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