Artificial nutrition and nutritional formula

Many patients with malnutrition need artificial nutrition, which is aimed at increasing muscle mass. Oral nutrition is difficult for patients with anorexia or having problems with food intake, digestion and absorption. Different behavioral approaches, including encouragement for food, heating or adding seasonings to food, cooking favorite or very fragrant dishes, cheering for every small portion eaten, drawing up a meal plan, feeding assistance, are sometimes very effective.

If behavioral approaches are ineffective, then artificial feeding is indicated: oral, enteral, parenteral nutrition. Artificial nutrition is not prescribed to the dying or to patients with severe dementia.

[1], [2], [3], [4], [5],

Forecasting food needs

The needs for food can be predicted by formulas or measured by indirect calorimetry. Total energy costs (OZE) and protein requirements are usually calculated. OZE is usually determined based on patient weight, activity level and metabolic rate (metabolic requirements); OZ varies from 25 kcal / kg / day for people leading a sedentary lifestyle and not under stress, up to 40 kcal / kg / day for people who are in critical condition. The OZE consists of basal (basic) energy costs (BZE, usually about 70% of the OZE), energy consumed by nutrient metabolism (10% of the OZE), energy expended in physical activity (20% of the OZE). Insufficient nutrition can reduce BES up to 20%. Conditions that increase metabolic needs (critical conditions, infections, inflammation, trauma, surgical interventions) can increase BSE, but rarely more than 50%.

The Harris-Benedict equation gives an opportunity to estimate BZE:

Men: kcal / day = 66 + [13.7 weight (kg)] + + [5 height (cm)] - (6.8 years old)

Women: kcal / day = 665 + [9.6 weight (kg)] + + [1.8 growth (cm)] - (4.7 age)

OZE can also be estimated by adding about 10% to sedentary lifestyle for Leders and up to 40% for people in critical condition.

For healthy people, the daily requirements for protein are 0.8 g / kg. However, for patients with metabolic stress or with renal insufficiency, as well as for the elderly, they can be higher.

OZ can be measured indirectly by calorimetry, using a metabolic chamber (closed respiration system, which determines energy expenditure based on total CO ₂ production ). The metabolic chamber requires special expertise and is not always available. Calorimetry can also be used to monitor energy consumption.

Approximate daily intake of protein by adults

Condition	Need (g / kg of ideal body weight / day)
Norm	0.8
Age> 70 years	1.0
Renal failure without dialysis	0.8-1.0
Renal failure with dialysis	1.2-1.5
Metabolic stress (critical condition, trauma, burns, surgical interventions)	1.0-1.8

Evaluation of the reaction to artificial nutrition

There is no "gold standard" to evaluate this reaction. Can help such indicators as muscle mass, body mass index (BMI), body composition analysis, body fat distribution. You can also use nitrogen balance data, reactions to skin antigens, measurement of muscle strength and indirect calorimetry.

Nitrogen balance, which reflects the balance between protein needs and its delivery, is the difference between the amount of incoming and released nitrogen. A positive balance (i.e., when more is received than lost) means adequate arrival. Accurate measurement is not feasible, but helps evaluate the response to artificial nutrition. The estimated nitrogen losses consist of the loss of nitrogen in the urine (calculated from the content of urea nitrogen in the correctly collected daily urine) plus the loss of feces (1 g / day, if there was a stool, and not plus if there was no stool), plus others that are not amenable loss determination (3 g).

Reaction to skin antigens (delayed-type hypersensitivity index) is often normalized when a patient with malnutrition responds positively to parenteral nutrition (it is adequate to him). However, other factors can influence the response to skin antigens.

Muscle strength indirectly reflects the increase in muscle mass of the body. This can be measured quantitatively (palm compression force by dynamometry) or electrophysiologically (usually by stimulating the ulnar nerve with an electrode).

Determining the level of whey proteins, especially the short-lived ones: prealbumin, retinol binding protein and transferrin, helps evaluate the response to artificial feeding.

[6], [7], [8], [9], [10], [11], [12]

Nutrition with the enteral probe

Such food is prescribed for those patients who have GIT, but who can not consume orally enough nutrients, because they need intensive intake of energy and proteins or do not want or do not want to eat through the mouth. Enteral nutrition, in contrast to parenteral nutrition, helps maintain the structure and function of the gastrointestinal tract; it is also cheaper and, probably, causes less complications.

Specific indications are long anorexia, severe BEN, coma, depressed consciousness, liver failure, inability to eat food orally due to head, neck, neurological disorders, critical conditions (for example, burns) that cause metabolic stress. Other indications are the preparation of the intestine for surgery in severe patients or patients with malnutrition, the closure of persistent enterostomy, the syndrome of the small intestine after massive intestinal resection or a disorder that can cause malabsorption (eg, Crohn's disease).

Methods and techniques. If the probe is fed for less than 6 weeks, a small-caliber, soft nasogastric or naso-genital probe (for example, nasoduodenal) made of silicone or polyurethane is usually used. If damage to the nose or its deformation makes it difficult to position the probe in the nose, then put orogastric or oroenteral probes.

Feeding through the probe for more than 6 weeks usually requires gastrostomy or an ejinostomy to install the probe. Such a probe is usually placed endoscopically, surgically or radiologically. The choice depends on the abilities of the doctor and the patient's preferences. Ejinostomnye probes are suitable for patients with contraindications to gastrostomy (for example, gastrectomy, intestinal obstruction above the jejunum). However, they are at the same risk of tracheobronchial aspiration (although many think less) than with gastrostomy. Ejinostomnye probes are easily shifted and are usually used only for inpatients.

Surgical setting of the nutritional probe is especially suitable if endoscopic and radiographic settings are not available, technically impossible or dangerous (for example, with intestinal curvature). Open laparotomy or laparoscopy may be used.

Nutrient mixtures

Commonly used liquid nutritional mixtures include nutritional modules (standard nutrient kits) and polymeric or other specialized nutritional mixtures.

Nutritional modules are commercially available products that contain only one nutrient: proteins or fats, or carbohydrates. Nutritional modules can be used individually to treat a certain deficit or combined with other nutrient mixtures to fully satisfy the food requirements.

Polymer nutritional mixtures (including homogenized and commercial lactose-free or milk-based milk mixtures) are commercially available and provide a complete, balanced diet. They can be used for routine feeding through the mouth or probe. Used for stationary patients, lactose-free milk mixtures are usually polymer milk formulas. However, milk-based milk formulas are more delicious than lactose-free milk mixtures. Patients with a lack of lactose tolerance can tolerate milk based milk mixtures with slow, constant administration.

Hydrolyzed protein or sometimes mixtures of amino acids are used for patients who are difficult to absorb complex proteins. However, these milk mixtures are expensive and usually not necessary. Most patients with pancreatic insufficiency, if they are prescribed enzymes, and most patients with malabsorption can absorb complex proteins.

Other specialized nutritional formulas (for example, high-calorie and high-protein for patients who have a deficiency of fluids, fiber-rich nutritive mixtures for patients with constipation) may be useful.

Application. Patients during enteral feeding should sit with the head restraint raised at an angle of 30-45, and then another 2 hours after feeding. Nutrition through the probe is performed bolus several times a day or by continuous infusion. Bolus nutrition is prescribed for patients who can not sit upright vertically. Continuous infusion is necessary if the bolus diet causes nausea; this method can reduce the likelihood of diarrhea and aspiration.

With bolus nutrition, the total daily volume is divided into 4-6 parts, which are injected through the probe with a syringe or infusion by gravity from a suspended package. After feeding, the probe is rinsed with water to prevent clogging.

Because nutrition through a nasogastric or nasoduodenal probe often initially causes diarrhea, feeding usually begins with small amounts of diluted drug, which increase as long as the patient sustains it. Most mixtures contain 0.5, 1 or 2 kcal / ml. Feeding often begins with a solution of 0.5 kcal / ml (50% dilution of a commercially prepared solution in 1 kcal / ml) at 50 ml / h. As an alternative, a solution with 1 kcal / ml of 25 ml / h is used. Usually, these solutions do not give enough water, especially if vomiting, diarrhea, sweating or fever increased water loss. An additional amount of water is injected bolus through the probe or intravenously. After a few days, the rate of administration or concentration may be increased to inject a solution of 1 kcal / ml at 50 ml / h or more to meet the energy and water needs. Feeding through a probe with an inostasis requires even more dilution of the drug and smaller volumes. Feeding usually begins with a concentration of <0.5 kcal / ml and a rate of 25 ml / h. After several days, concentrations and volumes can be increased to eventually meet energy and water needs. Usually the maximum that the patient can tolerate is 0.8 kcal / ml in 125 ml / h for 2,400 kcal / day.

Complications

The complications are quite common and can be serious. Probes, especially large ones, can contribute to the erosion of the tissues of the nose, throat or esophagus. Sometimes sinusitis develops. Dense (viscous) solutions or tablets can block the lumen of probes, especially small ones. Sometimes this blockage can be eliminated by introducing a solution of pancreatic enzymes or other commercial products.

The probes can move, especially the inostomous ones. It is much harder to replace the probe and complications are more likely if the probe was invaded than non-invasively.

Nasogastric probes can be displaced intracranially if the trellis plate is destroyed in severe facial trauma. Nasogastric or orogastric probes can be displaced into the tracheobronchial tree, causing coughing and vomiting reflex in sensitive patients. Tracheobronchial displacement can hardly cause symptoms in inhibited patients. If the tracheobronchial displacement is not recognized, then the food enters the lungs, causing pneumonia. Displaced gastronomic or ejinostomic probes can enter the abdominal cavity, then the inflow of the nutrient mixture into the intraperitoneal space will cause peritonitis.

Diarrhea and gastrointestinal discomfort develop in 20% of patients and in 50% of patients, due to intolerance to one of the main components of nutrient mixtures, especially in bolus feeding. Sorbitol, often contained in liquid medications injected through the probe, can aggravate diarrhea. Nausea, vomiting, abdominal pain and sometimes mesenteric ischemia may also develop.

There may also be aspiration, even though the probes are correctly placed, due to reflux or incompatibility of the oropharyngeal secretions and food. Aspiration can be avoided if the upper part of the trunk of the patient is in a raised state.

Possible development of violations of electrolyte balance, hyperglycemia, hypervolemia and hyperosmolarity. We recommend constant monitoring of body weight, blood electrolytes, glucose, Mg and phosphate (daily for the first week).

[13], [14], [15], [16], [17], [18]