PRODUCTS FOR PARENTERAL NUTRITION

A. Protein blood products are used restoration of the nutritional properties of blood. The products are solutions of protein hydrolysates containing essential and non-essential amino acids and low molecular peptides. The latter are fully disintegrated in the liver during transfusion. Casein hydrolysates are obtained from technical casein, while hydrolysin and aminopeptide are extracted from cattle plasma protein. Aminocrovinum is prepared from whole donor blood, RBC masses or blood clots, which are the remnants of blood products, as well as placental blood. As whole protein molecules cannot degrade in the liver, whole blood, plasma or serum may not be considered as liquid supplements for nutritional support. Whole blood or its components which contain whole protein molecules can only be used to make up for deficient blood components. If the amino acid complex to be transfused lacks at least a single non-essential amino acid, the synthesis of protein is very unlikely to occur.

Hydrolysate of casein contains 43-59 g of amino acid and simple peptides, 5, 5 g of sodium chloride, 0, 4 g of potassium chloride, 0, 4 g of calcium chloride, 0, 005 g of magnesium chloride in 1, 000 mL of non-pyrogenic water. It is available in 200 and 400 mL bottles at -10....+ 23 °C for 7 years. The product is easily assimilated by the body (nitrogen utilisation approximates to 80-93%) and does not cause anaphylactic reactions. Small particles of suspension visible during storage normally disappear upon shaking the bottle.

Hydrolysin. The solution contains 43-53 g of amino acids and simple peptides, 20 g of glucose in 1, 000 ml of non-pyrogenic water. It is available in 400 ml bottles at 4-20 °C for 5 years. The product does not cause anaphylactic reactions, nor does it sensitise the body, even when used repeatedly.

Aminopeptide 5% contains protein as amino acids and simple peptides. Of the 0, 6-0, 9% of general nitrogen content, amine nitrogen amounts to 50%. It is available in 200-400 ml and stored at room temperature for 3 years. Prolonged storage may result in formation of flaky sediments, which, however, can dissolve on heating in water at the temperature of 85-100 °C. If the sediments fail to dissolve on heating or if they reoccur on cooling to the room temperature, the product may not be used for parenteral nutrition.

Aminocrovinum comprises both essential and non-essential amino acids and simple peptides, the quantitative contents of which are similar to those in other hydrolysates. In addition, it contains glucose 5%. It is available in 400 ml bottles and stored at 4...20 °C for 3 years. A small amount of sediment that may appear during storage and disappears upon shaking the bottle is permissible. Persisting sedimentation and turbid appearance suggest that the product may not be used.

B. Amino acid formulation consists of a balanced formulation of crystalloid clear amino acids in proportion optimum for nutrition. The product contains all essential amino acids and especially valuable non-essential ones. The products of amino acid formulations are used as follows: polyamine (Russia), frialin (USA), aminofrusin Germany), moriamine (Japan), vamine (Sweden).

Polyamine contains crystals of L-amino acid 8% and D-sorbitol 5% in 100 ml of non-pyrogenic water. It is available in 200-400 ml bottles and is stored at -10...+20 °C for 2 years.

In total parenteral nutrition, the doses of protein blood products are estimated based on the daily protein allowances for each individual (1, 0-1, 5 g/kg ideal body weight/day), which is equivalent to 1, 500-2, 000 ml of protein hydrolysates, to 800-1200 ml of an amino acid formulation. In partial parenteral nutrition, the doses range from 700-1, 000 and 400-600 ml, respectively (i.e. half as much as that of the full parenteral nutrition). It will be noted that combination of protein products, amino acid solutions, and blood products (e.g. plasma, albumin) should be given based on the patient's total daily allowances for protein and protein contents of transfusion solutions.

Indications

Protein hydrolysates are used as one of the steps of preoperative workup. Various types of diseases (e.g. cancer, pyogenic infections, conditions associated with defective enteral nutrition, such as peptic ulcers, oesophageal or pyloric stenosis) may lead to hypo-/disproteinaemia. Because severe malnutrition increases the postoperative complications as a consequence of infection and poor wound healing, it is essential that patients who require perioperative nutritional support be identified early so that enteral or parenteral nutrition can be instituted. The application of protein hydrolysates and amino acid formulations allows correction of protein malnutrition. Prescription of protein blood products in the postoperative period, particularly after GIT surgeries, helps maintain nitrogen balance which, in turn, yields a more favourable postoperative outcome.

Protein hydrolysates are indicated for pyogenic infections (e.g. peritonitis, pleural empyema, lung abscess, huge phlegmon, osteomyelitis) and in intestinal obstruction, which invariably causes a dramatic decrease in blood protein levels and its loss exudates (e.g. pus) and faeces.

Protein solutions are of great importance in burns as they help compensate for protein loss owing to trauma itself, subsequent loss of plasma, and purulent infections that ensue thereafter.

Usually, protein hydrolysates and amino acid formulations are given intravenously, while occasionally they are administered subcutaneously or through a tube placed into the small intestine during operations on the oesophagus or stomach.

Contraindications involve the following conditions:

1) acute circulatory failure (haemorrhage, shock);

2) acute or subacute renal failures;

3) thrombosis, thrombophlebitis, thromboembolism.

C. Fatty emulsions

Intralipid 10% and 20%. These emulsions of soy oil consist of fatty particles (of 0, 1-0, 5 mm size). Their caloric concentrations are as high as 1, 000 and 2, 000 kcal/l.

Lipofundin 20% is a soy oil emulsion that comprises fatty particles (less than 1 mm in size) and caloric concentration of 2, 100 kcal/l. Fatty emulsions are primarily indicated for prolonged (3-4 weeks) parenteral nutrition, and also when large amounts of calories in a limited quantity of fluid are required. Fatty emulsions are contraindicated for patients with shock and in early postoperative period, severe liver diseases, fat embolism, thrombophlebitis, thromboembolism, pronounced arteriosclerosis, poorly controlled diabetes mellitus and hyperlipidaemia.

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