Effect of no prehydration vs sodium bicarbonate prehydration prior to contrast-enhanced computed tomography in the prevention of postcontrast acute kidney injury in adults with chronic kidney disease the Kompas randomized clinical trial

Importance Prevention of postcontrast acute kidney injury in patients with stage 3 chronic kidney disease (CKD) by means of prehydration has been standard care for years. However, evidence for the need for prehydration in this group is limited. Objective To assess the renal safety of omitting prophylactic prehydration prior to iodine-based contrast media administration in patients with stage 3 CKD. Design, Setting, and Participants The Kompas trial was a multicenter, noninferiority, randomized clinical trial conducted at 6 hospitals in the Netherlands in which 523 patients with stage 3 CKD were randomized in a 1:1 ratio to receive no prehydration or prehydration with 250 mL of 1.4% sodium bicarbonate administered in a 1-hour infusion before undergoing elective contrast-enhanced computed tomography from April 2013 through September 2016. Final follow-up was completed in September 2017. Data were analyzed from January 2018 to June 2019. Interventions In total, 262 patients were allocated to the no prehydration group and 261 were allocated to receive prehydration. Analysis on the primary end point was available in 505 patients (96.6%). Main Outcomes and Measures The primary end point was the mean relative increase in serum creatinine level 2 to 5 days after contrast administration compared with baseline (noninferiority margin of less than 10% increase in serum creatinine level). Secondary outcomes included the incidence of postcontrast acute kidney injury 2 to 5 days after contrast administration, mean relative increase in creatinine level 7 to 14 days after contrast administration, incidences of acute heart failure and renal failure requiring dialysis, and health care costs. Results Of 554 patients randomized, 523 were included in the intention-to-treat analysis. The median (interquartile range) age was 74 (67-79) years; 336 (64.2%) were men and 187 (35.8%) were women. The mean (SD) relative increase in creatinine level 2 to 5 days after contrast administration compared with baseline was 3.0% (10.5) in the no prehydration group vs 3.5% (10.3) in the prehydration group (mean difference, 0.5; 95% CI, -1.3 to 2.3; P < .001 for noninferiority). Postcontrast acute kidney injury occurred in 11 patients (2.1%), including 7 of 262 (2.7%) in the no prehydration group and 4 of 261 (1.5%) in the prehydration group, which resulted in a relative risk of 1.7 (95% CI, 0.5-5.9; P = .36). None of the patients required dialysis or developed acute heart failure. Subgroup analyses showed no evidence of statistical interactions between treatment arms and predefined subgroups. Mean hydration costs were euro119 (US $143.94) per patient in the prehydration group compared with euro0 (US$0) in the no prehydration group (P < .001). Other health care costs were similar. Conclusions and Relevance Among patients with stage 3 CKD undergoing contrast-enhanced computed tomography, withholding prehydration did not compromise patient safety. The findings of this study support the option of not giving prehydration as a safe and cost-efficient measure.Cardiolog

Education policy and its international dimension: theoretical approaches

The international dimension of education policies has been widely discussed in the last couple of years. This article argues that the activities of international agents involved in education policy formulation cannot be entirely and exclusively understood from a national perspective and, thus, should be studied as a discrete level of analysis. Questioning how we might best conceptualize this field of study, this paper presents three theoretical approaches - neoinstitutionalism/isomorphism, externalization, and the international regime theory. The focus here is laid on the analysis of international education policy based on international regime theory.A dimensão internacional das políticas públicas de educação tem sido bastante discutida nos últimos anos. Este artigo argumenta que as atividades dos agentes internacionais no domínio das políticas da educação não podem ser compreendidas inteira e exclusivamente a partir da perspectiva nacional e, por isso, devem ser estudadas em um nível distinto de análise. Questionando como melhor conceituar teoricamente esse campo de estudo, o artigo apresenta três abordagens teóricas: neoinstitucionalismo/ isomorfia, externalização e teoria do regime internacional. O foco dessa contribuição está centrado na análise da política internacional da educação a partir do último conceito indicado

Enabling successful aquifer storage and recovery using horizontal directional drilled wells (HDDWs) in coastal aquifers

Aquifer storage and recovery (ASR) of freshwater surpluses can reduce freshwater shortages in coastal areas during periods of prolonged droughts. However, ASR is troublesome in saline coastal aquifers as buoyancy effects generally cause a significant loss of injected freshwater. The use of a pair of parallel, superimposed horizontal wells is proposed to combine shallow ASR with deep interception of underlying saltwater. A shallow, fresh groundwater lens can thereby be enlarged and protected. This freshmaker setup was successfully placed in a coastal aquifer in The Netherlands using horizontal directional drilling to install 70-m-long horizontal directional drilled wells (HDDWs). The freshmaker prototype aims to inject a specific volume of freshwater and abstract the same volume of water (consisting of injected water and ambient native groundwater) within the targeted water quality. Groundwater transport modeling preceding ASR operation demonstrates that this set up is able to abstract a water volume of 4,200

Concentration and size distribution of particles in abstracted groundwater

Particle number concentrations have been counted and particle size distributions calculated in groundwater derived by abstraction wells. Both concentration and size distribution are governed by the discharge rate: the higher this rate the higher the concentration and the higher the proportion of larger particles. However, the particle concentration in groundwater derived from abstraction wells, with high groundwater flow velocities, is much lower than in groundwater from monitor wells, with minimal flow velocities. This inconsistency points to exhaustion of the particle supply in the aquifer around wells due to groundwater abstraction for many years. The particle size distribution can be described with the help of a power law or Pareto distribution. Comparing the measured particle size distribution with the Pareto distribution shows that particles with a diameter >7 μm are under-represented. As the particle size distribution is dependent on the flow velocity, so is the value of the "Pareto" slope β. © 2009 Elsevier Ltd. All rights reserved

Lipid Phase Distribution and Acoustic Response of DSPE-based Microbubbles

Microbubbles (MBs) are versatile ultrasound contrast agents that can be used for ultrasound molecular imaging and targeted drug delivery. However, a uniform and controlled response to ultrasound is essential for safe and effective use of targeted MBs in the clinic. It is suggested that the heterogeneous lipid distribution of currently available MB formulations causes variability in acoustic response. Hence, the objective of this study was to develop and characterize a new MB formulation with all coating components miscible and in the same lipid phase. MBs with 1, 2-distearoyl-sn-glycero-3-phosphoethanolamine (DSPE) as main lipid were produced by probe sonication (MBprobe) or by amalgamation, with 10% (MBshake-10) or 30% (MBshake-30) propylene glycol (PG). The lipid phase distribution, shelf-life, and acoustic attenuation were investigated. MBprobe and MBshake-30 had a homogeneous lipid distribution, while MBshake-10 had circular condensed phase domains. For all MBs the condensed phase increased over time. The PG concentration also affected the size and concentration: MBshake-30 had the largest mean diameter 20 min after production, while MBshake-10 had a tenfold higher concentration. All types of MBs had a short shelf-life stability, decreasing in size during the first hour post-production. The coating composition had a more significant effect on size and concentration than the production method. The MBs had a size-dependent resonance behavior and MBshake-10 and MBshake-30 had the highest peak attenuation, revealing a stabilizing role for PG in these MB formulations. Even though the in vivo applications for the DSPE-based MBs may be limited because of the short shelf-life stability, the newly developed MB formulations are interesting candidates for further studies on the effect of lipid phase distribution on acoustic behavior of MBs. </p