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Feeding Patients: Oral Diets and Enteral and Parenteral Nutrition
Chapter 15
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Feeding Patients: Hospital Food and Enteral and Parenteral Nutrition
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Up to 40% of hospitalized patients are malnourished
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Hospital food may be refused because:
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It is unfamiliar
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Tasteless (e.g., cooked without salt)
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Inappropriate in texture (e.g., pureed meat)
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Religiously or culturally unacceptable
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Served at times when the patient is unaccustomed to eating
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Feeding Patients: Hospital Food and Enteral and Parenteral Nutrition (cont’d)
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Meals may be withheld or missed
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Inadequate liquid diets may not be advanced in a timely manner
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Giving the right food to the patient is one thing; getting the patient to eat (most of it) is another
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Oral Diets
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Easiest and most preferred method of providing nutrition
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Oral diets may be categorized as:
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“Regular”
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Modified consistency
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Therapeutic
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Oral Diets (cont’d)
Normal, regular, and house diets
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Regular diets are used to achieve or maintain optimal nutritional status
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Regular diets are adjusted to meet age-specific needs throughout the life cycle
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Diet as tolerated (DAT)
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Oral Diets (cont’d)
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Modified consistency diets
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Modified-consistency diets include:
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Clear liquid
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Mechanically altered diets
Clear liquid diets may be used:
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After surgery
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In preparation for bowel surgery or procedures
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When oral intake resumes after a prolonged period
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Most patients can tolerate a regular diet for their second postoperative meal
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Oral Diets (cont’d)
Modified-consistency diets (cont’d)
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Mechanically altered diets contain foods that are chopped, ground, pureed, or soft
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Diets prepared in a blender provide food in liquid form
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Dysphagia diets are another variation of modified-consistency diets
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Oral Diets (cont’d)
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Therapeutic diets
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Therapeutic diets differ from a regular diet
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Used for the purpose of preventing or treating disease or illness
Nutritional supplements
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Some patients are unable or unwilling to eat enough food to meet their requirements
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Oral Diets (cont’d)
Nutritional supplements (cont’d)
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Categories of supplements include:
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Clear liquid supplements
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Milk-based drinks
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Prepared liquid supplements
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Specially prepared foods
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Oral Diets (cont’d)
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Nutritional supplements (cont’d)
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Liquid supplements are:
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Easy to consume
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Are generally well accepted
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Tend to leave the stomach quickly
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A good choice for between-meal snacks
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Oral Diets (cont’d)
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Liquid supplements
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Allow the patient to taste test several options available
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Explain the rationale for adding supplements and closely monitor acceptance
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Given on a rotation schedule
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Oral Diets (cont’d)
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Modular products
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Less frequently used option for maximizing a patient’s oral intake
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Generally composed of a single nutrient
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Disadvantages:
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Quality control (calculation errors)
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Bacterial contamination
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Higher costs than standard formulas
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Enteral Nutrition
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A way of providing nutrition for patients who are unable to consume an adequate oral intake
but have at least a partially functional GI tract that is accessible and safe to use
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Enteral nutrition (EN) may augment an oral diet or may be the sole source of nutrition
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Candidates for Tube Feeding
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Patients who:
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Have problems chewing and swallowing
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Have prolonged lack of appetite
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Have an obstruction, fistula, or altered motility in the upper gastrointestinal tract
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Are in a coma
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Have very high nutrient requirements
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Enteral Nutrition (cont’d)
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Contraindicated when the gastrointestinal tract is nonfunctional
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Patients who receive enteral nutrition experience less septic morbidity and fewer infections and
complications than patients who receive parenteral nutrition
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Significantly less costly than parenteral nutrition
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Has not been proven to reduce the length of the hospital stay and improve mortality
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Enteral Nutrition (cont’d)
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More high-quality trials are needed
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Factors that influence how and what is used to feed patients enterally include:
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The patient’s calorie and protein requirements
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Ability to digest nutrients
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Feeding route
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Characteristics of the formula
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Equipment available
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Method of delivery
Feeding route
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Depends on the patient’s medical status and the anticipated length of time the tube
feeding will be used
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Transnasal tubes
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Nasogastric (NG) tube is the most common
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Generally used for tube feedings of relatively short duration
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Enteral Nutrition (cont’d)
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Feeding route (cont’d)
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Ostomy feedings are preferred for permanent or long-term feedings
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Percutaneous endoscopic gastrostomy (PEG) tubes are placed with the aid of an
endoscope
Formula characteristics
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Formulary of various enteral products available within major categories
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Are designed to provide complete nutrition
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Enteral Nutrition (cont’d)
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Protein
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Enteral formulas are classified by the type of protein they contain
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Standard formulas
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Made from whole proteins or protein isolates
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Provide 34 to 43 g protein/liter
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Enteral Nutrition (cont’d)
Protein (cont’d)
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Variations
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High in protein
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High in calories
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Fiber enriched
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Disease-specific formulas designed for patients with diabetes, immune system
dysfunction, renal failure, or respiratory insufficiency
Enteral Nutrition (cont’d)
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Protein (cont’d)
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Hydrolyzed protein formulas
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Completely hydrolyzed formulas contain only free amino acids as their source of
protein
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Partially hydrolyzed formulas contain proteins that are broken down
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Intended for patients with impaired digestion or absorption
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Disease-specific formulas are available for liver failure, HIV/AIDS, and immune
system support
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Enteral Nutrition (cont’d)
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Calorie and nutrient density
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Calorie density of a product determines the volume of formula needed
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Routine formulas provide 1.0 to 1.2 cal/mL
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High-calorie formulas provide 1.5 to 2.0 cal/mL
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Nutrient density
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Varies among formulas
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Ranges from 1,000 to 2,000 mL/day
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Enteral Nutrition (cont’d)
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Water content
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Varies with the caloric concentration
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Formulas that provide 1.0 cal/mL provide 850 mL of water/liter
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High calorie formulas is lower at 690 to 720 mL/L
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Adults generally need 30 to 40 mL/kg/day
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Need additional free water
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Enteral Nutrition (cont’d)
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Other nutrients
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High-fat formulas are available for patients with respiratory disease
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Modified-fat formulas are designed for patients with malabsorption
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Diabetic formulas are available
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Electrolyte-modified formulas for renal disease
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Enteral Nutrition (cont’d)
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Fiber and residue content
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Terms fiber and residue are frequently used interchangeably
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Fiber
 Stimulates peristalsis, increases stool bulk, and is degraded by gastrointestinal bacteria
 Combines with undigested food, intestinal secretions, and other cells to
make residue
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Enteral Nutrition (cont’d)
Fiber and residue content
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Residue content of enteral formulas varies greatly
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Hydrolyzed formulas are essentially residue free
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Most standard formulas are low in residue
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Formulas prepared in a blender are a natural source of fiber
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Enteral Nutrition (cont’d)
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Osmolality
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Determined by the concentration of sugars, amino acids, and electrolytes
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Isotonic formulas have approximately the same osmolality as blood
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Some patients develop diarrhea when a hypertonic formula is infused
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Enteral Nutrition (cont’d)
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Equipment
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Tubing size and pump availability impact formula selection
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High-fiber formulas have a high viscosity and require a large bore tube (8F or greater) to
prevent clogging
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Hydrolyzed formulas have very low viscosity
Delivery methods
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Formulas may be given intermittently or continuously over a period of 8 to 24 hours
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Type of delivery method to be used depends on the type and location of the feeding
tube, the type of formula being administered, and the patient’s tolerance
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Enteral Nutrition (cont’d)
Intermittent feedings
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Administered throughout the day
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Generally used for noncritical patients, home-tube feedings, and patients in
rehabilitation
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More closely resemble a normal intake
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Allow the client freedom between feedings
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Enteral Nutrition (cont’d)
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Intermittent feedings (cont’d)
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Gastric residuals are checked before each feeding
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Residual volumes of 200 mL or more on 2 successive assessments suggest poor
tolerance
Bolus feedings
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Variation of intermittent feedings
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Large volume of formula delivered relatively quickly
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Often cause dumping syndrome
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Enteral Nutrition (cont’d)
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Continuous drip method
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Given at a constant rate over a 16- to 24-hour period
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Recommended for feeding of critically ill clients
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Continuous feedings should be interrupted every 4 hours
Cyclic feedings
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Variation of continuous-drip feedings
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Cyclic feedings are usually well tolerated
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Enteral Nutrition (cont’d)
Initiating and advancing the feeding
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Before initiating a feeding, tube placement is verified ideally by radiography, and bowel
sounds are confirmed to be present
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Regardless of the access route, tube feeding formulas are initiated at full strength
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Initial feedings may begin at 25 to 50 mL/hour and advance by 10 to 25 mL/hour every 8
to 12 hours as tolerated until the desired rate is achieved
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Enteral Nutrition (cont’d)
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Initiating and advancing the feeding (cont’d)
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Commonly recommended maximum flow rate for gastric feedings is 125 mL/hr
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Using a standard feeding progression schedule helps to ensure timely progression of
feedings to the goal rate
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Tolerance may be a problem for patients who are malnourished, who are under severe
stress, or who have not eaten in a long time
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Enteral Nutrition (cont’d)
Tube feeding complications
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GI, metabolic, and respiratory complications are possible
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Aspiration is the most serious potential complication
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More common than large-volume aspirations is a series of clinically silent small
aspirations
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Increases the risk of aspiration-related pneumonia
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Enteral Nutrition (cont’d)
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Giving medications by tube
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Should never be given while a feeding is being infused
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Some drugs become ineffective if added directly to the enteral formula
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Ensure the tube is flushed with 15 to 30 mL of water before and after the drug is given
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Enteral Nutrition (cont’d)
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Transition to an oral diet
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Goal of diet intervention is to ensure an adequate nutritional intake while promoting an
oral diet
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Gradually increase meal frequency until 6 small oral feedings are accepted
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Parenteral Nutrition
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Developed in the 1960s
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Infusion of a nutritionally complete, hypertonic formula
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Life-saving therapy in patients who have a nonfunctional GI tract
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Also used for other clinical conditions such as critical illness, acute pancreatitis, liver
transplantation, AIDS, and in patients with cancer receiving bone marrow transplants
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Parenteral Nutrition (cont’d)
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Overfeeding can cause a life-threatening complication known as the refeeding syndrome
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PN is expensive, requires constant monitoring, and has potential infectious, metabolic, and
mechanical complications
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Used only when an enteral intake is inadequate or contraindicated and when prolonged
nutritional support is needed
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Should be initiated when oral intake has been or is expected to be inadequate over a 7- to 14day period
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Parenteral Nutrition (cont’d)
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Catheter placement
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Patient’s anticipated length of need influences placement of the catheter
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For short-term central PN in the hospital, a temporary central venous catheter is placed
percutaneously into the subclavian vein
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If PN is expected to be more than a few weeks, these are the catheters of choice:
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A Hickman catheter or Port-a-Cath
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Peripherally inserted central catheter (PICC)
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Parenteral Nutrition (cont’d)
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Composition of PN
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Provide protein, carbohydrate, fat, electrolytes, vitamins, and trace elements in sterile
water
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“Compounded” or mixed in the hospital pharmacy
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2-in-1 formula (dextrose and amino acids)
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Used by most hospitals
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Lipids given separately
3-in-1 formula (dextrose, amino acids, and lipids)
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Parenteral Nutrition (cont’d)
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Protein
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Provided as a solution of crystalline essential and nonessential amino acids
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Amino acid formulations are available with and without electrolytes
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Providing adequate protein is a primary concern when formulating PN
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Nitrogen balance study can be used to determine adequacy of protein intake
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Parenteral Nutrition (cont’d)
Carbohydrate
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Carbohydrate used in parenteral solutions in the U.S. is dextrose monohydrate
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Minimal amount of carbohydrate needed to spare protein is generally accepted as 1
mg/kg/min
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Hyperglycemia is associated with immune function impairments and increased risk of
infectious complications
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High carbohydrate load may also lead to excessive carbon dioxide production
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Parenteral Nutrition (cont’d)
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Fat
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Lipid emulsions
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Made from soybean oil or safflower plus soybean oil with egg phospholipid as
an emulsifier
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Isotonic
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Available in 10%, 20%, and 30% concentrations
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Significant source of calories
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Necessary to correct or prevent fatty acid deficiency
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Parenteral Nutrition (cont’d)
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Electrolytes, vitamins, and trace elements
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Quantity of electrolytes provided is based on the patient’s blood chemistry values and
physical assessment findings
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Parenteral multivitamin preparations usually contain 12 to 13 essential vitamins
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Most adult formulations now contain a small amount of vitamin K
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Trace element preparations contain between 4 to 7 trace elements
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Parenteral Nutrition (cont’d)
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Medications
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Patients receiving PN may have insulin ordered if glucose levels are above 150 to 200
mg/dL
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Heparin may be added to reduce fibrin buildup on the catheter tip
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Medications should not be added to PN solutions because of the potential
incompatibilities of the medication and nutrients in the solution
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Parenteral Nutrition (cont’d)
Administration
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Administered according to facility protocol
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Generally initiated slowly (i.e., 1 L in the first 24 hours)
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Continuous drip by pump infusion is needed to maintain a slow, constant flow rate
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Rapid changes in the infusion rate can cause:
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Severe hyperglycemia or hypoglycemia
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Potential for coma, convulsions, or death
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Parenteral Nutrition (cont’d)
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Administration (cont’d)
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After the patient is stable, PN may be infused cyclically
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Cyclic PN allows serum glucose and insulin levels to drop during the periods when PN is
not infused
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To give the pancreas time to adjust to the decreasing glucose load, the infusion rate is
tapered near the end of each cycle
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Parenteral Nutrition (cont’d)
Administration (cont’d)
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During the last hour of infusion, the rate may be reduced by one half to prevent
rebound hypoglycemia
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When the patient is able to begin consuming food orally, the amount of PN is gradually
reduced to prevent:
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Metabolic complications
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Nutritional inadequacies