Parenteral nutrition is a method of nutrition that involves the administration of nutrients directly into the bloodstream, bypassing the gastrointestinal tract. In parenteral nutrition, mixtures individually composed according to the patient's needs are administered, which contain nutrients in the simplest form - absorbed directly from the blood into the cells of the body and not requiring digestion - amino acids, fatty acids, glucose, minerals and vitamins. What are the methods of parenteral nutrition and indications for its use?

Parenteral nutritionis used to prevent malnutrition in diseases that limit or prevent oral nutrition and after surgical operations. If one of the three nutritional aspects is impaired:

  • self-eating,
  • etching,
  • absorb,

which makes it impossible to provide the right amount of energy and nutrients, it is advisable to introduce enteral or parenteral nutrition.

Parenteral nutrition - indications for use

Parenteral nutrition should be used whenever a patient's illness, injury or general condition prevents or significantly restricts eating and / or absorption. Long-term inability to consume the right amount of nutrients and energy leads to malnutrition.

On the other hand, malnutrition significantly worsens the patient's condition, increases the susceptibility to complications, infections, and extends the recovery period and hospitalization time. Malnutrition is a very important problem of Polish hospitals. It applies to people after injuries, surgeries and people suffering from cancer very often, not only cancers of the digestive tract.

If the estimated duration of inability to receive oral or enteral nutrition exceeds 4-5 days, parenteral nutrition becomes necessary.

The states in which parenteral nutrition is introduced are:

  • failure to achieve the assumed effects of enteral nutrition,
  • mechanical or functional gastrointestinal failure - in diseases such as short bowel syndrome, acute pancreatitis, gastrointestinal fistulas, scleroderma, peristalsis, gastrointestinal infarction or ischemia, acute or chronic insufficiencyintestines, inflammatory bowel diseases, no access to the digestive tract,
  • severe postoperative gastrointestinal failure,
  • extensive and severe injuries, e.g. sepsis, burns,
  • coma,
  • malnutrition,
  • prematurity,
  • cancer.

Parenteral nutrition - total vs. partial

Total parenteral nutritionis a situation in which intravenous mixtures are the only source of food for the patient. Total parenteral nutrition is introduced in the case of gastrointestinal failure, which causes e.g.

  • Crohn's disease,
  • intestinal atony,
  • intestinal damage,
  • severe enteritis,
  • esophagus stricture

or in the intensification of catabolic processes, e.g.

  • as a result of severe burns,
  • extensive operations,
  • kidney failure,
  • liver,
  • heavy injuries,
  • acute pancreatitis,
  • sepsis.

Partial parenteral nutritionis introduced in patients who have access to the gastrointestinal tract, but whose oral nutrition ceases to cover the body's needs. This is often the case of cancer patients, whose mood makes them refuse to eat, thus increasing the wasting of the body which is so devastated by treatment.

The most common situations requiring partial parenteral feeding include:

  • radiotherapy and chemotherapy,
  • patients with features of malnutrition or cachexia (loss of 10% of body weight within 3 months),
  • patients with acute pancreatitis,
  • short bowel syndrome,
  • inflammatory bowel diseases,
  • extensive burns.

The choice of diet depends mainly on the patient's condition and the level of malnutrition, and to a lesser extent on the disease entity.

Methods of parenteral nutrition

Parenteral nutrition is carried out by infusing nutrients directly into the veins. The choice of a specific method and site of injection depends on the anticipated duration of parenteral nutrition. It is possible to feed the mixture:

  • for a period shorter than 7 days - by peripheral access to the veins of the limbs (a contraindication is the caloric value of the mixture administered above 2000 kcal or high osmolarity of the administered fluids),
  • from 7 days to 3 weeks - via central access to the superior vena cava, subclavian or internal jugular vein,
  • longer than 3 weeks - by using tunnel catheters insubcutaneous tissue or vascular ports.

There are two methods of parenteral nutrition - "many bottles" or "all in one":

1. Multiple Bottle Method

In parenteral nutrition using the multi-bottle method, three solutions are used separately:

  • carbohydrate (glucose) solution,
  • amino acid solution
  • and fat emulsion.

Minerals are added to glucose and amino acid solutions, and vitamins to the fat emulsion. Glucose and amino acid solutions are administered continuously around the clock.

2. All-in-one method

For all-in-one parenteral nutrition, the patient receives one bag containing a mixture of nutrients, water and minerals. It is possible to add some medications to the mixture.

The infusion takes place with the ability to control its pace. This method of administration is considered to be preferable to the multi-bottle method because it reduces the risk of metabolic complications, infection and the use of disposable equipment.

When parenteral nutrition is turned on for a short time, it is given continuously, around the clock. With long-term nutrition with this method, cyclic infusions are most often used, for 12-18 hours a day, mainly at night. This allows for increased mobility and for patients and improves their quality of life.

Composition of parenteral nutrition mixtures

A specialist who composes a mixture for parenteral nutrition takes into account the nutritional norms, body weight and nutritional status of the patient. Such a mixture includes:

  • water - 30-40 ml per kg of patient weight,
  • carbohydrates in the form of glucose, usually 3-5 g per kg of patient weight,
  • protein in the form of amino acids, usually in the amount of 1-2 g per kg of body weight, but depending on the disease state and the level of malnutrition, these values ​​may be higher,
  • fats in the form of medium and long-chain fatty acids, including essential fatty acids emulsified with phospholipids, usually 1-2 g per kg of body weight, additionally cholesterol and glycerol are included,
  • electrolytes - sodium, potassium, magnesium, calcium, phosphorus administered depending on the underlying disease and current test results,
  • vitamins and trace elements - in accordance with nutrition standards and patient interview.

The energy provided by parenteral nutrition formulas should cover the patient's needs. Due to increased catabolism, sick people often need more energy,than indicated by the standards. In such a situation, the excess energy should be covered by carbohydrates and fats.

When composing mixtures for parenteral nutrition, it is necessary to take into account the appropriate proportions between amino acids and glucose and fats. As a result, energy is drawn from carbohydrates and fats, and amino acids can be used as building blocks for tissues and organs, helping to prevent wasting. It is believed that 1 g of protein should correspond to 21-27 kcal.

Parenteral nutrition at home

Partial or total parenteral nutrition may be necessary for several days, months, and sometimes years. In such a situation, does the patient have to stay in the hospital all the time? No, it is not necessary.

There are procedures available in Poland that enable parenteral nutrition at home. It is a treatment method reimbursed by the National He alth Fund. After the patient is qualified for parenteral nutrition at home, specialized training is conducted for the patient himself or his caregivers. The training covers all activities necessary to conduct parenteral nutrition at home.

What does the process look like in practice? Bags with the mixture are delivered to the patient's home. The frequency of deliveries depends on the type of disease. After the bag is heated, the patient himself adds ampoules with vitamins, trace elements and additional substances to it. Then he rinses the venous line and connects it to the central line.

Feeding the mixture takes several hours. During this time, the patient does not have to lie down. It can move with the bag placed on the stand. It is most convenient to give the mixture at night, as it is the least difficult for everyday functioning.

Parenteral nutrition - possible complications

Parenteral nutrition is the "gold standard" in the nutrition of patients with insufficient gastrointestinal tract. However, it should be borne in mind that this is an invasive method that causes many side effects and complications.

Parenteral nutrition may result in:

  • infections,
  • sepsis,
  • thrombosis,
  • negatively affect the patient's metabolism,
  • impair the functions of the digestive tract
  • whether to weaken the immune system.

Patients on parenteral nutrition may often complain of shortness of breath, headache, hot flushes and fever.

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