Th. 3e cycle--Instrumentation phys.--Grenoble 1, 1982. N°: 93.

No description available.

No description available.

A research report submitted to the Faculty of Health Sciences, University of the Witwatersrand, Johannesburg in partial fulfilment of the requirements for the degree of Master of Science in Nursing Johannesburg, 2016 / The purpose of the study was to determine knowledge of nephrology nurses’ on evidence based guidelines for the prevention of haemodialysis catheter related infections. The study was done in 5 haemodialysis units from two university-affiliated, public sector and tertiary level hospitals in Gauteng which are: “Baragwanath Hospital and Charlotte Maxeke Academic Hospital”. Face and content validation of the research instrument “Evaluation questionnaire concerning nurses’ knowledge of interventions for prevention of haemodialysis catheterrelated bloodstream infections” was done by a panel of experts to ensure applicability of the instrument to the South African context. Prior to commencement of the study, ethical clearance and permission to conduct the study was obtained from the relevant authorities and the university committee. A non-experimental, descriptive, prospective study design was utilised in order to meet the objectives of the study. Descriptive and comparative statistics were used to analyse the data which was done in consultation with a statistician. Knowledge was reorganised as poor (0-50%), average (50-70%) and good (71% and above). Overall, participants performed well in the second part of the questionnaire where their knowledge was tested regarding evidence based guidelines in prevention of vascular access infection; the majority 72.50% (n=58) scored more than 71%, indicating they have knowledge of evidence based guidelines on prevention of vascular access infection, 20% of participants scored between 51 and 70%, whilst only 2% scored below 50%. A positive correlation (with moderate strength) between age and experience (r=0.563) was established indicating that as age increases the experience will also increase moderately. A slight negative correlation, which was very weak (null correlation) was also established between years of experience and performance as most respondents were above and below the regression line. Therefore years of experience has no influence over performance. / MT2016

The most important risk factor for developing a catheter-associated urinary tract infection (CAUTI) is the prolonged use of the urinary catheter. To address the CAUTI rate at the project site, which was higher than the national benchmark, a team of healthcare practice leaders developed an evidence-based algorithm addressing the appropriate indications for inserting or discontinuing a patient's Foley catheter. Using the plan-do-study-act model, the purpose of this quality improvement evaluation project was to evaluate the effectiveness of the evidence-based Foley algorithm for decreasing the use of Foley catheters and reducing the CAUTI rate and to explore whether using the Foley algorithm shift assessment tool would reduce the incidence of Foley catheter utilization. Data were compared on the rate of CAUTI and Foley catheter use over 4 months before and 4 months after implementation of the algorithm. There was a statistically significant decrease in the Foley utilization rate after implementing the Foley algorithm; the overall CAUTI rate did not decrease. The outcome of this quality improvement evaluation project could produce social change by highlighting the need for consistent application of the algorithm. In addition, reducing the rate of Foley catheter usage could decrease the incidence of CAUTIs, reduce hospital costs, and improve overall patient health during hospitalization.

Two-dimensionally (2D) braided tubular composites have been utilized in a wide range of applications including medical equipment such as braided stents and catheters. Catheters are long flexible tubes used in catheterization procedures, such as angiography and ablations. In this thesis, angiographic catheters were specifically targeted; which are referred as catheters for the remaining of the document. Catheters are typically used with guidewires which provide structural support to the often low rigidity catheters. In some catheterization procedures, it may be beneficial to use a 2D braided catheter for increased control and maneuverability in the body. The 2D braided catheter, if designed properly, may provide all the required rigidities for a successful procedure and decrease the dependency to the guidewire compared to conventional catheters. Hence, use of 2D braided catheters may decrease the procedure time, may provide superior control of the device due to its design, and may also decrease the inherent patient discomfort. A thorough understanding of 2D braided composites is of absolute necessity considering the delicate use of medical equipment, such as catheters, in the human body. The aim of this PhD thesis is to address the shortcomings of the available models in the literature by developing an analytical model geometrically consistent with small braided tubular structures and provide all the necessary tools possible to design a target specific braided catheter. An analytical model that accounts for the effect of diameter of a braided tubular product on the elastic properties, needed for catheter design, was developed. Parametric studies were conducted to highlight the effects of the change in radius on elastic properties of braided composites. Case studies that underline the important geometrical parameters that affect predictions were conducted and findings discussed. Effect of increased undulation length on elastic properties of braided composites was also investigated. The findings were compared to experimental work using three different fiber/matrix system composites. As predicted by the model, a decrease in the properties was observed experimentally; however, this decrease was found to be more important than predicted. Possible reasons for this behavior are discussed in the view of composite materials and geometrical factors. The experimental findings of the open-mesh composites were also used to further validate a regression based model available in the literature. Lower linearity limit values for the regression based model were calculated for longitudinal elastic and shear moduli predictions.

Two studies were performed to assess the function and longevity of a novel intraosseous (IO) catheter device. For the initial study, nine animals were assigned to three study groups. The first group received a 25 mm intraosseous device within the proximal humerus, the second group within the proximal tibia, and standard jugular catheters were placed in the final control group. Serial aerobic and anaerobic blood cultures were collected from jugular veins at day zero, then every third day while devices remained in use. Radiographs were obtained immediately after placement and again after removal of all IO devices. Goats were observed for overall clinical condition and lameness associated with catheter sites, and catheters were evaluated for patency and proper positioning. IO devices in the tibia remained in for less time than those in the humerus. Blood cultures in this study showed growth of Bacillus, Staphylococcus, and one colony within the genera Brachyacterium or novel Dermabacteraceae. Catheters also showed growth of Bacillus, as well as a single colony of Micromonospora chalcea. No animals in either IO group exhibited radiographic evidence of resulting damage or structural change within surrounding bone. In study two, eighteen goats were assigned to two study groups (25 mm intraosseous device within the wing of the ilium, or 45 mm catheter in the proximal humerus). Blood for serial aerobic and anaerobic blood cultures and CBC were collected from jugular veins at day zero, then every second day thereafter while devices remained in use. All clinical monitoring and removal criteria were identical to study one. Catheters in the ilium remained in significantly less time than those in the humerus. Several animals in the proximal humerus group demonstrated moderate lameness following removal. One goat developed an abscess near the insertion site and showed radiographic evidence of periosteal bone growth. Serial cultures showed growth of Bacillus, Streptococcus, Staphylococcus, and Enterococcus. Bloodwork indicated mild elevations of white blood cells from baseline in some cases. Our study indicated that catheters may remain safely in place for greater than 24 hours, but that animals should be closely monitored for negative side-effects for several days during the post-removal period.

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Hemodialysis catheter occlusion compromises hemodialysis adequacy and increases the cost of care. Repeated administration of alteplase in hemodialysis catheters typically produces only short-term benefits. The purpose of this study was to design, implement and evaluate the efficacy of a step-by-step algorithm to optimize the management of hemodialysis catheter occlusion. The study had a prospective quasi-experimental design in two parts. Baseline data on the use of alteplase and catheter exchange were collected during Part I; while, Part II consisted of algorithm implementation. Rates of alteplase use and catheter exchange per 1000 catheter days were main outcomes of the study. One-hundred and seventy-two catheters in 131 patients were followed up during the course of the study. The vast majority of the study population were on clopidogrel or aspirin (75%); whereas, approximately 11% were on warfarin. The adjusted rate of alteplase use was not significantly different after algorithm implementation (Part I vs. Part II relative risk: 1.10; 95% CI: 0.73 – 1.65, p > 0.05). Similarly, catheter exchange rates were not significantly different in both parts of the study (1.12 vs. 1.03 per 1000 catheter-days, p > 0.05). Regression analysis showed that the rate of alteplase use was inversely related to the catheter age (p < 0.05). In a secondary analysis on a subgroup of patients with occlusion-related catheter exchanges (n = 28), the number of alteplase administrations significantly increased with longer waiting time for catheter exchange (p < 0.05). In conclusion the hemodialysis catheter management algorithm was not effective in decreasing the rate of alteplase use.

Hemodialysis catheter occlusion compromises hemodialysis adequacy and increases the cost of care. Repeated administration of alteplase in hemodialysis catheters typically produces only short-term benefits. The purpose of this study was to design, implement and evaluate the efficacy of a step-by-step algorithm to optimize the management of hemodialysis catheter occlusion. The study had a prospective quasi-experimental design in two parts. Baseline data on the use of alteplase and catheter exchange were collected during Part I; while, Part II consisted of algorithm implementation. Rates of alteplase use and catheter exchange per 1000 catheter days were main outcomes of the study. One-hundred and seventy-two catheters in 131 patients were followed up during the course of the study. The vast majority of the study population were on clopidogrel or aspirin (75%); whereas, approximately 11% were on warfarin. The adjusted rate of alteplase use was not significantly different after algorithm implementation (Part I vs. Part II relative risk: 1.10; 95% CI: 0.73 – 1.65, p > 0.05). Similarly, catheter exchange rates were not significantly different in both parts of the study (1.12 vs. 1.03 per 1000 catheter-days, p > 0.05). Regression analysis showed that the rate of alteplase use was inversely related to the catheter age (p < 0.05). In a secondary analysis on a subgroup of patients with occlusion-related catheter exchanges (n = 28), the number of alteplase administrations significantly increased with longer waiting time for catheter exchange (p < 0.05). In conclusion the hemodialysis catheter management algorithm was not effective in decreasing the rate of alteplase use.