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PN (parenteral nutrition) should be standardised to ensure quality and to reduce complications, and it should be carried out in consultation with a specialised nutrition support team whenever possible. Interdisciplinary nutrition support teams should be established in all hospitals because effectiveness and efficiency in the implementation of PN are increased. The tasks of the team include improvements of quality of care as well as enhancing the benefit to cost ratio. Therapeutic decisions must be taken by attending physicians, who should collaborate with the nutrition support team. “All-in-One” bags are generally preferred for PN in hospitals and may be industrially manufactured, industrially manufactured with the necessity to add micronutrients, or be prepared “on-demand” within or outside the hospital according to a standardised or individual composition and under consideration of sterile and aseptic conditions. A standardised procedure should be established for introduction and advancement of enteral or oral nutrition. Home PN may be indicated if the expected duration of when PN exceeds 4 weeks. Home PN is a well established method for providing long-term PN, which should be indicated by the attending physician and be reviewed by the nutrition support team. The care of home PN patients should be standardised whenever possible. The indication for home PN should be regularly reviewed during the course of PN.
The practical implementation of artificial nutrition often does not correspond with current scientific evidence, mainly due to a lack of specialist knowledge and insufficient organisation. This particularly applies to the intensive care sector where nutrition support is often required . Less than 5% of hospitals in Germany have established nutrition support teams, which is a far lower rate than in some other European countries such as the UK , . The impact of nutrition support teams has been evaluated in various studies. With nutrition support teams, patients’ energy requirements are more likely to be met and mechanical as well as metabolic complications of nutritional therapy are reduced , , , , , . The authors of a meta-analysis of all studies published between 1970 and 1993  concluded that nutrition support teams reduce the rate of catheter sepsis and metabolic complications, improve documentation, and probably also lower costs, although the personnel costs of the team were not taken into consideration in all studies. The economic benefits of setting up a nutrition support team, and even of only a dedicated nutrition nurse, have been extensively documented , , , . Standardisation of product selection and of prescribing can result in significant savings .
If it is not possible to establish a nutrition support team, then at least a physician dedicated to nutrition support should be available, with support by other staff such as nursing staff and dieticians, wherever possible.
The nutrition support team should advise the ward on the choice of standard or individual PN solutions, how they should be prepared in individual cases, which hygiene and compatibility aspects must be observed, how PN should be administered (e.g. selection of access, tubes, pumps) and how possible complications may be prevented (cf. chapter “Access technique and its problems in parenteral nutrition” http://www.egms.de/en/journals/gms/2009-7/000078.shtml). The monitoring of PN comprises laboratory, clinical and anthropometrical parameters (cf. chapter “Complications and monitoring” http://www.egms.de/en/journals/gms/2009-7/000074.shtml). The team's task is to improve the medical quality and at the same time optimise the benefit to cost ratio of this expensive form of nutrition. This can be achieved by monitoring indication and composition of PN, by providing suitable quantities and selection of substrates, as well as suggesting alternatives as appropriate.
Legal regulations indicate the physician’s responsibility for decisions on PN, whereas the role of the nutrition support team is based on expert opinion because there is no published data. Involving a nutrition support team’s expertise can provide benefits, e.g. if it results in an increase in efficacy of PN , , , , , , , , , , , , , , .
Providing PN from multiple bottles should be avoided because it is often more expensive than the multi-chamber bag and it carries a higher risk for error , . The choice between commercial multi-chamber bags and individually prepared PN bags depends on the type and structural conditions of the hospital as well as patient needs. Individual PN compositions are usually preferred for long-term and home PN, as well as for a number of paediatric patients .
Prerequisites for preparing individually composed PN solution include the need for a sterile workplace, regular microbiological checks, and monitoring of compatibility and stability , . Further details are laid down in guidelines of the Federal Chamber of Pharmacists . In Germany PN solutions used in hospitals must be prepared under the responsibility of a pharmacist . Manufacture is defined in the German Drug Law: manufacture is the extraction, production, preparation, processing, working, filling, packing and labelling of drugs which includes PN . Manufacturing permits, know-how and authorisation with exceptions particularly regarding the pharmacy are regulated in the German Drug Law. PN can only be manufactured in pharmacies and without a special license. The preparation of nutrition bags for immediate use (within no more than 24 h) may be carried out by a physician or assistant staff.
Sterility of PN bags aseptically prepared in the hospital pharmacy may be guaranteed for up to 7 days at room temperature . However, this expert group recommends that such solutions should be used within 24 h after preparation if stored at room temperature, or within 7 days if stored at 4°C. This recommendation is based on the known risk of microbiological contamination and physicochemical changes, which are expected to increase with storage time. Industrially-manufactured multi-chamber bags can be stored for periods of months to years as specified by the manufacturer. Attention should be paid to the preparation of the multi-chamber bag for use, since the stability of added components such as vitamins is limited and often does not exceed 24 h at room temperature .
In hospitals pumps should always be used for PN administration to ensure a controlled flow rate and to help prevent metabolic and osmotic complications.
Some studies have associated PN with altered morphology and intestinal function, for example with reduced mucosa thickness, a reduced number of villi in the small intestine and increased intestinal permeability , , , , while other trials do not show such alterations , . If such effects occur, they depend on the duration of PN and are usually reversible.
In general a standardised advancement of enteral and oral nutrition is recommended after PN, because clinical practice has shown that incompatibilities may occur, particularly in the adaptation phase, regardless of whether enteral or oral nutrition. A standardised schedule should be established for the advancement of enteral and oral nutrition in the hospital. The speed of PN reduction depends on the tolerance of enteral or oral nutrition. Based on expert opinion, nutrition consultation during the phase of advancing enteral and oral nutrition is useful, particularly in patients who received PN for more than 14 days and in patients with gastroenterological disease.
Advancement of enteral and oral nutrition must be adapted to the patient’s tolerance, particularly in pancreatitis, where nutrition-related pain is well documented. Consideration should also be dedicated to the type and amount of protein given to patients with liver cirrhotic patients and imminent encephalopathy. Small meals and the use of medium chain triglycerides may be useful after gastrointestinal operations and in patients with dumping syndrome.
Standardisation includes a clear process for defining PN indications, which is provided by the attending physician and preferably checked by a nutrition support team (or a physician dedicated to nutrition support). PN is only indicated when sufficient oral or enteral nutrition is not achievable. Criteria for the choice of central venous catheters (individual or tunnelled catheters or PORT systems) should be laid down. The choice of macro- and micronutrient intakes depends on energy requirements, the patient’s metabolic situation, illness and other aspects of therapeutic strategies. Energy requirements can be estimated with the help of established formulas (i.e. Harris-Benedict formula). A limited number of products should be selected for PN, which can be decided on by the nutrition support team jointly with the drugs committee and the hospital pharmacy. If individually prescribed PN solutions are considered necessary the attending physician and the nutrition support team, these should be prepared by trained personnel under the guidance of a pharmacist following standardised procedures under sterile conditions. The application of PN must be monitored and documented, for example by the nutrition support team. The roles of the nutrition support team contribute greatly to establishing standardised implementation of PN, because the team is involved in most steps and hence can take over main coordination tasks. Documented reductions of medical complications and of unnecessary costs by inadequate PN are arguably the result of the work of nutrition support teams , , , , , .
Hospital accounting is needed to secure funding for central hospital services such as PN services , , , and the multidisciplinary nutrition support team jointly with the hospital pharmacy should aim at being involved in the evaluation of cost aspects of PN. The nutrition support team should be funded by the health care funds and not by industrial sponsorship to avoid potential conflicts of interests.
Complication rates during home PN are generally low. The most frequently occurring complications are catheter sepsis (0.34 occurrences per year), catheter occlusions (0.071/year), catheter-associated central venous thromboses (0.027/year), fluid and electrolyte disturbances (0.12–0.61/year), liver and bile duct problems (0.42/year) and other metabolic complications (osteopeny, hyperglycaemia, hypertriglyceridemia etc.) , , . According to a European study, catheter complications occur in approx. 0.25% of patients over the course of home PN, 50% of these complications being infections (equals 0.37/year) . Comparable results have been reported for children . Validated methods for reducing complications such as catheter infections or thrombosis have not been reported . For patients with short bowel syndrome or other forms of intestinal failure, the only alternative to long term PN is intestinal transplantation, which is still associated with high rates of complication despite impressive progress in this area .
Home PN is carried out in tumour patients with peritoneal carcinosis or (sub)ileus, in patients with intestinal failure, such as short bowel due to Crohn’s disease, after intestinal ischaemia with short gut infarction (e.g. superior mesenteric artery or venous thromboses), radioenteritis and in severe colonic motility disorders . Tumour patients receiving home PN contribute a smaller number to the home PN population in some other countries (e.g. Denmark, UK) .
Many of the underlying principles for supplying PN also apply to home PN and depend on general or organ-related considerations (see appropriate chapters). Some additional aspects must be considered with home PN. For example, it is important to estimation the patient’s prognosis and possible duration of home PN. Although there is no scientifically agreed lower limit of duration, a minimal duration of home PN of at least one month is consistently recommended. In adult patients the duration of home PN is usually shorter than one year, because patients either die (99% of tumour patients) or oral or enteral nutrition can be established , . There is expert consensus that patients bound to die usually benefit do not from (home) PN, which should be checked even more critically in the case of home PN than in hospital where there is usually a defined therapy objective. This question is difficult since definitions are imprecise and decisions often need to be taken on an individual basis, taking into account the (presumed) wishes of the patient and effects on quality of life, which should be given high priority. Home PN can positively influence in tumour patients if patients survive at least three months after commencing home PN . However, quality of life of patients on home PN was lower than in patients without home PN, which may in part be due to a more severe underlying illness in patients who require home PN , . The quality of life after small intestinal transplants is comparably higher in patients without rejection , .
Which catheter system is optimal for home PN remains controversial. Based on comparative studies we assume that tunnelled central venous catheter (i.e. Broviac® catheter) may present slight advantages over port systems with respect to infections and catheter sepsis , . Conventional non-tunnelled central venous catheters should not be used outside the hospital . The costs and particularly the long-term costs of consumables are significantly lower with the use of Broviac®-catheters than with implanted port systems, which require special needles for injection. Individual factors such as daily infusions or infusions with larger time intervals and cosmetic aspects should also to be considered selecting access catheters. Hence, the choice of catheter is influenced by many factors which have not been fully explored in comparative studies.
Preparation and organisation of Home PN is usually carried out prior to patient discharge from hospital and requires approx. 2–3 working days by the nutrition support team and other hospital departments. Tasks include:
(I) review of indication,
(II) detailed information, clarification and consent of patient and their relatives,
(III) preparation of individual composition,
(IV) authorisation of a qualified pharmacy, or a specialised home care company, for preparation of PN solutions, home delivery of the materials, and implementation of home PN, potentially in collaboration with a home care nursing service,
(V) individual instruction of the patient and its relatives – depending on the wishes and degree of independence of the patient – by the nutrition support team or the home care service organisation.(VI) setting up a plan for monitoring, which may by implemented by a general practitioner and/or a specialised clinic.
These standards have generally been developed empirically, but have also been tried-and-tested in various practical settings , , . There is no standard strategy to document complications and monitor home PN. We recommend controls of clinical and laboratory parameters every one to two weeks in the first three months, followed by monthly checks over the next three months, as recommended also in the Mayo Clinic schedule (cf. chapter “Complications and monitoring” http://www.egms.de/en/journals/gms/2009-7/000076.shtml).
Assuring stability and compatibility of the PN solutions is extremely important in Home PN, because the bags are often delivered only once a week or so to the patient and then are stored in the refrigerator at 4°C until utilised after hours of being warmed up to room temperature. The micronutrients (vitamins, trace elements) show a particularly limited storage time and should be added just prior to using the PN bag . The electrolyte and mineral concentrations should be taken into consideration in bags containing lipids, because they may result in the emulsion breaking (i.e. a separation of lipid and water components) (cf. chapter “Practical handling of AIO admixtures” http://www.egms.de/en/journals/gms/2009-7/000077.shtml) . The stability should be checked with the manufacturer whenever the composition is modified.
The administration of home PN should be employed by specially trained carers, or in individual cases by the patient, if the patient requests this and has been appropriately trained . It is important that measures associated with home PN are standardised by means of a suitable standard of care. The contents of these standards of care are usually established by empirical measures rather than hard scientific data, but they have been tried and tested and should form the basis of standard operating procedures until scientifically accountable guidance is available.
In conclusion, home PN is an area for which many standards have been established, but which have rarely been backed up by controlled, randomised trials. Thus, there is a great need for studies in this area which might contribute to improved quality of care and reducing the burdening of in-patient departments.
This article is part of the publication of the Guidelines on Parenteral Nutrition from the German Society for Nutritional Medicine (overview and corresponding address under http://www.egms.de/en/journals/gms/2009-7/000086.shtml).
English version edited by Sabine Verwied-Jorky, Rashmi Mittal and Berthold Koletzko, Univ. of Munich Medical Centre, Munich, Germany.