Enteral Nutrition

benefits of enteral nutrition versus parenteral nutrition

• better GI barrier function

• preserved GI immunity

• attenuate catabolic response

• better blood glucose control

• decreased rates of infection

3 categories of conditions that often require enteral nutrition

• impaired nutrient ingestion

• inability to consume adequate nutrition orally

• impaired digestion, absorption, metabolism

factors that affect enteral nutrition access

• anticipated length of time of enteral nutrition

• risk for aspiration or tube displacement

• clinical status

• presence or absence of normal digestion and absorption

• planned surgical intervention

nasogastric route (NG)

• short term: up to 3-4 weeks

• normal GI function

• bolus, intermittent, or continuous infusion

nasoduodenal or nasojejunal route

• short term: up to 3-4 weeks

• gastric motility disorders, esophageal reflux

orogastric route (OG)

• through the mouth

• short term

• less comfortable compared to NG

percutaneous endoscopic gastrostomy or jejunostomy (PEG or PEJ)

• nonsurgical technique

• preferred for longer than 3-4 weeks

surgically placed enterostomies

gastrostomies (G-tube) and jejunostomies (J-tube)

tube sizing

• French size of 5-12 typically is considered “small bore”

• more than 14 is considered “large bore”

factors to consider when choosing an enteral formula

• nutrient requirements

• clinical status and GIT function

• caloric and protein density

• form and amount of protein, fat, CHO, and fiber in the formula

• electrolyte content

• cost effectiveness

• patient compliance

most used formula companies

Abbott and Nestle

elemental or semi-elemental enteral formula

proteins are broken down into individual amino acids or short peptide chains

specialty or disease-specific enteral formula

i.e., for renal, diabetes, low volume/high protein needs

blenderized enteral formula

real food based

modulars in enteral formula

additives to add more of a specific nutrient— often protein or MCT oil

standard polymeric formulas

• lactose-free

• standard version is 1kcal/ml

• balanced CHO, fat, and protein

• ideal for MOST patients

• concentrated standard formulas: 1.2-2.0kcal/ml for fluid restriction

advantages of blenderized (homemade) formulas

• health benefits of using whole foods

• cost effectiveness

• tailor formula to meet individual needs

• social bond with caregiver

disadvantages of blenderized (homemade) formulas

• short hang time

• cannot use with jejunal feedings

• avoid in patients with multiple allergies, immunosuppression, fluid restrictions

• requires large bore feeding tube

• more likely to clog the line

• increased risk for cross-contamination

formula composition— protein

• intact protein, di- and tri-peptides, amino acids and/or crystalline amino acids

• special amino acids: branched'-chain amino acids, arginine, taurine

• content varies from 6-37% of total kcal

formula composition— carbohydrate

• content varies from 30-85% of total kcal

• lactose-free

• fiber

• FODMAPs

formula composition— lipids

• content varies from 1.5-55% of total kcal

• 2-4% of fat is linoleic acid to prevent essential fatty acid deficiency (EFAD)

• standard formula provides 15-30% kcal from fat

• medium-chain triglycerides

• omega-3 fatty acids

formula composition— vitamins, minerals, and electrolytes

• DRIs— many formulas meet micronutrient needs if at least 1500ml is consumed per day

• modified for disease specific formulas

formula composition— fluid

• 1kcal/ml formulas are about 85% waster

• 2kcal/ml formulas are about 70%

• provide 30-35ml/kg of body weight unless fluid restricted

• each formula is different— see the formulary for specific free water volume of each

• provide additional water via tube as needed through water “flushes” often before medications, after medications, and after feeding

  • if on continuous feeding, need to pause and provide flushes periodically throughout the day

bolus feeds quantity and timing

up to 500ml over 5-20 minutes via a large bore syringe 3 or 4 times daily

advantages of bolus feeding

• physiologic

• little equipment

• inexpensive

• ease of administration

disadvantages of bolus feeding

rapid delivery of feeding may cause GI intolerance

patient population for bolus feeding

• medically stable

• normal gastric function

intermittent feeds quantity and timing

start with 100-150ml and increase as tolerated to goal, 20-60 minutes, several times a day via gravity drip, pump, or syringe (similar to bolus feeds but over a slower period of time)

advantages of intermittent feeds

• physiologic— time unattached from feeding

• possible for larger volume feedings

disadvantages of intermittent feeds

• require gravity bags

• requires IV pole or device to hang bags

patient population of intermittent feeds

• medically stable

• normal gastric function

• extremely rare cases could be used if pump is unattainable

cyclic feeds quantity and timing

on a pump over the span of several hours but not 24 hours

advantages of cyclic feeds

• transition method from continuous

• nocturnal feeds may stimulate hunger during daytime hours

• allows for time off pump

disadvantages of cyclic feeds

• generally, feeding rate is higher volume/hour

• patient will likely be attached to pump while sleeping

patient population for cyclic feeds

• patients transitioning off EN

• supplemental EN

• mobile patients

• patients unable to tolerate bolus feeding

continuous feeds timing

via infusion pump over 24 hours; most appropriate for small bowel feeds

advantages of continuous feeds

• allows from small amounts of nutrition to be delivered

• little manipulation once pump set

disadvantages of continuous feeds

• patient attached to pump

patient population of continuous feeds

• critical care

• slow initiation necessary

• compromised GI function

• small bowel feeding

complications of enteral feeding

1. access problems

2. administration problems

3. GI complications

4. metabolic complications

refeeding syndrome

dangerous and potential fatal shifts in fluid and electrolytes when beginning to feed a patient that has been underfed (often from an extended fasting state, eating disorders, or malnutrition)

electrolyte balance in refeeding syndrome

• phosphorous → avoid hypophosphatemia

  • most notable deficiency for refeeding syndrome

• potassium → avoid hypokalemia

• magnesium → avoid hypomagnesemia

• thiamin (B1) deficiency

• fluid balance

• glucose levels → hyperglycemia

symptoms of refeeding syndrome

• double vision

• swallowing problems

• trouble breathing

• kidney dysfunction

• muscle weakness

• confusion and disorientation

• seizures

• cardiomyopathy (heart weakness)

• nausea and vomiting

• hypotension (low blood pressure)

complications of NG or OG tubes

• esophageal strictures

• gastroesophageal reflux resulting in aspiration pneumonia

• incorrect position of the tube leading to pulmonary injury

• mucosal damage at the insertion site

• nasal irritation and erosion

• pharyngeal or vocal cord paralysis

• rhinorrhea, sinusitis

• ruptured gastroesophageal varices in hepatic disease

• ulcerations or perforations of the upper GIT and airway

factors to consider in monitoring enteral nutrition

• abdominal distension and discomfort

• tube placement

• fluid intake and output

• gastric residuals if appropriate

• signs and symptoms of edema or dehydration

• stool output and consistency

• weight

• adequacy of enteral intake

• serum glucose, calcium, electrolytes, blood urea nitrogen, creatinine

how to determine a TF regimen

• start with estimated calorie needs and pick a formula that best meets needs

• determine which feeding administration type (i.e., continuous, cyclic, intermittent, or bolus)

• work backwards based on feeding plan schedule to meet calorie and protein needs

• determine extra fluids needed through water flushes to meet fluid goals

instructions for advancing feeds

• when feeds are initiated, start out at less than half the goal

• different patients need different starting or advancing rates— facility may use a protocol or best clinical judgment