Enteral nutrition (EN) is defined as “nutrition provided through the gastrointestinal tract via a tube, catheter or stoma that delivers nutrients distal to the oral cavity” . This therapy is used in individuals who are malnourished or at risk for malnutrition because they are unable to consume adequate nutrients by mouth. An early report using representative sampling and the Centers for Medicare and Medicaid Services (CMS) data estimated the home enteral nutrition (HEN) population to be increasing yearly, and was approximately 148,000 in 1991 . More recent estimates place the HEN population at 344,000 people of all ages in the United States . The American Society for Parenteral and Enteral Nutrition (A.S.P.E.N.) has developed Home and Alternate Site Care Standards for clinicians caring for patients requiring home nutrition support stating “a multi-disciplinary team with expertise in nutrition support should be involved in the planning, education, implementation, and monitoring of HEN patients” . Recent studies reporting on the team approach have noted reduced hospitalization rates [5,6]. Successful HEN therapy requires the expertise of multiple clinicians in order to achieve the best possible outcome. This chapter outlines the steps that are needed to achieve clinical and patient goals.
There are several criteria that make up an adult HEN candidate. Ultimately, this individual is one who cannot meet their nutrient requirements orally, who has sufficient bowel length for absorption of nutrients, and who is able to conduct therapy at home . Reduced oral intake can be a result of impaired swallowing, motility disorder, or obstruction. Small bowel length greater than 100 cm is needed for adequate absorption of nutrients. Table 8.1 outlines common diagnoses for patients on HEN. Frequently, HEN is initiated in patients with swallow dysfunction related to stroke or neoplasm of the head and neck, or dysmotility or obstruction of the upper gastrointestinal (GI) tract. Contraindications for EN include patients with obstruction, refractory nausea and vomiting, high output fistulas, and severe malabsorption.
Once the patient undergoes a full nutrition assessment, a plan of care will be developed taking into account the patient’s therapy goals. See Table 8.2 for components of a full nutrition care plan.
Assessment of the patient should also include past medical history, available laboratory data, swallowing ability, and bowel habits. The patient may have additional medical conditions that will impact the decision of enteral formula and enteral feeding route choices. For example, a patient that also has heart failure would need a fluid restriction, and a concentrated formula might be used with reduced water flushes. A nutrition-focused physical examination should be undertaken to determine muscle or fat wasting, dehydration, or evident vitamin or mineral deficiency. Medications should be reviewed with special consideration of medication that can or should be crushed, food–nutrient interaction, and dosing schedule (i.e., insulin, medications that need to be taken with or without food). See Table 8.3 for potential enteral nutrition–drug interactions .
Crohn’s disease (adult and pediatric)
Neurologic swallow dysfunction
Motility disorder (gastroparesis)
Congenital bowel dysfunction (chronic pseudo-obstruction) Prematurity
Inborn errors of metabolism
Nutrition goals; short term and long term, anticipated duration of therapy
Care of access device
Planned reevaluation of care plan at least every 3 months or as needed based on patient status
The patient and/or caregiver, and the home environment need to be considered during the planning of HEN. The patient/caregiver should be assessed for the ability to conduct safe home therapy, including willingness, cognitive ability, and physical ability. The home should have adequate water supply, electricity, telephone, and adequate storage area for formula and enteral equipment.
• Absorption may be reduced due to binding to enteral nutrition components or enteral tubing
• Generally recommended to hold enteral nutrition for 1 hour pre- and postdose
• Enteral nutrition can reduce bioavailability, more so for postpyloric feeding than gastric feeding, as it is acid stable
• Adequate dilution of the suspension (or slurry from crushed tablet) at least 1:1 with water prior to administration via feeding tube may help reduce drug loss
• Bioavailability appears reduced by enteral nutrition formulas
• Although data are limited, it is currently recommended to hold enteral feedings for 1 hour pre- and 2 hours postdose
• Two proposed mechanisms of reduced warfarin absorption are binding with an enteral nutrition component (likely protein) or to polyurethane tubing; however, the interactions have not been clearly delineated
• Potential methods of reducing the warfarin–enteral nutrition interaction include
• Using concentrated drug administered rapidly to minimize contact with the feeding tube
• Separating warfarin administration from enteral nutrition administration
• Increasing the warfarin dose until a therapeutic PT/INR is achieved
• Changing to an alternate anticoagulation therapy that does not interact with enteral nutrition
• Holding enteral nutrition for at least 1 hour before and after dose
• Routine monitoring of PT/INR, especially with changes to enteral nutrition regimen
Source: Rollins, C.J. 2012. Drug–nutrient interactions. In: Mueller C (ed.) The ASPEN Adult Nutrition Support Core Curriculum, 2nd Edition. The American Society for Parenteral and Enteral Nutrition, Silver Spring, MD, pp. 298–312.
As practiced in adult care, EN is the preferred route of nutrition support for pediatric patients as it has fewer deleterious effects than parenteral support, and is more physiologic. The primary indications for HEN of a pediatric patient are insufficient oral intake to promote growth and development, oral motor dysfunction, GI abnormality that prohibits sufficient oral nutrient intake, and as primary therapy [9,10].
INSUFFICIENT ORAL INTAKE
Insufficient oral intake to meet nutrient needs is a common indicator for HEN in the pediatric population. It may manifest as either a reduction in appetite, such as seen in children undergoing oncologic treatment, or as an inability to meet nutrient needs when needs are elevated above that seen in the general population. For example, children with cystic fibrosis and children with cerebral palsy hypertonicity have increased energy requirements and are often unable to meet their needs via an oral diet alone . Children with congenital heart defects also commonly require home nutrition support . Insufficient oral intake may also present secondary to a developed food aversion, such as seen in some infants with severe gastroesophageal reflux disease, or in children with sensory integration problems or autism. HEN provides the child with additional nutrition so that their needs in relation to their metabolic demands are met.
ORAL MOTOR DYSFUNCTION
Oral motor dysfunction is a common issue in infants born prematurely because the suck, swallow, breathe reflex is not developed until 34 weeks gestation. In addition, after birth, these infants are often intubated for ventilatory support, which inhibits the development of feeding skills and leads to oral motor dysfunction. Thus, it is not uncommon for a premature infant to be discharged with HEN. Children with neurological impairment often require HEN. Issues noted with these children that can lead to HEN include swallowing disorders, esophageal disorders (e.g., gastroesophageal reflux, esophageal dysmotility), and behavioral disorders (aversive feeding behaviors, sensory-based feeding disorders) .
GI abnormalities that can lead to dependency on HEN are those that inhibit the structure and/or function of the GI tract. For example, congenital malformations (e.g., tracheo-esophageal fistula), short bowel syndrome, tumors of the GI tract, and caustic ingestion). In these instances, HEN may be short term or long term depending on the degree of impact of the abnormality. Also, HEN may be the primary source of nutrition or delivered as an adjunct to parenteral nutrition.
HEN is used as primary therapy for the management of pediatric Crohn’s disease. Research indicates that a liquid-only diet for 8–12 weeks is as advantageous in inducing remission in Crohn’s disease as corticosteroid therapy [13–15]. Because of the difficulty of consuming only liquids to meet nutrient requirements for 2–3 months, many children opt to deliver all or part of the nutrition via a feeding tube. After remission has been achieved, HEN is commonly used as part of the maintenance regimen.
HEN is also used to manage inborn errors of metabolism and eosinophilic esophagitis when the child is not able or willing to follow the required diet via oral intake alone . For example, a child with phenylketonuria may refuse the metabolic formula orally and instead choose to receive it via a feeding tube. HEN may also be used to manage the child with uncontrollable seizures who is following a ketogenic diet given the highly restrictive nature of the ketogenic protocol and its limited palatability.
The type and location of the enteral access device depend on the length of need, and the GI anatomy and function. Adult and pediatric patients with adequate gastric function would be best served with a tube terminating in the stomach, whereas those with gastric dysfunction would best tolerate small bowel feedings. Pediatric access is addressed later in this section. For adults, short-term needs (less than 4 weeks) can be met with nasogastric (NG), nasoduodenal (ND), and nasojejunal (NJ) tubes. The position of the tube should be confirmed radiographically prior to use . When patients are transitioning from hospital to home, it is important to obtain information on the tube tip location, as there are several different manufacturers of tubes, and tube length and position can vary. Use of the ausculatory method or pH testing of aspirate is unreliable in determining feeding tip location. The external tube length should be measured or marked from the nose to monitor for displacement. On occasion, small bowel tubes can migrate upward into the stomach. Changes in tolerance to feedings or increased nausea, or vomiting of tube feedings should prompt radiographic testing of the tube location. Nasal tubes can be used for enteral feeding supplementation while the patient is transitioning to an enteral diet, or to determine enteral feeding tolerance prior to placement of a long-term access, or in patients where long-term access is contraindicated or not desired. Prior to long-term enteral access placement, Bankhead et al. suggests a multidisciplinary review to consider benefits versus risks of placement, in cases of end of life and where oral feeding is improving . In patients with adequate gastric function who will need long-term access, a gastrostomy tube (GT) should be placed. These tubes are larger in diameter and can accommodate different administration methods and medication administration. In cases of inadequate gastric function, a gastrojejunostomy (GJT) or jejunostomy (JT) tube could be placed. Enteral tubes are typically placed endoscopically and radiographically, and less commonly by surgical method. Regardless of access, position should be confirmed . All efforts should be made to avoid tubing not typically used for enteral feedings (e.g., drain tubes or catheters) as there is no internal or external anchoring device and connections with enteral feeding sets may not be compatible. Table 8.4 highlights indications for gastric or small bowel feedings . In patients with gastric dysmotility, a GJT has been useful to vent or decompress the stomach via the gastric port while feeding into the small bowel via the jejunostomy port. For patients who are concerned about the external appearance of a tube, who are active, or who are prone-sleepers, a low-profile device or skin-level device may be an option. These devices have an internal bumper and an external port or ports for gastric or jejunal feedings. Manual dexterity is needed for attaching the extension tubing to the low-profile tube in order to use enteral feeding sets or syringes for tube flush.
MAINTENANCE OF THE ENTERAL ACCESS
Efforts should be made to avoid skin irritation at the enteral access site. It is recommended to use mild soap and water to clean the site and avoid occlusive dressings or placement of gauze or cut drain sponges under the external bumper . Topical silver nitrate or steroid can be applied if granulation tissue develops.
Tube clogs can occur due to accumulation of formula sediment and/or improper administration of medications. Flushing the tube with 30 mL of water every 4 hours before and after feedings and medications may prevent or reduce clogging .
Normal gastric and small bowel motility
Adequate anatomy to place access
Small bowel indications
Gastric outlet obstruction
Gastric or duodenal fistula
Severe gastroesophageal reflux disease
Recent GI bleeding
PEDIATRIC ENTERAL ACCESS CONSIDERATIONS
Orogastric tubes are generally not used in the outpatient setting. Rarely, they may be seen in the home patient who has a facial dimorphism that prohibits the use of a NG tube. Even so, these tubes are generally replaced with a permanent tube for long-term nutrition support.
NG tubes are used for children requiring short-term enteral access (i.e., less than 12 weeks) , for example, infants/children with failure to thrive who are expected to become independent of nutrition support or children with altered appetite due to oncologic treatment. NG tubes can be used long term for children who are placing a tube nightly for enteral access as part of their treatment method for Crohn’s disease. NG tubes are appropriate for children with little or no gastroesophageal reflux, normal gastric function, and a low risk for aspiration . Ideally, NG tube placement should be verified using abdominal x-ray [17,20]. However, repeat exposure to radiation is a concern in the pediatric cohort. In addition, obtaining an x-ray to consistently verify tube placement is not feasible in the home setting. Thus the best approach in the home setting to assure proper tube placement is to monitor tube insertion length and to measure the pH of aspirated gastric secretions. Gastric secretions have a pH of 1–4. The literature supports using a pH of <4 to verify correct tube placement . The auscultation method should not be used. NG tubes generally can remain in place for 4 weeks before being changed. Placement of an NG tube is not a contraindication to initiating or continuing an oral diet provided that the child is medically safe to ingest oral nutrition .
NJ tubes are indicated for short-term enteral access and are appropriate for the child with gastro-esophageal reflux, gastroparesis, aspiration risk, or acute pancreatitis. Tube placement should be verified using x-ray. Because these tubes are located in the small intestine, they are not appropriate for bolus feedings. Generally, these tubes may remain in place for 4 weeks before being replaced.
GTs are indicted for children who require EN support long term (suggested for 12 weeks or more) and have a functioning GI tract . Conversely, GJTs are indicated for children with severe gastroesophageal reflux who are not appropriate candidates for a Nissen fundoplication or for children who have a GT in place, but are temporarily not tolerating feeds. In this case, the jejunal port should be used for pump-assisted feedings and the gastric port should be used for venting to improve feeding tolerance.
Jejunostomy tubes (JTs) are indicated for children with significant gastroesophageal disease and/or gastroparesis. They are also indicated for children with a high aspiration risk. Typically, these tubes are considered if enteral access is going to be needed for 6 months or longer . Like GJTs, these tubes are only appropriate for pump-assisted feedings. They also require routine flushing to prevent clogging.
ENTERAL FORMULA SELECTION
Planning the HEN regimen should take into consideration the patient’s medical history, GI capabilities, enteral access, administration method, short-term and long-term nutrition goals, and the patient/caregiver wishes.
There are enteral formulas that are manufactured for specific disease states; however, a standard polymeric formula will meet the nutritional needs of most home patients. The nutrient concentration of a polymeric formula can range from 1–2 calories/mL, and meet the Recommended Daily Allowance (RDA) for vitamins and minerals within 1.5 L per day. For a pediatric patient, the volume needed to meet the RDA is dependent on the age of the child and the type of formula being used. For example, a standard 1 calorie/mL formula is designed to meet the needs of a child 1–8 years of age in 1 L, but for a child 9–13 years of age, 1.5 L is required. It is important to consider the medical status of the child when choosing a formula. For example, a child that is neurologically impaired and hypotonic may do best with a calorie-reduced formula that will still provide ample protein, vitamins and minerals for age. Fiber-containing formula may help to regulate frequency or consistency of stool. Table 8.5 describes the categories and characteristics of the various enteral formulas available. Occasionally, the patient may require a higher amount of macronutrient, such as protein or fiber. Modular products are available that can be given in separate doses to meet the patient’s requirements. Protein modulars are available in liquid and powder forms. Fiber supplements are available as soluble fiber, and when mixed with water will dissolve and reduce risk of tube clogging.
Since the patient or caregiver will be responsible for the feedings, collaboration should take place to determine a feeding schedule. Several goals can be accomplished: the patient will begin feedings and advance as tolerated to the goal volume to meet his/her nutritional requirements, the feeding schedule and advancement will minimize complications and intolerance, and the tube feeding schedule itself is adaptable to his/her lifestyle. For adults with gastric access, formula can be administered intermittently (bolus, gravity drip) or by pump-assisted (cycle or continuous) method. One benefit of bolus or gravity drip is that it can mimic a meal time schedule, and may allow flexibility in daily activities. In some cases, where oral intake has been diminished for a period of time or the patient is undergoing radiation or chemotherapy, the gravity drip method may be better tolerated, as this allows for slower infusion. Initiation of enteral feedings for pediatric patients will be addressed later in this section.
For adults with jejunal access, feedings are best tolerated using a pump-assisted method. Consideration should be given to a cycle infusion to allow the patient freedom from feeding equipment. The hours of infusion should be discussed with the patient/caregiver, and the tube feedings advanced accordingly. For patients with some oral intake, a nighttime cycle schedule may be ideal to supplement daytime intake. Table 8.6 provides recommendations on initiation and advancement.
Recommendations for Use
• Contain macronutrients as nonhydrolyzed protein, fat, and carbohydrate
• Range in concentration from 1 to 2 kcal/mL
• 1–1.5 L usually meets RDA for vitamins and minerals
• May be disease specific and/or contain pre- and probiotics
Patients with normal or near-normal GI absorptive capacity
Fiber content intended to improve the health of the GI tract, regulating frequency and/or consistency of stool by maintaining healthy GI flora
Recommended for use among patients with diarrhea and/or to promote/maintain gut microbiota
Fiber content is typically below total daily fiber recommendations
May contain prebiotics in the form of fructooligosaccharides, oligofructose, or inulin
May also contain probiotics
Contains whole food ingredients in carton or ready-to-feed packaging.
Patients with normal or near-normal GI absorptive capacity
Available for adults and pediatrics
Homemade whole food/blenderized
Blenderized whole foods designed to allow patients to receive qualities of food not found in standard enteral formulas, such as phytochemicals
Due to infection/food-borne illness risk, use in medically stable patients with healed enteral access site
Best suited for patients with safe food practices and tube maintenance techniques
Should be provided as bolus/gravity drip administration to maintain safe food practices (hang time <2 hours)
RDN should be involved in the development of feeding composition to ensure adequate nutrient delivery
Intended to reduce hyperglycemia with macronutrient composition of 34%–36% carbohydrate, 40%–44% fat, and 20% protein
Use of DM-specific enteral formulas is not currently supported by strong research; instead efforts should be made to prevent overfeeding
Fat and soluble fiber content may slow gastric emptying and prevent elevated blood glucose
Research does not strongly support renal formulas over standard polymeric formulas with renal insufficiency
Contains lower amounts of electrolytes, specifically potassium and phosphorus, to prevent excessive delivery to patients with renal insufficiency
If significant electrolyte abnormalities exist or develop, a renal formula should be considered until electrolytes stabilize
Protein content varies
Patients receiving maintenance hemodialysis (MHD) may benefit from a renal formula with regard to electrolyte balance
In some cases, a standard formula may be used in MHD patients along with monitoring electrolytes
Macronutrients are hydrolyzed to maximize absorption
Intended for patients with malabsorptive disorders
Source: Adapted from Brown B, Roehl K, Betz M. Nutr Clin Prac 2015;30(1):72–85. Copyright © 2015 American Society for Parenteral and Enteral Nutrition. Reprinted by permission of SAGE Publications.