simulation methodology and computed Area Under the Receiver-Operator Curve (AUC) and average menu position at time of selection. We also compared this system with a similar association-rule-mining approach. Results A short order menu on average contained the next order (weighted average length 3.91–5.83 items). Overall predictive ability was good: average AUC above 0.9 for 25% of order types and overall average AUC .714–.844 (depending on domain). However, AUC had high variance (.50–.99). Higher AUC correlated with tighter clusters and more connections in the graphs, indicating importance of appropriate contextual data. Comparison with an association rule mining approach showed similar performance for only the most common orders with dramatic divergence as orders are less frequent. Discussion and Conclusion This study demonstrates that local clinical knowledge can be extracted from treatment data for decision support. This approach is appealing because: it reflects local standards; it uses data already being captured; and it produces human-readable treatment-diagnosis networks that could be curated by a human expert to reduce workload in developing localized CDS content. The BN methodology captured transitive associations and co-varying relationships, which existing approaches do not. It also performs better as orders become less frequent and require more context. This system is a step forward in harnessing local, empirical data to enhance decision support.
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    Knowledge Management For Quality Improvement of Service Methods - A Case Study of a Laboratory Instrument
    Nierste, Michael K.; McDaniel, Anna M.
    A systematic method can extrapolate tacit knowledge (hidden or subjective knowledge) so that it can become objective and discernable. This process focused on discovering causes of failures by extricating data from medical equipment service software cases closed by telephone by field service personnel. Their responses to observed failures were compared to troubleshooting guides in use by telephone support personnel to find new processes that would increase effectiveness of telephone support staff. We asked “What are indicators of device failure reported in technical support calls?” and then “What factors contribute to user reported device failures identified by callers to technical support?” A series of interviews with veteran personnel were used to validate responses from the “phone closed” cases along with ideas pulled from a review of documentation. Analysis of one hundred seventy three cases yielded over five hundred recommendations to make the telephone support personnel’s responses more accurate, consistent and reliable.