Search

The plant-availability of phosphorus (P) plays a central role in the ability of secondary P resources to replace mineral fertilizer. This is because secondary P plant-availability varies, often with large fractions of residual P that has no immediate fertilization effect. Therefore, if low quality secondary P fertilizers are applied, they will accumulate in soils that, in the long run, may increase the risk of P runoff and eutrophication. Substance flow analyses (SFA), used to identify potentials for improved P management, have not considered this well-known quality barrier. We, therefore, argue that traditional SFA over-estimates the fertilizer potential of secondary P resources. Using Norway as a case, we present a plant-availability extended SFA methodology that integrates SFA and the concept of relative agronomic efficiency. To account for the plant-available soil P stock and long-term soil interactions, we adjust the Norwegian P fertilization demand based on soil P values. We found that, while the method has uncertainties particularly for long-term estimations, it more realistically estimates secondary P fertilizer potentials and is adaptable to other countries. For Norway, we found the overall secondary P fertilizer potential reduced by 6–55% when considering plant-availability. The most important secondary resource was manure, which had the highest P plant-availability and quantities large enough (10.9 kt plant-available P/yr) to meet Norway's entire P fertilization demand (5.8 kt plant-available P/yr). However, barriers related to its transportability need to be overcome to efficiently use this resource. Fish sludge was also an important product, with 6.1 kt plant-available P/yr but with uncertain plant-availability data. We argue that high quality secondary P resources can theoretically meet Norway's P fertilization demand and, therefore, make Norway mineral P independent. However, it is important that their use is carefully regulated based on plant-availability to eliminate the soil accumulation of both available and residual P. [ABSTRACT FROM AUTHOR]

Summary: When planning parenteral nutrition (PN), the proper choice, insertion, and nursing of the venous access are of paramount importance. In hospitalized patients, PN can be delivered through short-term, non-tunneled central venous catheters, through peripherally inserted central catheters (PICC), or – for limited period of time and with limitation in the osmolarity and composition of the solution – through peripheral venous access devices (short cannulas and midline catheters). Home PN usually requires PICCs or – if planned for an extended or unlimited time – long-term venous access devices (tunneled catheters and totally implantable ports). The most appropriate site for central venous access will take into account many factors, including the patient''s conditions and the relative risk of infective and non-infective complications associated with each site. Ultrasound-guided venepuncture is strongly recommended for access to all central veins. For parenteral nutrition, the ideal position of the catheter tip is between the lower third of the superior cava vein and the upper third of the right atrium; this should preferably be checked during the procedure. Catheter-related bloodstream infection is an important and still too common complication of parenteral nutrition. The risk of infection can be reduced by adopting cost-effective, evidence-based interventions such as proper education and specific training of the staff, an adequate hand washing policy, proper choices of the type of device and the site of insertion, use of maximal barrier protection during insertion, use of chlorhexidine as antiseptic prior to insertion and for disinfecting the exit site thereafter, appropriate policies for the dressing of the exit site, routine changes of administration sets, and removal of central lines as soon as they are no longer necessary. Most non-infective complications of central venous access devices can also be prevented by appropriate, standardized protocols for line insertion and maintenance. These too depend on appropriate choice of device, skilled implantation and correct positioning of the catheter, adequate stabilization of the device (preferably avoiding stitches), and the use of infusion pumps, as well as adequate policies for flushing and locking lines which are not in use. [Copyright &y& Elsevier]