# Artificial nutrition

Under artificial feeding a nutrient supply with partial or complete circumvention of the natural food transport path is understood by the body. It replaces the diet of a person who cannot, may or will not eat or not enough, with the use of medical aids. Reasons for this can be physical or mental illness, operations or signs of aging, but also the conscious refusal of food. Tube feeding of premature babies is also artificial feeding, as is the administration of industrially manufactured milk food as a breast milk substitute in the first months of life of mature infants.

Artificial nutrition is - with the exception of the choice of infant formula - a medical therapy.

## Types of artificial nutrition

With artificial nutrition, part of the natural path of food through the organism is mostly replaced from ingestion with the mouth to the absorption of the nutrients into the blood. Depending on which route is replaced, a distinction is made between enteral and parenteral nutrition. With enteral feeding (tube feeding) the upper part of the digestive tract (mouth and esophagus) is bypassed or - with drinking food - only used for swallowing. With parenteral nutrition, all necessary nutrients are fed into the blood vessel system by means of infusions, so that the entire digestive tract is bypassed.

## Differentiation from natural nutrition

If a person can eat the necessary food naturally periorally - that is, through the mouth - this is called oral nutrition . This includes, for example, preparing or serving food to patients who are not able to do it themselves, but also enriching food with fats, protein powder and the like. In contrast, oral food supplementation (ONS) with oral balanced diets (“drinking food”, infant formula) is also referred to as “enteral feeding without a tube”. They serve as industrially manufactured drink supplements (in a specific composition and preparation form) for defined therapeutic goals and thus represent a form of artificial nutrition.

## Enteral or tube feeding

Enteral nutrition means the supply of food and fluids via the stomach and intestines (Greek enteron = intestine ). The term is mainly used for tube feeding by gastric tube , PEG or PEJ tube , jejunal tube or JET-PEG .

• A gastric tube (= nasogastric tube) or nasal jejunal tube is a tube that leads through the nose or mouth, throat and esophagus into the stomach or further into part of the small intestine . These nasal probes are mostly designed for short-term use only; If a long-term nutritional therapy intervention is planned (longer than four weeks), the insertion of a percutaneous tube is indicated.
• In a percutaneous endoscopic gastrostomy (PEG), the probe - usually guided endoscopically - is placed directly through the abdominal wall into the stomach.

Drinking foods and nutrient solutions suitable for enteral nutrition contain the necessary proteins , carbohydrates , fats , vitamins , minerals and trace elements in an optimal composition. They must be sterile and ready to use. For gravity infusion, the food container can either be connected directly to the probe via a supply line system, or the contents are transferred into a suitable bag system. If the probe is in the gastric position, manual bolus administration is also possible, in which the probe feed is administered directly into the probe access using a so-called bladder syringe in small portions of around 20-50 ml. A feeding pump only makes sense if slow, continuous administration has to be guaranteed, for example with jejunal tubes.

To avoid complications such as aspiration , diarrhea and constipation , certain storage, preparation and hygiene rules must be observed; For example, protein-containing food must not be heated above 30 ° C, and opened containers must be stored in a cool place and consumed within a short time. In addition, the patient should maintain an upright posture during administration and for at least half an hour afterwards; when lying down, the upper body should be raised at least 30 °. This reduces the risk of reflux and aspiration. Walking is possible when using a gravity system or pump-controlled administration with a rollable IV pole.

### Drug application

A drug that is suitable for administration via a probe must be administered in dissolved form separately from the nutrient solution as a manual bolus administration after the probe system has been flushed with water. If there are several different preparations, they must not be mixed, but must be administered individually. The probe must be rinsed between the individual doses and at the end so that it does not become blocked. The administration of solid dosage forms is usually an off- license application , as it is changed by pestling and dissolving it before administration. Retarded tablets must not be ground in a mortar, otherwise an overdose will occur and the desired duration of action will not be achieved. In this case, you have to switch to a non-retarded or a probe-compatible dosage form (for example granules).

### Decision criteria

Drinking and tube feeding largely maintain the biological processes of fluid and food intake in the gastrointestinal tract and are therefore preferable to parenteral nutrition. Tube feeding is also possible at home after the patient or relatives have been trained.

The patient's quality of life should be the decisive criterion for whether enteral nutrition is started. In the meantime it has been proven several times that tube feeding does not extend the survival time of people with dementia and only rarely increases the quality of life. There are also certain risks associated with this type of artificial feeding, such as developing pneumonia from aspiration. In the most severe disease, it may be necessary to adjust the composition of the food or reduce the amount of fluids in order to alleviate unpleasant symptoms. Tube feeding can also be stopped; For example, it is more of a burden for a patient in the dying phase .

## Parenteral nutrition

If nutrients are not administered via the gastrointestinal tract , but rather by infusion directly into the bloodstream (for example in the case of intestinal diseases), we speak of parenteral nutrition, in which the digestive tract is bypassed. This type of diet requires intravenous infusion access. If a central venous catheter is used, it is reserved for inpatient treatment, as complications can occur, such as inflammation of the entry point of the access or a dislocation . With a port catheter , parenteral nutrition is also possible in the home environment, with the involvement of home nurses and a homecare company . In general - if oral nutrition is not possible - enteral nutrition via the intestine has an advantage over nutrition via intravenous infusions because it is more physiological, less risky and cheaper.

## Artificial feeding of the critically ill

The nutrition of critically ill patients is of particular importance, as they are often unable to express physiological needs such as hunger or thirst (for example when ventilation therapy is necessary). The energy expenditure of such patients is therefore usually approximately estimated using formulas or determined via individual patient parameters using indirect calorimetry from the oxygen consumption and carbon dioxide production , the latter usually enabling a more precise determination of the resting energy expenditure. ${\ displaystyle VO_ {2}}$${\ displaystyle VCO_ {2}}$${\ displaystyle REU}$

${\ displaystyle REU (kcal / day) = [3.9 \ cdot (VO_ {2}) + 1.1 \ cdot (VCO_ {2})] \ cdot 1.44}$

## Ethical and legal aspects of artificial nutrition

Ethical and legal aspects must be observed, especially with patients who are unable to make decisions. On the one hand, artificial nutrition can have a life-prolonging effect; on the other hand, the insertion of a probe or a venous catheter constitutes an offense of bodily harm to which a patient or his representative must consent. This form of life extension, especially when used against the will of the patient, has led to heated discussions and legal disputes in recent years. The presumed will of patients must be appreciated or taken into account. In addition, artificial nutrition should not be used solely to reduce the amount of care required. A feeding tube should be used in a supportive manner, which means that a natural supply of food or fluids is given priority even with the tube lying down, if there are no medical reasons against it. Artificial nutrition should only be started when all other options for natural food intake as required have been exhausted. There must also be a clear therapeutic goal and medical indication. Above all, the measure should benefit the affected patient himself, for example if this enables care in his own home.

### Refusing to eat

So-called refusal to eat is not an indication for artificial nutrition if it is not due to illness. The voluntary renunciation of food and drink (FVNF or fasting to death ) can be an expression of the self-determined way of dealing with one's own life and death . At the end of life the appetite steadily decreases; a feeling of hunger like in healthy people does not occur. In this case, artificial nutrition is not only unnecessary, but potentially stressful, because it can lead to nausea, vomiting, diarrhea and fluid retention in the tissue. The body is then no longer able to process food. The patient has in his living will explicitly objected to the artificial feeding, it should not be done, otherwise vorläge a personal injury. In Germany, a legal justification is required, especially since such force-feeding can be accompanied by measures involving deprivation of liberty .

In people with dementia, refusing oral food intake is sometimes due to causes that may be easy to resolve, such as pain when eating due to inflammation of the gums, tooth decay or poorly fitting dentures. This must first be found out before a decision is made in favor of artificial nutrition.

### Force-feeding

Artificial feeding as force-feeding is less common when people are in a life-threatening situation due to a hunger strike or an eating disorder .

Whether and when force-feeding is permissible and can be reconciled with human rights is controversial.

In 2017, the Munich Higher Regional Court awarded a man compensation for pain and suffering whose father was force-fed for five years, even though he was already completely and irreversibly demented. The man had sued the father's family doctor. The Federal Court of Justice overturned the judgment in April 2019 on the grounds that continued living could not be harmful.

In Israel, the force-feeding of prisoners was legitimized after an accumulation of hunger strikes in 2013.

For the force-feeding of animals, see animal fattening , noodles (fattening) and foie gras (foie gras); on their ethical aspects animal rights , animal rights movement , animal protection law .

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12. Doctor maintains artificial nutrition - and has to pay pain and suffering . Southgerman newspaper.
13. tagesschau.de: Court judgment: No compensation for pain and suffering because of life extension. Retrieved April 2, 2019 .
14. Israel: Force-feeding of prisoners allowed. Der Standard , July 30, 2015, accessed December 4, 2018 .