Nutritional replacement support or parenteral nutrition is a method of introducing the necessary drugs (energy substrates) into the body intravenously, excluding the ingress of such solutions into the intestinal tract. Most often, it is the intravenous method of administration that is used, but in some cases it is allowed to resort to nutrition supplied by the intraosseous, intra-arterial and even subcutaneous method.
Unlike enteral feeding, carried out through a tube, parenteral is used in cases where it is impossible to affect the work of the gastrointestinal tract according to certain indicators, and the patient cannot eat naturally:
• after operations on the gastrointestinal tract or in preparation for them;
• with injuries or limited functionality of the jaws; • with exacerbations of chronic diseases that limit nutrition;
• for newborns with certain complications;
• when recovering from aggressive treatment (such as chemotherapy);
• in case of insufficient normal nutrition or its physiological impossibility;
• for patients with complications of anorexia, especially the cachectic form;
• in all other cases, when the patient is limited in standard food through the gastrointestinal tract.
The main task in parenteral nutrition is to provide, with the help of the injected solutions of nutrients, the level of biologically significant elements that is necessary to maintain the vital functions of the body. Both parenteral and enteral types of solutions belong to the group of metabolites: agents involved in cellular nutrition, regulating metabolic processes - fats, carbohydrates, proteins, etc.
The use of this type of body replacement support is less common than tube feeding, and parenteral administration also requires high sterility, professional knowledge to adjust the rate of drug administration, homeostasis tracking and the availability of technical equipment. Also, intravenous nutrition requires strict medical supervision, since as complications after temporary or prolonged inactivity of the intestine, its atrophy is possible.
The ultimate goal of parenteral nutrition is to restore the disturbed metabolism of all substances in the body.
Method - with solutions supplied by the method of temporary infusion, to provide the body's nutritional needs, to compensate for any types of deficiency in the balance of nutrients.
If we classify any parenteral nutrition according to the duration of its implementation, three types of replacement techniques are used: full, partial and mixed administration of solutions. Long-term full support of the body with the help of parenteral nutrition is used extremely rarely, the recommended support period is 2 weeks, possibly a little longer, according to current indicators. With partial and mixed nutrition, the introduction of nutritional solutions is carried out for up to 7-10 days, depending on the veins selected for the installation of the catheter.
Intravenously, a patient on parenteral nutrition is injected with the same substances that would enter the body in normal life, along with food. These are carbohydrates, proteins, fats, vitamins, electrolytes, and mineral elements.