Enteral Feeding in Preterm Infants - An Overview

Introduction:

Enteral feeding, also known as tube feeding. It provides nutrition to infants who cannot consume enough milk or formula through breastfeeding or bottle-feeding. This is often the case with very preterm infants born before 37 weeks of gestation who have difficulty in sucking, swallowing, and breathing.

What Are the Steps Involved in Enteral Feeding in Preterm Infants?

Enteral feeding in very preterm infants can occur with the help of a nasogastric (NG) tube or a gastrostomy (G) tube. The specific steps for enteral feeding vary depending on the type of tube used. In general, the process is done in the following steps -

• Preparation - The tube and pump will be set up with the appropriate formula or breast milk, and the flow rate and volume will be adjusted based on the infant's weight and nutritional needs.

• Placement - The NG tube is passed through the nose and down the esophagus into the stomach, while the G tube is surgically placed directly into the stomach. The tube is then secured with tape or a device to prevent it from falling out.

• Monitoring - The infant's vital signs, such as heart rate, respiratory rate, and oxygen saturation, will be monitored before, during, and after the feeding to ensure they are stable.

• Administration - The feeding will be administered through the tube at a controlled rate using a pump. The volume and flow rate will be adjusted to ensure the infant receives the appropriate nutrition.

• Maintenance - The tube and pump will be cleaned regularly to prevent infection or blockages. The infant will also be monitored for complications, such as infection, bleeding, or perforation of the tube site.

What Is Preterm Formula?

The preterm formula is designed for premature infants or those with special nutritional needs. It is typically more calorie and protein dense than the standard formula and may also contain different types and levels of lipids, carbohydrates, and other nutrients. The preterm formula is not a human milk substitute, but it is designed to closely mimic the composition of breast milk and provide a similar nutritional profile. It contains various ingredients such as protein, carbohydrates, lipids, vitamins, minerals, and other important nutrients for premature infant’s growth and development.

What Are the Goals of Enteral Feeding in Very Preterm Infants?

The goals of enteral feeding in very preterm infants include:

• Providing Adequate Nutrition for Growth and Development - Premature infants have a high metabolic rate and require more calories and protein per kilogram of body weight than full-term infants. Enteral feeding provides the necessary nutrition for the infant to grow and develop properly.

• Promoting Gut Maturity - Feeding helps to promote the gut's maturation and helps prevent problems such as necrotizing enterocolitis.

• Promoting Brain Development - Adequate nutrition is important for developing the brain and nervous system.

• Improving Survival Rates - It prevents complications such as necrotizing enterocolitis and can improve the survival rate of very premature infants.

• Minimizing the Risks Associated With Parenteral Nutrition - Parenteral nutrition (PN) is nutrition given via the veins, associated with certain risks such as sepsis, line infections, metabolic disturbances, and liver dysfunction. Enteral feeding is preferred to minimize these risks.

• Promoting Breastmilk Feeding - Enteral feeding by using human milk, either by providing breastmilk or human milk fortifiers to preterm formula, is preferred as it has been shown to have beneficial effects on growth and development and lower the incidence of necrotizing enterocolitis.

What Is included in Enteral Feeding in Very Preterm Infants?

Enteral feeding involves the following -

• Carbohydrates - The main energy source for premature infants is carbohydrates, usually in the form of lactose.

• Proteins - Proteins are important for growth and development, and the protein content of enteral feeds is typically higher than that of the standard formula.

• Lipids - Lipids are important for developing the brain and nervous system and provide a concentrated energy source.

• Vitamins and Minerals - These are essential for growth and development and are typically included in enteral feeds in appropriate amounts.

• Human Milk Fortifiers - Some preterm formulas are fortified with additional nutrients such as protein, minerals, and vitamins to provide more appropriate nutrition for premature infants and bring the nutrient content closer to human milk.

What Are the Disadvantages of Enteral Feeding in Very Preterm Infants?

The use of enteral feeding in very preterm infants can have some disadvantages, including the following:

• Feeding Intolerance - Some infants may have difficulty tolerating enteral feeds, resulting in problems such as necrotizing enterocolitis, gastric distention, or reflux.

• Aspiration - There is a risk of aspiration (food or liquid entering the lungs) when feeds are delivered via a nasogastric or orogastric tube.

• Infection - Using a feeding tube can increase the risk of infection.

• Metabolic Complications - Enteral feeding can cause metabolic complications such as hyperglycemia, electrolyte imbalances, and liver dysfunction.

• Dependence - Some premature infants may become dependent on enteral feeding for nutrition and may have difficulty transitioning to oral feeding.

• Cost - Enteral feeding can be costly, especially if the infant requires specialized formulas or supplements.

What Are the Complication of Enteral Feeding in Very Preterm Infants?

Complications of enteral tube feeding in very preterm infants can include the following -

• NEC is a serious condition in which the intestinal tissue becomes inflamed and dies, and it is more common in very low birth weight infants receiving enteral feedings. Infection can occur if the tube becomes contaminated or the infant develops a bloodstream infection.

• Diarrhea may occur if the infant receives too much glucose or the formula is not well tolerated.

• Aspiration can occur if the infant's feeding is not properly coordinated with their breathing or the tube becomes dislodged.

When to Stop Enteral Feeding in Very Preterm Infants?

The decision to stop enteral feeding in very preterm infants is typically made on a case-by-case basis, considering the infant's gestational age, weight, postmenstrual age, medical condition, and feeding tolerance. In general, enteral feeding can be discontinued when the infant can tolerate full feeds by mouth, maintain stable body weight, and show signs of appropriate growth and development. This typically occurs at around 37- 40 weeks of gestational age but can vary depending on the infant.

Conclusion:

Enteral feeding is an important nutrition method for preterm infants who cannot consume enough milk or formula through breastfeeding or bottle feeding. It provides a reliable source of nutrition, allows for the delivery of fortifiers, and helps to prevent NEC. However, it also carries potential risks and should be used cautiously and closely monitored.