Routine nutritional support of the premature infant
Optimal nutritional support is critical in helping to obtain a successful outcome for the ever-increasing number of surviving small premature infants. Although it is paramount to insure that the infant receives an adequate caloric intake, the ability of the very-low-birth-weight (VLBW) infant to digest, absorb, and metabolize enteral nutrients is limited. In addition, complications of prematurity, such as respiratory distress, cardiovascular instability, hemorrhagic diatheses, and an immature renal system, create a challenge to the provision of proper nutritional support.
To provide nutrition to the premature infant appropriately, one must have an understanding of the biochemical and physiologic processes that occur during the development of the gastrointestinal tract. By 28 weeks of gestation the anatomic development of the gastrointestinal tract in humans is nearly complete. Yet, as an organ of nutrition, the gut is functionally immature. Details of gastrointestinal tract development have been described previously, and have been summarized in tabular form (Table 39.1). Further, complications due to the incomplete development of gastrointestinal tract in the low-birth-weight infant have been well delineated by Sunshine (Table 39.2).
Gastric feeding: intermittent gavage or continuous infusion
Nasogastric (NG) feeds may be given continuously or intermittently. Intermittent feeding, also known as gavage feeding, is easy to administer, and it is possible to evaluate the gastric emptying time by checking the gastric residual before each meal. The stomach takes less time to empty with human milk than with formula and when in the prone or lateral position.