For parenteral nutrition use. Parenteral nutrition is the basis of intensive care. Technique of parenteral nutrition

The main objective criterion for the use of PP is a pronounced negative nitrogen balance, which cannot be compensated by the enteral route. Enteral nutrition is always better, provided it is able to restore a disturbed metabolism. If this is not possible, then parenteral nutrition is necessary.

Indications for PP can be absolute and relative.

Absolute readings arise in those cases when the body, in conditions of cessation or sharp restriction of the supply of nutrients from the outside, covers the sharply increasing plastic and energy needs due to the decay of its own tissues. Such a metabolic orientation, designed to ensure the vital activity of the organism, quickly loses its original expediency and begins to adversely affect the course of all life processes.

Absolute indications for the appointment of PP for injuries and surgical diseases:

1. Severe mechanical injuries, purulent-inflammatory diseases of the abdominal organs in the active phase of the process;

2. Severe catabolic reaction with extensive burns, combined injuries, severe purulent-septic processes;

3. A sharp restriction or impossibility of oral nutrition as a result of dysfunction of the digestive tract of traumatic, inflammatory or functional origin (chronic diarrhea, short bowel syndrome, pancreatic necrosis, etc.);

4. Temporary shutdown of the gastrointestinal tract after trauma and surgery on the esophagus, stomach, intestines, in the area of ​​the hepatopancreatoduodenal zone;

5. The presence in children of damage to the thoracic lymphatic duct with a clinic of chylothorax.

Relative readings to the appointment of PP occur when the enteral route of nutrition is preserved, however, it is not possible to restore the disturbed metabolism (sepsis, impaired intestinal absorption, the presence of intestinal fistulas).

In cases where we are talking about absolute indications, parenteral nutrition should be complete, i.e., include all the necessary ingredients: plastic, energy, electrolyte, etc. With relative indications, PP may be incomplete: nitrogenous substances are administered parenterally, and the remaining ingredients - enterally.

PP is divided into 3 types: full, partial, additional.

Complete PP - intravenous administration of all the substances necessary to ensure the vital activity of the body in quantities that correspond to the needs of the child.

Partial PP - the introduction of such a quantity of all the substances necessary to ensure metabolic processes, which supplements the insufficient introduction in other ways (through the mouth, through a probe).

Additional PP - the introduction of individual nutrients with an increase in the need for them in the child's body.

From the point of view of biochemistry, the main difference between PP and conventional PP is that the first one does not require the transformation phases of food polymers into monomers, with the exception of the partial need for the hydrolysis of neutral fat supplied with fat emulsions. The intracellular metabolism of monomers of nutrients that have entered the body in the usual way or parenterally has no differences.

Parenteral nutrition systems.

Currently, two fundamentally different systems are used: balanced PN and hyperalimentation, or the Dadrik system. In the first case, during parenteral nutrition, all the necessary nutrients, amino acids, carbohydrates (glucose), fat are introduced into the child's body, in the second case, fat is not introduced, and the body's energy needs are provided only by carbohydrates. In the latter case, to fully meet the energy needs of the child's body, it is necessary to administer a dose of glucose that exceeds the normal requirement by 2 times.

Components of parenteral nutrition.

Carbohydrates.

All biosynthetic processes in the body are reactions that consume energy. It has been established that for protein synthesis in the body, 150-200 kcal is required for each gram of nitrogen in the initial substances. Energy sources are mainly carbohydrates and fats. Providing the body with the necessary energy, they protect the endogenous protein from combustion, and at the same time have a nitrogen-sparing effect. For every additional 10 kcal introduced in the form of an energy substance, nitrogen losses are reduced by 3-15 mg. The nitrogen-saving effect of energy sources begins to manifest itself when at least 600 kcal per day enters the body.

It is quite obvious that with parenteral nutrition it is necessary to ensure sufficient intake of substances that are predominantly sources of energy into the body. For this purpose, carbohydrate preparations are used in the form of aqueous solutions of sugars and alcohols, as well as fats in the form of fat emulsions.

Considering that the main role of carbohydrates in nutrition is to satisfy energy needs, one cannot ignore the fact that they also have a plastic significance, being part of cells as structural elements and many active substances of a living organism. The daily requirement for carbohydrates in children is presented in Table. 20.2.

Glucose is the most abundant six-carbohydrate monosaccharide in nature. D-glucose molecules serve as the main type of cellular "fuel" and act as building blocks or precursors of the most common oligo- and polysaccharides. Glucose is the classic form of energy substrate for parenteral nutrition. Due to the fact that highly purified grades of glucose have been obtained that do not cause side reactions, the preparation of appropriate solutions from them, their sterilization, and storage do not present technical difficulties. If we add to this that the tolerance of this natural product by the body is very good (neither allergic nor toxic reactions are practically observed, and the drug has not only a nutritional, but also a detoxifying effect), it becomes clear why glucose is in first place in terms of the frequency of its use. for infusion therapy.

An important feature of glucose is that in the body it is oxidized to the final products - carbon dioxide and water. Glucose is one of the constituent parts of RNA molecules and in this regard is directly related to protein synthesis. The introduction of glucose allows you to save your own proteins from decay. At the same time, glucose also has an anabolic effect on amino acid metabolism, which is most likely due to an increase in insulin production by the pancreas in response to an increase in blood glucose levels. With the introduction of glucose, the same effect is observed as with the introduction of insulin - an increase in the process of incorporating amino acids into muscle proteins while simultaneously depleting the liver of amino acids. For this reason, when a large amount of glucose is administered, the simultaneous administration of amino acids should be considered mandatory. The anabolic effect of glucose in relation to amino acids is manifested when administered together, but if a gap of 4-5 hours is allowed between their administration, the nitrogen-sparing effect may not appear. The introduction of glucose together with insulin has a stronger anabolic effect than their separate administration. In the presence of insulin, glucose effectively prevents the development of ketoacidosis, promotes the normal distribution of potassium and sodium in the body. Glucose solutions of 5% are almost isotonic to blood plasma and are widely used for the correction of water balance, nutrition, detoxification and other purposes. Unfortunately, such a small amount of glucose in solution does not significantly affect the caloric balance of the body. A liter of this solution gives only 200 kcal, and in order to provide the body with the necessary energy, 10 liters of such a solution must be injected, which is unacceptable from a physiological point of view.

The energy value of glucose solutions is increased by increasing its concentration to 10-50%. Hypertonic glucose solutions often irritate the venous wall, lead to phlebitis, and therefore, solutions of more than 10% try not to inject into peripheral veins.

In recent years, the method of so-called hyperalimentation glucose, which consists in the fact that parenteral nutrition is carried out with highly concentrated solutions of glucose (30-50%), which is injected through permanent catheters inserted into the basin of the superior vena cava. The upper dose limit for glucose infusion should not exceed 1.5 g/kg/day.

Usually, combined parenteral nutrition is carried out with hypertonic glucose solutions and nitrogenous preparations. In order to prevent hyperglycemia with the introduction of significant amounts of glucose in the form of its hypertonic solutions, insulin is administered at the rate of 1 unit per 4-5 g of glucose.

With the accumulation of observations on the use of hyperalimentation, it turned out that the use of this monosaccharide as the only non-protein source of energy worsens the metabolic state of the liver, causes depletion of amino acids, reduces the intensity of albumin synthesis, and leads to fatty infiltration of the liver. In this regard, the question of finding other carbohydrates suitable for parenteral nutrition has become more relevant.

Fructose(levulose, fruit sugar) is a monosaccharide belonging to the group of hexoses. It is equal in calories to glucose. Fructose is attracting attention as a substance for parenteral nutrition due to a number of its positive features. In the body, fructose can be phosphorylated without insulin, and its metabolism, at least in the initial stages, is independent of this hormone. Fructose is mainly metabolized in the liver, and the products of its metabolism (glucose, lactic acid and lipids) entering the blood can be utilized by other tissues. Fructose is eliminated from the vascular bed faster than glucose, and its loss in the urine is less. With the introduction of fructose, the formation of glycogen in the liver occurs faster, it has a more energetic protein-preserving and hepatoprotective effect. Especially advantageous is the introduction of fructose in the post-aggressive period (surgery, postoperative period, trauma, shock), when, as you know, the absorption of glucose drops sharply and glucosuria can be observed.

At the same time, it should be pointed out that glycogen synthesis in muscles with the introduction of fructose proceeds more slowly than with the introduction of glucose. The independence of fructose metabolism from insulin is incomplete, since the bulk of fructose is converted in the liver into glucose, the metabolism of which depends on insulin. After the introduction of fructose, the content of glucose in the blood increases and glucosuria occurs. Fructose overload, like other monosaccharides, causes adverse effects. In particular, due to the danger of lactic acidemia and hyperuricemia, which is based on the rapid consumption of ATP for the phosphorylation of this sugar, fructose can only be administered in moderate doses.

For infusions, 10% fructose solutions are used. Naturally, at such a concentration, the amount of energy delivered to the body is relatively small and cannot have independent significance.

Fructose is used as an additive to some drugs and is included in the composition of multicomponent solutions for parenteral nutrition. The rationality of the creation of the latter is based on the fact that the utilization of individual carbohydrates (monosugars and alcohols) that make up their composition occurs in different ways, which makes it possible to avoid overloading the body with individual substances with a high calorie content of the drug. The complexity of industrial production and the high cost of fructose prevent its wider use in the practice of parenteral nutrition. The fructose dosage limit is 0.25 g / kg / hour and not more than 1.5 g / kg / day.

Sorbitol- a six-atomic sugar alcohol, equal in energy value to glucose and fructose. In the body, it is formed during the conversion of glucose under the action of sorbitol dehydrogenase into fructose, therefore, it is a natural product. It can be utilized in the body without the participation of insulin, and therefore is indicated for disorders of carbohydrate metabolism. However, it must be noted that the exchange of sorbitol in the body occurs due to fructose, which is partially converted into glucose, therefore, the independence of utilization from insulin is not absolute.

The antiketogenic effect of sorbitol is also associated, apparently, with its conversion into fructose and glucose. The dose for a single injection is 0.5 - 2.0 g / kg of body weight. To obtain an osmodiuretic effect, the drug is administered in a stream, in other cases - drip at a rate of 20-40 drops per minute. The frequency of local thrombophlebitis with the use of sorbitol is very low, which can be explained by the fact that the pH of its solutions is close to neutral - 5.8-6.0. For parenteral nutrition, 5-6%, i.e., approximately isotonic solutions of sorbitol, are used. The solution can be administered in combination with other parenteral nutrition media - protein hydrolysates, amino acid mixtures, fat emulsions, monosaccharide solutions. It should be noted that sorbitol solutions improve the rheological properties of blood, prevent erythrocyte aggregation, reduce tissue hypoxia, and have a normalizing effect on the hemostasis system.

When hypertonic solutions of sorbitol are infused at high speed, it has an osmodiuretic effect similar to mannitol, that is, it increases renal blood flow, prevents water reabsorption in the renal tubules, and increases diuresis. To stimulate diuresis, a 20% solution of sorbitol is used, which is administered intravenously in a jet at a dose of 1-2 g/kg of body weight. Hypertonic (20%) solution of the drug is also used to enhance peristalsis in intestinal paresis. For this purpose, it is administered dropwise, 50-100 ml every 6-8 hours until a therapeutic effect is obtained. Sorbitol does not react with amino acids in the so-called Maillard reaction (the formation of toxic compounds), and therefore it is often used as a caloric supplement to mixtures of amino acids, fat emulsions, and as a component of complex carbohydrate compositions containing glucose, fructose, maltose, alcohol, etc.

Ethanol(ethanol) has a long history of intravenous use for nutritional and medicinal purposes.

The calorie content of 1 g of the substance is 7.1 kcal, i.e., much more than other carbohydrates. Medical 96% ethyl alcohol is used as the initial product. Intravenously administered aqueous solutions of alcohol at a concentration of 5 to 30%. In the body, ethyl alcohol is oxidized mainly in the liver, being included in the Krebs cycle. On average, up to 10% of ethanol can be excreted in the urine and 50% in the lungs. It is utilized quite quickly, but it is very limited for use in children.

Xylitol is a polyalcohol with a pronounced antiketogenic effect, is metabolized independently of insulin and does not have a diuretic effect. It is used as an amino acid supplement. As a result of a special way of breaking down the pentose phosphate cycle, xylitol, regardless of glucose-6-phosphate dehydrogenase, which is inhibited during stress, shock, diabetes, is able to supply the pentose necessary for the construction of nucleic acids and proteins.

For the normal nutrition of infants, the qualitative and quantitative coverage of protein requirements is decisive. The state of protein deficiency before and after birth can cause severe brain damage or delayed CNS maturation. The minimum safe amounts of protein in parenteral nutrition required for children of different ages are presented in Table. 20.3

Amino acids. The biosynthesis of proteins is carried out mainly in the ribosomes of cells and is controlled by genes, the most important element of which is deoxyribonucleic acid, the carrier of genetic information that determines the human genotype. In accordance with this information, the sequence of amino acids of polypeptide chains is built. The number of amino acids in a protein molecule and the order of their arrangement predetermine the organo-tissue, species, individual properties and specificity of proteins.

As is known, foreign proteins taken with food during digestion are broken down into amino acids and simplest peptides and in this form are absorbed by the intestines, and then enter the bloodstream and are transported to tissues, where they are used for the synthesis of endogenous protein. With parenteral administration of amino acids, the second stage of protein digestion is artificially reproduced, namely, the entry into the blood of the products of their intra-intestinal cleavage. The now finally established fact that all proteins are built and synthesized in cells only from amino acids is the theoretical justification for modern monomeric protein nutrition with amino acids. Parenterally administered amino acids can be used by the body to reproduce its own protein structures, and in this respect they are an adequate substitute for natural protein nutrition.

Since amino acids are nitrogenous substances and serve as the main source of organic nitrogen absorbed by the body, parenteral nutrition with preparations containing them is commonly called nitrogenous parenteral nutrition. This name has become widespread as a synonym for parenteral protein nutrition.

For nitrogenous parenteral nutrition, protein hydrolysates and synthetic mixtures of crystalline amino acids are currently used. Hydrolysates are complete if they contain a complete set of amino acids, especially all essential amino acids. Electrolytes are usually introduced into the composition of protein hydrolysates to ensure their normalizing effect on water-electrolyte metabolism. There are significant differences in the compositions of amino acid mixtures currently produced. A coefficient is proposed to characterize the total ratio of essential and non-essential amino acids H/O, reflecting the proportion of essential (H) nitrogen in total (O) nitrogen (in foreign literature, E/T). High values ​​of the H/O ratio are necessary for parenteral nutrition of children and malnourished patients. If parenteral nutrition is carried out to maintain a slightly disturbed nitrogen balance, the H / O value may be lower. However, due to the fact that with the same H/O values, the quantitative and qualitative composition of amino acids in drugs can be different, this coefficient is not enough to resolve the issue of the anabolic efficacy of the drug and indications for its use.

As a rule, in modern preparations of mixtures of amino acids for parenteral nutrition include semi-essential amino acids - arginine and histidine. As for the non-essential amino acids, here you can find options with the inclusion of from one to the full set of non-essential amino acids.

Many authors emphasize the great importance of histidine, which is an essential amino acid for children and patients with uremia, as it reduces the level of residual nitrogen in the blood. Particular importance is attached to the inclusion of arginine and other urinary intermediaries in the mixture, which prevent the development of hyperammonemia. There is an opinion that alanine and proline, according to the degree of irreplaceability, should be placed next to arginine and histidine. Proline promotes faster healing of wounds. In the patient's body, the quantitative and qualitative need for amino acids changes, and selective insufficiency of individual amino acids may occur.

The composition of amino acid solutions also includes energy carriers (sorbitol, xylitol) and electrolytes. Particular importance is attached to potassium and magnesium ions, since they are the main cellular cations and are necessary for the “building” of tissues.

It is known that not only a deficiency, but also an excess of protein nutrition has negative consequences for the body. The introduction of too many amino acids leads to an overload of the corresponding catabolic and anabolic enzyme systems of the body and the accumulation of end products of nitrogenous metabolism (ammonia, urea and other nitrogenous wastes) and adversely affects the functional state of the body.

In addition, parenteral nutrition has its own specific conditions that practically do not allow large amounts of amino acids to be introduced into the body. Such a condition is the need for their slow introduction, so as not to cause aminoacidemia, aminoaciduria and dangerous fluid overload of the vascular bed.

It is practically impossible to achieve a perfect balance of amino acids in parenteral nutrition solutions, and therefore they are not fully used to build protein in the body. Therefore, in recalculating the introduced amino acids into a conditional protein, their weight is divided by an experimentally established coefficient of 1.23.

Sources of fat.

Fat preparations are highly dispersed emulsions of neutral fats (triglycerides) in water. In the body, they are included in metabolic processes and are used as a rich source of energy. 1 g of fat during combustion in the body forms 9.3 kcal of energy. The daily requirement for fats with balanced parenteral nutrition in children is presented in Table. 20.4.

The sizes of fatty particles are very small, as a rule, no more than 0.5 microns - like natural chylomicrons. Fat emulsions are a valuable source of essential fatty acids, which is of particular importance in debilitated and malnourished children. The presence of glycerin in fat emulsions provides isotonia and antiketogenic effect. Fat supplies essential fatty acids, especially linoleic and lenolenic acids, which maintain the functional capacity of cell membranes and stimulate wound healing. Fat emulsions are used in the form of 10-20% solutions with a calorie content of 1.1 and 2 Kcal / ml, respectively. Recommended doses of fat emulsions:

a) 5-10 ml/kg for the first 10 kg of body weight,

b) 2.5-5 for the next 10 kg of body weight up to 20 kg,

c) 1.25-2.5 ml/kg for each kilogram of body weight over 20 kg.

The maximum daily dose is 4 g/kg.

For the introduction of fat emulsions, a Y-shaped connection of the venous catheter and infusion systems is used. A fat emulsion is injected into one knee, and a glucose-amino acid solution with electrolytes into the other. This requirement is necessary to reduce the mixing time of fat emulsions with other drugs, since this may change the structure of the fat in the emulsion.

In modern medicine, artificial nutrition is one of the main types of treatment in a hospital setting. It is used in various fields of medicine. With certain diseases, it is not enough for the patient to receive natural nutrition (through the mouth), or this, for certain reasons, is impossible. In this case, additional or basic artificial nutrition is used.

It is introduced in different ways. Most often, this is practiced during surgical interventions, in patients with nephrological, gastroenterological, oncological and geriatric diseases. What types of artificial nutrition are practiced in modern medicine, as well as the features of enteral and parenteral nutrition will be discussed in this article.

Who needs nutritional support

Enteral and parenteral nutrition is aimed at providing nutritional support, that is, a complex of therapeutic measures, the purpose of which is to determine and correct violations of the nutritional status of the body.

With the timely provision of nutritional support, it is possible to significantly reduce the number and frequency of infectious complications and deaths, as well as stimulate the rehabilitation of patients.

Nutritional support can be either complete, when a person's basic or all nutritional needs are provided artificially, or partial, when such nutrition is in addition to the usual one.

There are many indications for artificial nutrition. To summarize, we are talking about any diseases in which adequate natural nutrition is impossible. As a rule, these are diseases of the gastrointestinal tract, metabolic problems.

Basic principles of nutritional support

The provision of nutritional support is carried out taking into account a number of important principles:

• Timeliness - you need to start practicing artificial nutrition as early as possible - even before nutritional disorders have begun.
• Adequacy - it is important that nutrition covers the energy needs of the body and is optimally balanced.
• Optimal - such nutrition should be carried out until the nutritional status stabilizes.
• Assessment of the patient's energy needs - it is important to correctly assess the patient's energy needs in EN and PN.

In medicine, the following types of nutrition are defined: enteral (probe ) and parenteral (intravascular ).

Enteral

Enteral nutrition - this is a type of additional therapeutic nutrition, in which the patient receives special mixtures, and the absorption of food occurs in an adequate physical way - through the gastrointestinal mucosa. Food in this case can come through the mouth or through a tube in the intestines or stomach.

According to the method of administration, enteral nutrition (EN) is divided into:

• the use of EN through a tube or sips (liquid hypercaloric mixtures for enteral nutrition; preparations from powdered mixtures (used for patients according to indications));
• probe (through the nasal opening into the stomach, through the nose into the duodenum or jejunum, a two-channel probe);
• through a probe that is inserted into the stoma (a hole in the abdominal wall).

It should be noted that tube feeding at home should not be practiced, since it is important to control the correct insertion and position of the probe.

Modern medicine offers convenient devices for performing EP. Its implementation is facilitated by a special pump, to which a gravity system is attached. Such a device can be bought at pharmacies.

If necessary, for adults and children, special mixtures from different manufacturers are used - Nestle ( Nestle Modulin and others), Nutricia ( Nutricia Nutrison ), etc. More details on the name of the characteristics of such drugs can be found on the manufacturers' websites.

Such mixtures are divided into the following categories:

• Nutrient modules are mixtures with one nutrient (proteins, fats or carbohydrates). They are used to eliminate the lack of certain substances. They can also be used with other drugs to fully meet nutritional needs.
• Polymer blends - are used to provide a balanced diet. Can be used for both mouth feeding and tube feeding. Often, patients are prescribed lactose-free mixtures.

parenteral

parenteral nutrition (PP) is a way when nutrients enter the body through intravenous infusion. In this case, the gastrointestinal tract is not involved. Such special nutrition is practiced if the patient, for some reason, cannot eat food on his own or is not able to absorb it through the mouth. This is also practiced if nutrition through the mouth is not enough, and the patient needs additional nutritional support.

For this type of meal, preparations for parenteral nutrition are used. Such drugs are administered if there are appropriate indications. The main purpose of their introduction is to ensure that a mixture of ingredients (nutrients) enters in an amount that fully meets the needs of the patient. It is important to do this so that the admission is as safe as possible and does not provoke complications.

Such nutrition makes it possible for a long time to provide the patient's needs for energy and protein. For patients from different age groups and for different diseases, a different composition is used. But in general, both for newborns and for patients of any other age, adequately selected solutions make it possible to reduce mortality and the duration of hospital treatment.

In medicine, the following classification of drugs for parenteral nutrition is accepted:

• for PP;
• fat emulsions;
• multivitamin complexes;
• combined funds.

It is also customary to divide PP funds into two groups:

• protein preparations (solutions of amino acids, protein hydrolysates);
• means of energy nutrition (carbohydrate and fat solutions).

All these funds can be bought at a pharmacy with a doctor's prescription.

Use of enteral nutrition

Specialized enteral nutrition is prescribed for people whose gastrointestinal tract is functioning, but who, for some reason, cannot consume enough nutrients.

Nutrients - these are biologically significant elements (microelements and macroelements) necessary to ensure the normal functioning of the animal or human body.

The use of enteral ingestion is preferable to the use of parenteral in view of the following points:

• so the functions and structure of the gastrointestinal tract are better preserved;
• there are fewer complications;
• the price of mixtures for EP is lower;
• with EP, strict sterility is not required;
• it makes it possible to better provide the body with the necessary substrates.

In medicine, the following indications for enteral nutrition are noted:

• prolonged anorexia ;
• , impaired consciousness;
• liver failure;
• protein-energy deficiency in severe form;
• inability to take food orally due to a neck or head injury;
• metabolic stress due to critical conditions.

Indications for its use are defined as follows:

• If the patient is unable to eat (impaired swallowing, lack of consciousness, etc.).
• If the patient should not eat (GI bleeding, acute and etc.).
• If the patient does not want to eat (anorexia, infectious diseases, etc.).
• If normal nutrition does not meet the needs (burns, injuries, etc.).

Also, the use of EN is advisable in preparing the intestine for surgery in seriously ill patients, when closing skin-abdominal fistulas and adapting the small intestine after extensive resection or a disease that can provoke malabsorption .

Contraindications to EP

Absolute contraindications to the use of enteral nutrition are:

• Expressed clinically shock .
• Full .
• intestinal ischemia .
• Bleeding of the gastrointestinal tract.
• Refusal of the patient or his guardian from the EP.

Relative contraindications to EP are:

• heavy .
• Partial bowel obstruction.
• External enteric fistulas.
• pancreatic cyst , spicy .

Enteral feeding regimens

The EP mode is chosen depending on the patient's condition, his illness and the capabilities of the medical institution in which he stays. There are the following types of power supply modes:

• at a constant speed;
• cyclic;
• periodic (session);
• bolus.

Blend selection

The choice of mixture depends on a number of factors: general condition, illness, regimen, etc.

However, whatever mixture is chosen for the patient, it is important to consider that none of these mixtures provides the body's daily need for fluid. Therefore, the patient must additionally take water.

For enteral nutrition in modern medicine, infant formulas or those prepared from natural products are not used. For adults, they are not suitable due to imbalance.

What complications are possible

In order to prevent complications, it is very important to strictly follow all the rules for conducting EP. But if a certain complication has arisen, then enteral nutrition is stopped.

The high frequency of complications is due to the fact that it is often used for critically ill patients in whom the organs and systems of the body are affected. The following types of complications are likely to occur:

• infectious ( , aspiration pneumonia, and etc.);
• gastrointestinal (, diarrhea, bloating, etc.);
• metabolic ( metabolic alkalosis , hyperglycemia , hypokalemia and etc.).

This classification does not take into account those complications that develop due to the technique of enteral nutrition - blockage and migration of probes, their self-extraction, etc.

To reduce the risk of complications, it is important to follow all recommendations for formula preparation and administration.

Parenteral nutrition is aimed at maintaining and restoring the water-electrolyte and acid-base balance in the body. With its help, it is possible to provide the body with plastic and energy substrates, macro- and microelements, vitamins.

Parenteral nutrition is advisable to use in the following cases:

• If oral or enteral ingestion is not possible.
• If the patient has a pronounced hypermetabolism , or significant protein losses have occurred, and EN does not make it possible to overcome the nutrient deficiency.
• The need for a time to exclude intestinal digestion.

Complete PP is indicated if it is not possible to eat naturally or through a tube, and at the same time catabolic processes are enhanced and anabolic are inhibited, a negative nitrogen balance is noted:

• In the period after extensive surgical interventions in the abdominal cavity or with complications in the postoperative period.
• In the period after severe injuries - after serious burns, multiple injuries.
• In violation of protein synthesis or its enhanced decay.
• Resuscitation patients who do not regain consciousness for a long time, or with severe violations of the gastrointestinal tract.
• In the case of neuropsychiatric diseases - anorexia, food refusal, etc.
• With severe infectious diseases.

PP classification

In medicine, the following types of PP are defined:

• Complete (total) - the entire volume of the body's daily need for nutrients, as well as maintaining metabolic processes at the desired level, is provided by PP.
• Incomplete (partial) - aimed at making up for the lack of those components that for some reason are not absorbed through enteral nutrition. It is practiced as an addition to other types of nutrition.
• Mixed artificial is a combination of EP and PP, with neither of these types predominating.

How PP is carried out

Nutrients are administered in a form that is adequate to the metabolic needs of the cells. Proteins are administered in the form of amino acids, carbohydrates - monosaccharides, fats - fat emulsions.

For PP, electronic drop regulators and infusion pumps are used. It is very important to strictly observe the rate of introduction of appropriate nutrient substrates. Infusion is carried out at a certain rate for 24 hours. The speed should not be more than 30-40 drops per minute to prevent overloading of the enzyme systems.

Infusion sets must be changed once every 24 hours.

If complete PP is carried out, then glucose concentrates must be included in the mixture.

A patient staying on PP needs liquid at the rate of 30 ml/kg of body weight. In pathological conditions, liquid nutrition should be more abundant.

There are several modes of administration of PP:

• round the clock;
• prolonged infusion (up to 20 hours);
• cyclic (for 8-12 hours).

There are also a number of important requirements for drugs that are used for PP:

• They must provide a nutritional effect (the composition contains all the substances important for the body in the right quantities and ratios).
• It is important that they replenish the body with fluid, since dehydration is noted in many pathological conditions.
• It is desirable that the funds have a stimulating and detoxifying effect.
• It is important that their use is safe and convenient.

Contraindications

The following absolute contraindications to PP are defined:

• electrolyte disturbances, shock, hypovolemia ;
• the ability to conduct adequate enteral and oral nutrition;
• refusal of the patient or his guardian;
• allergic manifestations to PP components;
• if PP does not improve the prognosis of the disease.

There are also a number of contraindications to the use of specific drugs for parenteral administration.

What complications are possible

Complications in the use of parenteral nutrition are divided into the following varieties:

• technical;
• metabolic;
• organopathological;
• septic.

In order to prevent such complications, it is important to strictly follow all the rules for the introduction of solutions and strictly monitor homeostasis.

Nutritional support is a necessary part of intensive care for various pathological conditions. The safest method is its implementation through the gastrointestinal tract. However, in some cases, an alternative method is needed - parenteral nutrition, which is used when enteral nutrition is not possible.

Parenteral nutrition (PN) is the introduction of nutrients necessary for the normal functioning of the body directly into the vascular bed (or other internal media). This means that nutrients administered as sterile nutritional solutions enter directly into the bloodstream and bypass the gastrointestinal tract.

In this article, we will acquaint you with indications and contraindications, types, options and rules for administration, possible complications and parenteral nutrition drugs. This information will help you get an idea of ​​this method of nutrient delivery, and you can ask your doctor any questions you may have.

The goals of PP prescription are aimed at restoring and maintaining the acid-base and water-electrolyte balance and providing the body with all the necessary energy and building components, vitamins, micro- and macroelements. There are 3 main concepts of such nutrition. According to the "European concept", created in 1957 by Dr. A. Wretlind, and the "American concept", developed in 1966 by S. Dudrick, different drugs for PP are administered separately according to different principles. And according to the "all in one" concept, created in 1974, all the necessary fat emulsions, electrolytes, amino acids, vitamins and monosaccharides are mixed before injection. Now, in most countries of the world, experts prefer just such an introduction of funds for PP, and if it is impossible to mix any solutions, their intravenous infusion is performed in parallel with the use of a V-shaped conductor.

Kinds

PP can be:

• complete (or total) - all the necessary substances come only in the form of infusion solutions;
• additional - this method complements tube or oral nutrition;
• mixed - simultaneous combination of enteral and parenteral nutrition.

Indications

PP can be appointed in the following cases:

• the impossibility of administering nutrients by oral or enteral route for a week in stable patients or at a shorter time in patients with malnutrition (usually with impaired functioning of the digestive organs);
• the need to temporarily stop the digestion of food in the intestines (for example, the creation of a "rest mode" with);
• significant protein losses and intense hypermetabolism, when enteral nutrition cannot compensate for nutrient deficiencies.

Contraindications

PP cannot be performed in the following clinical cases:

• there is the possibility of introducing nutritional components in other ways;
• on the drugs used for PP;
• the impossibility of improving the prognosis of the disease by conducting PP;
• a period of electrolyte disturbances, shock reactions or hypovolemia;
• categorical refusal of the patient or his guardians.

In some of the cases described above, the use of PP elements is acceptable for intensive care.

How drugs are administered

For PP, the following routes of administration (or accesses) can be used:

• by infusion into a peripheral vein (through a catheter or cannula) - usually carried out if such a method of nutrition is necessary for 1 day or with additional administration of the drug against the background of the main PP;
• through a central vein (through a temporary or permanent central catheter) - performed if it is necessary to provide a longer PN;
• alternative vascular or extravascular access (peritoneal cavity) - are used in more rare cases.

With a central approach, PP is usually performed through the subclavian vein. In more rare cases, drugs are injected into the femoral or jugular vein.

For PP, the following modes of administration can be used:

• cyclic administration for 8-12 hours;
• prolonged administration for 18-20 hours;
• round the clock introduction.

The main types of drugs

All funds for PP are usually divided into two main groups:

• donators of plastic material - amino acid solutions;
• energy donators - fat emulsions and solutions of carbohydrates.

Osmolarity of drugs

The osmolarity of the solutions administered during PN is the main factor that must be taken into account in this method of nutrition. It must be taken into account in order to avoid the development of hyperosmolar dehydration. In addition, when using high-osmolar solutions, the risk of phlebitis should always be taken into account.

The osmolarity of human plasma is 285-295 mosm/L. This means that only solutions whose osmolarity is close to such physiological parameters can be injected into the peripheral blood. That is why, when performing PP, preference is given to the central veins, since the vast majority of drugs used have higher osmolarity values, and the introduction of substances with an osmolarity of more than 900 mosm/l into the peripheral vein is categorically contraindicated.

Limits of maximum infusions

When conducting PP, the rate of receipt of solutions depends on the patient's condition and is regulated by his body. When prescribing such drugs, the doctor solves the problem assigned to him and strictly observes the maximum daily dosages and the rate of administration of drugs for PP.

The maximum rate of entry of solutions for PP into the vein is as follows:

• carbohydrate - up to 0.5 g / kg / h;
• amino acids - up to 0.1 g / kg / h;
• fat emulsions - 0.15 g / kg / h.

It is desirable to carry out the infusion of such drugs for a long time or use automatic devices - infusion pumps and line machines.

Principles of parenteral nutrition

For an adequate PP, the following rules must be observed:

1. Solutions of drugs should enter the body in the form of components necessary for the metabolic needs of cells (i.e., in the form of such nutrients that have already passed the enteral barrier). For this, proteins, carbohydrates and fats are used in the form of amino acids, monosaccharides and fat emulsions.
2. Infusions of high-osmolar drugs are performed exclusively in the central veins.
3. When conducting an infusion, the rate of administration of infusion solutions is strictly observed.
4. Energy and plastic components are introduced simultaneously (all essential nutrients are used).
5. Systems for intravenous infusion must be replaced with new ones every 24 hours.
6. The fluid requirement is calculated for a stable patient at a dose of 30 ml/kg or 1 ml/kcal. In pathological conditions, the dose is increased.

Amino acid solutions

There are practically no reserves of protein in the body, and under conditions of intense metabolic stress, a person quickly develops protein-energy malnutrition. Previously, protein hydrolysates, blood, plasma and albumin were used to replenish lost proteins, but they had a low biological protein value. Now, solutions of L-amino acids are used to compensate for the lack of proteins in PP.

The body's need for such substances is determined by the severity of metabolic stress, and the dosage of drugs for PP ranges from 0.8-1.5 g/kg, and in some cases reaches up to 2 g/kg. The introduction of higher doses by most specialists is considered inappropriate, since such dosing will be accompanied by adequate utilization of proteins. The rate of administration of these drugs should be 0.1 g/kg per hour.

The volume of administered amino acid solutions is always determined by the need to achieve a positive nitrogen balance. Such substrates are used exclusively as a plastic material, and therefore, when they are introduced, an infusion of energy-donating solutions is necessarily carried out. 120-150 non-protein (fat and carbohydrate) kilocalories of energy carriers are added per 1 g of nitrogen.

Pharmaceutical companies produce amino acid formulations of drugs for PN, guided by different principles. A number of solutions are created on the basis of the “potato-egg” amino acid composition that has the highest biological value, while other preparations contain all the essential amino acids.

Additionally, the composition of amino acid solutions can be introduced:

• electrolytes;
• vitamins;
• succinic acid;
• energy carriers - xylitol, sorbitol.

There are no absolute contraindications for the use of such protein preparations. Their use is relatively contraindicated in the following cases:

• acidosis leading to impaired utilization of amino acids;
• in need of fluid restriction;
• progressive severe liver pathologies (but in such cases only specialized solutions can be used).

Standard amino acid solutions

The composition of such funds includes essential and some non-essential amino acids. Their ratio is dictated by the normal needs of the body.

Usually 10% solutions are used, 500 ml of which contain 52.5 g of protein (or 8.4 g of nitrogen). These standard amino acid solutions include the following drugs:

• Aminoplasmal E;
• Aminosteril KE;
• Vamin.

In some protein preparations, the concentration is from 5.5 to 15%. Low-percentage solutions (Infezol 40, Aminoplasmal E 5% and Aminosteril III) can be injected into peripheral veins.

Specialized amino acid solutions

These drugs contain a modified amino acid composition.

There are such specialized solutions of amino acids:

• with a high content of branched chain amino acids and a low content of aromatic amino acids - Aminoplasmal Hepa, Aminosteril N-Hepa;
• including predominantly essential amino acids - Aminosteril KE-Nefro.

Energy donors

The group of these funds for PP include:

• fat emulsions;
• carbohydrates are alcohols and monosaccharides.

Fat emulsions

These funds are the most profitable energy providers. Typically, the calorie content of 20% fat emulsions is 2.0, and 10% - 1.1 kcal / ml.

Unlike carbohydrate solutions for PP, fat emulsions have a number of advantages:

• less likely to develop acidosis;
• high calorie content even at small volumes;
• lack of osmolar action and low osmolarity;
• reduction of fat oxidation processes;
• the presence of fatty acids.

The introduction of fat emulsions is contraindicated in the following cases:

• shock state;
• DIC;
• hypoxemia;
• acidosis;
• microcirculation disorders.

Three generations of fat emulsions are used for PP:

• I - long-chain emulsions (Lipofundin S, Liposan, Lipovenoz, Intralipid);
• II - medium chain fatty acids (or triglycerides);
• III - emulsions with a predominance of Omega-3 fatty acids (LipoPlus and Omegaven) and structured lipids (Structolipid).

The rate of administration of 20% emulsions should not exceed 50 ml/hour, and 10% - no more than 100 ml/hour. The usual ratio of fats and carbohydrates administered during PP is 30:70. However, this proportion can be changed and brought up to 2.5 g/kg.

The limit of the maximum infusion of fat emulsions must be strictly observed and be 0.1 g / kg / h (or 2.0 g / kg / day).

Carbohydrates

It is carbohydrates that are most often used in the clinical practice of PN. For this, the following solutions can be prescribed:

• glucose - up to 6 g / kg / day at an injection rate of 0.5 g / kg / h;
• Invertase, fructose, Xylitol, Sorbitol - up to 3 g / kg / day at an injection rate of 0.25 g / kg / h;
• Ethanol - up to 1 g / kg / day at an injection rate of 0.1 g / kg / h.

With partial PP, the dosage of carbohydrates is reduced by 2 times. At maximum doses, a break in administration is mandatory for 2 hours.

Vitamins and trace elements

Correction of the deficiency of such substances is carried out as necessary for various pathologies. The following preparations can be prescribed as vitamin and microelement solutions for PP:

• Vitalipid - is administered together with fat emulsions and contains fat-soluble vitamins;
• Soluvit N - mixed with a solution of glucose and contains a suspension of water-soluble vitamins;
• Cernevit - is administered with a glucose solution and consists of a mixture of water- and fat-soluble vitamins;
• Addamel N is mixed with amino acid solutions Vamin 14 or 18 without electrolytes, Vamin with glucose, Vamin 14 or with glucose at a concentration of 50/500 mg/ml.

Two- and three-component solutions

The composition of such funds includes amino acids, lipids, glucose and electrolytes selected in the required proportions and doses. Their use has a number of significant advantages:

• ease and safety of use;
• simultaneous administration;
• reducing the likelihood of infectious complications;
• economic benefit;
• the possibility of adding additional vitamin and microelement agents.

Such solutions are placed in plastic all-in-one systems and are separated from each other by sections, which, when using the drug, are effortlessly destroyed by the usual twisting of the bag. In this case, all components of the drug are easily mixed with each other and form a milk-like mixture. As a result, all PN solutions can be administered simultaneously.

Two- and three-component solutions for PP include the following drugs:

• Nutriflex special - contains amino acids and glucose solution;
• OliClinomel No 4-550E - intended for administration into peripheral veins, contains electrolytes in an amino acid solution and calcium in a glucose solution;
• OliClinomel No 7-1000E - intended for injection only into the central veins, contains the same substances as OliClinomel No 4-550E;
• OliClinomel - in three sections of the bag contains an amino acid solution, a fat emulsion and a glucose solution, it can be injected into peripheral veins.

Monitoring the patient's condition during parenteral nutrition

Patients on PN are regularly monitored for the following blood test parameters:

• sodium, potassium, chlorine;
• coagulogram;
• creatinine;
• triglycerides;
• albumen;
• urea;
• bilirubin, ALT and AST;
• magnesium, calcium, zinc, phosphorus;
• B12 (folic acid).

The following parameters are monitored in the patient's urine:

• osmolarity;
• sodium, potassium, chlorine;
• urea;
• glucose.

The frequency of analysis is determined by the duration of the PN and the stability of the patient's condition.

In addition, daily monitoring of blood pressure, pulse and respiration.

Possible Complications

With PP, the following complications may develop:

• technical;
• infectious (or septic);
• metabolic;
• organopathological.

Such a distinction is sometimes conditional, since the causes of complications can be combined. However, the prevention of their occurrence always consists in regular monitoring of homeostasis indicators and strict adherence to all the rules of asepsis, technique for setting up and caring for catheters.

Technical complications

These consequences of PP occur when access is incorrectly created for the introduction of nutrient solutions into the vessels. For example:

• and hydrothorax;
• tears in the vein into which the catheter is inserted;
• embolism and others.

To prevent such complications, strict adherence to the technique of installing an intravenous catheter for PN is necessary.

Infectious complications

Such negative consequences of PN in some cases are caused by improper operation of the catheter or non-compliance with asepsis rules. These include:

• catheter thrombosis;
• catheter infections leading to angiogenic sepsis.

Prevention of these complications consists in observing all the rules for caring for an intravenous catheter, using protective films, siliconized catheters, and constantly observing the rules of strict asepsis.

Metabolic Complications

These consequences of PN are caused by improper use of nutrient solutions. As a result of such errors, the patient develops homeostasis disorders.

With improper administration of amino acid compositions, the following pathological conditions may occur:

• respiratory disorders;
• azotemia;
• mental disorders.

With improper administration of carbohydrate solutions, the following pathological conditions may occur:

• hyper or;
• hyperosmolar dehydration;
• glycosuria;
• phlebitis;
• violations of the liver;
• respiratory dysfunction.

With improper administration of fat emulsions, the following pathological conditions may occur:

• hypertriglyceridemia;
• drug intolerance;
• lipid overload syndrome.

Organopathological complications

Incorrect PN can lead to organ dysfunction and is usually associated with metabolic disorders.

The drugs used in parenteral nutrition include glucose and fat emulsions. Solutions of crystalline amino acids used in parenteral nutrition also serve as an energy substrate, but their main purpose is plastic, since various body proteins are synthesized from amino acids. In order for amino acids to fulfill this purpose, it is necessary to supply the body with adequate energy from glucose and fat - non-protein energy substrates. With a lack of so-called non-protein calories, amino acids are included in the process of neoglucogenesis and become only an energy substrate.

Carbohydrates for parenteral nutrition

The most common nutrient for parenteral nutrition is glucose. Its energy value is about 4 kcal/g. The share of glucose in parenteral nutrition should be 50-55% of the actual energy expenditure.

The rational rate of glucose delivery during parenteral nutrition without the risk of glucosuria is considered to be 5 mg / (kg x min), the maximum rate is 0.5 g / kg x h). The dose of insulin, the addition of which is necessary for glucose infusion, is indicated in Table. 14-6.

The daily amount of glucose administered should not exceed 5-6 g/kg x day). For example, with a body weight of 70 kg, it is recommended to introduce 350 g of glucose per day, which corresponds to 1750 ml of a 20% solution. In this case, 350 g of glucose provide a delivery of 1400 kcal.

Fat emulsions for parenteral nutrition

Fat emulsions for parenteral nutrition contain the most energy-intensive nutrient - fats (energy density 9.3 kcal/g). Fat emulsions in a 10% solution contain about 1 kcal / ml, in a 20% solution - about 2 kcal / ml. The dose of fat emulsions - up to 2 g / kg x day). The rate of administration is up to 100 ml/h for a 10% solution and 50 ml/h for a 20% solution.

Example: an adult with a body weight of 70 kg is prescribed 140 g, or 1400 ml of a 10% fat emulsion solution per day, which should provide 1260 kcal. Such a volume is poured at the recommended rate in 14 hours. In the case of using a 20% solution, the volume is halved.

Historically, there are three generations of fat emulsions.

• First generation. Fat emulsions based on long-chain triglycerides (intralipid, lipofundin 5, etc.). The first of these, intralipid, was created by Arvid Vretlind in 1957.
• Second generation. Fat emulsions based on a mixture of long and medium chain triglycerides (MSH and LCT). Ratio MCT/LCT=1/1.
• Third generation. structured lipids.

Among lipids in recent years, preparations containing co-3-fatty acids - eicosapentoic (EPA) and decosapentoic (DPA) contained in fish oil (omegaven) have become widespread. The pharmacological action of co-3-fatty acids is determined by the substitution in the phospholipid structure of the cell membrane of arachidonic acid for EPA / DPA, resulting in a decrease in the formation of pro-inflammatory metabolites of arachidonic acid - thromboxanes, leukotrienes, prostaglandins. Omega-3-fatty acids stimulate the formation of eicosanoids with anti-inflammatory action, reduce the release of cytokines (IL-1, IL-2, IL-6, TNF) and prostaglandins (PGE2) by mononuclear cells, reduce the frequency of wound infection and the length of stay of patients in the hospital.

Amino acids for parenteral nutrition

The main purpose of amino acids for parenteral nutrition is to provide the body with nitrogen for plastic processes, however, with an energy deficit, they also become an energy substrate. Therefore, it is necessary to observe a rational ratio of non-protein calories to nitrogen - 150/1.

WHO requirements for amino acid solutions for parenteral nutrition:

• absolute transparency of solutions;
• the content of all 20 amino acids;
• the ratio of essential amino acids to replaceable 1:1;
• the ratio of essential amino acids (g) to nitrogen (g) is closer to 3;
• the leucine/isoleucine ratio is about 1.6.

Branched chain amino acids for parenteral nutrition

The inclusion of crystalline amino acids, essential branched chain amino acids (valine, leucine, isoleucine-VLI) in the solution creates distinct therapeutic effects, especially manifested in liver failure. Unlike aromatic branched-chain amino acids, they prevent the formation of ammonia. The VLI group serves as a source of ketone bodies - an important energy resource for patients in critical conditions (sepsis, multiple organ failure). An increase in the concentration of branched-chain amino acids in modern solutions of crystalline amino acids is justified by their ability to oxidize directly in muscle tissue. They serve as an additional and effective energy substrate in conditions where the absorption of glucose and fatty acids is slow.

Arginine becomes an essential amino acid during stress. It also serves as a substrate for the formation of nitric oxide, positively affects the secretion of polypeptide hormones (insulin, glucagon, growth hormone, prolactin). The additional inclusion of arginine in food reduces thymus hypotrophy, increases the level of T-lymphocytes, and improves wound healing. In addition, arginine dilates peripheral vessels, reduces systemic pressure, promotes sodium release and increased myocardial perfusion.

Pharmaconutrients (nutraceuticals) are nutrients that have therapeutic effects.

Glutamine is the most important substrate for cells of the small intestine, pancreas, alveolar epithelium of the lungs and leukocytes. As part of glutamine, about U3 of all nitrogen is transported in the blood; glutamine is used directly for the synthesis of other amino acids and protein; also serves as a nitrogen donor for the synthesis of urea (liver) and ammoniogenesis (kidneys), the antioxidant glutathione, purines and pyrimidines involved in the synthesis of DNA and RNA. The small intestine is the main organ that consumes glutamine; under stress, the use of glutamine by the intestine increases, which increases its deficiency. Glutamine, being the main source of energy for the cells of the digestive organs (enterocytes, colonocytes), is deposited in skeletal muscles. A decrease in the level of free muscle glutamine to 20-50% of the norm is considered a sign of damage. After surgical interventions and in other critical conditions, the intramuscular concentration of glutamine decreases by 2 times and its deficiency persists for up to 20-30 days.

The introduction of glutamine protects the mucous membrane from the development of stress ulcers of the stomach. The inclusion of glutamine in nutritional support significantly reduces the level of bacterial translocation by preventing mucosal atrophy and stimulating the immune function.

The most widely used dipeptide alanine-glutamine (dipeptiven). 20 g of dipeptiven contains 13.5 g of glutamine. The drug is administered intravenously along with commercial solutions of crystalline amino acids for parenteral nutrition. The average daily dose is 1.5-2.0 ml/kg, which corresponds to 100-150 ml of dipeptiven per day for a patient weighing 70 kg. The drug is recommended to be administered for at least 5 days.

According to modern research, alanine-glutamine infusion in patients receiving parenteral nutrition allows:

• improve nitrogen balance and protein metabolism;
• support the intracellular pool of glutamine;
• correct the catabolic reaction;
• improve immune function;
• protect the liver. Multicentre studies noted:
• restoration of bowel function;
• reduction in the frequency of infectious complications;
• decrease in lethality;
• reduction in the duration of hospitalization;
• reducing the cost of treatment with parenteral administration of glutamine dipeptides.

Technique of parenteral nutrition

The modern technique of parenteral nutrition is based on two principles: infusion from various containers (“bottle”) and the “all in one” technology developed in 1974 by K. Solassol. The technology "all in one" is presented in two versions: "two in one - two in one" and "three in one - three in one".

Method of infusion from various containers

The technique involves the intravenous administration of glucose, solutions of crystalline amino acids and fat emulsions separately. In this case, the technique of simultaneous transfusion of solutions of crystalline amino acids and fat emulsions in the mode of synchronous infusion (drop by drop) from different vials into one vein through a Y-shaped adapter is used.

Method "two in one"

For parenteral nutrition, preparations containing a solution of glucose with electrolytes and a solution of crystalline amino acids are used, usually produced in the form of two-chamber bags (Nutriflex). The contents of the package are mixed before use. This technique makes it possible to comply with the conditions of sterility during infusion and makes it possible to simultaneously administer parenteral nutrition components, pre-balanced in terms of the content of the components.

Three in one technique

When using the technique, all three components (carbohydrates, fats, amino acids) are introduced from one bag (kabiven). Three-in-one bags are designed with an additional port for the introduction of vitamins and trace elements. This technique ensures the introduction of a completely balanced composition of nutrients, reducing the risk of bacterial contamination.

Parenteral nutrition in children

In newborns, the metabolic rate in terms of BW is 3 times higher than that of adults, while approximately 25% of energy is spent on growth. At the same time, compared to adults, children's energy reserves are significantly limited. For example, in a premature baby with a body weight of 1 kg at birth, fat reserves are only 10 g and therefore are quickly utilized in the metabolic process with a lack of nutritional elements. The store of glycogen in young children is utilized in 12-16 hours, in older children - in 24 hours.

Under stress, up to 80% of energy comes from fat. The reserve is the formation of glucose from amino acids - gluconeogenesis, in which carbohydrates come from the proteins of the child's body, primarily from muscle protein. Protein breakdown is provided by stress hormones: corticosteroids, catecholamines, glucagon, somatotropic and thyroid-stimulating hormones, cAMP, and hunger. The same hormones have contra-insular properties, therefore, in the acute phase of stress, glucose utilization deteriorates by 50-70%.

In pathological conditions and hunger, children quickly develop loss of MT, dystrophy; to prevent them, timely use of parenteral nutrition is necessary. It should also be remembered that in the first months of life, the child's brain develops intensively, nerve cells continue to divide. Malnutrition can lead to a decrease not only in growth rates, but also in the level of mental development of the child, which is not compensated in the future.

For parenteral nutrition, 3 main groups of ingredients are used, including proteins, fats and carbohydrates.

Protein (amino acid) mixtures: protein hydrolysates - "Aminozol" (Sweden, USA), "Amigen" (USA, Italy), "Izovac" (France), "Aminon" (Germany), hydrolysin-2 (Russia), as well as amino acid solutions - "Polyamine" (Russia), "Levamin-70" (Finland), "Vamin" (USA, Italy), "Moriamin" (Japan), "Friamin" (USA), etc.

Fat emulsions: "Intralipid-20%" (Sweden), "Lipofundin-C 20%" (Finland), "Lipofundin-S" (Germany), "Lipozin" (USA), etc.

Carbohydrates: glucose is usually used - solutions of various concentrations (from 5 to 50%); fructose in the form of 10 and 20% solutions (less irritate the intima of the veins than glucose); invertose, galactose (maltose is rarely used); alcohols (sorbitol, xylitol) are added to fat emulsions to create osmolarity and as an additional energy substrate.

It is generally considered that parenteral nutrition should be continued until normal gastrointestinal function is restored. More often, parenteral nutrition is needed for a very short period (from 2-3 weeks to 3 months), but in chronic bowel diseases, chronic diarrhea, malabsorption syndrome, short loop syndrome and other diseases, it can be longer.

Parenteral nutrition in children can cover the basic needs of the body (with a stable phase of intestinal inflammation, in the preoperative period, with prolonged parenteral nutrition, with an unconscious patient), moderately increased needs (with sepsis, cachexia, gastrointestinal diseases, pancreatitis, in cancer patients), as well as increased needs (with severe diarrhea after stabilization of the VEO, burns of the II-III degree - more than 40%, sepsis, severe injuries, especially of the skull and brain).

Parenteral nutrition is usually carried out by catheterization of the patient's veins. Catheterization (venipuncture) on peripheral veins is performed only if the expected duration of parenteral nutrition is less than 2 weeks.

Calculation of parenteral nutrition

The energy requirement of children aged 6 months and older is calculated by the formula: 95 - (3 x age, years) and is measured in kcal / kg * day).

In children of the first 6 months of life, the daily requirement is 100 kcal / kg or (according to other formulas): up to 6 months - 100-125 kcal / kg * day), in children older than 6 months and up to 16 years old, it is determined at the rate of: 1000 + (100 p), where l is the number of years.

When calculating energy needs, you can focus on average indicators with a minimum (basic) and optimal metabolism.

In the case of an increase in body temperature on GS, the indicated minimum need should be increased by 10-12%, with moderate motor activity - by 15-25%, with severe motor activity or convulsions - by 25-75%.

The need for water is determined based on the amount of energy needed: in infants - from the ratio of 1.5 ml / kcal, in older children - 1.0-1.25 ml / kcal.

In relation to BW, the daily water requirement in newborns older than 7 days and in infants is 100-150 ml / kg, with BW from 10 to 20 kg -50 ml / kg + 500 ml, more than 20 kg - 20 ml / kg + 1000 ml. In newborns at the age of the first 7 days of life, the volume of fluid can be calculated by the formula: 10-20 ml / kg x l, where n is age, days.

For premature and low birth weight infants born with BW less than 1000 g, this figure is 80 ml/kg or more.

It is also possible to calculate the demand for water from the Aber-Dean nomogram by adding the volume of pathological losses. With a deficiency of MT, we develop due to acute loss of fluid (vomiting, diarrhea, perspiration), you should first of all eliminate this deficiency according to the standard scheme and only then proceed to parenteral nutrition.

Fat emulsions (intralipid, lipofundin) in most children, except for premature infants, are administered intravenously, starting from 1-2 g / kg-day) and increasing the dose in the next 2-5 days to 4 g / kg-day) (with appropriate tolerance). In premature babies, the 1st dose is 0.5 g / kg-day), in full-term newborns and in infants - 1 g / kg-day). When children of the 1st half of life with severe malnutrition are removed from the state of intestinal toxicosis, the initial dose of lipids is determined at the rate of 0.5 g / kg-day), and in the next 2-3 weeks it does not exceed 2 g / kg-day). The rate of lipid administration is 0.1 g/kg-h), or 0.5 ml/(kg-h).

With the help of fats, 40-60% of energy is supplied to the child's body, and when fat is utilized, 9 kcal per 1 g of lipids are released. In emulsions, this value is 10 kcal due to the utilization of xylitol, sorbitol, added to the mixture as an emulsion stabilizer, and substances that provide the osmolarity of the mixture. 1 ml of 20% Lipofundin contains 200 mg of fat and 2 kcal (1 liter of 20% mixture contains 2000 kcal).

Lipid solutions when administered into a vein should not be mixed with anything; they do not add heparin, although it is desirable to administer it (intravenously, in a stream in parallel with the introduction of fat emulsions) in the usual therapeutic doses.

According to the figurative expression of Rosenfeld, “fats burn in the flame of carbohydrates,” therefore, when conducting parenteral nutrition according to the Scandinavian scheme, it is necessary to combine the introduction of fats with the transfusion of carbohydrate solutions. Carbohydrates (glucose solution, more rarely fructose) according to this system should provide the same amount of energy as fats (50:50%). Utilization of 1 g of glucose gives 4.1 kcal of heat. Insulin can be injected into glucose solutions at the rate of 1 unit per 4-5 g of glucose, but this is not required with long-term parenteral nutrition. With a rapid increase in the concentration of glucose in intravenously administered solutions, hyperglycemia with coma may develop; to avoid this, it is necessary to increase it gradually by 2.5-5.0% every 6-12 hours of infusion.

The Dudrick scheme requires continuity in the administration of glucose solutions: even an hour's break can cause hypoglycemia or hypoglycemic coma. The concentration of glucose is also slowly reduced - in parallel with a decrease in the volume of parenteral nutrition, i.e. in 5-7 days.

Thus, the use of high concentration glucose solutions poses a certain danger, which is why it is so important to follow safety rules and monitor the patient's condition using clinical and laboratory analysis.

Glucose solutions can be administered in a mixture with amino acid solutions, and this will reduce the final glucose content in the solution and reduce the likelihood of developing phlebitis. With the Scandinavian scheme of parenteral nutrition, these solutions are administered continuously for 16-22 hours daily, with the scheme according to Dadrik - around the clock without interruption by drip or using syringe pumps. The required amount of electrolytes is added to glucose solutions (calcium and magnesium are not mixed), vitamin mixtures (vitafusin, multivitamin, intravit).

Solutions of amino acids (levamine, moriprom, aminone, etc.) are administered intravenously at the rate of protein: 2-2.5 g / kg-day) in young children and 1-1.5 g / kg-day) in older children . With partial parenteral nutrition, the total amount of protein can reach 4 g / kg-day).

Accurate accounting of the protein necessary to stop catabolism is best done by the volume of its loss in the urine, i.e., by the amino nitrogen of urea:

The amount of residual nitrogen in daily urine, g/l x 6.25.

In 1 ml of a 7% mixture of amino acids (levamine, etc.) contains 70 mg of protein, in a 10% mixture (polyamine) - 100 mg. The rate of administration is maintained at the level of 1-1.5 ml/(kg-h).

The optimal ratio of proteins, fats and carbohydrates for children is 1:1:4.

The daily parenteral nutrition program is calculated by the formula:

Amount of amino acid solution, ml = Required amount of protein (1-4 g / kg) x MT, kg x K, where the K coefficient is 10 at 10% solution concentration and 15 at 7% concentration.

The need for a fat emulsion is determined taking into account the energy value: 1 ml of a 20% emulsion gives 2 kcal, 1 ml of a 10% solution - 1 kcal.

The concentration of the glucose solution is chosen taking into account the amount of kilocalories released during its utilization: for example, 1 ml of a 5% glucose solution contains 0.2 kcal, 10% solution -0.4 kcal, 15% -0.6 kcal, 20% - 0, 8 kcal, 25% - 1D) kcal, 30% - 1.2 kcal, 40% - 1.6 kcal and 50% - 2.0 kcal.

In this case, the formula for determining the percentage concentration of a glucose solution will take the following form:

Concentration of glucose solution,% = Number of kilocalories / Volume of water, ml x 25

Example of Total Parenteral Nutrition Program Calculation

• MT of the child - 10 kg,
• the amount of energy (60 kcal x 10 kg) - 600 kcal,
• water volume (600 kcal x 1.5 ml) - 90 0 ml,
• protein volume (2g x 10 kg x 15) - 300 ml,
• fat volume (300 kcal: 2 kcal / ml) - 150 ml of 20% lipofundin.

The remaining volume of water for dilution of glucose (900 - 450) - 550 ml. The percentage of glucose solution (300 kcal: 550 ml x 25) is 13.5%. Sodium (3 mmol/kg) and potassium (2 mmol/kg) are also added, or at the rate of 3 and 2 mmol, respectively, for every 115 ml of liquid. Electrolytes are usually diluted throughout the glucose solution (except for calcium and magnesium, which cannot be mixed in the same solution).

With partial parenteral nutrition, the volume of solutions administered is determined minus the total number of calories and ingredients supplied with food.

Example of calculating a partial parenteral nutrition program

The task conditions are the same. The child's body weight is 10 kg, but he receives 300 g of formula milk per day.

• Food volume - 300 ml,
• the remaining amount of energy (1/3 of 600 kcal) - 400 kcal,
• the remaining volume of water (2/9 of 900 ml) - 600 ml,
• protein volume (2/z from 300 ml) - 200 ml 7% levamine,
• fat volume (1/3 of 150 ml) - 100 ml 20% lipofundin (200 kcal),
• the volume of water for diluting glucose (600 ml - 300 ml) - 300 ml.

The percentage of glucose solution (200 kcal: 300 ml x 25) is 15%, i.e. this child must be given 300 ml of 15% glucose solution, 100 ml of 20% lipofundin and 200 ml of 7% levamine.

In the absence of fat emulsions, parenteral nutrition can be carried out using the hyperalimentation method (according to Dadrik).

An example of calculating the program of partial parenteral nutrition according to the method of Dadrik

• The volume of food - 300 ml, the volume of water - 600 ml,
• protein volume (1/3 of 300 ml) - 200 ml of a solution of 7% levamine,
• glucose volume: 400 kcal: 400 ml (600-200 ml) x 25, which corresponds to a 25% glucose solution, which must be used in an amount of 400 ml.

At the same time, the child should not be allowed to develop a syndrome of deficiency of essential fatty acids (linoleic and linolenic), their required amount with this option of parenteral nutrition can be provided by plasma transfusion at a dose of 5-10 ml / kg (1 time in 7-10 days). However, it should be remembered that the administration of plasma to patients is not used to replenish energy and protein.

Partial parenteral nutrition. Intravenous therapeutic nutrition that supplements oral food intake and provides only a fraction of the daily requirement. Many hospitalized patients receive glucose or amino acid solutions in this manner as part of their usual treatment.

Total parenteral nutrition. Intravenous administration of nutrients, fully satisfying the daily requirements for them. Peripheral veins can only be used for this purpose for a short time; with the introduction of large amounts of concentrated solutions (to ensure a positive energy and nitrogen balance and proper fluid intake), these veins are easily thrombosed. Therefore, as a rule, Total parenteral nutrition is administered through central veins. In addition to long-term total parenteral nutrition in the hospital, many patients with impaired functioning of the small intestine can now receive parenteral nutrition at home and lead a relatively healthy lifestyle.

Indications. Preparing severely malnourished patients for surgery, radiation, or chemotherapy for cancer, and providing nutrition after these procedures. Morbidity and mortality after major surgery, severe burns and multiple fractures, especially those complicated by sepsis, are reduced; tissue repair is accelerated and immune defense is enhanced. Prolonged coma and anorexia often require total parenteral nutrition after intensive enteral feeding in the early stages. Often it is useful in conditions that require complete bowel rest (such as some stages of Crohn's disease, ulcerative colitis, severe pancreatitis), disorders of the gastrointestinal tract in children (such as congenital anomalies and prolonged non-specific diarrhea).

Methodology. Solutions are prepared under aseptic conditions in a laminar flow cabinet with air filtration. The introduction of a catheter into the central vein cannot be carried out urgently - this procedure requires complete asepsis and specialized conditions. Usually they use the subclavian vein, where special catheters are inserted. The catheter is removed through the subcutaneous tissue of the chest wall above the puncture site of the subclavian vein. The correct localization of the catheter tip (after insertion or repositioning) is confirmed by chest x-ray. The TPN catheter must not be used for any other purpose. The outer tube should be changed every morning when the first container of solution is connected. The inclusion of any filters in the system is not recommended. Special occlusive dressings are also required, which are replaced every 48 hours, subject to all the requirements of asepsis and sterility.

When introducing solutions, a number of precautions must be observed. Start parenteral nutrition slowly so that 50% of the patient's estimated needs are met initially. Fluid balance is maintained with 5% glucose solution. Sources of energy and nitrogen are administered simultaneously. Plain insulin is added directly to the nutrient solution; if the blood glucose level is normal (70-110 mg% on an empty stomach), then the initial concentration of simple insulin is taken, as a rule, 5-10 IU / l at a glucose concentration in the nutritional solution of 25%. Requires prevention of reactive hypoglycemia that occurs after the cessation of the introduction of high concentrations of glucose.

The composition of the solution. Various compositions are used. For patients with insufficiency of certain organs, special modified solutions are needed. In renal or hepatic insufficiency, modifications of the amino acid composition are especially important; in heart failure, volume (fluid) restriction; in respiratory failure, it is necessary to avoid increased formation of carbon dioxide (CO2), which is achieved by providing "non-protein" calories from fat emulsions. Children have specific nutritional needs; in addition, they may not tolerate fat emulsions well.

observation. Every day you need to conduct a complete blood count and measure body weight; levels of urea, glucose (several times a day until stabilization) and electrolytes; blood gases; precise fluid balance; daily diuresis. After stabilization of the patient's condition, these tests can be performed much less frequently. Twice weekly liver tests should be taken, plasma protein content, prothrombin time, plasma and urine osmolarity, as well as calcium, magnesium and phosphate levels should be determined (measure not during glucose infusion!). The results are recorded in a special card. At intervals of 2 weeks, the assessment of nutritional status is repeated and the complement component C3 is determined.

Complications can be metabolic (associated with the composition of the nutrient mixture) and non-metabolic (due to methodological errors). Often, it is the fear of complications that prevents the use of total parenteral nutrition. With an integrated approach, the frequency of complications does not exceed 5%.

metabolic complications. Careful monitoring and administration of insulin avoids hyperglycemia and hyperosmotic syndrome.

Hypoglycemia causes an abrupt cessation of continuous infusion of concentrated glucose solutions. Treatment consists of infusing a 5-10% glucose solution into the peripheral veins for 24 hours before re-feeding via a central vein.

Electrolyte and mineral imbalances in the blood serum should be detected by repeated tests even before the onset of clinical symptoms. Treatment includes appropriate modification of the composition of the injected solutions or (if necessary, more urgent correction) infusion of the desired solutions into the peripheral vein.

Long-term total parenteral nutrition is most likely to develop insufficiency of vitamins and microelements. During total parenteral nutrition, there is often an increase in the level of urea nitrogen in the blood, possibly due to hyperosmotic dehydration, which is usually offset by the introduction of free water (in the form of 5% glucose solution) through a peripheral vein. With currently available amino acid solutions hyperammonemia not terrible in adults, but children may have symptoms such as drowsiness, muscle twitches and generalized convulsions; correction of this condition is reduced to the additional administration of arginine in a total dose of 0.5-1.0 mmol/kg/day. In some cases, long-term total parenteral nutrition develops metabolic bone disease accompanied by severe joint pain, pain in the legs and back; it is associated with a drop in the level of the vitamin D metabolite, namely 1,25-(OH)2D, in the blood serum. The only known treatment is temporary or permanent withdrawal of total parenteral nutrition.

At the beginning of such nutrition, there is also often liver dysfunction, manifested by an increase in the levels of transaminases, bilirubin and alkaline phosphatase in the blood, but usually these changes are short-lived. This complication is detected during regular monitoring of the patient. A late or persistent increase in these parameters may be due to the infusion of amino acids, and the intake of protein in the body should be reduced.

Enlarged and sore liver indicate fat accumulation; at the same time, you need to reduce the carbohydrate load. Occasionally (usually in the early stages) there are reactions to fat emulsions, manifested by shortness of breath, allergic skin reactions, nausea, headache, back pain, sweating and dizziness. Transient hyperlipidemia may occur, especially in renal and hepatic insufficiency. Late reactions to fat emulsions include liver enlargement, mild elevation of liver enzymes, spleen enlargement, thrombocytopenia, leukopenia, and altered respiratory function, especially in preterm infants with hyaline membrane disease. In these cases, temporary or permanent withdrawal of fat emulsions may help.

non-metabolic complications. Most common pneumothorax and hematomas, but damage to other structures and air embolism. Before the introduction of solutions, it is required by chest X-ray to make sure that the catheter tip is in the correct position in the superior vena cava. The incidence of complications associated with incorrect localization of the catheter should not exceed 5%.

The most common serious complications are thromboembolism and sepsis, associated with catheterization. The latter is usually caused by Staphylococcus aureus, S. albus, Candida, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Enterobacter. During total parenteral nutrition, temperature should be measured systematically. If the temperature remains elevated for 24-48 hours, and no other causes of fever are found, the administration of solutions through the central catheter should be stopped. Before removing the catheter directly from it and from its location, you need to take blood for culture. After removing the catheter, cut off 5-7 cm from its end with a sterile scalpel or scissors and send it to the laboratory in a dry sterile tube for inoculation and analysis of bacterial and fungal cultures. In cases where, due to high daily energy requirements, it is necessary to inject large volumes of fluid, it is possible volume overload. The patient should be weighed daily; weight gain of more than 200-250 g/day indicates volume overload and the daily fluid intake should be reduced.

Ed. N. Alipov

"What is parenteral nutrition" - an article from the section