• The choice of nutritional supplement depends on the degree of inability to meet nutritional needs by diet alone, presence or absence of dysphagia, taste preference or sensitivity to taste fatigue, availability of labor and resource for preparation or presence of other safety and cost concern, degree of tolerance to lactose, sucrose or glucose or other dietary modifications

• The use of enteral feeding is increasing because of

1. The development of simple and low risk procedures for placement of tubes in GI tract particularly percutaneous endoscopic gastrostomies and jejunostomies.
2. The availability of wide variety of commercial enteral feeding formulas.
3. Enteral nutrition is generally less expensive than parenteral nutrition.

• It is important to realize that enteral and parenteral nutritional supports should not be viewed, as substitutes for each other as both these methods are complementary rather than competitive.

1. Selection of an appropriate formula
2. Formula delivery
3. Indications of nutritional status

• Signs of feeding intolerance

Neurological indications:

1. Severe Head injuries
2. Cerebrovascular accidents
3. Coma due to any cause
4. Neoplasms: Advanced primary and secondary intracranial tumors
5. Dysphagia associated with neurological disorders

Hypermetabolism:

1. Postoperative major surgery

2. Sepsis

3. Trauma Burns Organ transplant acquired immune deficiency syndrome

Surgical indications:

1. Facial and jaw surgeries
2. Head & Neck surgeries
3. Oropharyngeal surgeries
4. Pharyngoesophageal surgeries
5. Polytrauma associated with extensive abdominal surgeries
6. Patients with burns for surgeries unable to take oral nutrition
7. Surgery complicated with sepsis

Gastrointestinal (GI) disease

1. Short-bowel syndrome (if absorptive capacity of remaining bowel is sufficient e.g. approximately a minimum of 100 cm jejunal and 150 cm of ileal length of functioning small bowel with ileocecal value intact.
2. Inflammatory bowel disease
3. Minimal GI tract fistula output ( less than 500mL/d)
4. Pancreatitis
5. Esophageal obstruction
6. Malabsorption
7. Fistulas

Cancer

1. Oral malignancies
2. Oropharyngeal malignancies
3. Nasopharyngeal malignancies
4. Head and neck malignancies
5. Esophageal malignancies
6. Gastric malignancies
7. Chemotherapy
8. Radiotherapy

Resistance to oral intake

1. Anorexia
2. Dysphagia
3. Severe depression

Malnutrition

1. Protein energy malnutrition with inadequate oral intake for at least 5 days
2. Malnutrition preoperatively and postoperatively
3. Malnutrition in cancer patients
4. Malnutrition in-patients with Acquired Immune Deficiency Syndrome (AIDS) unable to take oral nutrition.
5. Malnutrition in debilitated aged patients

Organ system failure:

1. Respiratory failure
2. Renal failure
3. Cardiac failure
4. Central nervous system failure
5. Hepatic failure
6. Multiple organ system failure

Transition from parenteral nutrition

1. Malfunctioning of GI tract or conditions requiring extended bowel rest

• Insufficient absorptive capacity of intestinal tract e.g. short-bowel syndrome ( intestinal span suggested for sufficient absorption of nutrients)
• Mechanical obstruction of GI tract
• Prolonged ileus
• Severe GI hemorrhage
• Severe diarrhea
• Intractable vomiting
• High output GI tract fistula (> 500 ml/ day)
• Severe enterocolitis

1. Harm may exceed benefit for incompetent patients with end-stage illness, minimal levels of consciousness, and lack of advance directives, whose anticipated benefits may be uncertain or short-term; is likely against the patient’s best interests.

1. Provides good nutritional care plan
2. Nourishing child who can not take adequate nutrients orally
3. Helps family and health care professionals to see enteral alimentation as positive and optimal way rather than a punitive and optimal way of nourishing the malnourished child.

1. The recommended dietary allowances serve as initial guidelines in the selection and modification of a formula

• All nutrients of the final formula should be calculated and compared with RDA for age or for the developmentally delayed child for height age
• Vitamin mineral supplementation may be needed

1. The disease process itself indicates whether the requirements are changed
2. Drug induced nutritional deficiencies may develop from long-term use of medication that affects

• nutrient function and metabolism
• decrease nutrient absorption or synthesis

1. Feeding tube

The small-caliber tubing requires a finely dispersed product with low viscosity whereas the gastrostomy tube can accommodate blenderized feed

2. Fluid requirement

1. Protein components:

1. Protein quality attributed to amino acid profile: an amino acids of at least 40% amino acids as essential amino acids is suggested for anabolism.
2. Predominant sources of protein include soy and casein.

1. Carbohydrate components

1. Primary differences in carbohydrate components are related to the form and concentration of carbohydrate
2. The most predominant form of carbohydrate found in enteral formula is hydrolyzed cornstarch or maltodextrin

1. Fat components

1. Fat enhances palatability and flavor of formula
2. Vegetable oil contains variable amount of essential fatty acids (EFA).
3. Suggested EFA intake specially linoleic acid is 3% to 4% total calorie needs.
4. Sources of fat commonly found in formulas include a variety of vegetable oils

1. Fiber components

1. Water

1. Quantity water in the enteral formulas is often described as water content or moisture content
2. Quantity of water ( frequently reported in milliliters of water per 1000 ml of formula or milliliters of water per liter of formula)
3. Most of enteral formulas contain water in the general range of 690 to 860 ml per 1000ml of enteral formula. Standard infant formulas are 0.67 calories/cc. Whereas adult formulas are either 1 calorie/cc or 1.5 to 2.0 calories/cc

Table 6 water content of enteral formula for adults

1. Most nutritionally complete commercial formulas contain adequate vitamin and minerals when a sufficient volume of formula to meet energy and macronutrient needs is provided.
2. Some disease specific formulas are nutritionally incomplete in relation to vitamin and mineral content
3. Liquid vitamins and mineral supplements may be indicated for patients receiving nutritionally incomplete or diluted formulas for prolonged periods
4. Fat-soluble vitamins such as vitamin K may be indicated for patients with fat absorption or for patients with vitamin K deficiency; vitamin K deficiency is rare in as much as vitamin K is synthesized by intestinal flora, and most commercial formulas includes vitamin K.

1. Osmolality

1. Definition: function of size and quantity of ionic and molecular particles (protein, carbohydrate, electrolytes, and minerals ) within a given volume

• Unit of measure for osmolality is mOsm/kg of water Vs unit of measure of osmolality mOsm/L.

1. Factors affecting osmolality are:

• Minerals/electrolytes: due to dissociation properties and small size
• Protein: more hydrolyzed components such as amino acids have greater osmotic effect than larger molecular weight component such as intact protein.
• Carbohydrate: more hydrolyzed components such as glucose have a greater osmotic effect than larger molecular weight such as starch;

1. Formulas with greater hydrolyzed nutrient components have proportionately higher osmolalities.
2. Effect of osmolality on GI tolerance: gastric retention, abdominal distention, diarrhea, nausea, and vomiting.

2. pH

1. Gastric motility is reportedly slowed with solution lower than pH 3.5.
2. The pH level of most commercial formulas is > 3.5.

1. Calorie and nutrient density : gastric emptying time may be slowed by formulas containing higher calorie-nutrient density

Classification of formulas

1. Polymeric formulas:

1. Most of patients who are critically ill may be enterally fed with polymeric formulas.
2. Nitrogen balance has been reported to be similar for patient with normal digestive and absorptive capacity who were fed intact protein, partially hydrolyzed protein, and amino acids with approximately the same amino acid profiles.
3. Intrajejunal digestion, nutrient absorption, and nitrogen balance have been reported to be similar between intact protein and polymeric formulas compared with partially hydrolyzed (small peptides and amino acids) formulas in jejunal feedings in under nourished patients.

1. Partially hydrolyzed formulas:

1. Characteristics:

• Macro-nutrients may be partially or completely hydrolyzed via enzymatic activity into smaller components (e.g., free amino acids and peptides)
• Some formulas may have unpleasant odors and taste,
• Most of the formulas are expensive.

1. Composition may vary in free amino acids and peptides, type and quantity of fat, content of carbohydrate content.
2. Indicated for patients with partial digestive and absorptive capacity; patients with resolved acute illness might be capable of transition form partially hydrolyzed formulas to polymeric formulas.

1. Disease-specific formulas: some formulas are designed for specific organ dysfunction and some are for metabolic stress. Efficacy of the disease specific formulas is controversial
2. Modular formulas:

1. One purpose for using modular formulas is supplemental use

• May add calorie or protein density
• Tailor tube feeding to individual nutritional needs as a supplement to commercial enteral formulas.

1. Another advantage is that it can be de novo formulated for individualized designed of nutrient formula to meet specific nutrient needs of an individual.
2. Advantages of de novo enteral formulation include

• Customizing the formula to meet specific nutrient composition of the patient
• Select cases using de novo formulas have reported cost savings.

1. Disadvantages of de novo formula include

• Complexity of ordering specific nutrient composition as well as the method and rate of tube feeding administration unless a standardized orders form is used.
• Increased cost of labor
• Complexity of calculating nutrient composition
• Potential risk of bacterial contamination from excessive handling of formulas
• Potential physical incompatibilities with insoluble components.

Determining an optimal access route for enteral nutrition depends upon

1. Anticipated duration of enteral feeding
2. Risk of pulmonary aspiration, e.g.. In patients with diminished mental status or esophageal reflux

1. Determine total volume for adult man per day

a] Continuous feedings: example- formula to run at 75 cc/hr.

75 cc/hr X 24hrs = 1800 cc or 1.8 liters

b] Intermittent feeding: Example – formula to be given in volume of

400cc 5 times a day i.e. 400cc X 5 = 2liters.

1. Determine the calorie content of the formula by multiplying the total volume (cc) calorie/cc of the formula.

Example 1800 cc X 1.06 kcal/cc = 1908

2. Determine the protein content either per cc or per liter. This can be calculated by multiplying the total volume in liters by protein per liters or per cc.

Example 1.8 liters X 37 g protein per liter = 67 g protein.

Or 1.8 liters X 0.037 g protein per cc = 67 g protein

3. Determine the actual calories and protein provided by multiplying the calories and protein per liter by the strength of formula.

1. Prior to initiating enteral feeds, tube placement must be verified.
2. Placement can be confirmed by the aspiration of gastric contents.

1. It is recommended that a small syringe (10 to 30 cc) be used when checking small bore tubes to prevent exerting negative pressure and collapsing the tube.
2. If gastric content can not be aspirated through the tube, then radiographic confirmation of tube location should be done.

1. Isotonic solution can be initiated full strength at a rate of 25 to 50 cc per hour and advanced every 12 to 24 hours until the desired rate is achieved.
2. If intolerance develops at any time appropriate adjustment should be made.
3. Rate of the feeding is advanced to desired volume and then strength of the formula is gradually increased until calorie and protein needs are achieved.
4. Strength and rate should not be advanced concurrently.

Determining the method for the tube feeding administration

1. The method selected depend upon

1. Central access route
2. Stability of the patient (whether patient is critically ill or not.)
3. Gastric emptying rate
4. GI tolerance of tube feeding
5. Type of formula use
6. Calorie and protein needs
7. Ease of administration
8. Patients mobility.

1. The Feeds are given either by continuous drip, intermittent infusions, and bolus feed.

1. Continuous drip- Tube feedings are administered at constant, steady rate usually over 24 hrs of period. Use of an infusion pump is recommended, as accuracy of volume delivered is assured. However most enteral feeding is administered by gravity of force.
2. Intermittent infusions- Tube feeds are administered at specific intervals through out the day. The volume of desired feeding is divided into equal portion and been fed 4 to 6 hourly per day. The feedings are usually given by gravity drip over period of 30 min. to 1 hour.
3. Bolus feed – Rapid installation of feeding into GI tract by syringe or funnel. The majority of patients tolerate this method of feed.

For optimal results of enteral feeding the following points to be considered:

Temperature:

• Solution can be administered chilled if they are infused by continuous drip
• Decreased incidence of GI side effects may occur if intermittent and bolus feedings are allowed to reach room temperature prior to administration.

Bacterial contamination:

• Use close feeding containers to decrease risk of organism contamination.
• Extension tubing administration set and bag should be changed daily.
• Never add new formula to old formula.
• Prepared formulas should be refrigerated if not used immediately.
• Feeding solutions should not be allowed to hang for longer than 8 to 12 hrs.

• Placement of tube should be checked prior to feeds.
• Head of bed should be elevated at least 30 to45 degrees.
• Few drops of food color may be added to enteral formulas. This will help in detection of aspirated of tube feeding from pulmonary secretions but does not protect against aspiration.
• The technique of aspirating gastric residuals via the feeding tube is common practice although not based on scientific studies. Tube position or mechanical difficulty may give inaccurate assessment. In general the practice is limited to larger bore feeding tubes. The smaller tubes collapse when aspiration is attempted. Generally feeds are held if aspirate is between 75 to 150 cc.

• Feeding tube should be irrigated every shift washed with 40 to 50 cc of warm water after its use.
• Even after each feed stopped, tube should be flushed with 40 – 50 cc of warm water.
• In case of clogging flush the tube, using a syringe containing 30 to 50 cc of warm water.
• Medicine should be liquid if it has to pass through tube. The tube should be flushed with 20cc water before and after administration of medication.

1. Complications associated with enteral tube feeding may be prevented and managed with appropriate monitoring.

1. Monitoring schedules are diversified because of patients stability, institutional protocol, and feeding duration.

• Tube position confirmation prior to initiation of feeding or prior to intermittent feeding
• Daily weight
• Daily intake and output of urine fractionals every six hours until maximal tube feeding rate is established.
• Patients with history of diabetes mellitus should have urine fractionals daily until therapy terminated.
• Record of gastric residuals every four hours when feeding intragastric.
• Record of bowel movements/consistency
• Weekly serum electrolytes and blood count
• Weekly profile of liver function tests, phosphorus, calcium, and magnesium, total protein albumin, nitrogen balance.
• Weekly reassessment of nutritional indices with appropriate readjustment in energy and protein provisions needed.

1. Prevention of mechanical, GI, and infectious complications of tube feeding
2. Total quality care of tube feeding patients requires interdisciplinary team management.

Directions:

1. Measure all ingredients accurately. Pour into large mixing bowl and stir contents to combine.

• Blender method; add three cups of mixture to blender. Set at medium speed for three minutes. Pour into separate large bowl. Repeat above procedure until formulas have been thoroughly mixed.
• Mixer method: using an electric mixer, blend at medium speed five minutes or until thoroughly mixed

1. If mixture is thick, thin with water until the desire consistency is achieved.
2. Pour formula into individual jars. Cover and refrigerate immediately. Discard any unused formula within 24 hours
3. Take individual serving out one hour before needed and allow it to warm to room temperature before use. Always keep it covered.
4. The patient/caretaker should follow the direction given to him regarding feeding

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