Background and Objectives: Small chest drains are used in many centers as the default drainage strategy for various pleural effusions. This can lead to drain overuse, which may be harmful. This study ...aimed to reduce chest drain overuse. Methods: We studied consecutive pleural procedures performed in the radiology department before (August 1, 2015, to July 31, 2016) and after intervention (September 1, 2019, to January 31, 2020). Chest drains were deemed indicated or not based on criteria established by a local interdisciplinary work group. The intervention consisted of a pleural drainage order set embedded in electronic medical records. It included indications for chest drain insertion, prespecified drain sizes for each indication, fluid analyses, and postprocedure radiography orders. Overall chest drain use and proportion of nonindicated drains were the outcomes of interest. Results: We reviewed a total of 288 procedures (pre-intervention) and 155 procedures (post-intervention) (thoracentesis and drains). Order-set implementation led to a reduction in drain use (86.5% vs 54.8% of all procedures, P < .001) and reduction in drain insertions in the absence of an indication (from 45.4% to 29.4% of drains, P = .01). The need for repeat procedures did not increase after order-set implementation (22.0% pre vs 17.7% post, P = .40). Complication rates and length of hospital stay did not differ significantly after the intervention. More pleural infections were treated with drain sizes of 12Fr and greater (31 vs 70%, P < .001) after order-set deployment, and direct procedural costs were reduced by 27 CAN$ per procedure. Conclusion: Implementation of a pleural drainage order-set reduced chest drain use, improved procedure selection according to clinical needs, and reduced direct procedural costs. In institutions where small chest drains are used as the default drainage strategy for pleural effusions, this order set can reduce chest drain overuse.
Los pale fanguers fueron los encargados de crear y mantener las redes de drenaje agrícola en Valencia y otros espacios mediterráneos ibéricos desde el siglo XIII. En su mayoría procedían del reino de ...Francia y otras regiones donde la pala era la herramienta agraria por excelencia y donde la transformaciín de areas pantanosas ofrecía una magnitud y una complejidad mayores que en el medio mediterráneo. El desarrollo de la cualificaciín entre estos profesionales durante el siglo XV generó una diferenciación interna de la que emergieron los reconocidos como maestros. En ese proceso parece quejugó un papel destacado la dinámica migratoria favorecida por la discontinuidad de la demanda local.
The hydrologic and water quality impacts of subsurface drainage design and management practices are being investigated through field and simulation studies throughout the northern Corn-belt. Six ...years of data from an ongoing field study in south central Minnesota (
Sands et al., 2008) were used to support a modeling effort with DRAINMOD-NII to investigate: (1) the performance of the model in a region where soils are subject to seasonal freeze–thaw and (2) the long-term hydrologic and water quality characteristics of conventional and alternative subsurface drainage practices. Post-calibration model prediction and efficiency were deemed satisfactory using standard model performance criteria. Prediction errors were primarily associated with early spring snowmelt hydrology and were attributed to the methods used for simulating snow accumulation and melting processes, in addition to potential sublimation effects on ET estimates. Long-term simulations with DRAINMOD-NII indicated that drainage design and/or management practices proposed as alternatives to conventional design may offer opportunities to reduce nitrate (NO
3)-nitrogen losses without significantly decreasing (and in some cases, increasing) crop yields for a Webster silty clay loam soil at Waseca, Minnesota. The simulation study indicated that both shallow drainage and controlled drainage may reduce annual drainage discharge and NO
3-nitrogen losses by 20–30%, while impacting crop yields from −3% (yield decrease) to 2%, depending on lateral drain spacing. The practice of increasing drainage intensity (decreasing drain spacing) beyond recommended values appears to not significantly affect crop yield but may substantially increase drainage discharge and nitrate-nitrogen losses to surface waters.
Seasonal variations of tile drainage discharge were simulated in the 6 km2 Fensholt catchment, Denmark, with the coupled surface and subsurface HydroGeoSphere model. The catchment subsurface is ...represented in the model by 3 m of topsoil and clay, underlain by a heterogeneous distribution of sand and clay units. Two subsurface drainage networks were represented as nodal sinks. The spatial distribution of the heterogeneous units was generated stochastically and their hydraulic properties were calibrated to reproduce drainage discharge for one network and verified with drainage discharge for the other network. Simulated discharge was compared to that of another model for which the heterogeneous sand and clay units were replaced by a homogeneous unit, whose hydraulic conductivity was the mean value of the heterogeneous model. With the homogeneous model, drainage dynamics were correctly simulated but drainage discharge was less accurate compared to the heterogeneous model. Simulated discharge was also compared to that of a larger‐scale model created with the MIKE SHE code, built with the same heterogeneous model. HydroGeoSphere and MIKE SHE generated drainage discharge that was significantly different, with better simulated groundwater dynamics data produced by HydroGeoSphere. Nodal sinks in HydroGeoSphere reproduced drain flow peaks more accurately. Calibration against drainage discharge data suggests that drain flow is controlled primarily by geological heterogeneities included in the model and, to a lesser extent, by the nature of the soil units located between the drains and ground surface.
Plain Language Summary
In temperate regions, climate conditions may cause groundwater levels to be at or very close to the land surface, resulting in reduced crop yields. Therefore, a substantial part of agricultural lands is drained by subsurface pipes. While measuring drainage discharge is easy, identifying the origin of drainage water is complicated. This is where computer models are useful. Models allow for representing the underground of a selected region in numerical replicas. By building such replicas, we can virtually observe water flowing in the underground and at the land surface. Understanding the effect of drainage on water flow is essential to choose appropriate management techniques regarding fertilizer application by farmers for example. Yet reproducing drainage water flow with models is a challenge. In our case, we chose to build a replica of the Fensholt agricultural area in Denmark. Drainage outflow from two agricultural fields showed that the structure of the shallow underground, which is not thoroughly known, controls drainage outflow. This suggests that improving the underground knowledge is crucial to set effective farming strategies.
Key Points
We develop a 3‐D coupled surface‐subsurface hydrological catchment scale model focusing on local scale tile drainage
Multiyear seasonal drainage variations were simulated and adequately reproduced
Calibrated results suggest that shallow porous media properties control drain flow
•An overview of drainage and salinization problems of irrigated lands is presented.•Various structural measures and their aptness for salinity control is presented.•Application and limitations of ...surface and subsurface drainage system are provided.•The aptness and restrictions of tile, mole, and vertical drainage are detailed.
Convenient and sufficient water supply to crops is a necessity for sustainable food production to the rising total populace. Albeit adequate water supply is important for crop production, the surplus water in the rootzone is hurtful to plant development and yield. Poor drainage and associated salinization represent severe threats to the long-term sustainability of irrigated agriculture in several dry areas. Reducing soil submergence, salinity control, and making new land accessible for agriculture are the three main goals of agricultural drainage. Thus, an effective drainage system not only improves the existing agricultural lands but also brings new areas under cultivation. This paper provides an investigation of different structural and engineering measures adopted for the management of drainage and salinization problems of irrigated lands. The overview of drainage and salinization problems and the requirement of a drainage system are presented. Application and limitations of surface drainage system in agricultural areas and the processes involved in the removal of surplus water through subsurface drainage system are provided. The adaptability and limitations of tile drainage, mole drainage, and vertical drainage in managing the drainage and salinization problems of agricultural lands are also detailed in the paper. Finally, policy issues are discussed and some conclusions are provided.
Measurements of delta2H and delta18O in isotope-based field studies have fundamentally improved our understanding of water flow and transport time scales in soils and headwater catchments. Until ...recently, however, technical constraints have limited the temporal resolution at which water samples could be collected and analyzed. We introduce a new sample acquisition system--consisting of a four-channel peristaltic pump, custom flow manifold, and CTC LCPAL auto-sampler--that is paired with a field-deployable laser spectrometer (LGR LWIA). Our system enables high-frequency (subhourly) measurement of delta2H and delta18O in as many as four water sources. We deployed the system at a field site in Corvallis, OR, USA, where we measured the delta2H and delta18O composition of precipitation and the drainage from two lysimeters. The system produced delta2H and delta18O time series for precipitation and drainage from each lysimeter at a temporal frequency of one sample every 34 min, which, on average, corresponded to 0.84, 0.63, and 0.48 mm of precipitation or lysimeter drainage per sample. The high-frequency data showed substantially greater short-term variability than observed when sampling at successively longer time intervals. The system and sampling configuration are versatile and can be adapted to sample multiple water flows at variable frequencies depending on the characteristic transit times of each source.
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▶ Controlled drainage and subirrigation reduced nitrate-nitrogen losses in N-E Italy. ▶ Controlled drainage and subirrigation reduced nitrate-nitrogen losses by 71%. ▶ Few drainage ...events in the fall and spring caused most nitrate-nitrogen losses. ▶ Reduction of drainage flow was a key mechanism to reduce nitrate-nitrogen losses.
In northeast Italy, a regimen of controlled drainage in winter and subirrigation in summer was tested as a strategy for continuous water table management with the benefits of optimizing water use and reducing unnecessary drainage and nitrogen losses from agricultural fields.
To study the feasibility and performance of water table management, an experimental facility was set up in 1996 to reproduce a hypothetical 6-ha agricultural basin with different land drainage systems existing in the region. Four treatments were compared: open ditches with free drainage and no irrigation (O), open ditches with controlled drainage and subirrigation (O-CI), subsurface corrugated drains with free drainage and no irrigation (S), subsurface corrugated drains with controlled drainage and subirrigation (S-CI). As typically in the region free drainage ditches were spaced 30
m apart, and subsurface corrugated drains were spaced 8
m apart.
Data were collected from 1997 to 2003 on water table depth, drained volume, nitrate-nitrogen concentration in the drainage water, and nitrate-nitrogen concentration in the groundwater at various depths up to 3
m.
Subsurface corrugated drains with free drainage (S) gave the highest measured drainage volume of the four regimes, discharging, on average, more than 50% of annual rainfall, the second-highest concentration of nitrate-nitrogen in the drainage water, and the highest nitrate-nitrogen losses at 236
k
ha
−1.
Open ditches with free drainage (O) showed 18% drainage return of rainfall, relatively low concentration of nitrate-nitrogen in the drainage water, the highest nitrate-nitrogen concentration in the shallow groundwater, and 51
kg
ha
−1 nitrate-nitrogen losses.
Both treatments with controlled drainage and subirrigation (O-CI and S-CI) showed annual rainfall drainage of approximately 10%. O-CI showed the lowest nitrate-nitrogen concentration in the drainage water, and the lowest nitrogen losses (15
kg
ha
−1). S-CI showed the highest nitrate-nitrogen concentration in the drainage water, and 70
kg
ha
−1 nitrate-nitrogen losses. Reduced drained volumes resulted from the combined effects of reduced peak flow and reduced number of days with drainage.
A linear relationship between daily cumulative nitrate-nitrogen losses and daily cumulative drainage volumes was found, with slopes of 0.16, 0.12, 0.07, and 0.04
kg
ha
−1 of nitrate-nitrogen lost per mm of drained water in S-CI, S, O, and O-CI respectively.
These data suggest that controlled drainage and subirrigation can be applied at farm scale in northeast Italy, with advantages for water conservation.
In agriculture‐dominated watersheds where natural drainage is poor, agricultural ditches (narrow engineered channels) and tile drains (perforated pipes) are widely employed to enhance surface and ...subsurface drainage, respectively. Despite their relatively small scale, these features exert substantial control over the hydro‐biogeochemical function of watersheds and their effects need to be represented in the models. We introduce a novel strategy to incorporate the effects of artificial agricultural drainage into a fully distributed basin‐scale integrated surface‐subsurface hydrology models. In our approach, narrow agriculture ditches for surface drainage are resolved efficiently using ditch‐aligned computational meshes that are hydrologically conditioned to ensure connectivity in the stream/ditch network. For tile drainage in the subsurface, we use the physically based Hooghoudt's drainage equation as a subgrid model and route the water drained through tiles to the nearest ditch. Without site‐specific calibration, this model reproduced observed streamflow in the Portage River Watershed (>1,000 km2) as recorded by a USGS gauge with good accuracy (normalized KGE = 0.81) and outperformed a calibrated SWAT model (normalized KGE = 0.68). Numerical experiments confirm that artificial drainage reduces surface inundations and effectively controls the water table. At the watershed scale, artificial drainage increases baseflow but has little effect on watershed discharges above the 90th percentile. The strong physical underpinnings and reduced need for calibration allow us to study the impacts of artificial drainage on distributed hydrological response in terms of fluxes and states and provide a platform for investigating watershed‐scale nutrient transport.
Key Points
Novel strategy is developed to incorporate effects of artificial drainage into fully distributed basin‐scale integrated hydrology model
Without site‐specific calibration, our model reproduced observed streamflow well and outperformed calibrated SWAT model
Numerical experiments reveal the effects of surface and surface drainage on various hydrological states and fluxes
We describe the epidemiology of a protracted nosocomial clonal outbreak due to multidrug-resistant IMP-8 producing Klebsiella oxytoca (MDRKO) that was finally eradicated by removing an environmental ...reservoir. The outbreak occurred in the ICU of a Spanish hospital from March 2009 to November 2011 and evolved over four waves. Forty-two patients were affected. First basic (active surveillance, contact precautions and reinforcement of surface cleaning) and later additional control measures (nurse cohorting and establishment of a minimum patient/nurse ratio) were implemented. Screening of ICU staff was repeatedly negative. Initial environmental cultures, including dry surfaces, were also negative. The above measures temporarily controlled cross-transmission but failed to eradicate the epidemic MDRKO strain that reappeared two weeks after the last colonized patients in waves 2 and 3 had been discharged. Therefore, an occult environmental reservoir was suspected. Samples from the drainpipes and traps of a sink were positive; removal of the sink reduced the rate number but did not stop new cases that clustered in a cubicle whose horizontal drainage system was connected with the eliminated sink. The elimination of the horizontal drainage system finally eradicated the outbreak. In conclusion, damp environmental reservoirs (mainly sink drains, traps and the horizontal drainage system) could explain why standard cross-transmission control measures failed to control the outbreak; such reservoirs should be considered even when environmental cultures of surfaces are negative. PUBLICATION ABSTRACT
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