A cluster randomized trial to improve adherence to evidence-based guidelines on diabetes and reduce clinical inertia in primary care physicians in Belgium: study protocol [NTR 1369]

Contains fulltext : 70617.pdf (publisher's version ) (Open Access)ABSTRACT: BACKGROUND: Most quality improvement programs in diabetes care incorporate aspects of clinician education, performance feedback, patient education, care management, and diabetes care teams to support primary care physicians. Few studies have applied all of these dimensions to address clinical inertia. AIM: To evaluate interventions to improve adherence to evidence-based guidelines for diabetes and reduce clinical inertia in primary care physicians. DESIGN: Two-arm cluster randomized controlled trial. PARTICIPANTS: Primary care physicians in Belgium. INTERVENTIONS: Primary care physicians will be randomly allocated to 'Usual' (UQIP) or 'Advanced' (AQIP) Quality Improvement Programs. Physicians in the UQIP will receive interventions addressing the main physician, patient, and office system factors that contribute to clinical inertia. Physicians in the AQIP will receive additional interventions that focus on sustainable behavior changes in patients and providers. OUTCOMES: Primary endpoints are the proportions of patients within targets for three clinical outcomes: 1) glycosylated hemoglobin < 7%; 2) systolic blood pressure differences </=130 mmHg; and 3) low density lipoprotein/cholesterol < 100 mg/dl. Secondary endpoints are individual improvements in 12 validated parameters: glycosylated hemoglobin, low and high density lipoprotein/cholesterol, total cholesterol, systolic blood pressure, diastolic blood pressure, weight, physical exercise, healthy diet, smoking status, and statin and anti-platelet therapy. PRIMARY AND SECONDARY ANALYSIS: Statistical analyses will be performed using an intent-to-treat approach with a multilevel model. Linear and generalized linear mixed models will be used to account for the clustered nature of the data, i.e., patients clustered withinimary care physicians, and repeated assessments clustered within patients. To compare patient characteristics at baseline and between the intervention arms, the generalized estimating equations (GEE) approach will be used, taking the clustered nature of the data within physicians into account. We will also use the GEE approach to test for differences in evolution of the primary and secondary endpoints for all patients, and for patients in the two interventions arms, accounting for within-patient clustering. TRIAL REGISTRATION: number: NTR 1369

The Effect of Local Boiling on Pressure Drop and Flow Distribution in the Yankee Reactor Core

Where local boiling can occur in a semi-open heterogeneous reactor core consisting of parallel flow channels, differences in the terms comprising the total pressure drop in the local boiling regions and in parallel adjacent regions canse flow redistribution in the reactor. This report covers the study of the effect of local boiling on the friction factor and momentum components of the total pressure drop. The local-boiling to single-phase friction factor ratio has a maximum value of 1.42 when a linear relationship is assumed between the enthalpy of the coolant and the friction factor ratio. Analytical and gaphical methods for determining the region of the core in local boiling are developed. For a cylindrical reactor core similar to the Yanke reactor core the maximum possible region of the core in which local boiling should occur would be an ellipsoid whose surface is the locus of points of local boiling. In the Yankee core the maximum possible volume in local boiling is 10.4 cubic feet and 14.4 cubic feet in the first and second parameter studies, respectively. These volumes are 4.5% and 5.5% of the total volume of the core. The nature and mechanism of local boiling is discussed and its relation to the single phase and true two-phase pressure drop is reviewed. Flow redistribution out of the hot channel due to local boiling is 17.6% and 23.8% for the first and second parameter studies, respectively. The first parameter study is for a 392 megawatt reactor and the second parameter study is for a 482 megawatt reactor. (auth

Pressure Drop, Flow Distribution and Mixing Studies for a Model Heterogeneous Reactor Vessel

A series of hydrodynamic tests was conducted on a 1: 12 scale mcdel of the Yankee reactor vessel and core with four, three, and two loop operation. There was no depression of flow in the center of the core due tc the control rod shrouds or shroud support plate. With four loops operating, flow distribution tests at the core inlet indicated that for all operating conditions the highest velocities occurred in the center region of the core and were a maximum of 18% higher than the average velocities. The lowest velocities were in the region near the core baffle and were a maximum of 18% lower than the average velocities. The effective flow starvation at the points of high flux were less than the 7% design value. Mixing studies indicated that no inlet position of the core received more than 55% of its total now from one loop. The flow distribution did not change appreciably for four, three, or two loop operation. The measured pressure drop across the vessel correlated within 6% of the predicted value. (auth

Model Study of the Pressure Drop Relationships in a Typical Fuel Rod Assembly

A study was made of hydraulic characteristics of Yankee-type fuel rod assemblies using experimental and analytical methods. Two scale model fuel assemblies utilizing both ferrule and strap type arrangements were constructed and tested at atmospheric pressure and room temperature. Analytical methods using semiempirical relationships are substantiated by experimental results for both the fuel assembly having strap-type spacers and the fuel assembly having cylindrical ferruletype spacers. The experimental pressure drop across the assembly model using either straps or ferrules correlated within 5% of the value calculated by means of equations based on the equivalent diameter concept for flow inside pipes. The individual frictional drops along the rods and across the end plates and straps correlated within 15% of the predicted pressure drops. The indlvidual pressure drops across both the staggered ferrule sections and the full ferrule section correlated to within 17% of the predicted pressure drops. Comparison of the ferrule and the strap pressure drops indicates that the pressure drop across a level of straps was more than four times the pressure drop across a full ferruled section. It is concluded that the analytical methods based on the equivalent diametcr concept can be satisfactorlly used to calculate pressure drops for flow parallel to fuel rod bundles. Experimental tests on this fuel rod configuration with either straps or ferrules indicated no excessive energy losses due to vortex formations. (auth