PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Systems Analysis”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 811 records · Page 45Linked to original sources
PubMed1994

A computer-based simulator for air ambulance system analysis, design and optimization.

INTRODUCTION: Little is known about how best to quantitatively measure air medical system performance and optimally manage air medical emergency medical services start-up, operation and growth. Moreover, very little has been done to produce and distribute relevant tools for these critical tasks. SETTING: A hypothetical system modeled on the Ontario, Canada, air ambulance operation. METHODS: A user-friendly, high-performance computer simulation tool for air ambulance system design, quality management and optimization was developed. In this report, the authors describe the simulator's basic structure and method of operation and present the initial findings for application to the Ontario air ambulance system. The tool tested the hypothesis that if shorter patient transfer times positively influence patient survival and higher aircraft performance, as measured by block speed, has a positive correlation with aircraft direct operating costs, then there is a pattern of "best matching" between aircraft performance, flight economics and patient survival probability for the system. RESULTS: In the Ontario air ambulance system, an additional outlay in direct operating costs of $100 per flight yields an improvement in system quality, as measured by an improvement of 1% to 30% in the predicted patient survival probability, depending on the reference cohort and the efficacy of the life support procedures administered by the air crew. DISCUSSION: A notable feature of this model is that it separates the impact of air medical transport on patient survival from subsequent measures undertaken at the emergency department after delivery to the trauma center. The current needs of the air medical transport industry, combined with the progress to date, suggest that computer-based simulators can be a powerful, cost-effective means of extracting meaning from air medical data and applying the results to productive ends.

Air Ambulances↗
PubMed2006

Sequential injection analysis system for the sandwich hybridization-based detection of nucleic acids.

A sequential injection analysis lab-on-valve (SIA-LOV) system was developed for the specific detection of single-stranded nucleic acid sequences via sandwich hybridization of specific DNA probes to the target sequence. One DNA probe was tagged with fluorescein; the other was biotinylated and immobilized to streptavidin-coated porous beads. The system was optimized with respect to buffer composition, length of hybridization and wash steps, and volumes and concentrations of components used. On-bead oligonucleotide hybridization was studied using UV detection at 260 nm, while a final dose response curve was quantified using fluorescence detection. A dynamic range of 1-1000 pmol was obtained for a synthetic DNA sequence that was homologous to a segment in the B. anthracis atxA mRNA. A within-day variation of 7.2% and a day-to-day variation of 9.9% was observed. Each analysis was completed within 20 min. Subsequently, the system was applied to the detection of atxA mRNA expressed in a surrogate organism and amplified using NASBA. The SIA-LOV will find its application in routine laboratory-based analysis of specific single-stranded DNA/RNA sequences. Future improvements will include the integration of dye-encapsulating liposomes for signal enhancement used in lieu of the single fluorophore-labeled probe in order to lower the limit of detection.

Biosensing Techniques↗
PubMed2002

The Veterans Affairs root cause analysis system in action.

BACKGROUND: The patient safety program in the Department of Veterans Affairs (VA) began in 1998, when the National Center for Patient Safety (NCPS) was established to lead the effort on a day-to-day basis. NCPS provides the structure, training, and tools, and VA facilities provide front-line expertise, feedback about the process, and root cause analysis (RCA) of adverse events and close calls. MONITORING THE PROCESS: Facility patient safety managers determine the disposition of adverse events and close calls occurring at their facilities. They use a safety assessment code (SAC) to prioritize the actual and potential severity and frequency of an event. BEFORE-AND-AFTER STUDY: Before the new RCA system was implemented in 2000, the VA used another adverse event reporting system, focused review (FR). A comparison of the two processes indicates that the RCA process has shifted analyses of adverse events toward a human factors engineering approach-entailing a search for system vulnerabilities rather than human errors and other less actionable root causes. CASE EXAMPLES: Two case examples--on hazards in the magnetic resonance imaging (MRI) room and on a cardiac pacemaker malfunction--illustrate how the RCA system works in actual operation. The cases illustrate that broadly applicable, high-impact actions can result from a thorough RCA process. DISCUSSION: NCPS monitors the quality and completeness of RCAs through the immediate review and feedback process. Still to be investigated is the effectiveness of RCA actions addressing the hypothesized root causes and contributing factors of the close calls and adverse events.

Accidental Falls↗
PubMed1997

Validation of a new quantitative coronary angiography analysis system used to evaluate densitometric lumen remodelling.

Arterial lumen volume, determined by sequential coronary angiography, could have advantages over more commonly used variables (such as percent stenosis or minimal lumen diameter) as a primary endpoint in clinical trials evaluating post-angioplasty restenosis or atherosclerotic plaque progression. We validated a quantitative coronary angiography analysis (QCA) system aimed at measuring lumen volume from coronary angiography films by a densitometric method. Using images of polyacrylate models filled with different concentrations of contrast medium, accuracy (mean of the differences between known and measured values of a measurement) and precision (standard deviation of the difference) were lower than or equal to 0.09 and 0.21 mm, respectively, for diameters ranging from 1.5 to 16 mm. In terms of volume measurement, accuracy was 30.2 mm3 and precision 5.7 mm3 for a known volume of 620.2 mm3. To assess the short-term variations of lumen volume measurements under conditions resembling those encountered in clinical trials, a special image comparison program of the QCA system was used to measure the same coronary artery segment on two images taken 10 minutes apart in 21 patients. The mean difference between the two measurements was 1.7 +/- 12.4 mm3, with a coefficient of variation of 15%. An error of +/-2 frames in the selection of images to be analyzed had little influence on the results. We conclude that the QCA system provides easy-to-achieve standardization of the image acquisition process and sufficient reproducibility for repeated measurement of volume of a coronary artery segment, which can serve as the primary endpoint in clinical trials evaluating atherosclerotic plaque progression or restenosis after angioplasty.

Angioplasty↗