What is Enteral Nutrition for Adults?

According to StatPearls, enteral nutrition is the preferred method of feeding for patients with a functional gastrointestinal (GI) tract who cannot meet their nutritional needs orally. So, what is enteral nutrition for adults? It is a method of delivering nutrient-rich liquid formulas directly into the stomach or small intestine via a feeding tube.

Quick Summary

This article defines enteral nutrition for adults, detailing the process of tube feeding, the various types of access tubes, different feeding delivery methods, and the medical conditions that necessitate this form of nutritional support. Key benefits and potential complications are also covered to provide a comprehensive overview.

Key Points

• Definition: Enteral nutrition provides liquid nutrients and calories through the gastrointestinal tract, typically via a feeding tube, for adults unable to eat adequately.

• Access Routes: Depending on duration, tubes can be short-term (e.g., nasogastric) or long-term (e.g., surgically placed gastrostomy or jejunostomy tubes).

• Administration Methods: Feeding methods include continuous infusion via a pump or intermittent bolus feeding for greater mobility and convenience.

• Primary Benefit: Enteral nutrition is often preferred over intravenous (parenteral) feeding because it's safer, less expensive, and helps maintain the health and function of the gut.

• Indications: Common reasons for adult enteral nutrition include neurological disorders, head and neck cancers, critical illness, and malnutrition.

• Potential Risks: Side effects can range from minor issues like diarrhea or tube blockages to more serious complications such as aspiration pneumonia.

• Management Team: A multidisciplinary team including doctors, nurses, and dietitians develops and manages the patient's feeding regimen.

Understanding the Basics of Enteral Nutrition

Enteral nutrition (EN) is a critical intervention for adults who cannot consume enough nutrients orally to maintain their health. By using the gastrointestinal (GI) tract, it leverages the body's natural digestive and absorptive processes, making it a more physiological and often safer alternative to intravenous (parenteral) feeding. EN can serve as the sole source of nourishment or supplement oral intake, and its application varies depending on the patient's medical condition and anticipated duration of need. The ultimate goal is to provide adequate nutrition to support healing, maintain weight, and improve overall health outcomes.

Types of Enteral Feeding Tubes

The type of feeding tube used for enteral nutrition depends on several factors, including the expected length of therapy and the patient's specific GI function. Tubes are broadly categorized as either short-term, inserted through the nose or mouth, or long-term, surgically placed directly into the abdomen.

Short-term access (typically < 4-6 weeks):

• Nasogastric (NG) tube: Inserted through the nose and into the stomach. It is suitable for patients with functional gastric motility.
• Nasoduodenal (ND) or Nasojejunal (NJ) tube: Inserted through the nose, extending into the duodenum or jejunum of the small intestine. These are used when stomach feeding is not tolerated, such as with delayed gastric emptying or high aspiration risk.

Long-term access (typically > 4-6 weeks):

• Gastrostomy (G-tube) or Percutaneous Endoscopic Gastrostomy (PEG) tube: A tube inserted directly into the stomach through the abdominal wall. This is a common choice for long-term feeding due to lower visibility and ease of care.
• Jejunostomy (J-tube) or Percutaneous Endoscopic Jejunostomy (PEJ) tube: A tube inserted directly into the jejunum through the abdominal wall, bypassing the stomach.
• Gastrojejunostomy (GJ) tube: Combines access to both the stomach (for decompression) and the jejunum (for feeding) via a single tube.

Feeding Methods and Administration

Enteral feeds can be delivered in several ways, and the best method depends on the tube placement, tolerance, and patient lifestyle.

• Continuous feeding: Administers a slow, steady rate of formula over many hours using a pump. It is common in hospital intensive care units (ICUs) and for patients with jejunal feeding tubes.
• Bolus feeding: Delivers a larger volume of formula in scheduled intervals, mimicking a meal schedule. It is often preferred for home care as it offers more mobility, but it is typically only suitable for tubes placed in the stomach.
• Cyclic feeding: Administers continuous feeding for a set period, such as overnight, allowing the patient to be free from the pump during the day.

Comparison of Enteral Nutrition vs. Parenteral Nutrition

While both provide nutritional support, EN is generally preferred when the GI tract is functional due to its physiological benefits and lower risks.

Feature	Enteral Nutrition (EN)	Parenteral Nutrition (PN)
Delivery Route	Uses the gastrointestinal (GI) tract via mouth, nose, or feeding tube.	Bypasses the GI tract entirely, delivering nutrients directly into a vein.
GI Function	Requires a functioning GI tract capable of digestion and absorption.	Used when the GI tract is non-functional or requires complete rest.
Cost	Less expensive due to simpler administration and materials.	More expensive, requiring specialized formulas and central venous catheters.
Infection Risk	Lower risk of systemic infection, though localized tube site infections can occur.	Higher risk of systemic infection due to direct access to the bloodstream.
Physiological Effect	Maintains gut integrity and function, stimulating the immune system.	Can lead to gut atrophy due to disuse, potentially weakening the immune system.
Complications	Primarily gastrointestinal (e.g., diarrhea, constipation) or mechanical (e.g., tube blockage).	More severe complications, including metabolic imbalances and central venous catheter-related issues.

Indications for Enteral Nutrition

Adults may need enteral nutrition for various medical conditions that interfere with their ability to eat normally. Common reasons include:

• Neurological disorders: Conditions like stroke, Parkinson's disease, or multiple sclerosis can impair a person's ability to swallow safely (dysphagia).
• Head and neck cancers: Tumors or the effects of radiation and surgery in the head or neck can make eating difficult or painful.
• Critical illness or trauma: Patients on mechanical ventilation or recovering from severe burns or injuries often have significantly increased nutritional requirements that cannot be met orally.
• Gastrointestinal disorders: While the GI tract must be functional for EN, some conditions like Crohn's disease or short bowel syndrome can impair absorption. In these cases, specific formulas can be used, or the tube can be placed directly into the jejunum.
• Malnutrition or increased metabolic demand: Patients who have experienced significant weight loss or have a high metabolic rate (e.g., due to illness) may require supplemental nutrition to recover.

Potential Risks and Complications

While safer than parenteral nutrition, EN is not without risks. Careful management and monitoring are necessary to prevent issues.

• Gastrointestinal complications: These are the most common and include diarrhea, constipation, nausea, bloating, and cramping. Adjusting the formula or feeding rate can often resolve these issues.
• Mechanical complications: These relate to the feeding tube itself, such as blockages, leakage at the insertion site, or accidental dislodgement. Proper tube flushing and care are essential for prevention.
• Aspiration: If formula or oral secretions enter the lungs, it can lead to pneumonia. This is a serious risk, especially for patients with impaired swallowing reflexes or those fed lying flat.
• Metabolic complications: For severely malnourished patients, rapid reintroduction of nutrients can cause refeeding syndrome, a dangerous condition involving electrolyte shifts. Careful monitoring is crucial for these patients.

Conclusion

Enteral nutrition is a fundamental component of modern medical care, providing vital nutritional support for adults who are unable to eat sufficiently or safely via the traditional route. As a more natural and cost-effective option than parenteral nutrition, it plays a key role in promoting healing, maintaining gut health, and improving patient outcomes. The success of EN relies on a multidisciplinary healthcare team—including dietitians, physicians, and nursing staff—who work together to choose the right tube, formula, and feeding method for each individual's unique needs, while vigilantly managing potential complications. For many, enteral feeding is a temporary measure, paving the way for a return to oral intake, while for others, it provides long-term, life-sustaining support.

References

• Healthline. Enteral Feeding: How It Works and When It's Used. October 30, 2018.
• American College of Gastroenterology. Enteral and Parenteral Nutrition. September 15, 2011.
• Cleveland Clinic. Tube Feeding (Enteral Nutrition).
• NCBI Bookshelf (StatPearls). Enteral Feeding. December 26, 2022.
• PubMed Central (PMC). Enteral Nutrition Overview.

Frequently Asked Questions

What is the primary difference between enteral and parenteral nutrition?

The main difference is the delivery route. Enteral nutrition uses the gastrointestinal (GI) tract for feeding, while parenteral nutrition bypasses the GI tract entirely, delivering nutrients directly into a vein.

How long does an adult typically need enteral nutrition?

The duration of enteral nutrition varies widely depending on the underlying condition. It can be needed for a few weeks to aid recovery, several months, or even on a long-term basis for chronic conditions.

Can I eat or drink anything by mouth while on enteral nutrition?

Depending on your specific medical condition and swallowing ability, your doctor may allow you to consume some food or liquids by mouth. The enteral feeding may be used to supplement, rather than entirely replace, oral intake.

What happens if a feeding tube becomes clogged?

Tube blockages can occur, often due to thick formulas or improperly crushed medication. The tube should be flushed regularly with water to prevent clogs. If a blockage occurs, a medical professional can use specific techniques to attempt to clear it.

Is it possible to manage enteral nutrition at home?

Yes, enteral nutrition is frequently managed at home. Caregivers or patients are trained by a healthcare team, including a nutrition nurse specialist, on how to safely administer feeds and care for the feeding tube.

What are the first steps to take if a feeding tube is accidentally dislodged?

If a feeding tube, especially one surgically placed through the abdomen, is dislodged, you should seek immediate medical attention. For a newly placed tube (within 6-8 weeks), it is considered a medical emergency to prevent the stoma from closing.

What is refeeding syndrome, and how is it managed?

Refeeding syndrome is a potentially fatal metabolic disturbance that can occur when nutrients are aggressively reintroduced to a severely malnourished person. It involves dangerous electrolyte shifts. Management includes starting with a low feeding rate, slow advancement, and careful monitoring and replacement of electrolytes.